WM accuset issues or not?

delvis · October 10, 2013, 07:53:12 PM

We had WM come service and check out our LT40 hydraulic this spring and Dave said we had been making the right adjustments and everything looked good. He pulled the roller guides and checked the blade deflection and said all looked good there.

Here is the problem that has popped up: A month or so ago we were sawing 1" boards and I noticed the bottom board was 1/16" to 1/8" thin, with the 1/8" being more common.

Out came the measuring tools and we started checking the head height at various points. Keep in mind, nothing else had changed that I know of and we do a fair amount of sawing but it is still a part time venture for me. Our mill has an Accuset on it and I set it for 12" and the bottom tooth closest to the sawdust chute was dead nuts. The bottom tooth on the other side was 1/16" higher as it is supposed to be. Even with these numbers I calibrated the head at 12" and started taking measurements all the way down to the deck, At 2-3/32" the teeth were maybe a 64th" low, but nothing serious. However, when I drop down to the 1" mark the bottom tooth is at 7/8" to 15/16" low.

I fixed the problem temporarily by making the bottom board 1/16" thicker on the Accuset, but I hate not having it be right when it has been since we bought it. With this setting in the computer the bottom boards come out perfect.

I have not checked my roller guide deflection since this started happening because my train of thought is that the blade would be off at 12" as well as 1" if the guides are off. (Before calibrating for 12" that is.)

I am using 7 degree resharpened blades that I have been using right along. I am guessing that if the blade set is a little much I could be losing a fraction of an inch every time I go down and that would make the final cut that much lower based on the head being calibrated at 12". Is that thinking correct? My kerf is set at .096 which is where it has been all along. I tried bumping it up to .125 and the measurement was exactly the same after calibrating the head.

I am just trying to figure out if I have am alignment issue, a blade issue, or a computer issue. Any help or suggestions you may have will be greatly appreciated as always.

BBTom · October 10, 2013, 07:59:36 PM

I do not have an answer for you, but I have had the same issue from time to time, and then it goes away. I do not know what changed it, but I am certain that it was something that I adjusted somewhere to solve a different problem.

When you figure it out, I want to know what it is too!

Bibbyman · October 10, 2013, 08:02:51 PM

I go by the book to regulate the "set to 12". But then I verify by measuring a cant and a last board. Then I may need to adjust a smidgen.

Also, blade guides or unequal set could cause the cut to be higher or lower than what it measures from blade to bed.

MartyParsons · October 10, 2013, 08:46:19 PM

Hello,
The set on the blade tooth should not matter if you calabrate the head at 12"on the bottom set tooth on the drive side. I would suggest you set the blade to 12 1/16" then calibrate the head or push the button to make it set at 12" even though the blade is at 12 1/16". Sawdust may get between the last board or cant and the bed rail and make the cant off the bed just a little.
Another thing you may try is when you turn the log try putting down pressure on the cant with the clamp, you may break the side of the cant out if you pull down more than is needed this may make the last cut more accurate.
Hope this helps.
Marty

drobertson · October 10, 2013, 09:36:49 PM

I would have to check the kerf on the blade(s) you're using, then verify the kerf setting that is saved in memory. If, the blade is set to the bed height, and saved. It could be some stress in the cant, and it could be the blade guide changing the level of the blade as it moves in and out, this is one of those have to see things, hope you get it worked out,, david

POSTON WIDEHEAD · October 10, 2013, 09:44:27 PM

Marty has a good point. Sawdust DOES play a big role when it comes to producing an accurate thickness.
I'm very lucky that most of my milling is for barn boards.
So when my thickness is plus or minus 1/2 mile.....I'm Happy, Happy, Happy! :D

drobertson · October 10, 2013, 09:47:12 PM

So Poston, are you saying you have similar issues with board thickness on the last cut as well? And as far as this goes thickness issues in general? david

POSTON WIDEHEAD · October 10, 2013, 09:53:51 PM

Quote from: drobertson on October 10, 2013, 09:47:12 PM
So Poston, are you saying you have similar issues with board thickness on the last cut as well? And as far as this goes thickness issues in general? david

I often do....no kidding. But not very often. Sometimes the last board maybe a different thickness due to a PILE of sawdust under the head. This will affect the last board thickness.
Sap build up on a blade will affect your thickness.
But most of the time, if the last board is off, it's because a sawyer didn't start sawing at the top of the cant at the right measurement.
But all in all....my LT 40 is pretty dog gone accurate. 8)

Ga Mtn Man · October 10, 2013, 09:56:58 PM

Guys, keep in mind that he said he was measuring the blade height after each drop. Issues with sawdust and the cant bowing are not his problem.

