Priming oilite bushings with a vacuum chamber

[Jon]

This is a good place to start: Homemade Tools built by Frank S - HomemadeTools.net

[thehomeengineer]

Hi
Great idea and having the clear top to see what is happening in the chamber is great to.
On machining oillite bushes, I worked for a science research lab and we never reamed the holes due to the reamer potentially closing the pours of the material. (This is what I was told).
Therefore, we always machined the bores with a HSS tool to a bore gauge. Not sure if this was just company policy or this is the correct way to machine oillite?
The Home Engineer

[Canobi]

I ended up doing a fair bit of research and came to the conclusion that as long as the tool doing the cutting is fresh and sharp, it would reduce any smearing which would block the holes. I used a brand new reemer and indeed the vast majority of holes were visible afterward. Saying that, I don't intend to ream it next time as it's only shy by about a thou, so once it's been dropped into the pulley, I'll heat it up which should be enough to drop it on the shaft. Probably need a bit of elbow grease to loosen the pulley up after that but it'll negate any possible flaw I might introduce by messing with the bore on my old machines.

[Frank S]

I ended up doing a fair bit of research and came to the conclusion that as long as the tool doing the cutting is fresh and sharp, it would reduce any smearing which would block the holes. I used a brand new reemer and indeed the vast majority of holes were visible afterward. Saying that, I don't intend to ream it next time as it's only shy by about a thou, so once it's been dropped into the pulley, I'll heat it up which should be enough to drop it on the shaft. Probably need a bit of elbow grease to loosen the pulley up after that but it'll negate any possible flaw I might introduce by messing with the bore on my old machines.

If it is undersized before being pressed in the pulley it will be more so afterwards.be sure to used a proper sized mandrel in the bushing to press it in the pulley this will negate any reduction of ID. Some say this may not be the best practice but I like to freeze the bushing and the mandrel for several hours before pressing in the pulley. then allow them to warm naturally before pressing the mandrel out of the bushing For me it seems to help the install to go smoother and compacts the bushing slightly instead to deforming it. the bush should turn freely on the shaft to prevent the possibility of seizing and spinning in the pulley.

[Canobi]

The bushing was on size and moved freely but with no play prior to pressing it in the pulley. It was after pressing it in that I found the bore had become too small, which prompted the reeming.

I ran a very similar process to which you describe and I put the bushing in the freezer for a couple hrs, I hadn't considered turning the mandrel/press bar the same size as the shaft though, as you say, the bushing would have compressed to exact size when it warmed up, saving me an extra job and loss of precision. That's a little gem tip right there, I like it very much, thank you