I had 9 blades re-sharpened by a fellow here in town. Never used his service before so I didn't know much about him, just that a few guys use his service and they say the blades are better than new ones.
OK, cut a bunch of Black Walnut with one of the blades and it worked swell. Put on another one to cut a 28" White Oak and 2" into the cut the blade started to dive into the log. I backed the blade out and started looking for a problem. Sawmill was level, eveything else checked out OK so I tried a few more times. Same result.
Replaced the blade with a brand new factory blade and it cut like butter. Not sure what happened to the blade he sharpened but it's certainly acting strange and is basically unusable. I thought maybe it was just the White Oak causing the problem so I used the unstable blade on a 10" Poplar and it wouldn't even cut that without heading toward the center of the log.
Anyone have any ideas? Is it possible to put an incorrect pitch or taper or sometlhing on a blade when it's being re-sharpened?
Thanks in advance for any help.
Jim
Check the set.
What does that mean Kbeitz?
Check the set of your band. It will dive like crazy with little or no set.
Let's pretend like I have no idea of how to check the set of my band. And if that were the case, how would I do that?
You can use a caliper.
(https://forestryforum.com/gallery/albums/userpics/39553/blade_set.jpg?easyrotate_cache=1520634566)
(https://forestryforum.com/gallery/albums/userpics/39553/Tooth_anglr~0.jpg?easyrotate_cache=1520634844)
OK, I understand now. Thank you Keibtz!
When I bought my sawmill I had no idea how/where I would get my blades resharpened. I was referred a guy that owned an LT40 and sharpened blades for others as well as himself.
Long story short, one of his blades took a dive similar to yours in a relatively small SYP log. Also, I was having to make a 30 mile round trip twice to deliver and retrieve the blades.
That is when I decided to use Wood-Mizer Resharp. That happened 16 years ago and the rest of the story is history. :)
If your blade is level from front to back then your blade has more set on the outside face then the inside.
Wood Mizer sells a gage gizmo to check the set.
Wood Mizer will only sharpen their blades.
Some WM Resharp centers have relaxed this a bit but there are some mfg/profiles that they will not resharpen. Call your resharp center before shipping them other mfg blades.
Hi 50 Acre Jim,
FF supporters, Cook's sawmill has some good reading on bands
The Bottom Line about Sawing Straight - Part 1 (http://www.cookssaw.com/index.php/sawmill-blade-insight/the-bottom-line-about-sawing-straight-part-1)
lots of good info here and more links on the right side of the page.
best
D
Quote from: dgdrls on March 10, 2018, 08:30:51 AM
Hi 50 Acre Jim,
FF supporters, Cook's sawmill has some good reading on bands
The Bottom Line about Sawing Straight - Part 1 (http://www.cookssaw.com/index.php/sawmill-blade-insight/the-bottom-line-about-sawing-straight-part-1)
lots of good info here and more links on the right side of the page.
best
D
Very good reading... But I got a question...Tim states...I looked over all the pieces and saw that the blades with the crack of daylight dish on the inside ran very good and the blades that were dished on the log side would not cut at all without diving....
But nowhere does no say if the dish is facing up or down. Can anyone help with this? Concave or convex ?
I would interpret "dished" or "dish" as the face that is concave. Because he calls it "crack of daylight dish". Also because our usual view of a dish is the side we're eating out of.
So Dish on the inside would mean concave on the inside of the band.
Dish on the log side would be concave on the outside of the band facing the log.
I was kinda thinking that because you would thing after running for a while that the band would take shape of the wheel. But then he said...
I looked over all the pieces and saw that the blades with the crack of daylight dish on the inside ran very good and the blades that were dished on the log side would not cut at all without diving.
Does this mean that after running your bands for a while they will dish away from the wheel?
I have an English wheel. If I want to cup something it goes with the crown not away from it.
I watched some utube videos on rolling a band saw blade. It looks like they are trying to cup the inside of the band. That makes no sense to me. Why does the saw mill not cup the band with all the pressure pushing on the inside of the band to match the shape of the wheel. How can it cup the other way? I'm lost.
Also if you'r band is diving I would think all the bands teeth would be leaning down not up. So rolling the band would make the teeth point more up and that would fix the problem. So what I'm not understanding is how the band can cup the wrong way just from running on the mill.
This post says they cup down...
Cupping Band Blades...Too much Tension? in Sawmills and Milling (http://forestryforum.com/board/index.php?topic=33079.0)
To help the OP (50 Acre Jim)-
There is a chance that the blades you got resharpened were not done correctly. The fact that a new blade performed in an acceptable manner after trying the ones that were serviced would somewhat lead a person to assume this is the case. One or more things could have attributed to the problems you were/are experiencing. This is also one of those times a person has to make such assumptions based on the information provided.
Walnut saws relatively easy compared to White Oak. You also shared the White Oak was 28" dia. That's starting to get into pretty wide cuts with not much blade support from the "guides", regardless of species. The fact is was W. Oak probably didn't help the situation. Having blades best suited for your machine and what you're sawing makes a big difference too.
Because of your HP and description of your sawing situation, you may look at getting some 4 deg. blades.
