How much beam sag is acceptable?

[KiwiBro]

Setting up over first log I noticed the portable sawmill I bought has close to 10mm sag when carriage is mid span. Beam is 5.6m long.

Manufacturer says that's acceptable. I say it ain't right. What do you guys think?

[POSTON WIDEHEAD]

I don't know my M's.  say_what

[thecfarm]

Close to an inch??

[Den-Den]

That would not be acceptable to me.

[rasorbackQ]

If you think the builders are wrong then jack up the middle.

[mikeb1079]

if my conversion is right 10mm is just over 3/8", that does seem a little excessive...can you post some pics?  perhaps that would help with ideas?

[Magicman]

Any sag is too much if you know it is there and do not correct it.

[YellowHammer]

Yeah, that's a little less than 0.4 inches over about 18 feet.  That's a pretty long unsupported span and will saw some not so straight lumber.  I'd block it up or otherwise add some mid span support.
YH 

[wetdog]

0mm is acceptable, any more than that is considered excessive in my opinion. I would add more support.

[KiwiBro]

Thanks for the replies. I put a string line on it and shot a video with my phone but am not able to upload such a large file until I find a better internet connection. Will get a photo later today and see if I can figure out how to get it uploaded here.

I have to drive about 10mins to get phone coverage at the mo so might not get back on until tomorrow.

When I saw the sag I freaked out, rang the manufacture who said it's fine and go ahead and start milling as it won't be an issue in use. Well, I have milled one deliberately short log and it is an issue and does transfer into the cut.

I am keen to establish what others would consider acceptable. Some beam sag is going to happen. That's fine but approx 10mm? Maybe I am being too demanding relative to industry standards or what most consider acceptable.

[PC-Urban-Sawyer]

Upload video to youtube, then post link to it here.

[logboy]

Setting up over first log I noticed the portable sawmill I bought has close to 10mm sag when carriage is mid span. Beam is 5.6m long.

Manufacturer says that's acceptable. I say it ain't right. What do you guys think?

You said carriage, midspan, you're talking about a 5.6 meter beam, and your name suggests you're down under. I'm guessing you're talking about a swingblade mill with aluminum rails, not a bandsaw, correct?

[KiwiBro]

It is a turbo warrior swingblade mill with 16hp engine. The design isn't using any supports mid span. Here's a link to their site for reference:
http://turbosawmill.com/weekendwarrior/

I tried a ratchet strap and a mid span can under the beam but couldn't get much if any sag out. Given the manufacturer thinks this sag is fine, then if others in the industry do too then I'll have to accept I'm being unrealistic and will just have to cut my lumber waaay oversize. But I would not have bought this if I had known about the beam sag. Perhaps I should have asked about it but I just never thought that much sag would ever be on a mill beam.

Pretty dissapponted.

[dean herring]

What mill did you get?  I am  looking for a mill and might not want  that brand if  the manufacturer is o.k. with that much beam sag.

[logboy]

If thats the machine I think it is, I saw one operate in Ohio at the Paul Bunyan festival last year. Does the machine hop when you are cutting?

Are you saying the beam is sagging all the time, or only when the powerhead is on it? I cant remember, is that a once piece beam or a bolt together?

[golddredger]

I would call the weekend worrior guys Jake in NZ again and talk this out. I would suspect they would have put some crown in the beam so when the weight of the cutting head made it,s way it would be a flat cut.  This will turn into a pissing contest real fast here and I do not think worrior deserves that. I am not affiliated at all but I have done a good amount of research on swing mills as I am looking to buy one myself. The owners I have spoke with have been happy and results are good. I would like to think you diid not talk to the owner and maybe a dealer that does not know. I would call weekend worrior direct right away. Did you get the mill second hand or brand new? Maybe it was bent during transporting and shipping? I cannot imagine him saying 3/8 or 10mm off is acceptable. My home built bandsaw cuts with a 1/16 or 2mm.

[KiwiBro]

I too couldn't imagine he'd be happy with that much sag and I also am not interested in a slanging match. But having emailed and talked to him about this, he is quite adament it is OK and no problem in actual use. But disagreeing with what must be many decades of milling experience between him and Carl is not a stance I take lightly, hence me trying to establish what others consider acceptable.
On a few occasions already I have deferred to their greater experience on a few things, but this one I need others opinions on.

Here's a video:
https://m.youtube.com/watch?v=ByOKlAzPTFU

[golddredger]

Kiwi your video is set "private"  on youtube so un check that and make it public so we can view it. ;)

[KiwiBro]

Sorry, hopefully sorted now? Not sure how to delete my double post above sorry.

[golddredger]

Yep video works now good job!  8) Wow I am not sure what I would do about that sag. I am now very curious to know how much other warrior owners are seeing and also would like to see what a lucas mill with the carriage in the middle is showing for sag? Maybe a lucas owner could set up the same string test with the motor in the middle of the tracks and give us an idea of how they stack up. I wonder if you could add a U section of channel inside of the original extrusion that would help lift the center up. You could even put a slight bow up in the channel prior to putting it in to create some up pressure in the middle. Would add a little weight and I think it is a bum thing to have to deal with but at this point you need a solution. I would look into an aluminum I beam or U beam that will fit inside the original warrior beam if for nothing more than your piece of mind. Keep us posted.