POSTON WIDEHEAD · October 10, 2013, 09:58:19 PM

Quote from: Ga Mtn Man on October 10, 2013, 09:56:58 PM
Guys, keep in mind that he said he was measuring the blade height after each drop. Issues with sawdust and the cant bowing are not his problem.

I stand corrected.

I have re-read his post.
If I want 12 - 1 inch boards, I have to make my first cut at 12-3/4 inches. I set my simple set to saw 1-1/16 inch boards. By doing this, this makes up for the thickness of the blade.
Now keep in my.....these boards will not be exactly 1 inch but just a FROGS HAIR over. My simple set only sets to 1/16 of an inch increments. I could get the thickness closer if I had 1/32 increments.
But keep in mind also....this is sawmill lumber and my Woodmizer, mills my lumber very accurate.

Does this make cents, since, sense ?

drobertson · October 10, 2013, 10:33:07 PM

Yep, sure does, just had to know if you had a similar issue, no biggy,, I never let the debris cause an issue, a quick wipe when I notice it. It very well could be a communication error. I am dealing with an issue currently. the head will rise out of the cant without any error codes. Will be on the phone in the morning. This has been a reoccurring event through the life of my mill. Runs like a top, then hiccups, we will find it, david

POSTON WIDEHEAD · October 10, 2013, 10:39:26 PM

Do I need to bring some boiled peanuts over and see if we can figure it out? ;D

drobertson · October 10, 2013, 10:48:14 PM

Heck yea! had some Ohio Cajun ones this past week! purty good eat'n ;D the ole boy lived in Florida for a few years and converted! And made a good show of it too, I plan on calling back in the morning, I have a decent order that was to be done already, such is life, hopefully something will come of it tomorrow and be back sawing Saturday. Time will tell, worst case scenario, bucks are moving, temps are good, fall is near, and the bow is ready. Just no boiled peanuts :'( david

Ga Mtn Man · October 10, 2013, 10:51:34 PM

David,

I would have thought that your boards would be a FROGS HAIR under 1" since 1/16 = 0.0625 and your blade is close to 0.9".

But keep in mind...a Georgia frogs hair may be different than a S.C. frogs hair.

POSTON WIDEHEAD · October 10, 2013, 10:55:34 PM

Quote from: Ga Mtn Man on October 10, 2013, 10:51:34 PM
David,

I would have thought that your boards would be a FROGS HAIR under 1" since 1/16 = 0.0625 and your blade is close to 0.9".

But keep in mind...a Georgia frogs hair may be different than a S.C. frogs hair.

My blades are actually a FROG'S HAIR over 1/16 of an inch. I could get within a NATS HAIR if I had 1/32's on my simple set. ;D

drobertson · October 10, 2013, 10:55:52 PM

I have finally figured out in a few years of machining wood and metal, that a hair is the only universally understood unit of measure, regardless of color or origin. david

delvis · October 10, 2013, 11:06:21 PM

The thing that is stumping me is that I feel like I should see more of a difference in the height of the blade at the 1" mark when I make a change from .096 to .125 on the kerf setting. I realize we're talking a small amount but on a decent machinist's ruler, I feel there should be some change. Is it possible I have an issue with my potentiometer on the head?

I will be checking the roller guides to make sure they are straight and then trying to check the set in the blades. We send all of our blades to WM for resharpening and I haven't seen a problem with the set doing something like this before now.

Ga Mtn Man · October 10, 2013, 11:15:41 PM

1" above the bunks is 1" above the bunks regardless of kerf setting.

delvis · October 10, 2013, 11:39:09 PM

Quote from: Ga Mtn Man on October 10, 2013, 11:15:41 PM
1" above the bunks is 1" above the bunks regardless of kerf setting.

Exactly, but the computer doesn't know what 1" is unless it is calibrated at 12". Let's imagine a blade had a 1/2" set. If you set the kerf on the Accuset for .125, the computer is going to 'think' the set is thinner than it actually is and if the head is calibrated at 12" the bottom of the tooth at 1" is going to be quite a bit lower than that right? I'd like to be able to set the head at a physical 1" measuring from the bottom of the down tooth and calibrate it there. I have no idea if that would make a difference or not. What I do know is that up until now the mill has sawn accurate lumber to within a 64th". That is why this is bugging me.

That is why I thought that if I calibrate the head for 12" measuring the bottom of the tooth, I should see a little bit of difference between .096" and .125" at the 1" mark.

giant splinter · October 10, 2013, 11:41:00 PM

Quote from: Ga Mtn Man on October 10, 2013, 09:56:58 PM
Guys, keep in mind that he said he was measuring the blade height after each drop. Issues with sawdust and the cant bowing are not his problem.

