Need to fix missing pins on 1849 Colt pocket revolver

[Clark]

The revolver, made in 1859, breaks down by removing a wedge.
That exposes one big pin and two small ones.
I am missing the two small pins.
One small hole is a 0.114" go and the other a 0.115" go.
I don't know if the snapped off pins are threaded or pounded in.

I could drill and make new pins. I am not sure how to locate the holes.
I could put pointed dummy pins in the holes and scribe on Dichem, but that would just make two arcs.
I would need lines to cross, as these holes would need to line up perfectly to get the firing cylinder chamber to line up with the barrel.

What would you do?

[jdfoxinc]

They are press fitted. As to removing them I have no ideas.

[Der Gebirgsjager]

I'd take a lot of care in the set-up for the job, getting the frame set up precisely vertical in a milling machine or drill press vise, and then using a drill bit as close as possible to the size of the pin holes I'd drill them out. Preferably I'd use a carbide bit, but it might not be necessary as the pins of that age might not be as hard as one would expect to find today, and high speed steel might work satisfactorily. Don't know until you try.

[NoZombies]

A hole half the diameter of the pin drilled at least 3/4 through (they should be roughly 1 1/4 -1 1/2 diameters deep) and then an easy-out should break them free and pull them out.

[country gent]

I would set it up in an end mill. using the cylinder pin to indicate into square in both directions. Reason being the frame cut out may or may not be square its clearance for the cylinder. The cylinder pin is the pin that locates center. the 2 lower locate timing. Once the pin is square and true. Indicate the top of the holes with a broken pin. I would then use a 3/32 ( .093) end mill to slowly drill out the pin going as deep as possible. I would go thru the pin if possible. If longer is needed then a drill thru the end mills hole will now follow very closely. You should feel when it breaks thru in the spindle. In crease drill size till pin comes out. drill slow and easy as pin lets go it will compress on the drill. Repeat on second hole. Clean up the holes with a brush remove all the oils and chips. turn up the pins to a light snug fit and test. then for final assembly when everything is right s small wipe of Loctite on the pins and push in to depth removing any excess on the pins and in the corners.

In the mill using the end mill the broken end of the pin wont cause the cutter to walk like a drill bit does on an uneven surface. Cutting slow and easy will make a very straight clean hole if a drill is needed to go further then you have a good starting surface with side support there. I also would uses a 3/32 carbide endmill for the added stiffness of it. Last with the end mill use the knee to slowly drill the hole, its smoother and easier than the quill is. Work slow and carefull the indicator is your friend here

[skeettx]

Sorry for this response, but if you have to ask how, please take it
to a machinist and have it done correctly.
All the above is good procedure, but the talent in the task is crucial
Mike

[nekshot]

shucks skeeter, that would take all the fun out of a gun restorer like some of us. We won't do it on somebody else gun but our own are open to all thoughtful endeavers!!

[country gent]

Another way to look at it is this. With good detailed advice working slowly he learns something and gains another part of a skill. What used to be called an apprenticeship. With the same advice he can decide if he wants to tackle the project or have it done. With this information the person can make a better decision. A smart person asks for help if he dosnt know. I was always taught thru school, trade school, and in training the only dumb question is the one that you didn't ask.

A couple reason I prefer to recommend the knee mill over the drill press are one the mill is much more solid and ridged making for better work. 2 most hobby type drill presses may not be square enough. tables can be tramed in in one direction but are fixed in and or out, meaning a fussy shim job in this direction to get square. set an indicator in the spindle and swing the table on most drill presses, swing a 6" to 8" circle on the table and see what you actually have. The mill can be squared or trammed dead on to the table vise or part. Its rigidity and solidness contribute to this accuracy and ease of working. Better for this project would be a good jig bore drill for the higher accuracy of the machine.

[Clark]

I have had a mill for 15 years for amatueur gunsmithing. But I did make some jet engine starter/generator test fixtures for money.
3 years ago I upgraded from a beat up Rockwell 21-100 to a minty Bridgeport J2 with DRO.

[country gent]

That will do the job with a little set up work. The biggest thing is getting everything square and true to start with. Don't just clamp it up and go. indicate the cylinder pin in in both axis. make sure your square and true. This may take some shimming to get right in y axis due to the frame and solid jaw of the vise. In reality like a lot of repair work the set up may take more time than the job does.

[Bmi48219]

I recall once 45 years ago the company I worked for had me take some chrome plated steel dumbbell bars to a machine shop. There were broken hardened bolts in the threaded ends of the bars. I'm thinking the bars were 1 1/4" diameter and the bolts were 3/8", black metal, you couldn't drill them. The machine shop had a machine like a drill press. The machinist set the bar vertically under the work head, plumbed it up & put a piece of carbon gouging rod in the head. Turned the machine on and the rod arced down into the bolt, burned a hole in the center like a drill. Hole was about 3/4" deep. Then he put an easy out in the hole and backed the broken bolt right out. Didn't even have to dress the threads in the hole. He removed four studs in about 20 minutes. Don't remember what the process was called but it was pretty neat.

