Need help truing up and over sizing a hole in situ.

[D.sebens]

I’m redoing the bucket pins on my tractor. The tops are done. The bottoms are very egg shaped. My major dia that I measured is 1.075” and minor is 1.035. I need to make it round again. I could go up to 1 5/64(1.078) and oversize the buckets holes also or I could go big enough to put a sleeve in?

I don’t know which way would be best, I have a corded and battery hand drill. I thought about buying a mag drill but wasnt sure the if the loader arm steel is thick enough to provide enough holding power, also one arm is slightly buckled in the middle (can just make it out in the picture) and would have to flatten for the mag base.

I also wasnt sure what the best cutting tool would be. If I went with a 1 5/64” drill bit that would be really hard on the edges of the drill bit especially with it being egg shaped, i also am not sure about a reamer as it needs to go .030” larger. Maybe a tapered reamer of some sort? It I oversized it enough for a bushing a drill bit would have more engagement on the cutting face but I don’t know that I have an effective way as is to provide the force and hp to use the bit on the tractor.

Also this pin/hinge has no grease zerk. I plan on adding it to the loader arm. I don’t want to cross drill the pin a out of fear of weakening it.

I’ll attach pictures of my issue below.

 

[Nutfarmer]

There are commercial boring and welding set ups just for this type of repair work. They are way out of most of us cost range, but it may give you some ideas. What most are is shaft boring bar ( like a line boring set up on a lathe) with slip bearings welded to a stand off on each side of pin hole. A Google search should bring up pictures that will show it better than my explanation. The key is the support for the boring bar is welded directly to the machine being repaired. Good luck. The fun part is figuring out a way to do it with what we have.

 

[piper184]

+1 on the boring bar setup. On industrial equipment they often would set it up to bore both arms with a single setup, thus insuring alignment. I've never seen anyone do this kind of thing without welding the jig to the machine being bored. BUT, that is what is fast and easy for them, time is money...
For us DIY types, any kind of setup you can create to hold the cutter in alignment will be just fine. A drill will want to follow the easiest path, and wind up cutting a larger hole than expected and probably leave a poor surface finish unless you can fix up a really, really rigid holder. The mag drill idea would be a good one if you can get sufficient "stick down". Perhaps clamping a piece of plate to the loader arm?

Personally, I would drill and tap the pin for a grease fitting. You are not likely to compromise a 1" pin with an 1/8" hole down the center. Lack of grease is what caused this wear in the first place, now is the time to fix that situation. Ideally the pin is softer than the arm and will wear first as it is the easiest to replace. If you use a sleeve in the arm, try to get one that is harder than the pin. Just make sure the sleeve can' spin in the arm so this doesn't happen again.

If there is a good place on the arm to install a grease fitting where it can't get knocked off in use, and is easier to do than drilling and cross drilling the pin that is perfectly acceptable.

An excuse to buy a mag drill....can't argue with that and I would bet you won't use it only for this.

Maybe an end mill held in the mag drill?

 

[D.sebens]

The other option that one of my friends suggested is to torch the bushings off and fix them on the lathe. Then use a rod for alignment across the two bushings and weld them back on.

This thought seemed like the most intrusive at first but the more I think about it the more it seems like the fastest and best method I have on hand.

 

[Aukai]

Just a thought, but is there a way to seal/protect the grease in there? I'm thinking that grease holding sand/dirt as an abrasive may expedite any wear. I would not trust any hand held devise, one for safety, and it will never be straight.

 

[benmychree]

Thin bushings will quickly pound out, especially in a rough hole, it would be a waste of time to attempt it as suggested.

 

[D.sebens]

Well these bushings are 2.5” and I happen to have new 2.5 stock of 1045 so I will make them new with 1” pin size. I purchased(and mostly wrecked) a 2.75” carbide hole saw to cut it out. I ground down as much of the weld as I could then used the hole saw with the existing bushing as a guide. I still have some slop on the buckets connection point, hopefully I can just oversize the pins a smidge to get it firmed up in that portion. I will make the pins first so they fit the bucket then make the bushings to match the pin size.

 

[D.sebens]

Before I make a mistake, can 1045 used to make the bushing piece I cut out? I am asking because I would have to weld it on and that seems to not be recommened. What would the other option be? Would standard 1018 be fine? What the groups recommendation?

 

[Downunder Bob]

Have a look at Cutting edge engineering. This guy does these repairs for a living. Then you'll see how the pro's do it, and you can make your own mind up how you want to d it.