Take a good hard look at your ceramic guides. The effects of the guides themselves can/will play a role in poor blade performance. The heat generated from the friction (guides contacting the blade) and also the literal damage to the blade body itself from the guides "scrubbing" both the sides and the back edge of the blade. A blade that performed acceptable when new, may have damage that no amount of sharpening will ever correct.
Also check and make sure your blade is dead parallel to the bunks. This is critical, even more so than sawmills running a roller guide system. You may even contact Norwood about upgrading to roller guides. By far, one of the best investments you can make to improve both your lumber quality and blade longevity/performance, IMO.
Hope this helps you out.
Kbeitz,
Blade curvature has little bearing in the OP's case because of the guide system. Since the bandwheels themselves provide the foundation of support for the blade while in the cut, the ceramic guides are mostly a static fitment that guard against extreme deviation. BUT, it can can have an impact and play a role in poor performance and product produced. The process for servicing such blades is handled somewhat differently because of this.
Roller guide system, different case. TerrificTimbers is correct as to his summary.
The reasons for addressing/correcting curvature is a process NOT done on an English wheel. Similar influence on the steel, but far more precise and controlled.
Quote from: Cutting Edge on March 11, 2018, 06:59:41 AMThe reasons for addressing/correcting curvature is a process NOT done on an English wheel. Similar influence on the steel, but far more precise and controlled.
I was not even wanting to try rolling my blades with my English wheel. What I was saying was when I roll
a piece of steel with my English wheel it follows the crown of the wheels. So I would think the crown of a
bandsaw wheel would after running for a while would put a curvature in the band to match the curvature of
saws band wheel. But from what I get from reading everything the curve is going away from the wheel. How can
this happen?
Quote from: Kbeitz on March 10, 2018, 05:41:31 PM
I watched some utube videos on rolling a band saw blade. It looks like they are trying to cup the inside of the band. That makes no sense to me. Why does the saw mill not cup the band with all the pressure pushing on the inside of the band to match the shape of the wheel. How can it cup the other way? I'm lost.
Also if you'r band is diving I would think all the bands teeth would be leaning down not up. So rolling the band would make the teeth point more up and that would fix the problem. So what I'm not understanding is how the band can cup the wrong way just from running on the mill.
This post says they cup down...
Cupping Band Blades...Too much Tension? in Sawmills and Milling (http://forestryforum.com/board/index.php?topic=33079.0)
The cooks guys talk about anticlastic curvature in some of their literature/videos - If you look for those articles, it may clear things up for you? I'd guess it has something to do with the spring tension of steel and the alignment of various positions on the surface of the steel band; as it goes around the crowned wheels, it does cup the 'expected' direction (cup on the inside), but as it comes off the wheel that cupping means that the center of the band is actually longer (around the length of the band) than the back or front of the band... that extra length has to 'go' somewhere, but it can't cup to the inside for some reason - either the tension, or heat buildup, or something about the steel makes it pop back the other way? I don't have that answer.
The "anticlastic curvature" describes what is going on when a band is bent. You will see that effect when band of any material are bent. It has nothing to do with the wheel surface material but the radius for the wheel. Smaller wheel means harder effect. The band will always "cup" out from the wheel. If you would check a blade, with many hours in the saw, you will see the cup also when the blade is under tension and also all the way around the wheel. Check with a ruler cross over the blade outside and you will see it is concave.
An easy and clear way to see the effect is to bend a rubber band. Let say you have a 1/4" thick and 1" wide band, rubber, plastic or other homogen material, bend it to different radius and you will see the effect of anticlastic curvature.
The steel in the blade will "remember" more and more of the "maltreatment" on the wheel in the mill and it ends up in more and more cup.
I am sure it would be possible to run the blade on the mill, with the teeth backwards, and that way run it back to flat.
Thanks to all... Learned again something new on this forum.
Time to make a band roller.
Kbeitz, With 1¼ wide blade you won't need a roller, The blade will junk wore out and broke by then. :D :D
Quote from: Peter Drouin on March 11, 2018, 06:36:38 PM
Kbeitz, With 1¼ wide blade you won't need a roller, The blade will junk wore out and broke by then. :D :D
Thanks...
I also think by adding more set gets around having to roll you'r blades. It gives more clearance for the curve of the blade so it does not touch the log and push you off track.
More set works very well for me.
Quote
To help the OP (50 Acre Jim)-
There is a chance that the blades you got resharpened were not done correctly. The fact that a new blade performed in an acceptable manner after trying the ones that were serviced would somewhat lead a person to assume this is the case. One or more things could have attributed to the problems you were/are experiencing. This is also one of those times a person has to make such assumptions based on the information provided.
Walnut saws relatively easy compared to White Oak. You also shared the White Oak was 28" dia. That's starting to get into pretty wide cuts with not much blade support from the "guides", regardless of species. The fact is was W. Oak probably didn't help the situation. Having blades best suited for your machine and what you're sawing makes a big difference too.
Because of your HP and description of your sawing situation, you may look at getting some 4 deg. blades.
Take a good hard look at your ceramic guides. The effects of the guides themselves can/will play a role in poor blade performance. The heat generated from the friction (guides contacting the blade) and also the literal damage to the blade body itself from the guides "scrubbing" both the sides and the back edge of the blade. A blade that performed acceptable when new, may have damage that no amount of sharpening will ever correct.
