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Breaking Blades & Woodmizer Silver Service

Started by shopteacher, May 03, 2010, 04:06:08 PM

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shopteacher

Since getting the LT 40 super I've been breaking blades.  New blades, old blades, WM or others can't seem to find the problem.  I've gone through the alignment procedure and believe I've double checked everything to no avail.
   My question is concerning the WM field service and if it's worth the cost.  I thought the cost from the website was 295.00 for the silver service, but received a brochure that states it's 445.00.  It seems a strange way of pricing and somewhat confusing to me.  Seeing as how this is more a hobby than a job at the current time is it worth 500.00 to have the mill looked at?
Proud owner of a LT40HDSE25, Corley Circle mill, JD 450C, JD 8875, MF 1240E
Tilt Bed Truck  and well equipted wood shop.

Tom

I don't know about their field service, but if you are breaking all of your bands, it bears your studying it some more.  Take a look at how many board feet you are producing and see if you might not be expecting more from your band that it can deliver.

Examine the broken band for other breaks.  Breaks on the back of the band may indicate that the guides are too far back from the band. Breaks in the gullet might mean that the blade is riding on the guide flange all of the time.   Breaks at the bottom of the tooth might mean that you are pushing the head too hard.

It might be that your bandwheels are not co-planer. 

These things can all be checked by you for nothing.

Sometimes it just takes another set of eyes.  If you have another Wood Mizer owner close by, invite him to watch you saw for a while.

When I first bought my LT40, I took it to Newnan, Ga for a going over.  It was an enlightening process and I learned a lot.  There were some things wrong that I never would have found on my own. (broken and bent head-frame parts on the idle side.)  So, you might not have caused the problem and not have the experience to find it.  I didn't even know I had a problem.  Had not run the mill yet.

Steve_M

Shopteacher,

I have had issues two times with frequently breaking blades on my WM.  Both times I had a guide roller bearing that had gone bad and was putting excessive heat into the blade--this lead to loss of tension---I would add tension---then POP.    New guide roller problem solved.  Might not be your problem, but something to check.

Steve
2001 WM Super LT40 Electric and WM Twin Blade Edger, just a part timer custom sawing and cutting salvage logs.

Bodger

Most every time over the years I've had a problem w/premature blade breaking it has been due to problems with the sharpener.   Blade maintenance equipment needs to be checked, cleaned and re-aligned on a regular basis.   Little things like the screw on tip of the dial gauge of the setter will work it's way loose and give a false reading of the blade set.  The setter clamp will clog and not hold the blade tight enough causing an irregular grind.  I have sent short sections of blades to WM for inspection only to find out it was not the blade but the guy who sharpened it...pilot error.  That is one great advantage of using their blades, good tech support. 
Work's fine for killing time but it's a shaky way to make a living.

sgschwend

Can you tell us how old the mill is, how many hours, are all those moving part original?
Steve Gschwend

sjgschwend@gmail.com

ARKANSAWYER


  Belts on the wheels.  Most of the time when my belts get worn I will break several blades in a row.  I go through about 4 sets a year on the LT 40 and 3 on the LT 70. ( I saw a lot) Guides rollers are the next thing to look at.  Also look at the pads below the blade at the guide rollers.  You should be able to slip a business card betweem them and the blade when the blade is tight.
ARKANSAWYER

Chuck White

Quote from: ARKANSAWYER on May 03, 2010, 09:32:27 PM
  Belts on the wheels.  Most of the time when my belts get worn I will break several blades in a row.  I go through about 4 sets a year on the LT 40 and 3 on the LT 70. ( I saw a lot) Guides rollers are the next thing to look at.  Also look at the pads below the blade at the guide rollers.  You should be able to slip a business card betweem them and the blade when the blade is tight.


I agree, it's pretty likely that the blade wheel belts are worn thin.
With a blade installed and tensioned up, you should have near 1/8" clearance between the blade wheel and the blade, if not, change the belts.
~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

Kansas

I agree about the belts on the wheels. For the price of two belts, its cheaper than a blade. And for the LT 40, you can get those local.

Bibbyman

Quote from: Kansas on May 04, 2010, 07:30:14 AM
I agree about the belts on the wheels. For the price of two belts, its cheaper than a blade. And for the LT 40, you can get those local.

Better use belts from Wood-Mizer (on a Wood-Mizer) because they're made special by Goodyear with flat instead of crowned outside surface. 
Wood-Mizer LT40HDE25 Super 25hp 3ph with Command Control and Accuset.
Sawing since '94

Kansas

Bibby, I never knew that. All those years I just called the local parts store.

shopteacher

Thanks for all the replys and ideas.  This machine has 235 hrs on it and has been breaking bands since I got it. My old LT40 would run the bands till the teeth wouldn't hold a sharpening any longer.
I have replaced the belts and checked the guide rollers, which seem to be good.
I went through the alignment procedure last fall and that did seem to help a little, but not to the point of what I'd think is normal run time before breaking.
  The band seems to have a lot of cracks in the gullets when they break. I've tried the B57 and B56 belts and neighter seemed to work any better.
   I'm currently laid up with a back problem and can't get out to do much, but soon as I can I'll look to see if any of the suggestions or problem described are visible.
Thanks and glad to have a fine group to fall back on .
Proud owner of a LT40HDSE25, Corley Circle mill, JD 450C, JD 8875, MF 1240E
Tilt Bed Truck  and well equipted wood shop.

