[How do I?] Making a bronze bushing

[T. J.]

I could use some advice on making this part. I'm restoring a Marvel #2 power hacksaw (restoration thread here if you're interested). I need to make a bronze bushing with a 1.125" OD, 1.000" ID, and 7.5" long. The length and wall thickness (1/16") have me worried. I don't know if I can bore that length accurately from one end. If I have to bore it from both ends, then I'll have to worry about crushing the thin walled part in the chuck when I swap ends. I also have a question about materials. McMaster-Carr has 932 bearing bronze and "easier to machine" 936 bearing bronze. Is the 936 enough better to justify the additional cost? Any pointers would be appreciated!

 

[markba633csi]

You might want to buy the bushing already made- check out Bunting bushings catalog- Zoro carries them
Does the bushing need to be one single piece or could it be two separate pieces? Might be cheaper if you can do the latter
Mark

 

[T. J.]

Thanks Mark. I checked out Bunting's website. It doesn't look like they have one long enough. It does need to be a single piece.

 

[francist]

Could you line bore it?

 

[benmychree]

I would seriously doubt that it needs to be full length in one piece, generally, things like that are not made like that, two bushings with a length of 2 or 2 1/2" long would likely be adequate for the job.

 

[brino]

This Southbend document:
https://www.hobby-machinist.com/resources/southbend-bulletin-7s-how-to-make-bushings.3165/
has some useful hints for bushings. Like using a mandrel to support it during manufacture.

Joe Pie has a great video about thin-walled tubes:

It works since all the cutting forces are towards the headstock, not trying to collapse the tube.

Good Luck!
-brino

 

[machPete99]

Also see what McMaster Carr has for bushings. They will also have the raw stock.

 

[T Bredehoft]

I would expect one bushing one inch long on each end would do the job, (not knowing what the job is).

 

[Superburban]

If this is the location for the bushing, no reason you cannot do two 3.25", or even four 1.875" bushings.

 

[T. J.]

Well, its a bit more complicated than that. The shaft you see there runs inside the bushing in question. Since I have the machine totally disassembled, I can’t really take a photo to illustrate the situation, but here’s a diagram. The bushing has a shaft running on the inside and the saw frame assembly pivots on the OD. So yes, it does need to be one piece.