Also check and make sure your blade is dead parallel to the bunks. This is critical, even more so than sawmills running a roller guide system. You may even contact Norwood about upgrading to roller guides. By far, one of the best investments you can make to improve both your lumber quality and blade longevity/performance, IMO.
Hope this helps you out.
Thank you Cutting Edge,
The mill is level, the blade is "dead level" to the bunks, and I had just upgraded to roller guides. I have cut White Oak this diameter before and this experience was not what I expected. :-)
I agree 100% with the need to use 4* blades instead of the 9* I was using. But that being said, the blade was diving so deep, and so quickly, that there was over a 1" gap between the bandsaw blade and the right roller by the time I had gone a few inches.
I switched blades again yesterday to cut a few 4x4's and the saw ran great. Albeit, it wasn't White Oak but still, the saw ran as expected and that made for a good day.
Thank you, everyone, for taking the time to help me. It is truly appreciated!
Jim
Yup, Bad set.
if the new blade cuts good and the resharpened doesn't then something is wrong with the way it was sharpened and or the set in the teath
Well, the bad news (for me) is I just can't get rid of the wavy cuts. The bed is dead level. I have removed the rails (that the head rolls on) and reinstalled them, several times. The blade is level to the bunks. I've changed from the ceramic guides to the roller guides, and it's gone from bad to worse.
A brand new blade will produce almost acceptable results but within 10 minutes; it's producing wavy cuts again. Doesn't matter what species of wood I'm cutting. Hard, soft, it's all the same.
I've spent so much time on this problem that my frustration level is maxed out. I'm not having fun with this saw any longer. I know it can cut straight, I've seen it before, but it's been awhile.
About a month ago I was searching for better roller guides, and I found a sandwich type of guide. It had rollers on all three sides. Top, bottom, and back. Was pricy as all get out and I passed on it to buy Norwood's roller guides.
Now I'm looking for it again, and I can't find it anywhere. Anyone heard of these guides before? As I recall they were several hundred dollars but I've got to find a solution or this saw and I will have to part. I've got a bunch invested but not being able to cut anything reliably is unacceptable.
Thanks in advance,
Jim
Do you have the roller guides pushing the blade down 1/4". Steve
Jim, I believe the guides you're talking about are the Suffolk Machinery guides but I don't think they are the solution to your problem. Do you have a pic of the Norwood roller guides? I can't find them on their website.
Edit: The Suffolk Machinery guides are not the ones you're looking for.
Rollers or anything under the blade is totally unnecessary, if your running 1/4" down pressure and the blade dives its dull or something else is wrong. Steve
Steve is correct on this Jim . you might want to check for proper tension on your drive belt. I have had this cause the band to cause a wave.
Quote from: ladylake on April 18, 2018, 07:13:46 AM
Do you have the roller guides pushing the blade down 1/4". Steve
The design of the ceramics allowed for adjustment but if there is a way to adjust the roller guides, I am unaware of it. I don't think they are pushing the blade down 1/4 but it does appear to be pretty tight with the blade.
(https://forestryforum.com/gallery/albums/userpics/46073/DSC00656.JPG?easyrotate_cache=1524052836)
(https://forestryforum.com/gallery/albums/userpics/46073/DSC00659.JPG?easyrotate_cache=1524052830)
(https://forestryforum.com/gallery/albums/userpics/46073/DSC00657.JPG?easyrotate_cache=1524052830)
QuoteQuote from Slider: "Steve is correct on this Jim . you might want to check for proper tension on your drive belt. I have had this cause the band to cause a wave. "
Thank you Slider, I will check the tension.
I don't think this is the problem but it sounds like you are describing one of the larger Carter guides, Its got to be something missing in your setup;
http://www.carterproducts.com/band-saw-products/band-saw-guides (http://www.carterproducts.com/band-saw-products/band-saw-guides)
Well those aren't the ones I was talking about but they're along the same lines.
Thank you Don.
Guides need to be adjustable for horizontal tilt, vertical tilt, vertical position (down-pressure), and horizontal position (blade-to-flange gap). It doesn't appear that the guides pictured have these adjustment capabilities.
Quote
Guides need to be adjustable for horizontal tilt, vertical tilt, vertical position (down-pressure), and horizontal position (blade-to-flange gap). It doesn't appear that the guides pictured have these adjustment capabilities.
Finally broke down and called Norwood for support. According to Trevor:
1) My logs are frozen, and I'm using a 10* pitch when I should be using a 7*
2) The roller guides they sell can't be adjusted and I need to remove it, put a large washer under it to achieve the required down pressure.
3) My blades are not tensioned properly.
I am a bit miffed that Norwood sold me the roller guides without telling me I had to adust them with a washer but I'm glad to have a solution to that at any rate.
Also, I have been tensioning the blades per the instruction manual, which is 5 1/2 turns after I get the blade taunt. He says that is wrong and they had just released a video on proper tensioning. Which is to tighten the T-handle to where it meets the frame and then tighten 10 turns.
So anyhow, I have new hope now and will get back on it.
Thank you, everyone, for your help and suggestions.
