Another build thread... JoshNZ

JoshNZ · December 01, 2019, 02:10:41 AM

I took a few measurements of the gauges face plate and got to drawing something up on Photoshop. How cool is this ;D.

I could see the hour meter was entirely mechanical and I was able to fiddle it back to zero, so it'll count total hours of band running, why not...

I only have a monochrome laser in the office but I'll get a nice one printed in town on something decent tomorrow.

I have got a question for the experts, if I was going to put a green arc on it, where would it start and end? If at full noise out of a cut its doing 1106RPM which is 5350FPM, it might as well end there to say the gov is over speeding, but where's an acceptable place to start for bogging/pushing too fast?

Jack S · December 01, 2019, 09:05:45 AM

How about old bicycle speedometer or car speedometers cable assembly's from the old days only gotta get back say into the 80,s also farm tractor tach cables are still available.

Ljohnsaw · December 01, 2019, 01:36:15 PM

Quote from: JoshNZ on December 01, 2019, 02:10:41 AMI have got a question for the experts, if I was going to put a green arc on it, where would it start and end? If at full noise out of a cut its doing 1106RPM which is 5350FPM, it might as well end there to say the gov is over speeding, but where's an acceptable place to start for bogging/pushing too fast?

What is your engine size and band size? That will determine the sweet spot. I would do a dual scale. Larger numbers for the FPM of the blade (~4,000-4,500 preferred?) and a smaller set of numbers for engine RPM. How are you going to drive this with the speedo cable? My old 1967 Delmont 88 had a hollow front spindle that the speedo cable plugged into the grease cap for the bearings rather than the transmission. A little funky but it worked!

JoshNZ · December 01, 2019, 02:09:04 PM

It's a 22hp vtwin, standard 34mm or 1-1/4" I guess, I don't even know the set on it. 1.3tpi that sound right?

I'm still on my first one and it's still singing, been pretty happy with it considering the price!

It doesn't bog much I haven't been able to bug the engine yet. Maybe I should leave that face plate on it for now and run it for a day, see where the green arc should lie with what feels right.

Im either going to need a giant cable and run an S with big radii, to get it back to where the pressure gauge is, or I can build a bracket that hangs the gauge right off the end of the band wheel shaft, and not use any cable, just a little mini PTO shaft if you like. Will bore and thread into the back of the band shaft and machine a square on the end of it, and make the bracket bolts sliding so I can align it properly.

charles mann · December 01, 2019, 02:27:46 PM

We use colored fine point paint pens on the outside of the bezel and glass. That way a its easier to scratch off and replace in the appropriate rpm range.

JoshNZ · December 02, 2019, 04:15:02 PM

Yeah that's how this one is done, not a bad idea. That so when the well paying lifting jobs that are a little too big come in, you can shift the green arc for the pilot? ;D. I flew with a guy down south he always used to say "the only time I ever spend in the red arc is while I'm pulling through it!"

I got through the rest of the logs on my drive yesterday, glad to have the space back. I have decided a fold down extension at the head is the way to go. I tried a full length log and I've not much interest in doing it again. Don't want to lift the boards and the stack is still sitting in the rain because I can't do anything with it! Doesn't fit in my doors and too long to trolley. I'm prob going to cut it in half so I can add it to my other stacks...

Still nothing broken or amiss... That tensioning jack is spent though, I can't even get right through a cut without leaking down to no tension so it's gotta go. Not looking forward to redrilling a new one.
Tell me, do I get to be in the club with this one :D...

What causes this, is it just tension in the log or have I got some weird bed flexing or something going on? I think I was taking that cant about 1.5" above the pith

I had a big dirty native that I've been looking forward to getting around to, I ended up just doing thick live edge slabs and I think it was the right decision with how gnarly it is. It's a notoriously stable timber through drying so I hope it will behave and should yield some pretty furniture one day.

I guess everyone has to try this with their new mill sooner or later, managed to pull off a 2mm slab from an 850mm/33" log, I don't think I can complain with that. Probably not the best log to try it with, with all the inclusions in it but from what I can tell it's even all the way through

RAYAR · December 02, 2019, 04:52:05 PM

Blade tensioning, a good mechanical screw type set-up using a heavy spring for cushioning would be a good reliable and simple set-up.

Back stops, you need to design and install a blade guard that will contact your stops ahead of your blade and stop you from pushing your carriage any further until you lower your stops. Mine allows me 1/4" (6mm) clearance. Also mark your stops so you know the height you set them at.

btulloh · December 02, 2019, 05:04:48 PM

Quote from: JoshNZ on December 02, 2019, 04:15:02 PMWhat causes this, is it just tension in the log or have I got some weird bed flexing or something going on? I think I was taking that cant about 1.5" above the pith

Looks like log stress being released. Just a fact of logs, to one degree or another. Some logs have none or very little, some have a lot. Dealing with log stress being released while sawing is part of becoming a sawyer.

