Blades jumping off

DARRELL1972 · August 31, 2018, 01:07:28 AM

95 model lt40 hd. Past month we have been having blades come off. Tracking is good, wheel belts replaced,bearings checked,feed rate reduced nothing seems to have made a difference. The only thing we have noticed is a loss in blade tension ( as on tension dial ). We simply can not explain said tension lose. Any ideas ?

terrifictimbersllc · August 31, 2018, 05:18:00 AM

If it has a hydraulic tensioner, those need to be rebuilt occasionally. Seals leak.. Woodmizer sells a rebuild kit.

DARRELL1972 · August 31, 2018, 06:00:51 AM

Rebuilt the tensioner last year. No sign of leakage checked fluid about 2 wks ago.

ladylake · August 31, 2018, 06:10:31 AM

Check for any cracked or broken metal on the saw head that might be moving under pressure, also broken bolts. Steve

crowhill · August 31, 2018, 07:11:10 AM

Last time I had that happen, turned out to be tapered wear on my flat solid steel band wheels and bad idler wheel bearings.

Southside · August 31, 2018, 07:45:04 AM

What did you use for wheel belts? I went the cheapo route once and had the same issue.

DARRELL1972 · August 31, 2018, 07:49:18 AM

Have tried belts from napa and woodmizer. Neither made a difference.

Magicman · August 31, 2018, 08:10:06 AM

You said that you were loosing blade tension and you probably would not see any fluid. You will have to go back into the tensioner. Check that chrome piston. It will probably be rusty/pitted and preventing a good seal. You may can turn it around but replacing it is the best bet. I would use another rebuild kit to put it back together.

CCCLLC · August 31, 2018, 10:28:58 AM

Had similar problem with bands on my lt 40. Turned out to be drive side bearing was going out. That bearing can't have any play. In/out or radial.

Peter Drouin · August 31, 2018, 12:44:28 PM

Quote from: CCCLLC on August 31, 2018, 10:28:58 AM
Had similar problem with bands on my lt 40. Turned out to be drive side bearing was going out. That bearing can't have any play. In/out or radial.

Mine has been bad for over a year now, 1/16" of play. Blades stay on. Maybe this winter I'll fix it. :D :D

ladylake · August 31, 2018, 01:18:59 PM

Most likely MM is right, I don't thinks bad bearings would cause it to lose tension. Steve

barbender · August 31, 2018, 03:13:21 PM

I've had blade breakage and tracking issues from a bad idle side bearing, but never a loss of tension. I'm with Magic👍

DARRELL1972 · August 31, 2018, 09:39:20 PM

Thanks folks I'll recheck drive side bearings again. The idle side we replaced last week. MM I was thinking might be something with tensioner I'll check for rust on that piston.

Magicman · August 31, 2018, 09:47:26 PM

Mine was slowly bleeding down. When I disassembled it I noticed the pits on the piston surface so I turned it around to get me back to sawing. I ordered a new piston and it is still in my parts box and that was 12 years ago.

DARRELL1972 · August 31, 2018, 09:56:02 PM

That could be my problem MM. I have checked it for wet spots and there wasn't any so I've been looking elsewhere. The thing that gets me is the tension will drop and then come back up. Kinda like the blade is dull but new blades do same thing. Ofcourse if tension drops to low blade comes off.

Magicman · August 31, 2018, 10:50:54 PM

Don't know about that tension dropping off and then coming back. I would say that if you loose tension because of the tensioner loosing pressure it ain't coming back. A hot blade will cause the tension to drop and then after it cools it will regain some of the tension.

I don't want to lead you off on a "wild goose chase" with your tensioner.

DARRELL1972 · August 31, 2018, 11:01:22 PM

At this point it's the only thing that makes sense. To me anyway. I'll look at that piston this weekend and if nothing is obviously wrong I'll call Georgia Monday.

LeeB · September 01, 2018, 08:58:48 AM

Is your mill stationary? What is the relationship to the sun shining on the tensioner? You wouldn't think so but it will make a difference.

Beavertooth · September 01, 2018, 10:37:12 AM

I bought a used 88 model LT40HD in 2005. The guy I bought it from had put a lot of new stuff on it and put new blade belts on also. He had cut a oak log with it and then brought it to me and we cut a couple of small pine logs with it when he brought it. A few days after I got it the blade started running off the back of the wheels and I could not figure it out. I called him and he told me to check and make sure the belts were still up above the metal wheels and sure nough the belts had settled down even with the metal and the blades just would run off the back when you put it into a log. The wheels had been used so much that the grooves were just wore out. He sent me a brand new set of wheels and I installed them and problem solved. All of this was done with the blade that was on it when he brought me the mill. I had bought a new box of blades and when I got the new wheels installed I decided to put a new blade on and when I started cutting my blades kept diving down into the log instead of going straight. I tried 3 different blades and they all were doing the same thing. So I am thinking that I got something out of whack when I installed new wheels. (Keep in mind this was my first sawmill ever, so no experience before) I call the guy I bought it from and he told me to put the old blade that he had brought back on and try it. It cut perfertly straight. He told me to check the set on the new blades and sure nough everyone of them had way more set on one side than the other. I think one side was like 19 and the other 30 something. All blades had same stock number on them. They have long since quit putting all the same run of blades in the same box so if this problem was to ever come up with a run of blades you would not have a whole box that was bad. I sent them back to Woodmizer and of course they replaced them at no charge.