The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: Joey Grimes on June 12, 2018, 08:00:11 PM

Title: Lucas slabber chain jumping
Post by: Joey Grimes on June 12, 2018, 08:00:11 PM
Iíve been having issues while slabbing when pushing the carriage in a cut thereís a vibration it sound like the chain is jumping the sprocket but it is not .I bought the 8/25 secondhand and have been replacing normal wear parts I have installed new style bar 14 tooth sprocket new drive belts all rollers gas strut.The gearbox has a leak but there does not seem to be any slack but that seems to be the area the noise is coming from. I have shimed the bar so it is plained level.
Title: Re: Lucas slabber chain jumping
Post by: Don P on June 12, 2018, 09:35:56 PM
Are sprocket, bar and chain all the same? If you have the old bar maybe mount it and see if it goes away?
Title: Re: Lucas slabber chain jumping
Post by: Joey Grimes on June 12, 2018, 10:03:10 PM
 I tried that with the same results 
Title: Re: Lucas slabber chain jumping
Post by: chep on June 13, 2018, 07:28:37 AM
I have to assume you swapped out chains? I've had an aggressive chain jump around quite a bit.
Basic but helpful?
Title: Re: Lucas slabber chain jumping
Post by: fishpharmer on June 13, 2018, 11:11:41 AM
Hate to hear your having issues.  If you donít think its the gearbox, maybe check the belts and clutch, slippage there may cause the sound. Or not.  

Drain the gearbox and use a small magnet to collect any possible metal debris.  If none, it may be okay.

Title: Re: Lucas slabber chain jumping
Post by: Joey Grimes on June 13, 2018, 04:26:08 PM
 I did replace the clutch I think it is the belts I tightened them up and it got better but I think I got them hot and they are jumping when I push into a cut they may have stretched when I retightened the muffler is almost touching the swingframe
Title: Re: Lucas slabber chain jumping
Post by: Joey Grimes on June 14, 2018, 08:18:07 PM
So my new belts stretched so I replaced them with a new set and checked the engine rpms they were 3200 I turned them up to 3600 and itís been cutting great !!
Title: Re: Lucas slabber chain jumping
Post by: Don P on June 14, 2018, 09:43:23 PM
I was talking to fishpharmer and Xlogger at the slab workshop about us smoking belts pretty easily. We overtensioned the first set and cracked them, it's easy to overtighten them. I think we went the other way with the new set and were afraid of too much tension and were running too slack.