On Mon, 12 Sep 2005 09:48:46 -0700, Eric R Snow
wrote:
On Mon, 12 Sep 2005 11:22:17 -0500, "R. O'Brian"
wrote:
The standard rim thickness for the 22 rf is .044" Therefore the headspace
in a revolver needs to be .044" + enough to allow free rotation of the
cylinder. I don't have the industry standard dimensions to hand, but
.048"-.050" should be plenty. A real headspace gauge looks like a short
cartridge case with the proper thickness rim machined on it. They are
commonly made in Go and NoGo sizes. In practice you can use a cartridge and
a feeler gauge since the actual dimension is not too critical in a revolver.
BTW, the ratchet teeth do not determine indexing. It is controlled by the
cylinder bolt in the bottom of the frame window locking into the bolt
notches on the cylinder OD. Thus, the indexing accuracy is determined by
the accuracy of the cylinder machining when it was made.
The rest of your plan sounds good to me.
Randy
I see that cylinder bolt now that you told me about it. It not only
stops rotation but also keeps the cylinder from moving fore and aft.
From careful examination it appears that the cylinder bolt is part of
thr trigger. And the radius on the end of the bolt matches the radii
in the cylinder notches. So I need to make sure that when measuring
the trigger is pulled so that the cylinder will be in the proper
position.
ERS
As I posted before...pull the hammer back and hold it while pulling
the trigger. This loads the entire system, pawls, sear, etc
Gunner
"Eric R Snow" wrote in message
. ..
After reading responses about the two .22 revolvers only 1 is a good
candidate for what I want to do. So now comes the machining part.
First, measuring the cylinder shows that the ends are not parallel.
the ends may not be square to the central hole either. This hole is
tapered. On the back end the hole measures .191 and at the front .188.
the rod that goes through it measures .185 at the back and .186 at the
front. The hole in the frame at the front measures .191. At the tip of
the rod the diameter is reduced to .137. The hole in the pistol is
.142. It all seems pretty sloppy. I haven't checked the accuracy of
the hole spacing or the accuracy of the indexing teeth. It seems that
as long as the teeth all have the same relationship to their
respective holes (chambers?) then the chambers should all line up with
the barrel if one does. My proposed plan of action is to first remove
the taper from the central hole and then make sure the cylinder faces
are parallel and square to the central hole. Then, make the new rod
that goes through the cylinder. The rod will be .190 diameter with the
smaller diameter at the front being .141. I will make a dummy cylinder
out of brass and charge the ends with fine abrasive to lap the faces
in the frame where the cylinder contacts square to the cylinder. Next,
the faces on the teeth where they cantact the frame will be checked
for squareness and made square if need be. After this is done the
headspace needs to be checked. If too small I will face enough off the
back end of the cylinder to set the headspace correctly. What is the
proper headspace? Is there a way to determine this for any revolver?
After all that then the front of the cylinder where the play is set
will need to be changed. This little spud is .246 dia and protrudes
.108. I am going to counterbore the cylinder .250 dia. by .250 deep
and press in a short tube that's .180 I.D. by ..400 long before the
cylinder I.D. has the taper removed. Then when the frame is ready I'll
measure the inside dimension of the frame and make the cylinder .001
shorter. Finally, after all that's done, the barrel will be removed
and modified to set the proper clearance between the cylinder and the
barrel.
ERS
"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.
Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner
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