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LT 40 Pressure

Started by WH_Conley, April 13, 2010, 10:15:16 PM

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WH_Conley

Mill, 1997 LT40HD24

Problem. All of a sudden the pressure gauge starts jumping by a couple hundred pounds and the is a noticeable vibration of the sawhead.

History, everything fine til I sawed some really sticky pine, had a lot of trouble with sawdust build up under the belt on the powered band wheel, more than I have had since I bought the mill new. Now sawing oak, still getting some build up occasionally, never had that before.

Trouble shooting, changed blades several times, changed bandwheel belts, grooves are clean. Spin off side wheel by hand, bearing seems good, no sound. Take blade and belt off, put motor in gear, no vibration on the saw head. Take drive belt off and spin by hand, sounds fine.

The only thing I have found so far is the drive belt, looks new, it is the notched belt, about half of one notch is gone, hard to believe that is the problem.

Haven't had a chance to call WM yet. Anybody have any ideas?
Bill

taw6243

What about the adjustment  of the blade scraper in front of the blade guide roller?
4500 hours on my 2004 LT40HDG28, CBN sharpener and auto setter, 25" woodmaster planer with 9'auto leveling bed and trac vac chip handling system, 1998 L3010 kubota, 2010 L3200 kubota Festool TS75 rail saw with 42", 75" and 106" rails.

WH_Conley

Bill

backwoods sawyer

First thing, it sounds like a cracked saw, but you have tried several with no change or pitch under the belts and you have addressed that as well. Check for cracks in the wheels. Can you see a vibration in one wheel or both or in the drive belts?
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

Tom

It still sounds like there is something under one of the tires.  If the pressure gauge is the one for the band tension, then it is moving because the tension is changing.  That is indicative of the idle side wheel being moved, such as would happen if the band was traveling over a hump.  When there is something under the band-tire, there is usually an accompanying roaring sound.

Wipe the V-groove down with WD-40 or something like that, in case the sides of the groove are sticky.

Check both the power side and idle side grooves for a buildup.  Use a screwdriver and run it along the bottom of the groove as you turn the wheel.  It doesn't take much.

swap band-wheel tires one side for the other.

WH_Conley

Backwoods, I have not looked for cracks in the wheels, I will do so.

Tom, It is band tension gauge , I read your tutorial of "Let the Bandmill Roar".  I used a paint scraper. The grooves seem to be clean. The one thing I have not checked  is cleaning out the drill, balancing, holes to make sure they are clean.
Bill

amberwood

Grab the drive whel and give it a good shake laterally. If the bearings inside the carrier have let go it might be causing the drive wheel to whump around in an elipse pattern causing the blade tension to go up and down. MIne lasted 3800hrs and would have lasted longer if all of the oil had not snuck out.

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Chuck White

I think amberwood has it.
I believe it's the main drive bearing.

I would also put a band on and close the top sheild (for safety), put the mill in gear and go around
so you can watch the wheels and the band and check to see if any of your vibration is visible.
~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!

MartyParsons

Sounds like you have something under the belt or in the grove. If the tension gauge is moving the blade is getting tight and then loose.
If you need to check the drive bearing, the brake needs to be released and the drive belt also needs to have no effect on the bearing. Pull the clutch engaugement mid way to check the bearing. I would think if the bearing was loose the blade tracking would be effected.
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

Brucer

Check for sawdust building up in the balancing holes on the driver band wheel. If you find any be sure to clean the holes completely. It's not that the sawdust causes an imbalance -- it collects more sawdust and making a bump under the band.
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

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