Bushings for Pipe Roller Jack Stand

[garybdavis]

I'm in the process of making a couple of pipe jack stands. Instead of the standard "V" heads, these are going to have two 1/2" x 4" disc type rollers. I've turned them on the lathe already but want to press in bronze bushings instead of just driling a hole in the steel disc.

My question is this: What size should I drill/ream/bore the hole in the disc roller? The bronze bearings I've purchased are 3/4" OD and 1/2" ID. I've already drilled 1/2" holes in the frame for the pins and the bushings slide over them quite nice. However, I need to press in the bushings so they are tight in the disc rollers and don't spin. I've measured the bushings and they are pretty much spot on (0.7500 OD and 0.500 ID). I'm guessing I need to bore the holes slightly under and press in the bushing, but I'm not sure by how much. I guess I could bore a few test holes and figure it out, but thought you guys might help me get it right the first time.

Thanks

[DetroitRob]

Most of the time when I'm going for a decent cold press fit, I bore the holes .003" undersize and put a slight lead on the bushings with a file.

[garybdavis]

Taking a closer look at the bushings, they are 0.005 over. I can purchase a reamer that is 0.7490. Perhaps that would be an option instead of setting up and dialing in my boring bar. Would that be too tight or should I go with the 0.7500 reamer?

[Sberry]

If you goof up a bit Locktite them in.

[garybdavis]

Red or blue? You know, I can always count on Sberry for the old shop tricks!

I ordered a 0.7500 reamer because I'm too lazy to dig out my nice high dollar Kennamental boring bar and make multiple passes to dial it in. I had to order some more bushings and they are spec'ed at 0.0000 to -0.0005 or something like that. So, locktite may be required depending on how bad my lathe is vibrating that day.

[monte55]

It's looks like you have a hub. Why not drill a hole and use a roll pin. Very easy.

[garybdavis]

That's what I have up to this point. I started with a 1.25" thick piece of 4" flat bar, cut them into 4" squares, trimmed off the edges, drilled them with a 1/2" center hole and turned them on the lathe. I turned a 1/4" x 1" hub on each end and faced down the roller to 1/2" thick. But, I'd like to be able to replace the bronze bushings if they ever wear out in my lifetime. Realistically, the rollers will probably be trashed by then, but where's the fun in that?

[Sberry]

I suspect you would never wear out the bolts you have now, would take rotating pipe 24 hrs a day at higher speed than a man can do it. Little portable ones I can lay on my benches.

[garybdavis]

That's a cool idea. I need to find a set of steel caster wheels and save myself the hassle.

I know if I were to use bearings, I couldn't pass welding current through them (ground clamp placed on the jack stand), but I'm hoping the bushings will work for this. If not, no big deal.

[nocheepgas]

I like the fact that you have them in your dining room!