Jim
What brand blades are you using? Maybe try another. Have you recently switched brands? has all this happened with blades from the same order?
Quote
What brand blades are you using? Maybe try another. Have you recently switched brands? has all this happened with blades from the same order?
I was using Norwood 1-1/4 X 7/8 X 167 but switched to Cooks of the same size. I'm a fan of the Cooks blade, seems to be more robust and about $90.00 less (per a box of 10 blades). Waviness persists, regardless of which blade I'm using.
I'm hoping to find some improvement when I add more tension to the blade. Although, I've been using the same method of tensioning my blades and didn't have the waviness problem before. But maybe Trevor is correct, and it's because the logs have frozen. One thing for sure, it's been 80* today so come Saturday I'll know whether or not it's because of frozen logs or not.
Frozen logs will raise heck with most any mill.
let the logs thaw,
FWIW in-general the harder the log the less tooth angle u want to use.
good luck
D
This is the worst suggestion that I can possibly think of, because you can't possibly have done this.
But I did once... in front of a customer...
Are you teeth going the right direction?
I sharpened some of my bands, but forgot to invert them after setting the second direction (single tooth setter), and didn't even realize it when putting the band on the mill. The *DanG thing CUT! Once or twice.
But not 3x and not more than 6" in a cut.
It was all me. I sharpened it. I set it. I forgot to invert it. And I didn't notice it when I put it on.
A very embarrassing mistake to make in front of a customer.
But he did end up with some fine ray-flecked 6/4 oak to make his wine racks with, after I turned my blades right side out again.
I find that I have to be extremely diligent with sharpening and setting when sawing frozen timber. Also found that a bit more set (30 - 32 thou) helps too. I think set may be the critical factor. Drive belt tension is important as well. Dont use the blade TOO long either. The mill will let you know when it time to change.
I'm sawing frozen white oak and what ever else with no problems with wavy cuts, frozen wood is not the problem. The first thing I'd do is to make sure there is 1/4" down pressure, if those rollers are just touching the blade they do no good. Someone mentioned the brand of the blades, I've run across 2 brands that wouldn't cut straight even brand new, put on a old Simonds sharpened over 10 times that cut perfect for over 2 hours in wide white oak . Steve
Well, I tried the recommendations I got from Norwood support. One was to thaw out the cant and to try a brand new blade. So I put up a 12" poplar that has been in the sun all day. Soft wood, very much not-frozen. Brand new Cooks blade.
Here is a video of what I got.
https://youtu.be/y_nI45_dIgs (https://youtu.be/y_nI45_dIgs)
Jim You need to get that 1/4" down pressure then report back. Steve
Quote
Jim You need to get that 1/4" down pressure then report back. Steve
I agree Steve. But here's the problem. There isn't any "easy" way to do that. The roller guides were supposed to be a "plug-n-play" replacement for the ceramic guides, but to get 1/4" downforce on the blade is surely NOT plug and play.
According to Norwood Support today, I can take them off and put a washer in to shim it down. But it's not anywhere as easy as it sounds. I hate to go through all that and not see an acceptable difference.
The only reason I even invested the money on the roller guides was because I didn't like paying Norwood $25.00 for a .50 piece of ceramic each time one of them wore out.
I would be pulling my hair out.
The only time mine ever cut anything remotely like that is when I first got it, I was not tightening the band as much as I thought, or at least not as much as it needed to be, but it would still cut pretty much fine, but start waving pretty quick as it started dulling.
Is there a possibility the bands are rubbing on the wheels and flattening the set?
Any chance the bands were somehow damaged during shipping and or handling.
Besides the guides, what else has changed or been worked on, since it presumadly cut straight?
Maybe band brand change?
The way you reached up and turned the guide with the band tight, does not seem right, I don't think I could do that very easily with mine, but It seems like it should cut straighter than what it is, with NO guides at all.
Check your drive belt tension or maybe replace it. Do you hear the engine bog any at all while sawing?
I agree with Steve, the blade guide rollers need to be 1/4 inch lower than the band wheels
Quote
Check your drive belt tension or maybe replace it. Do you hear the engine bog any at all while sawing?
Seems like something I would have noticed so I don't think so.
Edit: There has been a couple of references to the Drive Belt in the previous posts. How would a drive belt how the band is cutting? I mean, if it were so loose that it was slipping I could see it. This one isn't loose, shows no wear and is quite taunt.
If the blade isn't achieving full speed due to a slipping belt it will wander all over the place. Even without guides, a sharp, properly set blade should cut straight.
Jim, in a previous post you stated that the blade is level to the bunks. To be clear, "level to the bunks" means that the blade is running parallel to the bed of the mill lengthwise. How did you check this? Do you have a blade alignment tool? I agree with LeeB, you should be able to cut straight even without guides, especially poplar.
I'm with GMM. Your drive belt is also the one the band sits on, right? All I can think of is that either your band is running far enough back on the wheel to take the set out of the teeth (unlikely) or one of your roller guides it slightly tilted up or down. That seems like the culprit from where I sit. A blade guide alignment tool would identify that in short order. Making a suitable substitute wouldn't be hard to do.
