not cutting same height

REGULAR GUY · May 18, 2014, 02:34:09 PM

I just started sawin again this year. I'm sawin 20' SYP and there is 5/8" difference in thickness/height from entering the log and the rear. All the rails on the mill seem to be level and aligned. The blade is the same height at all rails, the mill is level. I put the log on the mill, take the first cut off the top, flip it 180 degrees, and whether I level the log or not the log (bottom "first" cut is setting approx. 5/8" off the first rail?????? Every log!!! I'm thinking if feed to fast, dull blade etc. it would not be consistent, but it is. I can't figure it out. I see nothing in the book. I got a Timberking 1400 and seem to have checked all that is obvious but I missed something. Any clues ? Regular Guy

REGULAR GUY · May 18, 2014, 02:53:59 PM

Me again, don't think I'm explaining good. After I take the top cut, flip the log 180 degrees, set the blade for 10", the can't at front will be approx. 9 3/8" while the rear (back) will be 10"s, cuz the front of log (where blade starts cutting) is off the rail that much. rails are clean. This happens every log. Regular Guy

sealark37 · May 18, 2014, 02:58:22 PM

Borrow or rent a builder's level. Set it up and level it 20-30 feet to the side of the mill rails. Have a look at every point on your mill, measuring with a carpenter's rule. Then, move the saw head down the track and make sure it stays along the same height. If everything is parallel, then look somewhere else. Regards, Clark

ladylake · May 18, 2014, 03:45:17 PM

It could be stress in the logs, are the slabs bowing up when you saw, if so the log is bowing the other way and when turned from one side to the other won't touch the bunk with the bigger end touching and the smaller end off the bunk. If you want true lumber you would need to take a couple of skim cuts. One other thing is to make sure you don't have to much pressure on the center jacks, they should just touch plus another turn or 2 with the head in the center of the mill . Steve

slider · May 18, 2014, 05:04:07 PM

Sounds like stress to me.But on every log ? If you have checked the distance from each bunk up to the band then like Steve said try flipping and skimming until the cant will lay flat on all the bunks.

Nomad · May 18, 2014, 05:18:50 PM

Quote from: REGULAR GUY on May 18, 2014, 02:53:59 PM
Me again, don't think I'm explaining good. After I take the top cut, flip the log 180 degrees, set the blade for 10", the can't at front will be approx. 9 3/8" while the rear (back) will be 10"s, cuz the front of log (where blade starts cutting) is off the rail that much. rails are clean. This happens every log. Regular Guy

Sounds to me like you've got logs with lots of stress in them. Do you always flip the cant 180 for every cut? I'd only do that if the cant was moving.
If you flip the cant and the ends are raising, it's stress in the cant. If you don't flip the cant, does the middle raise up? Get somebody to stand on it while you clamp it. The stress won't go away, but the board will still be even.
I suppose I'm just reiterating what ladylake stated. And of course, the longer the cants you're cutting the more obvious the error will be.

POSTON WIDEHEAD · May 18, 2014, 05:50:32 PM

If the beds level......take a measurement from blade to bed starting off.......then run the head down the real AS IF you were sawing (without a log). When you get to the end, measure the blade height from the bedrail again...see if they are the same. This will tell you if the head is rising or falling.

Ga Mtn Man · May 18, 2014, 06:01:17 PM

Pull a tight string down the length of your mill to make sure your mill is straight.

ladylake · May 18, 2014, 06:31:28 PM

Quote from: POSTONLT40HD on May 18, 2014, 05:50:32 PM
If the beds level......take a measurement from blade to bed starting off.......then run the head down the real AS IF you were sawing (without a log). When you get to the end, measure the blade height from the bedrail again...see if they are the same. This will tell you if the head is rising or falling.

The head cant rise or fall in relation to the bunks but if there is too much pressure on the center jacks it can cause the center to hump up a bit which will result with the cant ends off the bunks on the ends when turned over. Steve

BBTom · May 18, 2014, 06:52:48 PM

Quote from: Ga Mtn Man on May 18, 2014, 06:01:17 PM
Pull a tight string down the length of your mill to make sure your mill is straight.

I second the tight string test, first empty then with a log on the bunks. If everything is right, you must have tension in the logs.