The drop is not always uniform by the looks of things as well, have you got simple set or accuset on that LT 40 ?, If you set the bottom tooth of your blade at 1" off the deck and then step up 1" at a time with acccuset untill marking each stopping point with your pencil when you get to the top of the highest 1" board that you can get from the cant .... and then cut down through all the layout marks is the error progressive or is it irregular?
With simple set you cant step going upwards so start up at the 1' mark and mark the stopping points each time you stop then verify the marks are getting wiped off by checking it on the way down through the cutting cycle. this should help you identify the accuracy and repetitive trueness.
After that try adding a hair to see if you can find the sweet spot where the setworks registers where you need it.
I always just start at the top and set the blade so it rests on the top right where i made my last pass and go downward till I get just over an inch from the deck and then if I can get a 1" board by taking off a thin strip from the bottom board Im good, if not I have sticker material i can make when Im edging.
I hope this makes sense and helps you figure it out GS

Ga Mtn Man · October 11, 2013, 12:03:25 AM

I don't have Accuset but if it works similar to other setworks I'm familiar with then changing the kerf should have no effect on your final 1" measurement. For your hypothetical 1/2" kerf the computer would calculate the drops from the bed up as follows: 1, 2.5, 4, 5.5, 7, 8.5 and so forth.

I believe the computer does know what 1" is. When calibrating at 12" you're simply telling it where the bed is. But, like I said, I don't have accuset and I could be full of it. ;D

delvis · October 11, 2013, 12:12:01 AM

Quote from: giant splinter on October 10, 2013, 11:41:00 PM
Quote from: Ga Mtn Man on October 10, 2013, 09:56:58 PM
Guys, keep in mind that he said he was measuring the blade height after each drop. Issues with sawdust and the cant bowing are not his problem.

The drop is not always uniform by the looks of things as well, have you got simple set or accuset on that LT 40 ?, If you set the bottom tooth of your blade at 1" off the deck and then step up 1" at a time with acccuset untill marking each stopping point with your pencil when you get to the top of the highest 1" board that you can get from the cant .... and then cut down through all the layout marks is the error progressive or is it irregular?

I have the Accuset. What I noticed when measuring from 12" down, in pattern mode, every stop was right where the computer said it was with the exception of the stop at 2-3/32" being a very small amount low and the 1" mark being off between 1/16" and 3/32". When sawing a 12" board at the 1" mark the boards consistently come out 7/8" on the drive side and 15/16" on the other side.

Every other board or cant is dead on always.

delvis · October 11, 2013, 12:14:20 AM

Quote from: Ga Mtn Man on October 11, 2013, 12:03:25 AM
I don't have Accuset but if it works similar to other setworks I'm familiar with then changing the kerf should have no effect on your final 1" measurement. For your hypothetical 1/2" kerf the computer would calculate the drops from the bed up as follows: 1, 2.5, 4, 5.5, 7, 8.5 and so forth.

I believe the computer does know what 1" is. When calibrating at 12" you're simply telling it where the bed is. But, like I said, I don't have accuset and I could be full of it. ;D

GMM, I see what you're saying now. I have been looking at it backward, thinking the mill was measuring from 12" down and not from the bed up. I wonder why the Accuset doesn't have a 1" calibration setting considering this.

giant splinter · October 11, 2013, 12:23:06 AM

I added a few things to my last post but I think you guys are figuring it out and I dont think anything is wrong with your setworks, I have simple set and it works fine I also think that accuset allows you input on the kerf thickness but I'n not sure about that.
Stay with it your on the right track, also your accuset does know where one inch is and can hit it going up or downwards so look into that to make sure its showing up on your panel read out, try adding or subtracting the fractional segments to see if it will roll up to 2" and back down to 1".
Some of the stuff I mill is unpredictable,I have had to tweak my simpleset for cottonwood when it is green is like that and I find if I add 1/8th" or 1/4" when it is dry it can be very close to an inch so I try to fix that by adding a little for the shrinkage so far I have lucked out.
Delvis you are getting very close to solving this problem and if you try a few things you will figure it out. Hang tough and "Git Er Dun"
GS

YellowHammer · October 11, 2013, 01:03:43 AM

Accuset uses a very accurate positioning transducer that is calibrated at the factory. If it is working correctly then it only needs to know a single initial position to be accurate within its entire range of travel. On the housing is a number labeled "gain" which must match the gain entered in your Accuset software. If incorrect, Accuset is reading position from an incorrect calibration.

As mentioned, the saw kerf doesn't matter if you are using Accuset to get direct measurements to the bed.
YH