Old Greenhorn · December 02, 2019, 05:39:26 PM

First on your stops, yeah, if it cost you a blade, you are in, since there are photos, it must have happened. ;D

On your spring board log, I too would go with stress. Did you cut this tree? If so, was it a leaner, I find this a lot. The lean stress comes out in the cut, and then more when drying, a LOT more. If you gt the log from somebody without know the history, I would still go with stress and in any event I would have "some kind of weird twist in the bed" way way down the list because we all watched you build that mill and know it is extremely unlikely.

I like your paper thin cut, it shows what the mill can do. I did one of those last year trying to hit a particular size and threw them on the burn pile. But then I re-thought and pulled them out and used a 2' long one for a sign over the mill shed thinking it would last a month or two and curl up. It's still there a year later and the other ones I had I put on the drying skid with some weight. hey dried nice and flat. Not sure what I will do with them yet, but I keep moving them around.

Man, I would love to get my hands on one of your dirty native slabs. Nice figure.

JoshNZ · December 02, 2019, 06:00:09 PM

Haha it didn't cost me a blade. I noticed it at the end of the day, not sure when it happened. I'll have to keep trying.
I've been meaning to add the back stop guard, just want to make sure I'm happy with where everything sits first.

The tree was felled before I got there, all in pieces. It might even be a branch actually, I don't know. I'll forget about that one.

They're quite pretty huh, I actually went to the effort of painting the ends, figured they'd be worth it. I can't seem to bring myself to paint the other hundred boards =/.

I might try one more jack, identical to that one. If it didn't leak it would be perfect, I do like it, it's nice to be able to read real time tension while pushing. Otherwise I'll turn some kind of threaded jack and spring like you say.

charles mann · December 02, 2019, 08:00:51 PM

Quote from: JoshNZ on December 02, 2019, 06:00:09 PM

I might try one more jack, identical to that one. If it didn't leak it would be perfect, I do like it, it's nice to be able to read real time tension while pushing. Otherwise I'll turn some kind of threaded jack and spring like you say.

several on here have said i should use hydraulic for tensioning. i would venture to agree, since it'll take around 2800 lbs of force to tighten my blade. iv got 18" of 1.5" acme rod left, and can buy 2 more nuts, weld 1 on the rod and the other to maybe 1"-1.5" of steel. just need to find a spring, regardless if i go hydraulic or acme. the closest i can find is a 2300 lb compression spring.
as for hitting your stop, don't do that, it can mess up your blades.

JoshNZ · December 05, 2019, 05:21:04 PM

I bought a new jack, a 4T one this time figuring less pressure would be easier on things. I ended up having to make an adapter plate to get it to fit on the pad already made for the old one. Also snapped a drill bit inside the jack foot while tapping it for the hydraulic gauge. Also had to skim the edge off the top of the reservoir side to get it to clear the beam sleeve. All in all, the dread of swapping it out was well founded... And I'm thinking about trying it one last third time, with what I've learned.

The bottle jacks' cylinder, seats on a washer/seal in the cast iron foot, I think the best advice I could give anyone wanting to tap a jack for pressure would be keep your passage well away from this seat, I think that is why I'm having issues. The bottom of the cylinder is taper threaded into the cast iron foot but you could drive a bus down this thread while it's snugged up, without a perfect/clean washer it will leak. I had this idea that this seat was only to retain the balls in the check valve mechanisms - over simplifying it and not giving it enough thought. @charles mann Going back for me I'd either be looking at a ram with a seperate pump so you didn't have to touch it (tap into hose for pressure) or stay right away from hydraulic tensioning...

charles mann · December 05, 2019, 05:39:49 PM

Josh, if i go hyd, i would use a porta-power but having that bulky hand pump will make it just look gaudy. With the amount of tension ill require, hyd probably IS the best option, but i dont see the harm in trying the acme rod at first. I figure with that 1.5" rod, i should be able to manage 3000 lbs of pressure with not issues. If i cant find a spring, maybe an airbag or body mount may work.

JoshNZ · December 05, 2019, 07:28:02 PM

I was going to stick one of those small engine mount bobbins between the jack and sleeve if it needed it but it seems to go good without it. Have never seen the needle move during cutting. You probably need it even less with having more band and more frame to give, if needed.

charles mann · December 05, 2019, 07:59:52 PM

True. My carriage is very shaky. I noticed it the other day when i was manually lifting the sawbeam to max height. Granted i have NO cross bracing anywhere just yet. I will put some short (24") on the front legs, parallel to the sawbeam to help support the legs for the sawhead linear rails, then do some 36" running from the same front legs, parallel to the mill bed and aft, then go from aft legs to the front, then again 36" tying the aft legs again parallel to the sawhead. In total, 8 cross brases. Hopefully that makes the carriage more rigid.
After cranking on the motor today, trying to get it to run on its own, it shakes/rocks side to side like 10.0 earthquake. Not sure if i wanna keep and add at least 2 more rubber isolator mounts (bobbins for you josh) to help absorb some of the shake.

