Pistolero
Well-Known Member
OK, intheshop asked about this and here it is. The price at a gun show with the
action locked up was $100, but I noticed the side plate was not all the way down,
figured someone had pulled it apart, couldn't get it back together and had parts
out of place, locking it up. Turned out to be correct.
Here's the story:
I bought a 5" Colt Police Positive, which is a .38 S&W gun. The price was very
low, so I figured it had to have something significantly wrong with it, but OK it
would be fun to see if I could figure it out and fix it. A close inspection prior to
purchase showed that the cylinder, chambers, barrel and frame were in good
shape with no rust and good smooth critical interior surfaces.
The first order of the day was to buy a new head for the ejector, which screws on
to these guns and it was missing. I located one for a few bucks and ordered it,
it fit and functioned fine.
The next item is check the timing. It would not drop the cylinder bolt into place
reliably when cocked manually at a very slow speed. A rapid single action or
double action cocking would 'sling' the cylinder far enough that the bolt would drop,
but not when done slowly. This means that the hand is not pushing the cylinder
around far enough - the hand is "too short", from wear on it and the star on the
cylinder which engages the hand. I got Jerry Kuhnhausen's book on double action
Colts, and dissasembled the little gun, my first full dissasembly for a Colt dble
action revolver. I have done or assisted in almost everything that can be done to
and for a S&W revolver, but Colts, while in the inventory, had not been cracked
open yet. Surprise - they are VERY different inside!
After 'stretching' the hand, I got the timing correct. But the gun still would bind
up in fast double action shooting with live ammo. More study showed that the
end play of the cylinder was excessive, and this lets the front face of the cylinder
drag on the back face of the barrel when the hand is pushing the cylinder around -
and simultaneously pushing the cylinder forward into the barrel. The official
Colt repair is to use a very fancy swaging tool to swage the tiny ring at the front
of the cylinder out a bit to take up the slack. Lacking one of these special tools,
and having no intention of buying one, I started studying Colt revolver on the
web. Eventually, I found an amateur gunsmith that was fixing this end shake
problem in Colt Pythons by turning off the little snout on the cylinder, then
counterboring this area for a new, longer bushing to be pressed in place. I have
the lathe that is required, but did not want to start carving on the cylinder of
a 1930s vintage Colt unless there was no other choice. I know that Ron Power
Custom makes shim washers for different locations in the S&W revolvers, but his
web site does not show any for Colt revolvers.
A feeler gage showed that the total movement of the cylinder was about .008".
I wanted to keep the cylinder off of the back of the barrel, so I decided to make
a .006" shim. A good friend is a tool and die maker, has a REALLY nice machine
shop with two NC mills and all the other tools that you need to make almost
anything. He also is a champion pistol shot and a great pistolsmith, mostly on
his own guns, with occasional assists to friends. I discussed the issue with him,
and showed him a few sketches of jigs that I had designed to make a shim. It is
not obvious that making a shim would be big deal, but the issue is that this shim
has an outside diameter of 0.400" and an inside diameter of 0.330", and needs
to be about 0.006" thick. He offered a .006" feeler gauge for material and a couple
of suggestions on how to do it better.
I used the lathe to turn down the OD of a piece of scrap stainless steel to .400,
and then drilled a 3/16" hole down the middle. I turned a .330" diameter snout
on the rod, about .100" long, then cut of this piece at about 1/2" length. I then
faced of the remaining piece and drilled it from the end with a "Q" drill, which will
drill a .332" diameter counterbore, 0.002" larger than the crane where the shim will finally
reside; about perfect. After parting the second bushing, I reamed the pair up to
a slight clearance on a 3/16" aircraft bolt. These will be the OD jig.
Now, for the jig to make the ID, I cut a small piece of 1/8" steel and a similar sized
piece of 1/4" thick aluminum. These pieces are about 3/4" by 1.5". I drilled
through the steel piece and the aluminum block and tapped the aluminum 10-32
to accept a short aircraft AN3 bolt in two places. Between these two there was
room for a 1/2" wide feeler gage. I used a piece of gifted 0.006" Starrett feeler
gauge as my shim stock.
After clamping the shim stock between the two plates, I drilled through the
aluminum, shim and steel plate with a "Q" drill, making a shim with a squared
off oversized OD, but a .332" ID hole and no damage because it was supported
fully during drilling.
Next the partially completed shim is slipped onto the snout of the OD jig and
the snout inserted into the counterbore in the opposite part of the OD jig. A
3/16" aircraft bolt runs up the middle and clamps the shim in place.
The jig supports the thin shim between two faces, and the excess material sticks
out past the jig. I roughly ground away the excess with a Dremel tool and
abrasive wheel. The final cutting off of the excess shim stock, was done with
a fine cut file until the shim was flush with the OD, which was made to 0.400"
diameter. I unbolted the two OD jig parts and had a nice, concentric shim ring
that is .006" thick and has a .400" OD and .332" ID. This is a tiny little ring and
it took a bit of time to make the fixtures and then the shim, but the shim
should last for quite a while and with the fixtures, I can make another one if I need
it.
I installed the shim between the cylinder snout and the crane and it removed
essentially all the end shake, maybe about 0.002" is left, and there is a 0.006"
cylinder gap to the barrel.
Here are some pix of the jigs and the part, and assembling it.
In the last picture you can see the shim in place, and in the second to last the shim is
slipped onto the crane.
Double action is now smooth with no binding, and I am looking forward to shooting the
little guy.
****
This was written long ago, and I have shot it a good bit since. It can be quite accurate with
good cast loads. I got two old Ideal molds made for this cartridge, and they work well. It is
a low power cartridge, and I won't hotrod it, but it is great and with the long 5" bbl, works well.
