Fixing the Deep-hole Syndrome on the Colt Walker

[Norton Commando]

My Uberti Colt Walker had the ubiquitous deep-hole syndrome, meaning the frame would make contact with the barrel before the arbor made contact with the bottom of the arbor hole in the barrel.

I read Pettiffogger's article on correcting the problem using a Dillon Locator Button and a drill press but was aprehensive about doing a neat repair using his approach. You see I do not know a Dillon Button from a coat button and have no idea where to find one. Also, I had reservations about drilling my arbor. For one thing, I wasn't too comfortable about being able to securely clamp the frame to my cheap-ass bench top drill press. Also I was concerned about being able to drill a centered hole that was parralel to the arbor axis.

However, I do have a small 110VDC MIG welder, so I decided to build up the end of the arbor with weld metal. I needed to add about 0.150" of material to the end of the arbor and was concerned about slopping my weld metal all over the end of the arbor. So I made a weld metal capturing device out of a short piece (0.125") of carbon steel tubing that had an OD just slightly smaller than the arbor. I then clamped the frame with the arbor looking upward in my vice followed by clamping the tubing to the top of the arbor with shims and a pair of vice-grips. I struck an arc through the open end of the tubing and onto the end of the arbor. I kept adding weld material until the tubing was filled with a slight dome rising out of the top.

Getting the exact arbor length was then a file and fit process and I finished the job with some 125 grit sand paper.

It was a pretty easy procedure even for a novice welder like me. And the end results look fairly neat; see pics. So for those of you out there that have been wanting to fix the deep hole problem on your Walker but don't have Dillon buttons or a drill press, you can make an effective repair with a MIG welder.

 

[AlexanderA]

Maybe I'm missing something, but why is it important that the arbor bottom out in the hole in the barrel? I would worry more about the wedge slots in the arbor and the barrel lining up properly. The wedge, in connection with those slots, keeps everything in alignment and takes the force of firing. In fact, I would think a little excess depth in the arbor hole would be a good thing. That means that the barrel has a better chance of bearing evenly against the front of the frame when the wedge is driven in.

 

[Norton Commando]

I have three original cap and ball Colts and all of them are manufactured such that the arbor bottoms out at the same time that the barrel contacts the frame. That was Colt's design intent for open-top revolvers. If the barrel only contacts the frame, the wedge is capable of cocking the barrel relative to the frame to the extent that the cylinder will bind against the barrel. Making the barrel, frame and arbor make "square" contact together optimizes a somewhat weak, open-top design.

 

[Mizar]

Not only that, but when the arbor contacts the frame and the wedge is driven in you have a non slack, solid assembly. Shorten the arbor and you introduce slack into the game - this is what literally kills wedges. This is one of the reasons why Colt open tops have a somewhat bad reputation for being of week design - improper fitting found on so many replicas. Cap & Ball revolvers operate different than a cartridge revolver in terms of recoil forces - upon firing, the cylinder is only pushed backwards against the recoil plate, so the wedge assembly (if fitted right) is more than adequate to deal with the force generated by the bullet entering the barrel. Open tops became "weak" only after cartridge conversions were invented, but that was because a cartridge cylinder has a different recoil forces - it pushes fist to the front of the gun and then to the back. Only then the open top design showed that it was not well suited for that kind of firearm.

 

[AJumbo]

Norton, those Dillon locator buttons are available from Dillon Precision, the reloader manufacturer. I like your solution, though.

 

[drobs]

Looks nice!

I wonder if you couldn't use a free floating spacer - with an un-drilled arbor? Flatten the head of the arbor, cut the tail off the centering pin, and grind, stone, sand down the remaining button head to fit.

When I was building AK's I used my cheap Harbor Freight bench top drill press for lots of things. I used this cheap fixture which was a major pita to get perfectly centered below the drill bit.
https://www.harborfreight.com/4-inch-jaw-capacity-drill-press-vise-30999.html

I think if I was going to do it again, I'd get better fixture. Something like this;
https://www.harborfreight.com/5-in-Rugged-Cast-Iron-Drill-Press-Milling-Vise-69159.html

I'd need a taller drill press though.


Here's the relevant Pettifogger Articles:
http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_3.pdf
http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_4.pdf

Link to Dillon locator button:
https://www.dillonprecision.com/locator-buttons_8_48_25280.html


Pietta Tuning articles:
http://www.theopenrange.net/articles/Tuning_the_Pietta_Part_One.pdf
http://www.theopenrange.net/articles/Tuning_the_Pietta_Part_Two.pdf

Uberti Open Top Colt Tuning:
http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_1.pdf
http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_2.pdf
http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_3.pdf
http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_4.pdf

 

[44 Dave]

Your term "deep hole" is better than "short arbor". I fill the hole with shims from small washers then JB Weld them in place. I have some guns that have 2 different barrels and the barrel needs the mod not the arbor.
The impotent thing is that the gun is made to fit tight together and not hammer its self to destruction, good work.

 

[45 Dragoon]

Yap, I agree with 44 Dave. If your arbor isn't bottoming under tension, your revolvers assemblies are moving when you shoot (and not together!!)
My contention with "weak open tops" is, a properly setup open top with a .002" or less barrel/cylinder clearance (mine are .0015") can easily handle standard .45 C cartridge ammo just fine. I believe a proper open top made from the the same grades of material that S&W, FA, MR, Ruger, Colt use, would prove to be every bit as strong as a contemporary offering. The compact/greater cross sectional design of the arbor design elements would render an excellent platform for the intended caliber.

Don't mean to sound like a broken record but, I've never bent an open top revolver while loading it like I have a Remington copy. The proof is in the puddi . . . . . design!

Mike

 

[LonesomePigeon]

Well I agree with everyone. The wedge slots(and wedge screw) need to be aligned properly in order to prevent up, down or twisting pressure on the arbor. The arbor needs to be bottomed out in the arbor hole to prevent front to back pressure and the cylinder gap needs to tight in order to minimize hammering of the recoil shield and forcing cone. I will also add that the base of the arbor needs to sit on a solid foundation. That's why it's harder to build a good open top than it is to build a good top strap design.