[golddredger]

Well you got me poking around a bit now. I am looking at the warrior web site and it looks like your mill uses the same beam as the original chainsaw powered versions use. The new 8" with a 20hp Honda have " new heavy duty beam with centre split as standard" Which looks much beefier than the other model. I suspect your 16hp model is an early model and they used the lighter duty beam that was used with the chainsaw power head. I am sure that Honda and the saw head look bigger and heavier than the chainsaw model. Which probably is a bit to much for the original beam style so they upgraded to the "new" split beam for the heavier 4-cycle head rig. You may have gotten a "good deal" on yours as it was a transitional model. It has the lighter duty beam not the new one. If you go to there site you will see the chainsaw models use the same frame and beam you have but the 4-cycle models all use the new heavy duty split beam. It looks like you could easily slide a channel or I beam inside yours to add more strength. I would be doing that and I would put some arch upward to the channel before you slide it inside to create a bit of upward preload.
Only good thing I will say is the new split beam model is a stronger beam so the issue has been addressed already and if you bought a new 8" or 10" it has the new beam and should be a solid unit. Bummer is you got one with the lighter duty beam. But I suspect that is why you got a great price to.

[Nomad]

     Kiwi, your video is working now.  I wouldn't be happy with that sag either.  Does it droop like that without the weight of the head on it, or only when it's loaded?  If the beam strength is insufficient, it would be interesting to see what it does when it's in a cut. 

[longtime lurker]

over that sort of distance I don't think any sag in the beam is acceptable, but it might not be the end of the world either. So long as the sag is consistent from cut to cut the timber should come off at a consistent thickness. It would however have about 10mm of bow cut into it, which over that sort of distance would be within the acceptable limits of most grading standards for rough sawn timber.
Having said that, I think most of us can get enough bow with a beam that doesn't sag - getting more from a design or production or freight problem sounds like a poor deal to me.

If the timber is coming off thick in the middle it's not beam sag that's your issue - to me that sounds more like a log tension issue. Face cut on your next log and see what happens: ie drop the power head 5 mil or so after you've taken your deck of boards, and "plane" the top of your sawn face with the blade to remove the hump where tension is bending your log.

Don't think you're the first person who can't talk with Jake either, he'd have sold me one of the big ones several years back if he didn't know what I needed better then I did. Great designs, but built too light for the roads I travel.

[KiwiBro]

Golddreger, I had concerns pre sale and Jake was adament the beam would be fine. I only learned a few days ago our ideas of fine don't match so why I'm asking what others think is acceptable. the price for an ex demo unit was great but I don't feel that justifies problems I was assured would not be problems.

Have tried to tension and cam the underside but only have ratchet straps onsite in .middle of nowhere and it didn't help.

Beam sags about 4mm when carriage at the ends, so the sag about doubles when carriage gets mid span.

I need this like a hole in my head at this point of the season.

[Swatson]

I would be curious if it has that much sag while it is cutting or if maybe being in the wood provides a little bit of support?  It seems as if there is a good bit of area to add extra support.  A plate of steel (albeit heavy) or aluminum could probably take the negative sag out if it was the length of the beam and was bolted into place with a bit of positive "sag". 

Just an opinion...I have no experience with a swing mill.  Good luck.

[Ga Mtn Man]

I fall into the "that's an unacceptable amount of sag" group.

[Joe Hillmann]

If it really is a problem(I have no idea if it is)  Could you run a cable stretched tight under the beam (anchored at both ends), and then wedge a block of wood or piece of metal between the cable and the bottom of the beam?

With a tight enough cable and a tall enough wedge it would be able to pull out any sag that is in it.  I don't know how the head is attached to the beam so the cable and wedge may get in the way of the rollers.

[Left Coast Chris]

If it has 4mm sag with no weight in the middle it makes you wonder if the beam is designed to have 4mm camber upward and it was installed upside down.    Can you flip the beam and see if it makes a difference? 

[barbender]

First, I don't think that is an acceptable tolerance, and I would second checking to see if the beams should have had some positive camber and could be upside down. The cable trick with a block could also work, not something you should have to do but sometimes you have to do what it takes.

[NZJake]

Hi all,

Advised this customer to send the beam back where we would provide a crown to compensate.

Advised that we do have a much heavier duty beam option available. Standard with all larger 4-stroke models now.

Advised this mill's beam would have sag when he purchased. I explained it would be fine.

My opinion... yes 3mm of actual deflection is acceptable. Noting that all beams will have deflection. Just like other swing-blade mills every board is relative to its previous. At each end it needs roughly 1m to support and pivot the blade. So that 7mm of sag (relayed to me) works out to be only 3mm over the log length. Converts too... .118" (7/64)

Our new Galv. beam has only 3/64 sag over the log length with the power-head mounted in the centre.

My advise from timber retailers is what's really important is dimensional accuracy/consistent thickness. A little bow in the length of your timber will be an absolute reality regardless of how straight and tensioned you can make a runner beam.

This is just a reality with beam saws.

Cheers.
Jake.

[RayMO]

If it was mine I would be sawing a few logs and see how the lumber turned out before I got to worried.

[Evergreen Man]

Hi all,

Advised this customer to send the beam back where we would provide a crown to compensate.

Advised that we do have a much heavier duty beam option available. Standard with all larger 4-stroke models now.

Advised this mill's beam would have sag when he purchased. I explained it would be fine.

My opinion... yes 3mm of actual deflection is acceptable. Noting that all beams will have deflection. Just like other swing-blade mills every board is relative to its previous. At each end it needs roughly 1m to support and pivot the blade. So that 7mm of sag (relayed to me) works out to be only 3mm over the log length. Converts too... .118" (7/64)

Our new Galv. beam has only 3/64 sag over the log length with the power-head mounted in the centre.

My advise from timber retailers is what's really important is dimensional accuracy/consistent thickness. A little bow in the length of your timber will be an absolute reality regardless of how straight and tensioned you can make a runner beam.