(https://forestryforum.com/gallery/albums/userpics/20011/2410/DSCN1205.JPG?easyrotate_cache=1290474354)
This is not the Wood-Mizer way but it works if the bed rails are all level. The "Blade Guide Alignment Tool" (BGAT) allows you to insure that the blade is perfectly aligned with the sawmill bed rails. Open the blade guide arm completely and check and insure that the blade is absolutely horizontal at each blade guide roller.
Yes, the sawmill should saw straight even without blade guides, but it needs a good (sharp) blade to do so.
You have mentioned "taunt" several times, but that does not accurately describe "how" taunt. In your video you turned the roller blade guide easily by hand. This should be virtually impossible to do.
To properly saw the drive belt must not slip which will slow the blade speed down. As Steve has mentioned several times, the blade guides must be ¼" below your blade wheels. The blade must be tight, not taunt. The blade's vertical tilt must be adjusted so that the blade is horizontal to the bed rails (as illustrated above). Your blade guides should have a slight horizontal tilt toward the idle side. Your blade must be sharp and properly set. Match your blade hook angle to the log species. Don't push your feed rate beyond your engine's hp capability.
Insure that the above items are all in order and your wave problem will disappear.
I notice that all the users recommending ¼" down pressure with the roller guides are all Woodmizer owners. But Jim has a Norwood and Norwood designed their guides without any down pressure. Same on my EZ Boardwalk and many other mills and they all cut straight boards. That saw should cut straight without any roller guides at all, so obviously the problem lies elsewhere.
Jim, since you've checked everything for alignment, sharpness, etc, I'm thinking that the only thing left that would cause that problem is lack of blade tension. I suggest you over tension the blade and see if it doesn't resolve your issue. This possible solution has the added benefits of being easy and free!
I missed this earlier, but Starmac's had this problem and his solution was to increase blade tension (and simultaneously pull his hair out).
Quote from: starmac on April 19, 2018, 07:38:50 PMI would be pulling my hair out.
The only time mine ever cut anything remotely like that is when I first got it, I was not tightening the band as much as I thought, or at least not as much as it needed to be, but it would still cut pretty much fine, but start waving pretty quick as it started dulling.
Jim, you also mentioned you got different instructions for blade tightening from the factory rep than what you had been using. I'm betting that the blade is still not tight enough and that you just haven't found the right tension yet.
Short story, you get dives when the blade twists for whatever reason. Figure out why the blade is twisting and you will have the problem solved. Most common cause is forcing a dull blade into the wood, which forces the blade back into the guides, plus changes the blade tracking..
Prior to learning plenty on this forum I followed cooks videos for setup on my Enercraft. I bought the blade alignment tool and tension gauge. The alignment tool would be easy to make but it was cheap enough. I agree it should cut straight without the guides but they're there for a reason. I've got 1/4" down pressure on mine. I have little literature on my mill so I wanted to know what tension I've been running. Been going by the alignment mark on the spring tensioner. With the tension gauge I now see I've been running at about 3500 psi. Kinda high from what I believe it should be. Put it down to about 2800 psi and it seems OK. At least I know tension and can always verify it. I guess some mills have dial gauges built on them. I'd definitely like that.
Quote from: Skipper11A on April 20, 2018, 10:15:41 AMI notice that all the users recommending ¼" down pressure with the roller guides are all Woodmizer owners
Wrong. Steve, (ladylake) owns a TimberKing B20.
There is something seriously missing in this entire "wavy board" situation. Norwood sawmills, as set up from the factory, will and do saw straight lumber every day.
Quote from: pineywoods on April 20, 2018, 10:41:25 AM
Short story, you get dives when the blade twists for whatever reason. Figure out why the blade is twisting and you will have the problem solved. Most common cause is forcing a dull blade into the wood, which forces the blade back into the guides, plus changes the blade tracking..
Found this out for the first time yesterday. Knew the blade needed changing, could feel it, but wanted to finish the log I was in. Should've stopped and changed the blade when I first felt it getting dull. Pulled the stack of 4 2X6's off and two of them had waves or dives at a knot. Didn't ruin the lumber, but I am glad I wasn't sawing a birch slab, or sawing lumber for someone other than myself.
Both WM and Cooks recommend 1/4" down pressure, TK recommend 1/8" but that got changed to 1/4 right after I got my mill as it saws straighter with 1/4". Steve
Had this happen on manual mill before my concrete slab was poured because different logs caused bed to flex. Even though it was level when nothing was on or running. (Check this first)
Also blade tensioner loosened once in my LT-10 (actually snapped) and after I realized that was there for a Very Important reason I check it each startup for tightness...no more wavy lines. I tried a bush fix with eye bolts and nuts, get the right tensioner from the factory; and keep one on backup.
And lastly what MM said, slow down to a crawl and cut once at a foot per 10sec rate and see if it comes out straight. This way you are taking the extra factors caused by "stress" out of the equation. Like letting a chainsaw cut without pushing, sharp blade should not go sideways if working correctly.
(https://forestryforum.com/gallery/albums/userpics/33352/IMG_5602.JPG?easyrotate_cache=1472522129)
While it is interesting, none of this discussion about roller guide down pressure will help Jim identify his problem. I think we all agree that his saw should cut straight without any blade guides at all. So the problem must lie elsewhere. More to the point, I think that having Jim adjust his guides is an incorrect diagnosis for his problem.
