Check your top links!

[asantangini]

I use a Farmi 501 winch which has both an upper and lower snatch block. The upper block is recommended for pulling until the load is a few feet from the winch.So far this has not caused any problems for the top link or the attach point on the JD5105m.Recently I replaced the mechanical top link with a 3000psi hydraulic link but have not used it on the winch yet. Any opinions on whether this should cause a problem? Thanks.

 

[Reg]

What Spyderlk said, GOTTA use that lower pulley for MOST of the skidding in, the upper is for lifting onto the carrying chains.
Top links are little more than turn buckles, not rated for n thousand pounds of pull.

I have to believe that using JUST The top pulley could break a top link (even if you have many turns of thread engaged) ANYWAY if a log hangs up and you are on just that top pulley. It is ABOVE the top link, so there is a lever at work multiplying the cable pull - lower links are actually in compression
Using that top pulley for skidding raises the line far too high, two problems with that a) If/when something lets go the cable is going to whip around HIGH off the ground - think decapitation. b) It has the potential to pull the tractor over backwards, while your attention is on the logs coming in - depends on tractor size, winch capacity, drag, etc.

BTW, I think the rule of thumb is that THREE turns of a screw hold things together, after that more don't help i.e. when 3 strip the 4th goes then there is a cascade failure- the whole durned thing strips out.

 

[Reg]

I use a Farmi 501 winch which has both an upper and lower snatch block. The upper block is recommended for pulling until the load is a few feet from the winch.So far this has not caused any problems for the top link or the attach point on the JD5105m.Recently I replaced the mechanical top link with a 3000psi hydraulic link but have not used it on the winch yet. Any opinions on whether this should cause a problem? Thanks.

I'll "theorize" on it;
From memory the 501 boasts somewhere around 11,000 lbs line force.
If you use the bottom pulley MOST of the pull against the tractor should be shared between the lower link arms and the ground(dig in, let the tractor get pulled back until your "anchor is SET").
My guess is that the hydraulic top link SHOULD come under relatively little tension -IF you do things right (I don't always do things right).

 

[SPYDERLK]

... ... BTW, I think the rule of thumb is that THREE turns of a screw hold things together, after that more don't help i.e. when 3 strip the 4th goes then there is a cascade failure- the whole durned thing strips out.

:thumbsup: This rule of thumb is out there, but dangerous to follow w/o some critical thot. 1st note that every standard nut you find provides an engagement length approximately equal to the minor diameter of the bolt. This turns out to be about 5 threads on coarse pitches and nearer 10 on fine. Both of course include a safety factor; however it is important to note that more fine threads have to be engaged to get proper thread area. The best thumb rendition would be that length of engagement should be at least 70% of the bolt minor diameter. BUT, altho this would provide full axial clamp, or straight tension capability, it would not be fully durable to extreme off axis loading where the pull vector could shift/oscillate a bit. Hence the observed nut/bolt engagement convention of ~ 90% minor diameter. More for bolts into castings which tend to be unpredictably weaker than a Graded bolt.
larry

 

[asantangini]

Reg&Larry-thanks for your advice on the top link situation with the Farmi. I checked the 501 manual and on pages 18 & 19 they suggest using the top pulley for winching the load.When I have done this vs. the lower pulley there is far more shaking of the tractor and obviously more loading on the top link-which is why I raised the question.In the future I will be using the lower pulley since this will minimize the chances of a broken top link as well as a flipped tractor. Andy.

 

[Reg]

Reg&Larry-thanks for your advice on the top link situation with the Farmi. I checked the 501 manual and on pages 18 & 19 they suggest using the top pulley for winching the load.When I have done this vs. the lower pulley there is far more shaking of the tractor and obviously more loading on the top link-which is why I raised the question.In the future I will be using the lower pulley since this will minimize the chances of a broken top link as well as a flipped tractor. Andy.

Please don't take this personally, but I do KNOW about the Farmi manual and I have disagreed and written to them about it many times over the years.
Yes, I get that it produces a slight down force that helps dig the dozer blade in.
Yes, I get that it provides a SLIGHT up angle to the pull that helps butts off the ground.
It is STILL not worth pulling against your tractor any higher up than absolutely necessary.
They seem to ignore a natural tendency to watch the log and ignore any back tipping of the tractor.

A couple of feet higher pull point on 100 or 150 ft cable doesn't lift a butt over anything very much
but could make a big difference to stresses on the tractor and its stability.