New Holland 851 Round Baler

Mikethewannabe · Aug 11, 2010

I need to repair the double groove pulley that runs the apron chains, the set screws came loose, and the key fell out and dissappeared. Upon removing the pulley I found that the key slot in the pulley measures 5/16" toward the inside of the shaft, and 3/8" at the outer edge of the shaft. I then measured the slot in the pulley and it also measures that way.. Is this key actually supposed to be tapered? Does anybody have a part number for this key, or the actual replacement key measurements? Thanks!!!

Mikethewannabe · Aug 11, 2010

I should add that the pulley is the "driven" pulley,,the larger one..

TimChandler / S-OK · Aug 11, 2010

Mike I would suppose that the key was suppose to be a 5/16" and it has wore the additional material. You might get by getting a 3/8" square key and making it the dimensions that you have with a grinder and file. If it works tighten the heck out of the set screws and check it often. I never been around a NH 851. You could double check this key by going to external_link and check the online parts manual They even list prices and ship pretty quick. I"ve used them Hope this helps Tim

Mikethewannabe · Aug 12, 2010

Thanks a million and then some,,,you are right!! I went to external_link and low and behold, there was the key--it is 5/16" square and 2 1/8" long. I have never heard of their website, but you can be sure that I now have it saved in my "favorites"!
Thank you again

Chris (WA) · Aug 12, 2010

If you must do a patch repair like this and want it to stay together longer, stop at the parts store or hardware and get some Locktite cylindical parts bonder. Assemble it all once to make sure everything goes together ok, Make sure your bastardized key fits TIGHT. Take it apart clean it GOOD and use the locktite when you reassemble. ALLOW IT TO CURE as long as it recommends. That sucker will stay put!

Mikethewannabe · Aug 12, 2010

Thanks Chris, that is very good advice. I will definately do that!

Moline_guy · Aug 12, 2010

It was years ago when we had that pulley off to put a bearing in, and i think its a tapered key. From top to bottom anyway, unless you are talking about side to side. Any new holland dealer should have it, it has a "handle" on the end of it for tapping it in and removing. A lot of hesston machinery used this type of key also, there is a name for them but i don't recall what it is.

RodinNS · Aug 12, 2010

There are actual tapered keys that are known as Gib keys... but those are tapered for thickness rather than width. I've also never seen a gib key on any NH equipment... so I'd tend to think that the keyways are just worn.
Short of removing the shaft and having the keyway widened and straightened OR attempting to do that with a grinder and then having he pulley milled out... I'd say your best option is a 7018 rod. Weld the key to the shaft and then to the hub. Just spot it; not a big bead. You can then grind it off later if needed.

Rod

TimChandler / S-OK · Aug 13, 2010

Mike ,just a shot in the dark ,glad it helped you. I know how it feels to have hay on the ground and one of the pieces of equipment is broke. Farmers know pressure and hay is one of the most time sensitive crops. Been that way since humans started harvesting forage for wintered animals. Doesn"t matter if ya bale 5000 acres, 50 acres or .05 acres, hay on the ground is stress. Broke equipment makes it a disaster. Later Tim from the Rocking TJC

New Holland 851 Round Baler

Mikethewannabe

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TimChandler / S-OK

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Chris (WA)

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