The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: 47sawdust on June 12, 2016, 07:38:37 PM

Title: WM split tapered bushing/drive sheave bolts sheared
Post by: 47sawdust on June 12, 2016, 07:38:37 PM
The bolts that attach the bushing to my drive belt sheave sheared right off.The mill is a '97 Lt30.The  bushing and sheave are less than 2 years old.I installed them myself.
What did I do wrong? 100 hours sawing time since installation.
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: Kbeitz on June 12, 2016, 08:01:11 PM
Most bushings are keyed to the sheave ...
Are you missing a key?



 (https://forestryforum.com/gallery/albums/userpics/39553/Keyed_bushing.jpg?easyrotate_cache=1465776838)
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: elk42 on June 12, 2016, 09:00:22 PM
Kbeitz
I think Browning flange type taper lock bushings are the only one that has a keyway
in the taper fit. T B woods does not.
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: Ga Mtn Man on June 12, 2016, 09:06:37 PM
Sounds like you may not have gotten the bolts tight enough allowing the bushing to slip and shear the bolts off.
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: derhntr on June 12, 2016, 09:07:41 PM
Ouch sounds costly
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: elk42 on June 12, 2016, 09:29:47 PM
 47
Be sure that the shaft and taper is very clean of trash sawdust and fretting corrosion if
so file and sand to clean.Use the torque value for the screws and check pulley for wobble
with dial indicator.
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: 47sawdust on June 13, 2016, 07:04:24 AM
The key and the bushing are intact and where they should be.I will pull them this morning.I might be able to get the sheared bolts out of the sheave,get new hardened bolts ,clean everything up as Elk suggested,and put it back together.
Thanks for your help.Mick
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: ladylake on June 13, 2016, 09:09:54 AM
Quote from: Ga Mtn Man on June 12, 2016, 09:06:37 PM
Sounds like you may not have gotten the bolts tight enough allowing the bushing to slip and shear the bolts off.

  Yes, when tightening those bolts you have to go around several times, there is no key on the taper.  Steve
Title: Re: WM split tapered bushing/drive sheave bolts sheared
Post by: sealark37 on June 13, 2016, 11:26:23 AM
If you have a local Caterpillar dealer, purchase their grade eight bolts.  Assemble as above, then re-torque after an hour's sawing.    Regards, Clark