Shorten Bushings, How Would You Do This?

MrWhoopee

MrWhoopee

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Jan 20, 2018
Messages
5,864
I have to shorten these little bronze bushings. They are 1/4 id x 5/16 od x 1/4 long. They need to be shortened to 3/16", sometimes 5/32". Simply grabbing them in a collet causes the ID to close up, which is not acceptable. How would you do it?

20241013_103406[1].jpg

I already have a method, which I will post later. Just wanted to see what you guys come up with.
 
If it were me, and I mean if it were me I would machine a a bar the same diameter as th bore and use that to stop the collet crushing the bush.

I have done that more than once and it saved me not only time, but having to switch chucks.

As regards @ChazzC's recommendation, the Acetal arbor is the better idea as it can be made to be a tight slip fit for the ID of the bush.
 
So I would make an expanding mandrel. I no longer believe I have to saw it to make it. Give me a minute and I'll link to a utube that makes those obsolete.
These work so nicely. can't find it. it was a SolidRock you tube video.

So you just make a normal shaft. you cut off a small piece .. you thread the shaft(internal). you then take the cut off, put a countersink in for a flat head screw. Then you split that. When it opens it will hold the piece solidly to the mandrel. It works nicely ..

Found it. https://www.hobby-machinist.com/threads/hints-and-tips.95416/post-953726
 
Last edited:
If you have a few to do...
For expanding mandrels..
 
Last edited:
I would make a sacrificial mandrel about 2" length and the same OD of the bushing. Then cut down a 3/16 length to the ID with a tight slip fit. Slide the bushing over the mandrel. Slide the mandrel and about 1/8" of the bushing in a collet and tighten. Part off the overhang. If you have to make a fair number of them, use a collet depth stop for positioning. Then you can lock down the carriage and not have to measure each piece.
 
Interesting to note the 5C collet. Since you did not mention 5C in you initial post, I assumed (wrongly as it turned out) that you were referring to ER collets, hence my comment.

As for your solution, that is exactly what I would have done had I got a 5C system.
 
Expanding mandrel or a tapered lathe mandrel .
 
Figured I’d mention this as some may not know of the material.


Fusable alloys.


www.belmontmetals.com

Low Melting Point Alloys and Their Industrial Uses

Low melting point alloys can be used in several industrial applications and products, from fuses and thermostats to molds and tube bending.
www.belmontmetals.com www.belmontmetals.com




These are great to have around the shop for milling thin walled parts like a heat sink or fixturing.

For the bushings in question, pot them in a tray of the disable alloy and mill to size.

Then a hot water bath releases them and recollects your alloy for the next use.

It will even reject most contaminants, chips, dirt, oils etc.
 
You must log in or register to reply here.
Back
Top