Pin to bushing clearance?

[Steve in MT]

I used 1" x 3/8" wall DOM tubing when I built the pin on style quick attach for the loader on my tractor. I had to take a die grinder with a burr bit to clearance the tubing to get a 1" pin to slide through it. Obviously this is not a precision way to do this although it did work. I have been looking for a hand reamer to do this and the closest one that I could find is a 1-1/16". This reamer would make the pin to bushing clearance 0.0156. My feeble mind tells me that this is too large and that the clearance should be closer to 0.006.
Does anyone know what a good clearance fit between a pin and bushing should be? And more importantly, where in the Sam Hill do I find a hand reamer ? I'm toying around with the idea to build my own backhoe and it sure would be nice to have a faster and more precision way to ream a bunch of bushings. Thanks for your time.
Steve


.

 

[Buty]

I think if the holes line up correctly .010 would be a good clearance.

 

[joshuabardwell]

.10 should be plenty. Consider getting an adjustable reamer and then you can take it out little by little until it's exactly where you need it.

 

[yomax4]

I did nearly the same thing but I took the tube to the local machine shop and they bored it to accept 1" pins. Charged me $20.00. Another option besides a carbide burr would be a 1" cartridge roll at about 36 grit on a long mandrel. Or even a 1 1/4 flap wheel. Takes a little lomnger than a burr but you wont get the internal dings that a burr causes. Nice job by the way..

 

[joshuabardwell]

Likewise on the machine shop, but lots of people prefer to weld, then ream, since welding distorts the tube slightly,

 

[jmc]

I think 1/16 would wear and rattle.

Misc. thoughts:

Can you measure the pin precisely, ie mics or calipers?

Try inserting a feeler gauge along one side of a factory hole/pin assembly to get an idea of proper clearance.

Could your tubing be slightly oval?

25mm bar would be .985". Might work with your existing tubing and be easier to find than a reamer.

Some company must make off the shelf bushings like this for all the manufacturers.

Lastly, find a hobby machinist or vocational school and have them tweak the bushing ID in a lathe. An expensive machine shop would be overkill for such a simple job.

 

[rankrank1]

My method for non-critical fitments:
a) Carbide burr in die-grinder for roughing in. (Use the biggest diameter burr tool that I can for hole size as it helps keep it round when free-handing).
b) Sand roll in die-grinder for finishing or minimum material removal. (again use biggest diameter roll that I can for the hole to help keep round).
c) If you want to get super critical then you can use a cheapo brake cylinder hone in a drill for the final few thousands of finishing.

Obviously critical tolerance fitments should be done in the machine shop realm which I do not have.

 

[Willl]

c) If you want to get super critical then you can use a cheapo brake cylinder hone in a drill for the final few thousands of finishing.

I'm lacking a reamer in my shop and this is what I ended up using. Slow but got the job done.

 

[dkhntr04]

Ask about "repair sleeve" at your local steel supplier. I do not know the specifics on the steel alloy or brand name, but it is a much harder/tougher steel than A36 but it machines and welds nicely. It comes in over/under sizes, so if you wanted a 1" ID and 1.5" OD the repair sleeve would be something around 1.010" ID and 1.490" OD give or take. I have not mic'd it. You can weld on the tube and for the most part a nominally sized pin will still fit even with distortion. I have used it to rebush an entire FEL on a row-crop tractor, and on a multitude of other projects.

If it is an existing unit you are working on, I second the adjustable reamer.

 

[mrmikey]

If you get a 1" reamer, 1"Ø cold rolled or stress proof will fit as it's done to a more precise size usually nothing over and only a few tho under.....Mike