how to use an expansion reamer?

[oxford]

From the way it sounds, I don’t think he has a .750” reamer.

[Mike Burch]

Would it be easier to bore/ream/whatever it accurately to 0.750" and turn a thou off the piston instead?

[Richard P Wilson]

This^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^

??????

[Doozer]

Forget about expanding reamers. Just use a standard 3/4" machine reamer to get to 0.750, then spill ream it. Thats simply packing wooden spills down several of the flutes on one side, and taking the reamer through again. Thats always good for taking out an extra thou or so.

Sounds like a shot in the dark to me.

-D

[macona]

Take it rough to an auto machine shop and have them put it on their sunnen hone for doing piston wrist pins and have it done right the first time. There is a very good chance of screwing it up with those expanding reamers.

[Richard P Wilson]

Sounds like a shot in the dark to me.

-D

Possibly, but probably no more so than an expanding reamer.

[J Tiers]

Sounds like a shot in the dark to me.

-D

Not really. It's old-school, though.

??????

The idea is a good one...... Classic way to get something on-size when the reamer you have is a little small, or you just need another "skosh" cut.

[Doozer]

Possibly, but probably no more so than an expanding reamer.

You want to pack the flutes of a reamer with splinters of wood?
Do I have that correct? You are saying expanding reamers
are just as sketchy? Hmmmm... Ok.

-D

[J Tiers]

You want to pack the flutes of a reamer with splinters of wood?
Do I have that correct? You are saying expanding reamers
are just as sketchy? Hmmmm... Ok.

-D

getting just an extra thou with an expanding reamer can be "extra good fun"...... certainly with the type that has the sliding cutters, and the two lock rings to set. The type that have a tapered screw down the middle are easier to set up, as they do not quite change diameter as fast when you turn the screw. The sliding cutter type have a large range, the central screw type usually only have a few thou range.

Either way, too little and it rubs, a hair more and it can take too big a bite.

The softwood packing actually works, if the hole is smooth to begin with. Not worth a cuss if there is roughness. The usual problem is too small a cut, which is the better problem to have....