This is just a reality with beam saws.

Cheers.
Jake.

I didn't want to say nothing as I'm new to sawmills and this forum but I've been working with wood since I was strong enough to hold a hammer.
If he was sawing lumber for me. I would not be concerned about it at all. The boards will all come out the same dimensions.

[golddredger]

Nice to see Jake at Warrior chime in. Sounds like he is willing to get your machine on track and working fine. As I suspected the new models have a heftier beam. I am still considering an 8" myself.

[5quarter]

Jake...Thanks for chiming in. 8mm over 18' might be acceptable for finished lumber, but not green off the saw. It is difficult enough finding the best saw logs, sawing to minimize tension and drying lumber such that it lays flat over its length, without making bowed lumber to start with. Perhaps it may be fine for construction material, but not for hardwood destined for cabinetry or furniture making. It is very good of you to offer to straighten out the situation, so to speak. I hope you guys get it all sorted out. just my 2 pence cents.

[beenthere]

but not for hardwood destined for cabinetry or furniture making

Then again, for cabinetry and/or furniture, cuttings are not often longer than a few feet.

I don't see where bow is an issue, but it is in the eyes of the beholder.

[NZJake]

Hi been-there,

Thanks for your input.

Squarter it's 3mm over 16ft not 8mm FYI. You'll also be very surprised to find that there are realistic tolerances in finished extruded alloy over that length too. So a perfect razer straight edge is pretty hard to find out there in the real world. But we will try our best if and when he get his beam back.

I was also advised I should be making our beams out of carbon fibre in this case too.  :

[RayMO]

I thought a strait line, jointer and planer were used to correct imperfections in lumber destined for cabinetry and furniture .

[giant splinter]

Not sure if its too late but maybe you could set them "Crown Up" like Chris was mentioning.

[5quarter]

I noticed the portable sawmill I bought has close to 10mm sag when carriage is mid span. Beam is 5.6m long.

   My mill has 0mm sag, doesn't matter where the carriage is. If it was showing the sag that kiwibro showed in his video, I wouldn't saw another log until I fixed it, for the reasons I already mentioned. It is already hard enough to produce lumber without defects, especially for someone like myself who does not always have access to the best logs. I certainly wouldn't want to start with bowed lumber, not even a small bow if I can help it.
   What I would like to know is why, on the one hand, you feel that 7,8,10,3 or what ever mm is a perfectly acceptable amount of sag (bow) over 16'; and on the other hand, increase size, weight and rigidity of the monorails on your newest saws in an effort to reduce the amount of sag over the beams length? My guess is that it's not really acceptable to you either.

Ray...many woodworkers have perhaps one of those three shop tools, so the flatter and straighter, the better. My customers Check boards for flatness before they buy. not flat? they don't buy...period.

... for cabinetry and/or furniture, cuttings are not often longer than a few feet.

sure, except for dining room tables, hall benches, built ins, desk tops, doors. etc etc...

I don't see where bow is an issue, but it is in the eyes of the beholder.

Try delivering an order of bowed lumber to a cabinet shop. it'll never make it off the truck. Remember, the beholder is the fellow who writes the checks.  ;)

 

[NZJake]

Hi Squarter,

Everyone is entitled to their own opinions. I guess that's what this forum is about.

I am assuming you have a ground based bandsaw unit (not sure). But the reality is a bandsaw does need to have a very straight runner so that the blade maintains its feed correct and does not dive or rise up as it cuts. Secondary to that the way a bandsaw works is that you need the log rolled to square up your timber. You wouldn't want a thinner mid section beam.

Ground based sawmills certainly have the advantage enabling you to shim your runners. However they get in the way - that's where our design offers some very nice advantages.

All circular mills cut sections off the log with out needing to rotate anything. Every piece of timber is relative to its previous. So naturally we don't get any drawback from sag or crown.

We have built extra long machines where the possibility was maintained that later on down the track the buyer may add a rolling facility so that extra large beams may be sawn (say 16" x 16"). Obviously an extra long beam will have extra sag - so the answer for rolling the log was quite simple. Engineer your log turner bed to have the very same sag to match the beam. That way the beams would remain dimensionally correct all along the length.

Just a couple of scenarios to ponder...

1) Take an 8" x 1" board on its flat 4m long. Lift one end. How much sag do you get from your board?
2) Take an 8" x 8" beam 4m long. Place a support at each end of it and measure its natural sag under its own weight at the centre. You may be surprised. In fact having a slight bow in it could be an advantage to compensate for its own weight if its spanning a certain length.

Timber is unpredictable and will bow according to your sawing pattern - Quarter sawn or flat sawn.

As far as timber buyers rejecting timber 4m long with 3mm sag in it... really??

Cheers.

[NZJake]

I forgot to answer your other questions.

We increased the beam size for the following reasons...

1) We chose to use a much heavier engine with more hp.
2) We preferred offering 7.2m of beam length as standard.
3) Our preference was to remove as much bounce as possible without the use of anti-bounce roller devices (roller and arm that runs on the log).

That being said if someone wanted our lightweight beam with a 13hp Honda engine I would have no hesitation in offering this mill.

We discovered on the first day at the Paul Bunyan show that there was a little more bounce when sawing hard oak then I expected. Specifically with the AUTO unit your not pushing the saw by hand (dampens this effect). So any little resonance became gradually worse. The second day of the show I installed our standard anti-bounce rollers and things performed much better for the remaining 2 days. However personally I felt it needed a little more strength - we had to give away some portability because of this. That's why we now offer the trailer option for ease of transport.

[beenthere]

As far as timber buyers rejecting timber 4m long with 3mm sag in it... really??