Bibbyman

I noticed you have an E25 mill.  Are you clutching between cuts or when you turn/clamp, etc.? Or are you keeping the blade running?

If you're running the blade all the time, you are stressing the blade more than if you're clutching or turning off the motor.

Two schools of thought on this.  I do three.  If I'm going to make another cut real soon,  I keep the blade running.  If I pause for maybe 30 seconds,  I clutch.  If any longer,  I'll turn the motor off to keep from scorching the main belt.
Wood-Mizer LT40HDE25 Super 25hp 3ph with Command Control and Accuset.
Sawing since '94

ARKANSAWYER


  When I got the LT70E25 we were breaking blades all the time.  I went to 0.045 blades and it helped some but could not cut as fast.  On the LT 70 you could not shut the blade off once started with out turning the key off.  Then you had to wait for the accuset to reboot.  So I wried the thing up so I could turn the blade off with out turning the key off.  Now we do not break many blades.  If we are not going to be making cuts back to back then we trun the blade off and restart at the next cut.  We are back to 0.055 blades and cut about 700 bdft an hour.
  So like Bibby asked, are you letting the blade run alot?  If so, it will break them before they get dull.
  I buy my LT40 belts down town at the parts store.  They are cheaper and last as long.  The blades ride on them just fine on Wanda and more often then not they get pulled becasue a blade breaks and cuts them.  You have to remember we saw over 300,000 bdft a year on her.
ARKANSAWYER

shopteacher

I usually let the blade run.  I never thought about it over stressing the blade.  Just goes to show how great it is to be able to ask questions and get answers from experienced sawyers.
Thanks again guys.
Proud owner of a LT40HDSE25, Corley Circle mill, JD 450C, JD 8875, MF 1240E
Tilt Bed Truck  and well equipted wood shop.

Chuck White

The way the Wood-Mizer guys in Hannibal described common blade breakage, was like taking a piece of wire and bending it back and forth continuously, and after a while the wire will break.

The blade on the mill is continually bending and straightening, so after so many times, it will break.

I always stop my blade before returning the saw head to the front of the mill.

~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

Bibbyman

With the electric motor there is a trade off of blade life or main drive belt life.  The main belt would probably last forever if left running all the time.  But you'll break blades sooner.  If you break every cut like you would with an engine, then you'll burn the belt more but save the blade.

The main belt is more tedious to get just right between tight enough and still not burn when the clutch is applied.  It's also hard to know when the belt is slipping under load as you can't hear it.

I think the later model LT70s don't even have a clutch.  They intend to turn the motor on and off.

Have you re-tensioned your main drive belt since you got the mill?  

I think the manual says after the first 50 hours.  I've always had to re-tension a new belt a couple of times in the first few hundred hours.  After that it will work pretty good until dead.
Wood-Mizer LT40HDE25 Super 25hp 3ph with Command Control and Accuset.
Sawing since '94

John_Haylow

Have you had the mill back to  Wood-Mizer, or has this been over the phone? If not I would take it in to them and have them go over it. It will save you time and much easier for them to diagnose the problem.

John
2004 Wood-Mizer LT40HDG28

shopteacher

Bibby:  I haven't adjusted the main belt and left the blade run due to smelling rubber burning. I'll adjust the belt first chance.

John_Haylow: Mill is stationary
Proud owner of a LT40HDSE25, Corley Circle mill, JD 450C, JD 8875, MF 1240E
Tilt Bed Truck  and well equipted wood shop.

Bibbyman

Unless they've made some updates on the newer models (ours is a 2002),  adjusting the clutch/break so that the belt is tight enough but will disengage loose enough not to burn and yet have the break hold is pretty "persicular".   It's not on the top of my most fun things to do.

One trick I try is to move the motor over a little bit for fine adjustments after a new belt is broken in.  Note, this won't work unless the clutch break is working in the right range.  1/16" of an inch at a time is usually plenty.  Move the motor to the loader side to tighten the belt, to the rail side to loosen. 

You can get a gauge to measure the belt tension.  It's a little cumbersome to use and I scratch out a lot of hair figuring out if I'm using it right.

Also,  Sooner rather than latter, you'll need to change out the main belt.  They (Wood-Mizer) make one specifically for electric motors.  I had got one by mistake that was intended for an engine rather than a motor.  The length and otherwise look the same.  But I fought with it for a good little bit until Sparks came up with checking the belt part number.
Wood-Mizer LT40HDE25 Super 25hp 3ph with Command Control and Accuset.
Sawing since '94

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