3-Point Hitch Hitch Pin Torque

[reb]

Just acquired a JD rotary cutter. The lower hitch pins are relocatable, with a high position for large tractors and a low position for small tractors. I assume that the 1500D is in the latter category. The manual states the torque on the lock nuts should be 435 lb-ft. That is beyond the capability of my torque wrench. Why is the spec so high? What are the likely consequences if they are tightened somewhat less than that?

reb

 

[Ozarker]

The likely consequence is that they will loosen from vibration.

 

[JJT]

I can attest to that. The pins on my tiller are torqued as tight as my impact will go, and they have lock washers. I had to double nut them to keep them from vibrating loose.

 

[EdKing]

Do a search in the Parts/Repairs forum, and the Attachment forum, for "torque multiplier". There is quite a bit of info on using a torque multuplier to increase the amount of torque you can apply with your torque wrench.

 

[Anonymous Poster]

You can also drill an 1/8" hole in the corner of the nut and another one in the pin and then safety wire them together. I had to do this to the rear wheel bolts of my YM200B. They backed out on me 3 different times. The last time I was down to the last bolt hanging by a thread before I noticed. I posted some pictures of this in one of Roger Scotty's miscelaneous files. I think it was at the second Yanmar Yahoo club, but I'm not sure. If Roger know's where they are maybe he could post a link. Ernie

 

[roger_scotty]

Reb, I don't know of anything that uses that large of a torque, but if you do a search on the old messages you'll see that Yanmar's ability to make mistakes when converting from metric measurements is well known. I recommend that you always look up the factory torque in metric values and do the conversion yourself. And particularly when the value is so unusual.

 

[Ozarker]

Of course that didn't occur to me. Here is an online conversion calculator.

<A target="_blank" HREF=http://www.onlineconversion.com/torque.htm>http://www.onlineconversion.com/torque.htm</A>

 

[reb]

Roger: The conversion checks out.

Ed pointed me in the right direction. A post there addressed the same question. A torque multiplier will fix the problem. However, the cost would be hard to justify. If I can find a way to take them off, maybe I can get it to the local mechanic to tighten after I move them down. Or maybe I should just weld them on.

The same problem exists in the spec for tightening the blade hardware, tho. Maybe I need to submit a request to the treasurer for a torque multiplier. Trouble with that is that the associated costs (new dresses, living room furniture, sewing machines, etc) of such requests can get out of hand.

Thanx for the help.

reb

 

[hosejockey2002]

I don't have a rotary cutter, but I've got a tiller. I tightened the hitch pin nuts as tight as I could with a 12" crescent wrench and check them periodically. They've never loosened. Maybe you could just get them as tight as you can and check them often at first. If they loosen, I wonder if some Locktite might help. I don't have much experience with this, I'm just throwing out ideas.

 

[Anonymous Poster]

From time to time, I start thinking folks are overdoing it a bit when it comes to reading and implementing spec sheets.
Most likely, a set of hitch pins is never going to get reloacated after they are installed, and the only concern is tightening them up the first time, and keeping them there.
When setting up a machine, it is always a good idea to leave things a bit loose to aid assembly, and then torque them down when you're satisfied.
After torquing, a prick punch or cold chisel does a wonderful job of upsetting a few threads and prevents loosening from vibration, as well as tampering and parts borrowing.
As far as acheiving 400 ft# of torque on a thread, a 100# woman dangling from a 4 foot piece of pipe on the handle of a wrench equals 400 ft# of torque. If you can't find a hundred pound woman, adjust the length of the pipe to your body weight. Chances are pretty slim any bolt capable of being torqued to 400ft#s will break when you are hanging on a wrench handle. Dang cheap torque multiplier and readily available.