Splitting cat hairs here.
Doubt that the footers or base blocking for air drying stacks are that straight, but the fact is that our US and CA lumber grading rules do allow a surprising amount of bow (in softwoods the bow is about three times the allowable crook and the 3mm or 1/10 of an inch is about 1/3 of allowable crook).
In hardwood grades (NHLA) there is only the warp (crook, bow, twist) that will not plane out of the cuttings that make up the grade that enters into the picture, IIRC.

Am thinking the confusion/excitement may be the metric measure and conversion to inches.

[KiwiBro]

With the 1.4m beam extension sold with the mill:

http://youtu.be/EwkMilpn0Zs


Again, turbo have advised they have no problem with this on their beams and such sag is perfectly acceptable. So, I'm asking again, do you guys think that is acceptable?

If I want to spend time and money I don't have getting this back to them, they will crown it.

[beenthere]

So, I'm asking again, do you guys think that is acceptable?

How many more answers do you want?

[uler3161]

I don't have any experience with that kind of mill, so I can't say whether it's acceptable. I think you're right to be a little concerned, but I wonder if you've even ran the mill to see what the lumber is like that comes off it? I think that should be a decisive answer. And if the lumber isn't good, I hope the manufacturer would work with you to make it right.

If I had to guess at what will happen, boards will end up uniform (in terms of the cuts being parallel), but possibly have a bow. I think the bow might depend on how thick the board is and what species. It may be possible to sticker and put weight on your piles to fix that, which is a good idea regardless.

But even with that, I'm curious how the grain of the wood would react. Because it seems like instead of making a straight slice through the log, you're doing more of what I'd call a "scoop". Also, I would fear that cutting beams on this mill would result in the beam taking more of an hourglass shape because of that scoop. And the longer the beam, the skinnier the center is. But as I've never used a mill like this, I have no idea whether that's the case.

[coastlogger]

A mobile dimension saw sure as heck doesnt sag in the middle. AND theyve sold thousands of them that seem to last forever. Give your head a shake Jake. Sorry that just came out. I can see where the lumber may be acceptable,most of the time,but the image of a mill that cuts crooked lumber will be enough to kill major sales IMO

[NZJake]

For those that think there should be zero sag in a beam or 'elevated track' sawmill could prove to me as a fact 'that other manufacturers have zero sag with an unsupported 6m span I will give Kiwibro a heavy duty beam. Place the carriage at the centre of the unsupported span and measure the deflection. I'd like this verified too. I've been from show to show and have compared other mills rails/beams and I know what I've seen first hand.

Also I'd like to note...
This mill was sold 2K lower than list price. A slabbing attachment was also offered with the mill at no charge. Most of the sag shown will be coming from the joiner inserts on the extension. We put a little crown on the inserts which correct it.

So it was a very good deal on the basis that it was our first 4-stroke unit Warrior (close enough to cost price). This model as mentioned earlier was a transitional unit before we upgraded to heavier chains and a heavier Galv. beam that spans 7.2m (23.6ft). Measured deflection with the carriage (22hp Honda) at its centre was 2.5mm (0.0984") FYI. The light weight beam works very well for our chainsaw mills all the way up to our 13hp units. We sell the light weight beams with the 4-stroke in the islands as the mills are usually carried into the bush by hand.

My hesitance to jump at the opportunity to send a new heavy duty beam out to Kiwibro is that I have had numerous emails from him stating that the mill's beam was too heavy and that I needed to design my beam out of carbon fibre to reduce the weight. I explained that we had moved toward a heavier stronger beam and that was our end direction.

Now I'm being told that the beam is actually too light. Well yes it is light (designed to be carried).

Regardless whether I feel its acceptable or not. I have offered to provide a crown. Its a 2 - 1/2 hour drive to our factory??

[NZJake]

Please find footage taken of our Warrior AUTO with the very same beam as being used by Kiwibro. Note that the sawmill is performing very well when sawing. Also note the quality of timber at the end of the video - to me this is acceptable.
I also have numerous videos on YouTube sawing all sorts of hard timber all around the world.

The timber was collected by a local timber retailer with out any negative feed back.

The larger beams were introduced later on.

http://youtu.be/Y1z7lkkpBNk

[Magicman]

Thanks for the video.  That is certainly a uniquely designed machine.

[shinnlinger]

Is it possible to sandwich two stiffeners on both sides of the beam and not affect saw head travel?

[beenthere]

Impressive machine, and design. And well within any tolerance for even finished board or dimension lumber grading rules, let alone rough sawn.
Thinking you are being held up at the pass for an upgrade without additional cost, but that is just a take on the flow of this thread.

[Dave Shepard]

A friend of mine went to a World's Fair in the '60's and someone had a 1' piece of high rail set up between two blocks. You could push down on it with your finger and get a reading on a very sensitive indicator. Millionths of an inch, or maybe even smaller, but the point is, everything deflects. To say that a beam could be built that would not deflect is erroneous. I don't think a couple of mm is going to be an issue. You better hope for the most well behaved logs ever sawn to think that you will have lumber without any deviation.

[Ga Mtn Man]

Clearly Turbosaw and Kiwibro have different ideas of what is "acceptable".  Why not just take the mill back and give him a full refund and be done with it?

[Joe Hillmann]

With the 1.4m beam extension sold with the mill:

http://youtu.be/EwkMilpn0Zs


Again, turbo have advised they have no problem with this on their beams and such sag is perfectly acceptable. So, I'm asking again, do you guys think that is acceptable?

If I want to spend time and money I don't have getting this back to them, they will crown it.

Have you run cut any logs with it yet?  That would be the place to start.  Measuring the lumber is more important than measuring the beam.