As I work down my troubleshooting checklist, I think that Jim has verified that the blade is sharp and the wheels are in alignment, but I'm not sure that he has checked off the box next to "Proper blade tension". I know he addressed the blade tension, but I didn't get the impression that he had fully ruled this out as an issue. So increasing blade tension would be my next troubleshooting step. In fact, he should lubricate all of the blade tensioning equipment on his mill as this could simply be an issue of lack of lubrication.
After ensuring the blade tension is correct, I would check to make sure something isn't taking the set out of the blades. Originally the problem appeared after Jim had blades sharpened by a local guy. New blades cut fine (see his original post). At that time it appeared to be faulty sharpening/improper set.
Now he has the problem with a new set of rollers and new blades. The video of the wavy cut makes me think something is flattening the tooth set. Could be my inexperience with sawmills but my woodworking experience leads me this way.
If the blade loses its set on the inside (the side against the wheels) wouldn't it want to cut to the outside aka dive?
What does the sawdust between the cant and the board look like? Fine and loose or packed tight? Insufficient set would leave packed dust in the cut. I still think the dive belt is slipping, weather that be on the drive wheel or the blade itself slipping on the drive wheel. Does not the Norwood use the drive belt as the wheel belt as well? Change the belt.
Quote from: 50 Acre Jim on April 19, 2018, 06:54:05 PM
Well, I tried the recommendations I got from Norwood support. One was to thaw out the cant and to try a brand new blade. So I put up a 12" poplar that has been in the sun all day. Soft wood, very much not-frozen. Brand new Cooks blade.
Here is a video of what I got.
https://youtu.be/y_nI45_dIgs (https://youtu.be/y_nI45_dIgs)
Blades should run flat on the entire surface of the guide rollers. Pictures can be deceiving, but in your picture their is a shinny streak along the front of the roller the length of the blade. IMHO this would indicate the blade is not running flat on the roller and pitched at an angle is causing it to dive. In the dark, shine a light under the roller and see if it has full contact to the roller's full width or if it is indeed twisted or you can check with a "Blade Guide Alignment Tool". Again it may just be an illusion in the picture.
I m running a norwood with the same set up and had the same problem last summer. after discussing it with the guy the dose my sharping for me we found the problem. On a norwood mill the roller guides are just that "guides" they are not meant to hold the band. after checking everything we found the roller guides had worning down from front to back and where guiding the band down. after replacing the rollers it ran great for about 2 logs then same thing "diving". I discussed it again with the sharping guy he told me to "get the used band off the mill and try to coil it". BINGO it didn't coil up easily. turns out when it started to dive from the worn out rollers I would over come that problem by tighting up my bands more and by over tighting them. the bands lost some temper. the old bands would sharping and cut fine till the heated up the they would lose set. costly lesson learned. with the new rollers and all new bands it cuts straight as an arrow again.
check you roller guides with calipers they cant be more then 1/10000 out from front to back. I replace them every fall now. but im doing a ton of milling and use the bands for you self and when they start to dive. throw them away
nothing wrong with reshaping( i use bands till they done. usually 4 to 5 sharpings) but for whatever resin your bands have lost the temper in the steel and will never wok properly again.
and make sure the bands are running about 3/4 on the belts. if the teeth of the band are running to close to the belts it will also take the set out. and the backs of the roller guides should be a 1/4 inch from the back of the band
One item that I have not seen mentioned is buildup on the blade. In the video and also in the pictures on the previous page I am seeing some buildup. It has been cleaned off between the blade guides, but between the guides and bladewheel, I am seeing buildup.
Buildup on the blade will cause wavy cuts so one other item to address is blade lube/cleaner, or lack thereof.
Quote from: Magicman on April 21, 2018, 02:26:25 PMOne item that I have not seen mentioned is buildup on the blade. In the video and also in the pictures on the previous page I am seeing some buildup. It has been cleaned off between the blade guides, but between the guides and bladewheel, I am seeing buildup.
Buildup on the blade will cause wavy cuts so one other item to address is blade lube/cleaner, or lack thereof.
MM has sharp eyes. At 1:10 in the video you can clearly see the buildup, shiny to the left of the blade guide, but just dark crap between the guides. This is the shiny streak that Remle noticed. It doesn't look like enough to affect the cut in softer woods but I wonder what the outside of the blade looks like.
Took a power washer to the mill and cleaned every bit of build up anywhere on the machine. But it made no difference in how the machine cut.
When I spoke to support at Norwood, they suggested some things, all of which I tried with no change in cut. Their final suggestion was to change back to the ceramic guides, which I did yesterday morning. It made a little bit of difference. I found that if I cut extremely slow, and I mean extremely slow, I can push the blade through the log with minimal waviness.
The product wouldn't be acceptable for sale; no way anyone would want to buy it. But I did at least get a few boards cut to finish a deck that I had been building. (Nothing makes me angrier than to have to buy lumber at Lowes because my mill can't produce what I need.)
