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Need help. Split taper bushing on LT40 band brake drum. Key or no key?

Started by Delawhere Jack, April 30, 2017, 05:53:05 PM

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Delawhere Jack

Interesting failure on the mill today. Nearly finished, and the band brake drum fell off!  :o Draw bolts had sheared and the bushing worked loose. Got new holes drilled and tapped in the drum. The shaft is cut for a 3/8" key, and the bushing is the type that would except a key, but the drum itself has no keyway.

The parts manual does not list a key in this location, but I just wanted to confirm that I don't need one.

Mill is a 1995 LT40HDG24.

Thanks.

ladylake

 No key needed on a split tape just make sure to get it tight.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

paul case

Them are the kind you need to tighten and run a while and retighten.

PC
life is too short to be too serious. (some idiot)
2013 LT40SHE25 and Riehl edger,  WM 94 LT40 hd E15. Cut my sawing ''teeth'' on an EZ Boardwalk
sawing oak.hickory,ERC,walnut and almost anything else that shows up.
Don't get phylosophical with me. you will loose me for sure.
pc

Delawhere Jack

Thanks guys. I figured it didn't use one, but I wondered why they would use a bushing with a keyway and no key?

Off to fit it up. There was some minor galling on the shaft.... hope I can get it to lock up tight.

ladylake

 

Most have 3 bolts. just keep going around tightening them until all are tight and as Paul  says recheck after running.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Kbeitz

I also take a small hammer and tap the bushing in while tightening it up.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Delawhere Jack

It's going to need some more fixin'...  ::) The taper bore inside the drum galled to the point that the bushing bottoms out against the flange before it draws down tight on the shaft. I think I can mount the drum on a face plate in the lathe and cleanup the taper, then I'll face off the boss 100-200 thou and see if it will draw tight. The bushing looks good, but I'll order one from MSC just in case.

Looks like this may be grounds for a new thread on the forum.... Johnny saves the day with his lathe!  ;D

It may well take me half a day.... but I didn't have anything urgent to do tomorrow.. :)

safdchief2

I would urge "Caution" when snugging up the taper bushing. One persons 'snug' can be another persons 'too loose.' I was 'snugging' the taper bearing on the drive pulley and it caused the pulley wheel to crack!! That was a $200 fix for a new wheel. It took chatting with several folks at Woodmizer to find out the torque specs are only about 14 lbs. In all the manuals I have for my Harley's, Ford's, GMC's, Farmall's, etc., there are recommended torque specs. Sure would be nice if Woodmizer would include torque specs.
WM 1995 LT40HD OnanG24 - Farmall M - Selfmade 32" log arch - 2011 FLHTCU FFSE

paul case

One of the most important things to do when tightening a taper lock bushing is to do it evenly. Tighten one bolt only to specs for tight and you will break something for sure. Only tighten each bolt like 1/4 turn at a time and go across from each other so it pulls in evenly. Very important.

PC
life is too short to be too serious. (some idiot)
2013 LT40SHE25 and Riehl edger,  WM 94 LT40 hd E15. Cut my sawing ''teeth'' on an EZ Boardwalk
sawing oak.hickory,ERC,walnut and almost anything else that shows up.
Don't get phylosophical with me. you will loose me for sure.
pc

Delawhere Jack

Thanks, I will use a torque wrench and alternate side to side as suggested.

My attempt to save the drum failed. It was galled out something terrible at the large dia of the taper. The bushing was barely making contact at the small end of the taper. There was not enough meat left to reclaim the bore.

Turns out Johnny could NOT save the day with his lathe..  :-\ At least I didn't waste too much time trying. New part due here Wed.

MartyParsons

Hello,
  There are a few designs, The later version has the pulley and drum all in one unit. The early design had two piece design. Everyone I had apart has a key. It does not show a key for the brake drum in the manual. It does show a key for the drive pulley.


Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

Delawhere Jack

Quote from: MartyParsons on May 01, 2017, 09:17:21 PM
Hello,
  There are a few designs, The later version has the pulley and drum all in one unit. The early design had two piece design. Everyone I had apart has a key. It does not show a key for the brake drum in the manual. It does show a key for the drive pulley.


Marty

When I spoke with Doug at WM, he said the part available was updated in 1997 (?). Still just the brake drum alone, separate from the drive pulley. Maybe it is keyed, it would make sense. I'll find out Wed.


Kbeitz

If the hub was made by Browning then you could buy one with
a smaller hole.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

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