The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: terrifictimbersllc on December 29, 2010, 06:47:14 PM

Title: Drive belt stretch
Post by: terrifictimbersllc on December 29, 2010, 06:47:14 PM
Wondering whether anyone drives around with the sawmill drive belt tight (engaged) and when this is really helpful.    Let me explain......

For many years I engaged the engine after packing up the mill (tight belt) on my LT-40/42Hp Kubota prior to road travel.  Sometimes would forget to disengage when I got home.  Don't remember where I read to do this which was a move to prevent the engine from bouncing around.   Had my first drive belt change at about 725 hours.  Would make belt tension adjustment every 10 hours or so to keep the right tension.  The squeal of a slipping belt was usually the alarm.

More recently in the last 100 hours I've not been engaging the engine for travel, and I have noticed a substantial lengthening in the time between drive belt tension adjustments.   Maybe at least 5 times longer, probably haven't had to adjust it in 50 hours now.

Title: Re: Drive belt stretch
Post by: tyb525 on December 29, 2010, 07:00:45 PM
The engine has it's own supports, I can't see how keeping the belt tight would help anything. A drive belt can stretch under constant load, albeit slowly. So keeping it tight would cause it to stretch some.

Also, like a band blade, it can hold its shape when stationary for a length of time.
Title: Re: Drive belt stretch
Post by: Chuck White on December 29, 2010, 07:17:01 PM
In the book, it says to engage the engine drive belts when in travel to prevent the engine from bouncing.

I engage mine when traveling most of the time.  Also, my travel is rarely over 15 miles and then I disengage the belt!
Title: Re: Drive belt stretch
Post by: Peter Drouin on December 29, 2010, 07:24:21 PM
I would not travel without the engine engaged, I don;t think it will hurt the belt or stretch it out,but you have to keep it adjusted,when I gut my mill and I didnot keep it up and it split in half ,put new one on 150 hrs later again in 1/2,well this is expensive call to WM toll me to keep  it tight check it 50 hrs or so, ok now,  :D :D :D
Title: Re: Drive belt stretch
Post by: ladylake on December 29, 2010, 07:39:21 PM
I've got around 8000 hours on my mill now, I replaced the first belt after 5000 hours when I put the diesel on, I had to run a lot more tension on the old belt to keep it from squeling and I still had too run about the same tension on the new belt. The diesel just had that much more torque.   Steve
Title: Re: Drive belt stretch
Post by: Peter Drouin on December 29, 2010, 08:13:58 PM
 :D :D ya my 51 horse cat has torque and with the 7s ,keep the belt tight :D :D 8) 8) 8) ;D ;D ;D ;D 8) 8) 8)
Title: Re: Drive belt stretch
Post by: tyb525 on December 29, 2010, 09:26:10 PM
I stand corrected, the way my mill engages the engine is different from the bigger mills.
Title: Re: Drive belt stretch
Post by: Brucer on December 29, 2010, 09:36:30 PM
I always travel with the clutch engaged (not that I travel much anymore). Forgetting to disengage the clutch led to a few nasty surprises -- like firing up the engine with the clutch still engaged.

I solved that problem with a little "mistake-proofing" trick. I wrapped a red plastic bag around the clutch lever whenever I was traveling, and that was my warning that I had to disengage the clutch first. When I switched to the auto clutch, I wrapped a piece of red electrical tape around the switch for the clutch.

This didn't help me remember to disengage the clutch as soon as was off the road, so I also got in the habit of wrapping a length of red tape around the hitch lever. As soon as I went to unhitch the mill, I'd remember to release the clutch.
Title: Re: Drive belt stretch
Post by: sparks on December 30, 2010, 10:27:54 AM
The old belts we use to sell were standard rubber belts. The new ones have Kevlar in them for better durability. We recommend the belt it tight when towing so that the engine does not bounce around. A lot of belt manufacturers are going to Kevlar.
Title: Re: Drive belt stretch
Post by: pyrocasto on January 09, 2011, 10:29:41 AM
My engine is bolted down so  bouncing around isnt a problem. I leave the belts loose all the time, and the "clutch brake" will hold the belts there when towing. Spring loaded clutch and kevlar belts so stretching wont be a problem. I guess it depends on the setup.