[RayMO]

The old saying "make a mountain out of a mole hill" comes to mind  8)

[longtime lurker]

For those that think there should be zero sag in a beam or 'elevated track' sawmill could prove to me as a fact 'that other manufacturers have zero sag with an unsupported 6m span I will give Kiwibro a heavy duty beam. Place the carriage at the centre of the unsupported span and measure the deflection. I'd like this verified too. I've been from show to show and have compared other mills rails/beams and I know what I've seen first hand.

Now I'm being told that the beam is actually too light. Well yes it is light (designed to be carried).

Jake I've always said you're one of the more innovative sawmill designers out there, and I get what you're saying. Particularly given that the warrior mill is designed to be ultra portable, making things heavy is self defeating. There was a time in my life when I've had given a testicle to have something like what you're now building in terms of weight for those "carry it in on your shoulder" jobs.

Sadly a lot of people dont get that every sawmill - regardless of whether you spend $5000 or $500,000 - is a series of compromises, and that for a machine thats designed to be portable one of the design issues is going to be weight vs stifness. It's impossible to build a mill that weighs little but has the stiffness of a fixed mill.

I've seen a beam saw that had zero sag - it weighed close on 5 ton. But I'm not going to verify that because it would be comparing apples with oranges.

Kudos to you for being prepared to back your product to that degree.

[Holmes]

  The proof is in the pudding, old saying. Cut some wood and see the results.  My guess is the lumber will be fine.

[Nomad]

     I still say that 10mm sag (one figure mentioned) is too much droop.  However, 2.5mm (another figure mentioned) wouldn't be a problem in my view.  Sounds to me like NZJake is being more than reasonable trying to make things right.

[Woodbilly]

I have the c/s warrior. I am happy with it, suits my needs. The sag in my 5m beam measured mid span is 5-6mm with carriage 3mm without. Acceptable, just. I have been watching Jakes progress with the 4/stroke version and my concern was the wieght of the whole engine setup, not really portable, engine setup weighs alot, so why mate it with a limp beam?.  If kiwibro had concerns about beam stiffness pre sale and Jake knew the beam was on the light side, why send it out?. Why not insist on going heavier as the beams are now. Would have made for a happier customer. I think if Jake really cared about his customers he would meet the cost of returning the beam to be crowned or sort the Kiwibro out with a heavier beam at a reasonable price. Wouldnt even consider using the slabber attachment with that much sag in the beam it would translate to the slab, timber might be ok. Wonder what Mahoes acceptable beam sag is?. Jakes a clever dude no doubt, but i think he could do better listening to the end user.

[NZJake]

Hi Guys,

Thanks for variety of views. I just want let you know that the light weight beam does have options. we offer the beam split kit as an option with your purchase. It includes 3 insert tubes and the bolts.

What this allows you to do is crown your beam to the degree of your satisfaction. We put a crown in the steel inserts which then bolts to your beam. Same goes for the extension part.

So my suggestion maybe that I send out Kiwibro these inserts with pre set crown in them. If he's not keen on sending the beam back he can cut the centre of his beam and drill a few holes to accomodate the join.

Solves a couple of things. Beam breaks down lighter. Suddenly he can crown the beam to his hearts delight.

Does that sound like a reasonable offer?

Going to the heavier beam... If his beam is brought back to the factory we will exchange it for the bigger steel beam. Will offer it to him at a very low cost.

[ladylake]

How many of our beams or lumber turn out perfect due to stress with any mill? Say you get 2 sides perfect at 6" then while taking the other 2 side off it will bend the 6" way. Once in a while lumber behaves good, most time not.  Steve

[KiwiBro]

There is an unwarranted and incorrect inference being made that my posts are some sort of twisted negotiation for a cheap steel beam.

It hardly deserves a response but let me clear up any misunderstanding. I do not and have never wanted a steel beam from Turbo.

What I have always needed is a 4-stroke, portable mill I could set up over logs by myself and be proud of the lumber I can produce with it, and the service I can provide. The weight of the ali beam is at my absolute maximum safe personal carrying capacity over rough terrain like paddocks and back yards, etc. Anything heavier would not be my kind of 'portable'.


Further, to address some of Jake's points; just like the earlier statement of fact that I was advised of these levels of beam sag, I cannot ignore, and must dispute, the assertion the mill was sold to me as "transitional" or anything other than rock solid, warranted, and fit for purpose. Amongst the reasons given for the great deal I was being offered, which in case it was ever in dispute I acknowledged in my earlier video posted here, were that he had just got a big export order so had economies of scale and that I had been waiting a while for them to bring to market a 4-stroke option, so he was looking after me. At no stage was I ever told this was some sort of experimental, hail-mary, suck it and see product, rather one born from their vast sawmill experience and design skill. In fact, I was told the beam had been beefed up from their chainsaw powerhead options and was solid. I'll leave viewers of the videos I have posted to decide if that beam is their idea of solid.

I made a mistake of not insisting the mill was set up so I could inspect upon collecting it. I should have, in hindsight, insisted rather than assumed that would be the case, and I should not have deferred so easily to what I believed at the time was a strong enough foundation of experience and competency within Turbo to absolutely ensure the mill would not fail to meet my expectations of what I feel I was lead to believe I was buying. If this beam was experimental, I consider it unreasonable to withhold such information.

All along with this beam saga, Jake has said there is no fault so no warranty claim. That the levels of sag are acceptable. All along, it is clear we differ in that regard, hence why I'm asking others what they think. I can tell you absolutely no manufacturer that I have approached recently has advised of such levels of sag in their mills. One was in the ball park to the sag of this 5.6m beam, but using longer beams and much bigger engines. Another has nothing like such sag when using way longer spans and way heavier engines. Granted, it's hearsay and I have no idea if they'd sign affidavits to back up what they are telling me.

