New Wood Mizer cut tolerances

Crhall · May 11, 2017, 08:50:37 AM

I just bought a new Wood Mizer LT15 wide. I ran into a pretty big job to resaw a bunch of 1" boards down into 1"x1". So i sold my old lt15 gas and got this wide one that is electric. This could be a long term thing so i wanted electric in a building. This will be my first time really running a mill hrs and hrs day after day, ( should say my workers, not me) My old one was strictly for personal use. I mainly use to cut up logs, then ran through a wood planer for my own use. So some slight "wave" in the cuts were no big deal. With what i'm doing now, i want them to be as straight as can be.

I've been talking to WM, at least 10 times now about making sure everything is adjusted right. I've went through all the checks and got it best i could. Drive belt tension, roller adj, blade tension, new blades 9* & 10*, and slow speed. I've tried to get someone out to make sure they fell i got things set right as well, but WM is 2.5 weeks out.

So right now i've noticed that running full width will effect it some, seems to move a bit more "jerky" and maybe few more deeper waves in it. (it does have auto drive) if i run it down to 18" wide or so, seems be bit better. as one would expected even though WM keeps telling me i should be able cut full widths. So my question is, how much of a cut tolerance do you guys fell is normal on these machines? Meaning if you lay a 6' straight edge across top, What size gaps underneath are normal if any? Right now i'm just under a 1/32" (about 0.021) Thats on a 18" wide cut. I have yet to check a full or 28"ish cut exact, but i know it was closer to 3/32 gaps. Do you guys feel this is pretty normal with band saw? BTW the wood is mostly ash. Thanks

paul case · May 11, 2017, 09:08:26 AM

3/32 is almost 1/8'' and might not be noticeable until you put a straight edge on it.

For me it all depends on what the lumber will be used for and that customer's tolerances. I do know that when I went from a manual feed mill to a auto feed mill there was quite a learning curve to figure out when to change the band and how hard to push it. The Woodmizer competition sawyers had an article in the WAY that told how they judge how hard fast to saw and it had to do with the band sliding sawdust out on the top and bottom of it in the cut.

Bands are different and the hardness of the wood and dryness affect their cutting ability greatly so There are many things to consider. Me? I would put on a new band and see if it cuts more accurately when I get waves. I can usually tell dullness before I get wavy cuts. The band may rise on entering the log and fall off the other end. Or I have seen a dull band cut ok but bounce forward when exiting the log.

Going from gas to electric power also will be a learning curve as you could tell when the gas motor luggs down and the electric doesn't sound slower. You do not want to be slowing the band speed when in the cut as that can cause waves also.

A new band should cut a 18'' wide cut real true, If it doesn't you may have an issue.

Happy sawing and congrats on the new mill. I sure like that electric, and I think you will too.

PC

woodworker9 · May 11, 2017, 09:32:13 AM

I don't know if this is part of the equation for you or not, but another issue to consider cutting small pieces like that is that wood is organic, and it moves. Cutting boards off of a log releases internal stresses that have built up in the tree, and this along could be accounting for some, if not all, of your the deflection you may be seeing.

If you are absolutely certain that your issue is due to a blade dipping and diving, then you can disregard what I'm saying. I just thought it might help to mention wood movement.

I hope you can work it out. One certain way to do this is to overcut and plane to size, but boy oh boy, that would add a lot of extra work to the job, and probably make it not worth doing.

GAB · May 11, 2017, 09:51:30 AM

You might want to experiment with the blade tension. 500# higher can make a lot of difference in some material.
Also knots can cause blade wave.
Gerald

Ga Mtn Man · May 11, 2017, 12:13:53 PM

I would try a 7° or 4° blade. I think you will be surprised at the difference it makes.

Crhall · May 11, 2017, 01:16:46 PM

I tried added blade tension, and i do think it helped. i may even go more. Guy at WM said its hard to make them too tight, he clams the bearings will hold up to it long term. Maybe i should of ordered some 7* or 4* to try, but i was going off what wm guy said to get for what i'm doing. now i have box of 15-10*'s and 15-9*'s. We are playing more with it today,

Percy · May 11, 2017, 02:38:49 PM

In addition to all that's been mentioned here, you may want to try increasing the set of your blades. I can cut a Sitka spruce(miserable) full width on my lt70 with no deviation. I achieve this by running 38-40 thou. set on my blades. Just a thought b

ladylake · May 12, 2017, 05:58:16 AM

Those wide cuts in hard wood are going to be tough no matter what anyone says, as GMM says try a 4° blade. Plus try not to cut wide if possible. Steve