Bill
action locked up was $100, but I noticed the side plate was not all the way down,
figured someone had pulled it apart, couldn't get it back together and had parts
out of place, locking it up. Turned out to be correct.
Here's the story:
I bought a 5" Colt Police Positive, which is a .38 S&W gun. The price was very
low, so I figured it had to have something significantly wrong with it, but OK it
would be fun to see if I could figure it out and fix it. A close inspection prior to
purchase showed that the cylinder, chambers, barrel and frame were in good
shape with no rust and good smooth critical interior surfaces.
The first order of the day was to buy a new head for the ejector, which screws on
to these guns and it was missing. I located one for a few bucks and ordered it,
it fit and functioned fine.
The next item is check the timing. It would not drop the cylinder bolt into place
reliably when cocked manually at a very slow speed. A rapid single action or
double action cocking would 'sling' the cylinder far enough that the bolt would drop,
but not when done slowly. This means that the hand is not pushing the cylinder
around far enough - the hand is "too short", from wear on it and the star on the
cylinder which engages the hand. I got Jerry Kuhnhausen's book on double action
Colts, and dissasembled the little gun, my first full dissasembly for a Colt dble
action revolver. I have done or assisted in almost everything that can be done to
and for a S&W revolver, but Colts, while in the inventory, had not been cracked
open yet. Surprise - they are VERY different inside!
After 'stretching' the hand, I got the timing correct. But the gun still would bind
up in fast double action shooting with live ammo. More study showed that the
end play of the cylinder was excessive, and this lets the front face of the cylinder
drag on the back face of the barrel when the hand is pushing the cylinder around -
and simultaneously pushing the cylinder forward into the barrel. The official
Colt repair is to use a very fancy swaging tool to swage the tiny ring at the front
of the cylinder out a bit to take up the slack. Lacking one of these special tools,
and having no intention of buying one, I started studying Colt revolver on the
web. Eventually, I found an amateur gunsmith that was fixing this end shake
problem in Colt Pythons by turning off the little snout on the cylinder, then
counterboring this area for a new, longer bushing to be pressed in place. I have
the lathe that is required, but did not want to start carving on the cylinder of
a 1930s vintage Colt unless there was no other choice. I know that Ron Power
Custom makes shim washers for different locations in the S&W revolvers, but his
web site does not show any for Colt revolvers.
A feeler gage showed that the total movement of the cylinder was about .008".
I wanted to keep the cylinder off of the back of the barrel, so I decided to make
a .006" shim. A good friend is a tool and die maker, has a REALLY nice machine
shop with two NC mills and all the other tools that you need to make almost
anything. He also is a champion pistol shot and a great pistolsmith, mostly on
his own guns, with occasional assists to friends. I discussed the issue with him,
and showed him a few sketches of jigs that I had designed to make a shim. It is
not obvious that making a shim would be big deal, but the issue is that this shim
has an outside diameter of 0.400" and an inside diameter of 0.330", and needs
to be about 0.006" thick. He offered a .006" feeler gauge for material and a couple
of suggestions on how to do it better.
I used the lathe to turn down the OD of a piece of scrap stainless steel to .400,
and then drilled a 3/16" hole down the middle. I turned a .330" diameter snout
on the rod, about .100" long, then cut of this piece at about 1/2" length. I then
faced of the remaining piece and drilled it from the end with a "Q" drill, which will
drill a .332" diameter counterbore, 0.002" larger than the crane where the shim will finally
reside; about perfect. After parting the second bushing, I reamed the pair up to
a slight clearance on a 3/16" aircraft bolt. These will be the OD jig.
Now, for the jig to make the ID, I cut a small piece of 1/8" steel and a similar sized
piece of 1/4" thick aluminum. These pieces are about 3/4" by 1.5". I drilled
through the steel piece and the aluminum block and tapped the aluminum 10-32
to accept a short aircraft AN3 bolt in two places. Between these two there was
room for a 1/2" wide feeler gage. I used a piece of gifted 0.006" Starrett feeler
gauge as my shim stock.
After clamping the shim stock between the two plates, I drilled through the
aluminum, shim and steel plate with a "Q" drill, making a shim with a squared
off oversized OD, but a .332" ID hole and no damage because it was supported
fully during drilling.
Next the partially completed shim is slipped onto the snout of the OD jig and
the snout inserted into the counterbore in the opposite part of the OD jig. A
3/16" aircraft bolt runs up the middle and clamps the shim in place.
The jig supports the thin shim between two faces, and the excess material sticks
out past the jig. I roughly ground away the excess with a Dremel tool and
abrasive wheel. The final cutting off of the excess shim stock, was done with
a fine cut file until the shim was flush with the OD, which was made to 0.400"
diameter. I unbolted the two OD jig parts and had a nice, concentric shim ring
that is .006" thick and has a .400" OD and .332" ID. This is a tiny little ring and
it took a bit of time to make the fixtures and then the shim, but the shim
should last for quite a while and with the fixtures, I can make another one if I need
it.
I installed the shim between the cylinder snout and the crane and it removed
essentially all the end shake, maybe about 0.002" is left, and there is a 0.006"
cylinder gap to the barrel.
Here are some pix of the jigs and the part, and assembling it.
In the last picture you can see the shim in place, and in the second to last the shim is
slipped onto the crane.
Double action is now smooth with no binding, and I am looking forward to shooting the
little guy.
****
This was written long ago, and I have shot it a good bit since. It can be quite accurate with
good cast loads. I got two old Ideal molds made for this cartridge, and they work well. It is
a low power cartridge, and I won't hotrod it, but it is great and with the long 5" bbl, works well.
Bill
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