Sloppy Keyway in Sprocket

I recently bought a New Holland 630 round baler sight
unseen on an online auction. It has several sloppy
repairs I need to fix. The first is a couple sprockets
have sloppy keyways. Does anyone have a fix besides
buying a new sprocket or re-keying? This one is the
worst. Thinking about getting new keys and applying
Loctite retaining compound. Maybe putting in a set screw
above the key.



If anyone has one of these balers, I could use pictures of
a couple specific areas.

A machine shop can weld up and rebroach the keyway, but the key socket may be as damaged. Remaking the socket to a larger size and rebroaching the hub is one option, milling the shaft for a full length square key is probably least expensive. Then reassembly with Stud and bearing mount LockTite. Jim

If sprocket teeth are worn as bad. Probably more economical to replace sprocket.

If the bore fits snug, take it to a machine shop and have them cut new key ways on the opposite side.

Is the shaft keyed the full length of the sproket bore? If so, just put a full-length key in, drill and tap a set screw or two over the key, and use what Jim suggests to set it in place.

I doubt the Loctite or added set screw will be very effective for this repair. Is the key way in the shaft full length or is it a woodruff/half moon key. If full length you could just get a piece of key stock and cut a full length key. Then the unworn section of the key way would carry the load. The weld and broach approach suggested would probably be cost prohibitive but I may be wrong. There may be a possibility that the hub could be re-broached at 180 degree from the original key way. If the new sprocket is crazy expensive from the manufacturer there are universal sprockets that may be less expensive but they require a welder. A hub is chosen to fit the shaft and then a proper tooth number and chain size is selected. Then the two are welded together. However, factory centering and hub side spacing has to be considered to utilize these, see link for an example I have not personally used this company. Many implement and farm stores carry these. Hope the price you paid for you baler online sight unseen reflected the fact that the machine required some repairs. This is a factor that should always be considered on these types of bids.
Weld on sprockets

By the texture, it seems the sprocket might be cast. You could braze and re-broach, but good luck welding it up.

X2

This bore of the sprocket shows wear also ,so that has to be corrected. Or keyway work Is for not. Also shaft has to be corrected .
Cant have that sprocket sloppy on your shaft.

If you have room for it I would change out to a taperlock bushing and sprocket. You will never have to worry about it again.

I'll second the Taperlock or QD bushing sprocket.

That will get you a fresh bore and good keyway, plus tighten down securely on a less than perfect shaft.

Shaft only has a woodruff key. I like the idea of milling the shaft for a full length key or re-broaching the sprocket. The sprocket has two sprockets on one hub. New one is $250-350. Not sure which is which in the diagram yet

a setscrew over the key will tend to lift the sprocket keyway off of the key. if you d/t the set screw 180 from the key, when you tighten the setscrew, it will force sprocket tighter to shaft at keyway. setscrew over key is to hold key in place. good luck with your project.

I go with a taper lock bushing as Steve suggested. Does the hub have enough meat in it to allow machining for a taper lock bushing?

I would just weld the sprocket to the shaft. If you have to change the sprocket cut the weld with a dremel cut off wheel and weld another one on there. When equipment becomes worn out you have to do whatever is neccessary to get it working for the forseeable future. Don't worry about hurting the value of it.

Weld is probably how most farmers would approach that fix. The downside it's a "one and done" fix.

Around here we don't have any problems spending other people's money. Just get a new shaft and a new sprocket and fix it right for the next guy. Ignore the fact that the baler is on its last go-round...

If you're decent with an angle grinder and death wheel you can cut your own keyway in the shaft right on the machine.

On the sprocket I'd file the keyway out to the next size wider, or at least get it straight, then custom file a key to fit everything tightly.

That's what I did. Decades ago I had just started baling a 25 acre field of hay when a sprocket on my NH 855 baler spun. I really needed to get this field baled so I went home and after sizing up the situation I decided to weld the sprocket on the shaft. (I had done this on a NH haybine and it held for several years until I was able to fix it right). I went back to baling the field way in the back of the farm. Shortly after I could not see my buildings, but I saw a big black cloud of smoke coming up in that general direction. I thought holy crap I had set my machine shed on fire! We had just purchased cell phones so I was able to call my wife who was home from work to go quickly and check the machine to see if it was on fire. Thankfully it was just a neighbor burning a big brush pile. My heart was pumping pretty hard for a while !!! The weld held many more years with no problems. The weld is still holding on that baler down in the machine shed.

I think I will broach a new keyway into the sprocket. The shaft side seems pretty decent. Toss a new key in and see what I have. I would rather not pull the shaft if I don't have to.