So the ceramics made a little difference, but they aren't fixing the problem, just masked it a bit. What I have noticed though is that the three planks I cut yesterday have a washboard look to them. Saying "washboard" probably doesn't really describe the effect I'm seeing, it's more like the cutting edge, or teeth, on a file. I know it's an exaggeration, but if I could pick up the plank and flip it over, I could use it to file something.
I'm going to dismantle and reassemble the bed this weekend. May do the same with the carriage. Not sure what the next step will be if all this fails but given there is no Norwood support in my area I may be faced with a new purchase. There is a limit to every man's patience, and I've found mine.
Hate to sound like a broken record, but again I have to ask, is this only happening since you changed blade brands? Are the problems all from the same box of blades? I know you mentioned the resharpened blades were a problem too. Have you tried any of the other resharps? Have you tried any other batch of blades than these two? Have you tried changing or adjusting the tension of the drive belt? You don't have to see the belt slipping to be loosing blade speed. Can you hear the engine speed decrease as the blade begins to cut or does it remain the same in and out of the log? Years ago I had these same issues on a different brand mill and finally narrowed it down to a slipping drive belt. Couldn't see a thing. Belt was slipping ever so slightly at the engine pulley, just enough to loose blade speed. Tightening helped some but changing the belt solved the issue.
I don't mind sounding like a broken record, you need to put 1/4" down pressure on those roller guide no matter what it takes. Without down pressure you may as well not use them. Steve
On the mill I mentioned in my last post the guides were set at 1/4" down pressure and I still had the wavy cuts until I got the blade up to speed by changing the belt.
For sure there can be other problems, but it's not going to cut straight with no down pressure plain and simple. That is the first thing to fix. Steve
Quote from: LeeB on May 02, 2018, 07:34:42 AM
Hate to sound like a broken record, but again I have to ask, is this only happening since you changed blade brands?
A: No, I have used Norwoods blades, resharpened Norwood blades and now brand new Cooks blades. Problem persists.
Are the problems all from the same box of blades? I know you mentioned the resharpened blades were a problem too. Have you tried any of the other resharps?
A: No, blades have come from several sources.
Have you tried changing or adjusting the tension of the drive belt?
A: Yes, I have adjusted the tension of the drive belt, I have dissasembled the bed and reassembled it. I have used both the roller guides and now I have put the ceramics back on.
Can you hear the engine speed decrease as the blade begins to cut or does it remain the same in and out of the log?
A: No decrease in engine speed. Sound is consistant.
Years ago I had these same issues on a different brand mill and finally narrowed it down to a slipping drive belt. Couldn't see a thing. Belt was slipping ever so slightly at the engine pulley, just enough to loose blade speed. Tightening helped some but changing the belt solved the issue.
LeeB, I answered your questions in your quote as it was easier to address them individually.
Quote
I don't mind sounding like a broken record, you need to put 1/4" down pressure on those roller guide no matter what it takes. Without down pressure you may as well not use them. Steve
I have removed them, Steve. I am now working with the factory default ceramics. I see a little difference, but I think it's just that the ceramics are helping to camouflage the problem. I am now in the process of disassembling and reassembling the carriage. Hopefully, whatever it causing the problem will get fixed along the way. :-)
With roller guides you NEED 1/4 down pressure to work right. If ceramic guides are tight to the band with no wear they would control the blade good but tight to the band and no wear only happen when brand new and adjusted tight. Why do you spend time and money messing with the carriage rather than fixing the problem. I give up trying to help. Steve
I bought some cooks bands a box of ten
They never made a good cut on my mill
Won't stay on the wheels and make wavy cuts.
I not bashing cooks at all.
But the box I got Don t work for me even when resharpebed.
I have WM,Timber wolf,Ripper 37 and Kasco all cut great
Tonight I removed the rails from the bed and reinstalled them. They just didn't feel right, even though the alignment tool that Norwood sends with the saw indicated everything was aligned correctly. Felt like the carriage was binding as I pushed it along. Not bad, but not real smooth like you would expect.
I put an aluminum 4' level along the side of the rails, and it was obvious that there were inward and outward bows along the track. Not visible by looking at it and not picked up with the alignment tool, but they were there for sure.
I took a finish hammer and tapped them until the entire run on each side was perfect. Ran the carriage down the track and wow, what a difference. Not saying that was the entire problem, but I believe that was where the problem was starting.
Next, I re-adjusted the band-wheels so that the teeth of the bandsaw blade were about ½" (perhaps a little more) away from the edge of the belt. The blade teeth were much closer to the belt previously. I reassembled the rest of the saw, put on and tightened a new cooks blade, filled the lubricant container, and fired it up.
The first cut was marvelous! So was the second, third and fourth. It's dark now so that was all I could do tonight. But tomorrow I'll toss on another log and see what happens.
But here is what I "think" has been happening, and yes, it was touched on earlier in this thread by GMM and Nomad both. I believe the (out of true) rails were binding the carriage as I pushed it, which caused the blade to push back against the rollers to the point that the back side of the blade rode up on the back of the roller. In this position, the blade would be pointing down and was forced to dive into the cut. As such, it would straighten up as soon as I slowed down on the cut and the blade got back into correct position.