JoshNZ · December 06, 2019, 02:53:57 AM

Haha sounds like it's going to look like a jungle gym. I will say those two funny cross braces I did through all three planes each really stiffened the thing up, I don't get any shake while cutting whatsoever now, as opposed to quite a noticeable shimmying before they went in. Any bracing will make a huge difference of course. Not sure isolator mounts will help with wobble type movement? I don't know. Vibration and chatter maybe.

JoshNZ · January 01, 2020, 08:42:54 PM

Nothing like Christmas break to put a damper on progress of things! Happy new year etc everyone hope you've all managed somewhat of a break.

The next thing I want to do on this mill is a slab machining attachment. But I wondered if it'd be more smart to make a stand alone machine which would mean I'd have to build tracks and wheels etc again, or if I should use the carriage to support just a spoilboard spindle attachment... Anyone ever added anything like this?

Couple of projects I got tied up with leading up to the Christmas break. Some a bit crude and last minute, some I should have started a long time ago! Been good to get back into the woodshop. I'm really looking forward to using some of this timber when it finally dries!

Crusarius · January 02, 2020, 06:01:10 AM

Josh for the slab surfacer use the existing rails and make a router sled that rides on the rails. chances are it was cut on the mill once it can be put back on again. The existing clamps on the mill will hold it in place nicely.

That was my thought originally but I am not near electric so it kinda kills my idea. Really do not want a gas engine running it.

Vautour · January 02, 2020, 05:09:59 PM

I'm thinking of adding an edger on my mill that will flip down when needed .. why not use that power to edge a few boards till you squared off you logs!!!!

Crusarius · January 02, 2020, 08:11:20 PM

I need to go work with someone else to learn the ins and outs of this sawmilling thing. Then I may be able to figure out how to do that.

I typically make a 3 sided cant so I have one square edge so I can run the boards through the table saw or have live edge if thats what I want.

JoshNZ · January 03, 2020, 03:28:18 AM

I usually cut square cants/slabs too, remove from mill then replace and cut my dimensional stuff out of it. Never needs to see an edger. But then again I'm not in a rush.

Greg9504 · January 03, 2020, 09:56:01 AM

Nice build. One observation/question. You are using a steel nut with your acme threaded rod for your raise/lower mechanism. Are you not worried about galling between the nut and threaded rod? Be a shame to ruin the rods after all that machining work.

charles mann

Quotei wish i could find a bronze flange nut that didn't cost an arm and 2 toes. i think mc master carr wants $232 per flange nut in 1.5-5
thank you for the inspiration

Have you looked at Roton?
https://www.roton.com/family/acme-right-screws-and-nuts-7061240/
$90 for bronze nut + $70 for steel flange. Bit cheaper.

FWIW I think the 1.5" acme screw is way overkill for raising and lowering the cutting head. Bronze nut is rated at 11k lbs operating load. You'll have two, that's 22k operating load. While it wont save you much money you could go with plastic nut, your operating load will be reduced to 5.6k lbs each, but you run less risk of galling. If you are worried about using plastic, there is an automotive hoist made by a German company called Hofmann. It uses a plastic nut for lifts rated to 7k lbs (they do have a fail safe steel nut as well). You could save a bit more by going with a 1" rod and still have plenty of load capacity, 10k lbs for two bronze nuts. Sorry rambling now.
To JoshNZ - maybe I missed it, but would like to see a video of the saw cutting! Looks awesome.

charles mann · January 03, 2020, 06:34:37 PM

@Greg9504

I did look at roton, but there was no flanged bronze.

Greg9504 · January 03, 2020, 06:56:52 PM

@charles mann
The nut with outer threads "Acme Threaded Mount Nut", screws into the steel flange they sell. Both the nut and the flange are on the page I linked above. I use one of their steel flanges with a plastic nut for another application.
Picture from another manufacturer but same principle:

charles mann · January 03, 2020, 08:35:31 PM

@Greg9504

Gotcha!! I didnt see a all in 1 flange, so i didnt look much further. I just went with a regular steel nut and built a capturing flange, but will modify it when its time tear it down for sand blasting and paint. I bought 2 2 3/8" sockets that i will cut the sq drive off of it and heavily tack weld the sockets to the flange plate.

Not sure i have pics of it, will get some when i get back from canada at the end of the month, and post on my build thread.