[golddredger]

Kiwi,
At this point what is the problem here? Jake has offered just in this thread alone several times that he will gladly crown your beam and even get you inserts for it to add more crown to whatever you like. How can that be beat? He is offering you the fix 100% free. You have to drive to his shop drop the beam and coome back and pick it up done? Yes it is going to cost you a little time and some petrol but he has offered to solve the problem. If it where me here in Ca. And his shop was only 2 1/2 hours away I would have already made the trip and been back to cutting lumber. My first post was on your side and This is to much sag for me. But it has been addressed by Turbo mills and numerous guys here. At this point what are you looking to acheive? Yes it is starting to look a bit strange to all of us. I can see why it is starting to come accross as you are trying to push for something we are just not sure what? Load up the beam and go get it crowned or better yet modified so it can take the inserts and you can set the beam up for what you want. Problem solved. Now you can get to work and make some lumber to be proud of. Good luck in your milling adventures.

[KiwiBro]

The issue of deflection is itself a symptom of beam softness. Will the softness br splved so that the bounce problems will be solved or will I simply get back a crowned but soft beam that still has the bounce problems? I will get up a video of the bounce. Most people will be shocked. Further, take a good look at the beam profile. Forces acting in one plane translate into the other plane. When bouncing in horizontal cut, it is also bouncing vertically putting even more load on the blade.

Did you watch the second video where o said its about 8 hrs driving to get this back? I note Jake has trouble accepting that too, asserting its way less. If he had thought to ask instead of dismissing my words so easily and inserting for his brand of the truth he would have been told I'm on location in middle of nowhere near Kaitaia in far north.

But I guess people still prefer to believe Jake and dismiss what I say. They probably still think this beam sag translates to 3mm in the cut. I have spent tpo such time today doing another video that shows that with the 5.6m beam with 1.4m extension on, there is approx 18mm sag and 12mm horizontal bow in beam that creates 14mm or so and 10mm or so in the cut, respectively.

I cannot see how crowning the beam can fix all this, solve the bounce, and generally make such a soft beam behave, but certainly remain open to being convinced it will but you'll have to excuse me if I need more than blind faith that it will solve these problems, when blind faith contributed to the mess I  am in.

[NZJake]

Hi Kiwibro,

Sorry didn't realise you were on some remote job.

You'll find many videos of the mill being used without bounce. You'll need to use the anti-bounce device if you are experiencing this. Certainly one could make the mill bounce if so desired - just pull it hard enough and you'll get it. We do have a roller kit for this however (just as other manufacturers do), I have already offered this to you.

Its obvious that I haven't been able to explain the reality of the sag your mentioning. So I've attached a drawing taken from my program showing true sag which you would experience in the log. After you take away the ends where the saw pivots. You might notice with other saws that the end extension components are loosely fitted and have there own sag situation going on - that's because this support area at the ends really are not that important.

The beam's standard length you will get 3mm sag as I've pointed out.

In the extended beam you will currently experience around 9mm of sag in the timber (that's assuming that your getting 18mm due to actual sag, rather than a loose fitted extension). So understandably adding say 7mm crown over that full length will certainly bring the beam into an acceptable personal tolerance which you have stated earlier (2-3mm).

The side bow. You'll note the beam width is 150mm instead of the 200mm, so it has a little more tendency to extrude a certain way. I'm pretty sure we can get that to your tolerance too (if you can provide me your expected tolerance while being realistic). I expect a lot of that will just be a matter of being a little more fussy assembling the extension joiner together.

Also note that by splitting your current beam and adding the steel inserted joins you will actually gain strength too. That's one of the options I suggested earlier.

I note that you are suggesting that the beam is soft. Fortunately I have done many FEA's on the beam before it was extruded and does not come any where near its elasticity limit. That's to the point of stretch that it can not recover.

Sorry for bothering everyone. Just figured I needed to respond. I'm signing out now...

Hopefully this attachment helps...

[NZJake]

Kiwibro, noting your comments regarding the beam being too heavy carting it across a paddock. It seems to be an impossible task to offer any scenario that will satisfy your special set of requirements.

Although I will not accept any money back scenario (you've had the mill for some months now) I do recommend bringing the saw back to us where we will be happy to on sell it for you. I have a number of customers that would snap it up in a flash. I can not see it lasting a couple of weeks at the price you bought it.

I'd actually like a first hand look at what your noticing too.

[dgdrls]

Kiwibro, noting your comments regarding the beam being too heavy carting it across a paddock. It seems to be an impossible task to offer any scenario that will satisfy your special set of requirements.

Although I will not accept any money back scenario (you've had the mill for some months now) I do recommend bringing the saw back to us where we will be happy to on sell it for you. I have a number of customers that would snap it up in a flash. I can not see it lasting a couple of weeks at the price you bought it.

I'd actually like a first hand look at what your noticing too.

I have read this thread with great interest,
 
Kiwi,  I sympathize with you.  You had an expectation and it was not met.
I do not profess to know your situation or your expectations in a mill, however,
fact remains, it can only be so light and still meet a certain spec. of weight V. transportability as you have learned.

IMHO NZJ has made numerous reasonable offers to resolve this issue.
The last being to sell the mill for you,  NZJ would still be the point of sale and any issues
that may arise later will be in his court not yours with a potentially unhappy buyer calling,
I'm certain there are some associated cost for both of you to absorb here
but to continue belaboring the point is not a productive solution.