But more importantly, with the blade being shoved back that far, the teeth were probably running against the band-wheel, compressing them into a configuration that wasn't conducive to any kind of straight cut. Once the blade was damaged to this degree, it wasn't ever going to cut correctly again, and wavy cuts were all it would ever produce from that point on. This would explain why the first cut with a new blade was always good and the following cuts were always crap.
So that's where we are tonight. I'm closer to having this figured out than I've been in a very long time. The tricky part here was that there were so many small things contributing to the problem, and not one big thing.
So fingers crossed that the saw works as well tomorrow as it did tonight.
In retrospect, it was probably just the dirty water in the lubricant tank and the new water did the trick... J/K of course. :-)
Good to hear an update from you Jim! Your decision to go back to factory default ceramic guides is a good one. You want to eliminate all the variables so that you can focus on the real issue. To risk sounding like a broken record, "That saw should cut straight without any guides whatsoever!"
You did well by straightening your guide rails but that's not where your blade issue is. Your blade diving issue is in the carriage. I'm concerned with your wheel tracking adjustment which puts your teeth 1/2 " in front of your wheel. You are now in the area where you will begin throwing blades off of your mill. I'm not worried because when you throw your first blade you will correct the alignment immediately, (yes, it's that dramatic).
Jim, I'm wondering if you have tried to over tension your blade? I mean I want you to over tension the s*** out of your blade and see if it cuts straight. Best of luck, and we are eager for updates.
(That saw should cut straight without any guides whatsoever)
If that was any where near the truth why would any saw put roller guides on? Steve
Holding my breath in anticipation, I put a pine log on the mill. And 20 minutes later I had some of the prettiest 4x8x12' beams you have ever seen !
I honestly don't know what the problem was but it appears the latest combination of adjustments cured it. Or maybe the saywer God's just felt it was time to give me a break. Either way, I am happy to be back in the action.
8)
Good to see you are happy now. If you would have the same problem again it can be more to check like this: If you are looking down on your roller guides, from a bird position, the guide rollers shafts has to point a little to the right. (Let say the centerline for guide rollers shaft would be the minute hand on the watch, it has to show "a half minute past twelv".) That means when the roller flange starts to press the blade, the friktion bladeback to rollerflange, will keep the blade up in good contact to the rollers.
As I understod you had have the problem as soon the blade starts to be dull but it cut well when sharp.
Do you get frost around your mill?
In the spring I level mine every day
Quote from: 50 Acre Jim on May 02, 2018, 09:01:11 PM
Next, I re-adjusted the band-wheels so that the teeth of the bandsaw blade were about ½" (perhaps a little more) away from the edge of the belt. The blade teeth were much closer to the belt previously.
This is very likely the solution to the diving problem. The set was being removed from the inside teeth of the blade by riding on or very close to the wheels.
Regardless, I'm glad the sawmill is back to producing quality lumber and I hope it continues to do so.
Been using the saw all day, cut a bunch of 4x8x12 beams, 4x4 beams and a slew of 2xX, all without any drama. So whatever I did when I reassembled the carrage has worked. I wish I knew for sure just what it was but I may never really know for sure.
Anyhow, i'm up and working now, and that's a good thing.
Thank you everyone for the handholding and all the help.
Jim
Quote from: 50 Acre Jim on May 02, 2018, 06:57:24 AMTheir final suggestion was to change back to the ceramic guides, which I did yesterday morning. It made a little bit of difference. I found that if I cut extremely slow, and I mean extremely slow, I can push the blade through the log with minimal waviness.
I'm glad you're cutting well now. When you said this...slowing down allowed you to cut flat, tells me that your blade speed may not be what it should be. Meaning that you may have a drive belt tension issue- slipping.
I don't know the workings of your mill. I have a Woodmizer LT15. I had some diving issues when drive belt tension was brought to my attention. I was not aware that you had to monitor that. I found out that WM had a simple tensioner tool and procedure. I checked my drive belt tension and it WAS way too loose. From then on I check it every 20 running hours or so. It's a rubber V-belt and it does stretch over time. If you have a similar drive system, Jim. You should monitor the tension every so often to prevent an issue.
Regards, Brad
Quote from: Brad_bb on May 03, 2018, 06:44:50 PM
Quote from: 50 Acre Jim on May 02, 2018, 06:57:24 AMTheir final suggestion was to change back to the ceramic guides, which I did yesterday morning. It made a little bit of difference. I found that if I cut extremely slow, and I mean extremely slow, I can push the blade through the log with minimal waviness.
I'm glad you're cutting well now. When you said this...slowing down allowed you to cut flat, tells me that your blade speed may not be what it should be. Meaning that you may have a drive belt tension issue- slipping.
I don't know the workings of your mill. I have a Woodmizer LT15. I had some diving issues when drive belt tension was brought to my attention. I was not aware that you had to monitor that. I found out that WM had a simple tensioner tool and procedure. I checked my drive belt tension and it WAS way too loose. From then on I check it every 20 running hours or so. It's a rubber V-belt and it does stretch over time. If you have a similar drive system, Jim. You should monitor the tension every so often to prevent an issue.
Regards, Brad
Thank you Brad. I have added several things to my maintenance check list and this is indeed one of them. Thanks again!
Jim