POSTON WIDEHEAD · May 18, 2014, 09:11:52 PM

Quote from: ladylake on May 18, 2014, 06:31:28 PM

The head cant rise or fall in relation to the bunks but if there is too much pressure on the center jacks it can cause the center to hump up a bit which will result with the cant ends off the bunks on the ends when turned over. Steve

If a band mill has a positioning sensor, my Woodmizer does, and it starts going bad.......the head can rise and fall......I've been through it. When mine went bad, I had a 1/4" difference in thickness before I figured out what was going wrong.

5quarter · May 18, 2014, 10:33:16 PM

5/8" out of level on every log? I don't think it's stress (at least on the logs part). A log here and there, ok. But every log? something is either not right with the saw or the blade. Make sure you mill alignment is good as others mentioned. put on a new blade. make a cut and see what happens. Make sure your sawhead is not drifting up or down while in the cut. increasing the set will also help to make straight cuts in pine. If it is stress in the logs, maybe you're slabbing too heavy. try taking smaller bites off of each side and see if that doesn't fix it.

Doug Wis · May 18, 2014, 10:58:02 PM

I 2nd the thought of too much pressure on the center jacks. I bought a new TK 1600 3 years ago. We sawed an 18' white pine while the delivery guys were here. It came out exactly like you describe. Called TK and they really didn't have an answer. said to keep an eye on it and see what happens. delivery guys setup instructions were to make ground contact with the center jacks and give them 3 more turns. I have found that by doing basicly the opposite solves the problem. That is, make ground contact with the center jacks and then back them off a couple of turns.

ladylake · May 19, 2014, 05:39:31 AM

Make sure to have the head close to the center when adjusting the center jacks. Steve

slider · May 19, 2014, 07:11:54 AM

Are some of you saying that the main frame is flexing on his mill.May be tk needs to build a stronger frame.

POSTON WIDEHEAD · May 19, 2014, 08:43:39 AM

Quote from: slider on May 19, 2014, 07:11:54 AM
Are some of you saying that the main frame is flexing on his mill.May be tk needs to build a stronger frame.

i agree.

ladylake · May 19, 2014, 09:11:30 AM

Yes the frame flexes some and so does your WM mills or any mill 25' long. There was a tread a while back of WM mills doing the same think if the jacks weren't set up right. If it didn't flex you wouldn't need jacks. We don't need to start bashing TK or any other mill. Steve

ely · May 19, 2014, 09:22:55 AM

put on an oak log and see if that does the same thing.... im betting its your blade and syp combo,
or just look and see if there is a buildup of sap/ resin on your band while sawing.
do you saw from the butt of the log or the top of the log.?

drobertson · May 19, 2014, 09:32:55 AM

It almost sound like an immediate steady constant dive that straightens itself out by the end, blade guide alignments could be the simple factor,

slider · May 19, 2014, 10:19:51 AM

I was not bashing TK at all.I think they are a good company but if flexing is the problem it should be addressed .Hopefully with closer attention to the stands.I have fixed this problem with flat bed trailers by welding a bridge under the rails.It will stiffen them up .

ladylake · May 19, 2014, 10:28:57 AM

Every 25' long mill will have flexing and the jacks need to be adjusted right when cutting long . Not a problem that needs to addressed by TK as they build stout mills. Steve

barbender · May 19, 2014, 10:34:31 AM

Blades often dive a bit when entering a log. I would check your guide roller alignment, make sure your blades have enough set, etc. Wide cuts in pine can be a bugger.

beenthere · May 19, 2014, 11:09:38 AM

QuoteI have fixed this problem with flat bed trailers by welding a bridge under the rails.It will stiffen them up .

Yes, stiffen them, but will not take out the flex when the trailer is loaded vs. when it is not loaded.

ladylake · May 19, 2014, 11:47:47 AM

I've noticed flatbed trailers with 20" or so beams arched way up empty and flat when loaded plus they bounce when loaded. No such thing as long beams being 100% ridged. Steve

backwoods sawyer · May 19, 2014, 01:28:24 PM

Guides would be the last place I would start.
I would start by moving the mill out, cleaning up and repositioning by the book then work my way up from there.

The carriage rocks the mill and if the ground under the one leg is not as firm as the rest :-\
I notice the front leg on my mill tends to work its way into the ground more then the rest. I have set the mill up in the morning and by lunch have to do a reset.

Moving the carriage on a soft set up you can have consistant measurement from the blade to the each bed rail as the weight of the carriage flexes the main rail as it moves down the length. I picked up a 20' 2x2 square tubing to check that all bed rails are the same hight, one being high will give you issues like this as well.