[ulav8r]

Before setting up the frame, place the barrel in the mill with new pins fitted into it. Use the mill DRO to measure the spacing between the pins and their location from the side. Consider making the replacement pins .116-.118 in diameter and re-cutting all 4 holes so alignment is perfect.

[Clark]

I made some measurements to find the distance between centers.
I took some pictures with a $16 chinese digital microscope


With 0.114" and 0.115" pin gauges inserted, is seems the centers are 0.488"

microscope set up

right broken pin magnified

left broken pin magnified

[Ballistics in Scotland]

I'd do it myself. There are jobs, like procreation, that it really hurts to delegate to someone else.

I can think of two ways to do this. The primitive way is to make an indented centre point as close as you can get to the centre of the pins. It can be with a punch, probably a specially made one to let you see the work, or with a tiny ball burr in a Dremel tool, which lets you work the indentation this way and that until it is really close to central. Then drill it as large as you can get without touching the sides of the original hole, and enlarge it until it does touch on one side.

This last can be done with the Dremel tool and a small-diameter diamond burr, which you can find in plenty on eBay, surprisingly cheap as diamonds go. I also once bought a collection of the little carbide drills used for drilling printed circuit boards. They aren't all that useful, being so thin in the web that they break very easily in metal. But they accidentally included a solid carbide four-flute end mill, about 3/32in. diameter with a ⅛in. shank, which would be perfect for the job. When you have a sort of Islamic crescent shape, new hole touching the old hole, I think it will come out. If not, just repeat the process on the thick side. This is a locating hole, not a bearing, so very slightly grooving Col. Colt's metal will do no harm.

A marginally less primitive way is to simply drill out the pins with full-size holes in one go, which would be fine if you could repeat the process if it goes wrong. You can if you do it to make a little jig of ⅛in. or thicker steel. Drill it for the axis pin first, then punch the hole positions with pointed pins in the holes in the barrel. (but make sure those pins, probably 33 or 33 drill rod, aren't tight enough to stick in those holes. You will feel a fool if they do.) Scribe and file the jig flush with the sides of the barrel, to make the line you will use to align it with the frame. Then temporarily epoxy it to the frame and drill.

If you can't get the right drill rod, get a drill. The butt end is often softer than the cutting edges, or if need be you can cut a couple of pieces with the Dremel cutoff wheels.

[Clark]

I drilled and tapped the a hole for 2-56.
I could have done 4-40, but I would have to be within 0.004" of center.
I tried pulling out the broken pin.
I tried pounding out the broken pin.
I could not get anything to come out.



In the end I shortened a 2-56 screw and turned the head down.
That works perfectly, but looks wimpy.
I wonder if I could do the other side too.
It is not easy having 2-56 parts fall on the floor, snap taps, snap drills, and get lost.

[Ballistics in Scotland]

I've just been looking at my only cap and ball (or nearly cap and ball) Colt. It is an apparently factory conversion of the 1862 Pocket Police with a serial number in the fourth thousand and unfluted cylinder, still stamped .36 on the trigger-guard although the rimfire cartridge would be .38.

It has what everybody calls the rebated cylinder of the 1860 generation, although really it seems more correct to call it a reinforced cylinder for all but the last ⅜in. To this end the frame has been milled to accommodate that slightly deeper cylinder - and just look at what it has done to my locating pins!




I've just been assuming from what I have heard that they are separate pins, but I can see no trace of this through the silvering. Perhaps they did it differently at different times, for I'm not sure I don't see toolmarks concentric with the pins on Clark's revolver. I don't believe mine would be reliable unless they were soldered in place before that milling, and you aren't going to pull that out with a 2-56 screw.

In fact I don't believe you would pull out a tightly fitted pressed-in pin with one of those either. If they are pressed in, though, a drill and tap which just touches the sides of the hole, or lightly grooves it, would be useful. It would preserve the alignment and yet leave you with just a spiral of triangular wire pick out.

Incidentally although I rate these revolvers quite highly, the rimfire cylinder leaves the rear of the cylinder frighteningly thin in the area that was meant to have nothing but percussion nipples. It would be pretty safe as bursting firearms go, and perhaps not even impede the other four shots. but I wouldn't be surprised if replacement cylinders were frequent, and a lot of people stuck to cap and ball in this model. In the situations for which it was designed, how many people have to reload quickly?