Best
DGDrls

[pine]

I too have been following this thread with interest as not only do I think the reader can learn about a newer device that looks absolutely fascinating in its capability but also it is very instructive in how a thread can be allowed to develop and the reader can have their initial impressions be modified as the topic develops.
I know next to nothing about hybrid swing blade mill designs and mills that are truly portable versus the term we often use for portability with our WM, TK Baker, Cooks and others.  While I do think that the Warrior mill would still be a bit of a stretch to pack in on your back it is still very portable to some out of the way sites. I can see something like that having a big market in places like Alaska where rivers and air are often the only way in.

When the thread started I was completely on the side of KiwiBro in that the amount of sag he was seeing "seemed" to be excessive.  While I still tend to believe that it is excessive, when I see how the mill operates, the design and functionality seem  to counter that a good bit.  As was pointed out there are always tradeoffs.  You cannot have light weight, true portability and not have a higher degree of flex in a beam. For the design and weight of the beam that looks pretty good.  With the techniques that Jake seems to have/offer to counter the natural beam sag I would think that it would be quite acceptable.  Having followed and spent the time to look at all the videos (thanks Jake for the 27:05 video link that was great, just wish you had finished all the way to the bottom of the log. I was interested in how the last couple of cuts would go, Oh Well)
I would not hesitate to look at the product if I needed a mill such as the one that is demoed and discussed here. 

Kiwibro
You may have been an uninformed buyer as you did not do enough research or talk to enough other end users of the product to understand the limitations of the design.   Maybe the seller, Jake if he was actually the sales guy, did not push hard enough to make certain that you understood the limitations of a mill that is designed to be that portable and light but it is not the sales guys prime job to accomplish the buyers due diligence on a purchase. That job falls to the buyer.
From the postings that have been made here it appears that Jake has made nearly every reasonable effort to satisfy your issue with a solution.  I am not saying that his solutions are going to resolve the problems but you have not availed yourself of the possibility of a solution.  You just keep saying the same thing over and over.  I understand you are not happy, I might not be either but you have not allowed Jake's attempts to resolve your problem come to fruition. 
Yes it is a good distance drive to have to drag the device back to him.  I would not be happy either to make the drive.  Unless he agrees to drive and meet you half-way or something you are getting no where at the moment.  You are not happy with the mill but you have done nothing to help Jake resolve it with you.  You have, or so it seems, done nothing but complain while Jake has tried to offer you solutions.  You have prevented him from  helping you.  Now he seems to offer to help you sell it for the price you paid (I think I interpreted that correctly). 

Overall Jake and his product have received what I feel is actually pretty good publicity as a result of your actions.  (seems hard to believe but I think so)
People now know of a device that they otherwise would never have seen.  They see what looks like pretty reasonable customer service.  You complain about an issue that seems at face value to be valid.  The company offers a solution and or multiple solutions that should help you. You publicly kind of ignore them and keep complaining.  Now you seem to be the bad guy.  Not saying that there may not be more going on in the background but Jake comes out smelling like roses and you end up with the bad smell on you, as you fail to take him up on any solution offered.  Yes, time is money but how much time have you spent and gotten nowhere near a solution.

Thanks Jeff for letting the thread play out.  It is a win-win in my opinion for the members. 

[Nomad]

     I'm thinking Pine said it pretty well.

[KiwiBro]

Jake, is the joiner you suggest like the one i have already for the extension that has close to 50 parts, including 24 Allen key bolts to line up, four others for the tension plates and then a tension bolt? With  bright steel rhs with nuts tacked to it?

Do you propose cutting the 5.6m be in half and adding the joiner, so that when needing to go to 7m I have two sets of joiners in this beam?

I agree it will provide some stiffness. It will need to and can you tell me please what is the max acceptable level of hoz bounce for such a reworked beam, with extension on ?

The horizontal bounce is outrageous in two main scenarios when can't use anti bounce device. First cut on each drop, including opening cut. On large logs dont have luxury of taking small opening bites. Also Sub 4" cuts when device doesn't work. Because of the way this beam profile transfers load between planes, that hoz bounce becomes vert load on the blade.

Both vert and hoz anti bounce devices work well when they can be applied. I have both.

The locking spring, when in vert blade position is too short and weak causing the blade to unlock and try swinging back to hoz orientation. Exteremly unsafe and I can tell you things get very ugly very quickly when it happens.

What is the level of mid span beam deflection with carriage mid span and using the extension I have that you suggest the reworked beam will have and the cut will have please?

[NZJake]

Hi Kiwibro,

There are 12 small m8 CSK bolts to each side of the join. Although 50 is a close estimate I guess.

Yes the inserts are the same. The little tensioners your talking about have been removed from the kit. They are no longer required. Rather a simple crown is added to the inserts. So when you bolt the beam together it's crowned. You can actually bend these quite easily to provide what ever crown you need. Place a board at each end of the inserts and give them a little hit with a sledge at the centre. Say 3mm crown (that should equate to a large overall beam crown).

Horizontal bounce...I advise all large horizontal cuts must be made in two passes. It's easier on the saw and is more accurate. I would take a 2" first cut and follow though with whatever is needed to finish the cut (with your anti-bounce unit set for the largest depth). There are many ways to skin a cat. I would be very happy to advise you on numerous productive ways to saw timber without bounce, however I have not been asked for this until now. So please give me call and I'll talk you through solutions (although I am happy to offer suggestions here too). In some cases you can actually use the collar of the saw too. Simply over bite to the collar and then move the saw back to your required smaller desired end cut at the other end. This way you are always over cutting without using any extra hp. You can also set one end over the full depth you need horizontally. Saw through at an angle then move the far end over to the same desired width, pivot and finish the cut. Its actually quite a benefit being able to independently crank each end as it opens up new options unheard of on other saws.

