reaming barrels

[Don Krag]

For .500 - 1.25" bores...and I guess any bore for that matter...what kind of reamers do y'all use? I've always used hand turned straight fluted ones for small holes. Ive been searching through ebay, and there are a crapload of different types of reamers available. How well do expandable ones work? What does a twist reamer do different than a straight fluted?

[GGaskill]

By "expandable", do you mean this kind

or this kind ?

The first kind is useful only for through holes as the blades are arced to reach size and you can't cut all the way to the bottom of a hole.  The second kind is pretty much like regular chucking reamers with only a few thousandths of adjustment available plus they are a little more fragile.

Spiral reamers are supposed to work better in bores with cross holes since the edges don't line up.  Also supposed to have less of a tendency to chatter.

[Don Krag]

Most of what I've been looking at were lots with all different types. I do a lot where I bore a through-hole, then come back and plug the breech end, or where I'm starting with seamless tubing and stepping up to a specific bore, so both types could be useful. I've never used an expandable one or spiral fluted ones, though, and was just curious on other's opinions who have. By fragile, what exactly do you mean? Ie...they tend to fall apart with use or won't hold tolerance due to play in fittings? I figure I'll get a few fixed size in specific sizes that I often use and buy some lots of varied ones just to have a variety on hand.

[GGaskill]

By fragile, I mean that the expansion reamers (the bottom picture) have a very small range of size and will break the flutes if you try expanding beyond the published maximum size.

[Don Krag]

Ahh...got it. Thanks for the info! How difficult are the larger ones (1.5-2") hand reamers to use?

I've mostly just used sharp drillbits and very small increments for the final boring, then finished with "homemade" grinding pads/inserts to polish the bore. I'd like to start getting more precision and accuracy out of my guns, which of course requires tighter tolerances on the bores.

[GGaskill]

I've never done any hand reaming so I can't help there.  My experience with machine reaming deep holes has not produced the results I expected.  Perhaps my expectations are too high.

[Double D]

Good reaming takes patience..When a gunsmith form reams a chamber he only feeds about .100 a pass.  The last .100 even less.

When I ream a bore for a cannon I go a little faster feed but then my hole is only a few thousandth smaller than my reamer, .005 at the most. Its not the same as form reaming.   My feed is based on what  I feel in the way of chip load. Forced lubrication  I can feed more, hand lube very much slower.  Stop and clean often even with forced lubrication.