The junction of horizontal and vertical frame surfaces is a point of weakness, but not, I feel, nearly as much so as it is in shotguns. I think they would have done better to make the rimfire cylinder full diameter all the way back.

[Cap'n Morgan]

I believe BIS is on to something here. The "pins" was probably part of the casting. Had they been true inserts they never would have broken to begin with and they certainly would NEVER have had the crystalline surface your microscope pics show.

[Ballistics in Scotland]

I think that must be right about the construction of these model Colts, although least when you can do a complete 360 degrees of a hole as with Clark's, insertion of pins would be a satisfactory means of dealing with the problem. It means you need have no qualms about using the 4-4o thread. You could do it without knowing how they were fitted, if you can position the hole correctly. Either they are inserted and the pieces of triangular wire come out, or they are integral and you can use the threaded hole.


An original Colt receiver wouldn't be a casting, but a drop-forging. Here is Charles Dickens's description of a visit to Col. Colt's London factory:

"Out of the hot atmosphere, and the all-pervading odour of hot oil, we pass a yard ancle deep in iron chips (which make a dry hard road in all weathers, very destructive to leather) into a long out-building, in which the only genuine smiths are at work. Here the very beginning of the pistol is made; if we except the cutting and polishing of the stock, which have been already described in these pages. There is little of the noise of a smithy here except the roaring of the furnaces. A workman rams the end of a long bar of steel into the fire; and, taking it out glowing with heat, strikes a bit off the end as if it were a stick of peppermint; while his companion, giving it a couple of rough taps upon the anvil, drops the redhot morsel into a die. This die is a plug-hole shaped something like a horse-shoe, at the foot of a machine, bearing a painful resemblance to a guillotine. While they have been breaking off the bit of steel, a huge screw has been slowly lifting up the iron hammer-head, which plays the part of the axe in the guillotine: and now the great hammer drops, and with one stroke beats the piece of iron to the form of the die. It has cooled to a black heat now, and is shaped something like the sole of a very-narrow shoe; but it must be heated again, and the heel end must be beat up at right angles to the long part—taking care that it be bent according to the grain of the metal, without which it will be liable to flaw. Thus the shield, and what may be called the body of the pistol, are made in an instant.
In Birmingham, the barrels of fire-arms are made of old nails that have been knocked about, and which are melted, rolled into sheets, twisted again, and beaten about, till they are considered to be tougher and less likely to burst; but the American gunsmiths know nothing about this. They merely beat the end of the bars of cast steel again and beat it with steam hammers; for it would not do to draw it through holes, as thick wire is drawn, or to roll it as with ordinary round bars. These hammers are fixed, five in a frame, where they quiver with a chopping noise too rapidly to count the strokes, over a little iron plate, never touching it, though coming very close. Into the first of these the smith thrusts the red end of the bar, and guides it till it is beaten square. The next hammer beats it smaller, but still square: the next hammer beats it smaller and longer still, but rounder. The fourth hammer beats it quite round, and the fifth strikes off the exact length for the barrel. This gradual process is absolutely necessary, for the steel will not bear being beaten round the first time; and, although five barrels may be thus forged in one minute, the rapid strokes of these hammers are said to make it quite as tough as the Birmingham plan; which seems to be borne out by the results at the Proof House. On the same floor, the barrels and cylinders, after polishing, are case-hardened, and tinted blue, by burning in hot embers; processes which are well known."

I used to have a London Navy in which, though I don't believe it had ever been rusted, constant handling had shown up the grain of the metal, which flowed neatly around that right-angle. Integral pins would be mild steel, very little strengthened by case-hardening. It still beats me what intellectual process succeeded in breaking them off. Maybe someone thought the barrel was screwed onto the axis pin, as is the case with Lefaucheux and some other open frame revolvers.

[country gent]

While it wouldn't be unusual for the pins to be forged and machined as part of the frame on a piece from this time period especially since the holes arnt 100% ( flats on top of pins matching the frame). drills and reamers were expensive to make and maintain. The set up with a plug cutter in a multiple spindle machine would cut both plugs to size and depth in one pass, then the exess can be removed easily with a simple mill set up or files. Manufacturing wasn't near what it is today with the horizontal mill shapers and hand tools being state of the art. Even in production skilled craftsman ran these machines. A lot of these shops were still running on flat belt driven machines from ceiling mounted jack shafts.

It is possible to locate drill and tap then turn studs with threads and correct dia ends easy enough. turn outer ends long so the driver can be taken off and length set after installation. THe partial hole can be taken care of by drilling with a end mill slow and easy or clamping a piece of steel to the frame to allow drill to cut full dia 100% hole.

[Cap'n Morgan]

With a little ingenuity and a lengthened drill, the barrel part could be used as a drill jig to mark the hole centers.