Crhall · May 12, 2017, 07:28:16 AM

Would my travel speed have to be slower with the 4*? I can't go much slower than i already am with the auto feed, running so low of hertz as it is now, the motor hardly wants to run. WM swears up and down its ment to make good cuts at 24" wide. Has any of you ever checked your cuts with a straight edge? 0.021 is pretty dam thin and you can hardly notice it unless you run your hand very fast across it, i can feel it slightly. I'm just worried about when blade starts to get the new worn off, it starts waving worse. I can't be changing blades every hour, to me thats just not going to be worth it. The way it looks now if i can get 1 day out of a blade, that would be a goal to shoot for. I've got maybe 3hrs of actual run time on this blade, and i can noticed it is not traveling as smooth, its getting pretty jerky feeding down the track. The first day i ran it i swapped out 4 blades trying to get good cuts

Magicman · May 12, 2017, 08:23:48 AM

Quote from: Crhall on May 12, 2017, 07:28:16 AMits getting pretty jerky feeding down the track.

Jerky feed rate is a sign of a dull blade.

Den-Den · May 12, 2017, 08:34:10 AM

Expecting a single blade to make wide cuts for a whole day is not realistic for carbon steel blades, I do not know if bimetal blades could do this.

Jim_Rogers · May 12, 2017, 10:34:36 AM

In your first post you said you have to make 1" x 1" pieces.
You could saw a big one in half or less and then you won't have that much span between the blade guides. Shorter is easier to hold true.

If accuracy is your goal then make it easier for the mill do to do it by shortening the distance between guides.

I don't believe you've mentioned what type of wood you are cutting. Or why you need such a tight tolerance out of a rough sawing machine.

Jim Rogers

4x4American · May 12, 2017, 10:54:43 PM

I agree with many of the above, and might add that if you want to run one blade all day, how about trying one of WM's new carbide tipped blades? I believe they are swadge blades so they should leave a smoother finish and a guy on the facebook said he was able to saw 6mbf with one blade before it got dull. They are much more expensive but maybe it's worth it. Couldn't hurt to try.

4x4American · May 12, 2017, 10:57:02 PM

If you're resawing 1" boards into 1x1's maybe just don't have 18 boards up there at once? Or maybe you'd be better off with a gang ripsaw.

GDinMaine · May 13, 2017, 07:41:08 AM

Did you try a different log or this is only one? If your motor has enough HP, try 7s or 7 turbo blades. Ash can be temperamental.

killamplanes · May 13, 2017, 08:17:13 AM

Jerky blades is also a sign of to much blade, I would venture to say drop to 4 or 7 and you might gain feed rate...

Crhall · May 15, 2017, 08:49:37 AM

I've looked into gang saws, my one problem is i don't have enough power to run one. They have large motors, (25hp) i'm running all my 3phs off of converters and i'm about maxed out. Eventually i will add more power, and look into buy a gang saw. I've got the saw cutting pretty well now i think. it doesn't need to be a perfect cut by any means, but i just always try and do best i can, or run machinery to the best of its capabilities!
I just wanted to check with you guys to see where your tolerances are when cutting. I've been through lots of boards now, few blades. and i think the end product will be just fine.
Again main reason for this topic was to see where you guys are at when sawing, how close to perfect can you get. One thing i might add, i worked with metal my whole life. Its very precise. I always tell wood guys, "when i buy 2x4 sq tubing, it measures 2x4 lol :D! So this whole wood thing is a bit different for me. I'm not going to be the one running these machines, so the tolerances in cuts will only be as good as the workers i have hired. But i just want to know the machines capabilities. I'm going to look into some of these new blades that are out there, maybe try few see how they work

Andries · May 16, 2017, 12:22:29 AM

Quote from: Crhall on May 15, 2017, 08:49:37 AM
. . . I just wanted to check with you guys to see where your tolerances are when cutting. . .
Again main reason for this topic was to see where you guys are at when sawing, how close to perfect can you get. . . . But i just want to know the machines capabilities.

Sawmills produce "rough" lumber.
Dried lumber is brought to final size by jointers, planers and woodshop based machinery.
So, after doing my Spring alignment and tune up, it was time for a test.

A limber piece of wood.

Andries · May 16, 2017, 12:32:05 AM

My LT30 is a 1992 model, with extensions of more than 50 feet.
My timber frame crew likes to try to push my buttons but letting me know that I was off by 3/32" on that last 50 footer.

If possible, getting as close as I can without getting stoooopid about it, is a fun way to see how well dialled in the mill is.

12" wide 21' long 2mm thick

The break in the cut is where the 12' extension meets the mill - get a wee jump there.
I can live with that.
Close enough for the kids I play with. ;D