Download - 45 Colt Chamber Reamer (2)
45 Colt Chamber Reamer
by sb327
I needed a chamber reamer, so I made one. Here is the process I use. I started with square stock 1095, not because
it was the best choice, but because it is what I have.
First pic is starting cut, this cut will tell you if your ts is way out.
Next is the roughing cut.
And then the first cut on the mill. This is where starting with square stock really helps, you don't spend any time
indexing. This cut is made to take a little more than past center and deep enough to leave some meat for the cutting
edge below this one. Just visualize here. The next cutting edge you cut will make more sense because you will
index this cut toward you and you can see the relationship of the two as you cut the next one...... and so on.
The first pic here shows how I cut just past center. What this does is basically makes the cutting edge <90 to the
tangent.
The next one shows how I mark the cutting edge (part that did not get touched by mill) with a sharpie. What I am
going to do is give a little bit of relief to the back side of the cutting edge before I harden it. Marking it shows you
where you are filing, forgot to mention you do this with a file. Leave just a tad there by the cutting edge, we will
get to that part later. If you have a bur on the cutting edge, leave it. It (in my mind anyway) helps to keep from
accidentally burning the carbon out in the hardening process.
The last here shows how much I leave for later.
First here is a pic after I hardened it. You can get all the scale off, I don't.
Next is marking the part of the cutting edge you left alone before. We are going to do the same thing as before, only
this time I use a diamond whetstone, held with both hands. I cut along the cutting edge, starting with the part of the
mark furthest from the cutting edge (right side of sharpie mark in pic). I work the stone until the mark just
disappears at the cutting edge. Do not sharpen that part any more. If you left the bur on there, it will shine up just
before you get to the cutting edge and a small, fine line will appear just beside the cutting edge, sharpen until this
line disappears and you are done. There should be no sharpie mark left when this step is done. Remember to relieve
behind the edge of your tapers. The tapered parts of reamers cut more material than the rest of the reamer.
The next one shows it making a cut. (I will splain the barrel situation in a bit)
And a completed chamber.
That was just the way I do a chamber reamer. The most important steps are getting it turned on the lathe to correct
dimensions ( I usually take the last coupe of .001's off with a file in the lathe) and the final sharpening (to keep
those dimensions you started with). The milling process is not that particular, I do not measure anything in that
step. Be aware you can cut the flutes backwards, still no big deal, just turn it to the left when you use it.