I don't understand why you cannot make small opening cuts on large logs. The frame is designed to slide and cut any size log available.

Spring... Haven't experienced this as of yet so happy to send you a heavier spring. It maybe you just need to tighten up the lock arm a bit so it doesn't rattle?

Crowned sag. That's really up to you, we can have a crown when the carriage is in the middle if that's what you want. We will aim for + - 3mm though. I believe that was your expectation. The cut works out to be roughly half that.

FYI I have had an idea for some time to experiment with the likes of styrofoam injected into the light weight alloy beam. I have a theory that we may experience a significant increase of strength as the outer faces of the beam will no longer distort (similar to the way airplanes are built). I've been meaning to try this out for some time but just haven't found the time to begin the experiment.

I'll take some time out on Monday and let you guys know how it went as far as the increase gained (if any). I'm just curious to know is all. We still use the light weight beams on our chainsaw mills and if there is a way to gain strength to weight ratio fantastic.

Cheers.
Jake.

[JustinW_NZ]

Interesting thread.
I like the foam idea, sounds good!

Interesting hearing other peoples allowable tolerances, I've run into similar things before with different customers acceptable limits (i'm in NZ as well)
Cutting doug-fir beams currently for a timber merchant and at 6 meters they find 5mm bow unacceptable (off the saw)
Whereas a while ago a joinery customer I was basically knocking out cants for them to resaw later and they didn't care how bent they were within reason!?!

Anyway, love the look of these VERY portable units.

Cheers
Justin

[longtime lurker]

Interesting hearing other peoples allowable tolerances, I've run into similar things before with different customers acceptable limits (i'm in NZ as well)
Cutting doug-fir beams currently for a timber merchant and at 6 meters they find 5mm bow unacceptable (off the saw)
Whereas a while ago a joinery customer I was basically knocking out cants for them to resaw later and they didn't care how bent they were within reason!?!

Cheers
Justin

Off topic but...
I used to put up with customers like that, then one day decided I'd had enough of it. Now I point to the deflection tables of AS 2082 (Australia's hardwood grading standard includes maximum tolerances for bow/cup/spring/twist etc) and point out that my "regular" timber has no-where near that amount of spring or bow straight off the saw. Then I explain that all timber comes from the saw bent, and that if they want it straightened we can do that - either with a plane or with the resaws but either way there is a fee to do it and it's all theirs.

Most of them get it. Most of them happily pay more for gunbarrel straight timber when they need it, and most find they didn't need it that straight all the time anyway. My moulder actually started to pay its own way from that time on because invariably people choose DAR over straightened rough sawn when the price is the same.
( paragraph removed by admin for inappropriate language)

[longtime lurker]

i]FYI I have had an idea for some time to experiment with the likes of styrofoam injected into the light weight alloy beam. I have a theory that we may experience a significant increase of strength as the outer faces of the beam will no longer distort (similar to the way airplanes are built). I've been meaning to try this out for some time but just haven't found the time to begin the experiment.

I'll take some time out on Monday and let you guys know how it went as far as the increase gained (if any). I'm just curious to know is all. We still use the light weight beams on our chainsaw mills and if there is a way to gain strength to weight ratio fantastic.

[/i]Cheers.
Jake.

Jake,
Not telling you how to build a sawmill but my experience with boat building tells me you need to be very carefull with what foam compound you use. A lot of the spray foams tend to be hydroscopic - this would lead to a weight increase over time as the foam structure takes up moisture, and also leads to corrosion issues where unpainted metal is in constant contact with moisture laden foam. It might pay to seek expert advice from one of the manufacturers like Dow as to what grade of foam would be best to get the desired result with whatever grade you are using for the rail. I've seen alloy boat hulls that have rotted from the inside underneath the wrong grade of foam.

[NZJake]

Hi Longtime,

Thanks for the advise. Yes I did consider the moisture scenario. Right now I'm just looking toward proof of concept. Definitely will seek advice if it turns positive. We have filled one beam today with a Sika product. Will let you know if there was any gains tomorrow once it sets. Going to measure the deflection between a standard beam and this filled one.

Cheers.
Jake.

[NZJake]

Well we did our little experiment. Unfortunately the gains were insignificant, lucky to be .5mm gain in strength. You could feel a difference but certainly not worth introducing as a process.

Interesting experiment though. So if a small degree of sag (5mm with our chainsaw mills, equating to 2.5mm in the log) is an issue for anyone you'll have to order the beam split so we can crown it.

The bigger depth galv. steel beam will not have this sag scenario unless lengths over 7.2m are required.

[KiwiBro]

Jake, please have your buyers contact me.

[NZJake]

Hi Kiwibro,

I really don't understand your thinking? If the mill isn't right for you why not bring it back? We will sell it on your behalf pretty quick. It should be in the hands of someone that will appreciate it. No use hanging on to something that's not right for you. No need to hold a grudge. I've offered you solutions. If your not keen for them its time to move on.

If you want to discuss any issues you maybe having give me a call or send me an email. Better yet bring the saw down to the factory. We will put a nice hardwood under it. Get some real time footage of it sawing and post it right here on the forum!

We have testimonials on our website and facebook.

[Jeff]

 KiwiBro, you have made your concerns known, and they have been acknowledged here in person by the manufacture. The only purpose for you to continue this topic would be outside of what is allowable on the Forestry Forum. I'm going to lock it. its obvious to me that you have the needed avenue of contact available to you via email to finish up your business with Turbo Saw.