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Old January 5, 2020, 11:53 AM   #1
Head Tomcat
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Uberti 1851 Navy London and Kirst Converter...Issues

Guys,

Continuing down the path of converting my new Uberti 1851 Navy London to fire metallic BP cartridges, the Kirst gated converter arrived yesterday in the mail.

Taking apart the pistol, I followed the instructions and slid the converter ring down the arbor and it properly set in place against the recoil shield. The surprise came when I slid on the conversion cylinder…and it would not slide in all the way! Once the ratcheted “neck” of the cylinder started to enter the ring it contacted the ring and would go no further. To make sure there was no contact with the frame I took the converter ring out and slid the cylinder onto the arbor and it went completely down to the recoil shield and spun freely…no frame contact anywhere.

Now this sort of mystified me that with no converter ring in place the cylinder would slide all the way down the arbor and rest against the hand, and in fact, would function correctly as I worked the hammer and observed the timing (which was fairly good).

Taking the cylinder off and re-installing the conversion ring gave the same results…with the ring in place the cylinder would stop when the neck started to enter the ring. For some reason, the ring/cylinder/arbor combination simply did not have the stacked clearances to allow the cylinder to seat all the way down against the hand.

This got me thinking that perhaps the arbor itself was not square to the recoil shield? Even though it is a new pistol and has never been fired, the fact the Kirst gated conversion assembly would not drop on is leading me in this direction. I am fairly sure the Kirst is not the issue as it is very well made.

A few days ago I took 45 Dragoon’s advice and re-checked the arbor length (it is a Uberti) and sure enough it was too short. Three #6 stainless steel washers dropped into the arbor hole “added” .087” of length and this was exactly what it took to get a correct overall arbor length. The wedge was filed a slight amount on one side and it now locks nicely into the arbor with a screwdriver handle tap, with the spring lip just extending out the right side.

And this got me to thinking….

Could the arbor have been bent slightly off-square to the recoil shield when the factory assembled the pistol and then forced the wedge in…which would have moved the arbor upwards a bit? In turn, this slight amount of off-square was more than enough to overcome the tolerances in the Kirst gated converter assembly such that the cylinder could no longer enter the converter ring?

Your thoughts are most welcome as the London is a truly beautiful pistol and if the arbor is in fact off-square to the recoil shield I would like to try and fix it.

Thanks!

Head Tomcat
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Old January 5, 2020, 12:56 PM   #2
45 Dragoon
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HT, install the ring on the cylinder and slide them on as a unit. You'll probably need to open the loading gate a little because there is some contact until you clearance out the recoil shield.

Mike
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Old January 5, 2020, 03:54 PM   #3
Head Tomcat
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Just did...and still no go

45,

I tried that several times and the combined ring/cylinder unit slide on a little further...but they still stopped well short of being seated. I made sure the loading gate was open as that did have a bit of clearance issues with the frame.

Now, if I reverse the cylinder and slide it in backwards, the combined ring/cylinder unit does slide all the way back and seat against the recoil shield. So, only when the ring and cylinder are in correct orientation does it fail to seat.

To me, this seems to indicate that when the cylinder is installed correctly, the slight tolerance between its ratchet "neck" and the ring are more than taken up by an arbor which for some reason is not positioned properly.

Am still stumped. Might take a break with this and come back tomorrow using some layout fluid to see where the interference might be.

Head Tomcat (with tail dragging)
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Old January 5, 2020, 04:13 PM   #4
45 Dragoon
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HT,
You probably have clearance problems because of the "feet" or pads on the bottom of the ring. You can check to see if the ratchet contacts the ring "off center" towards the bottom (under the arbor) by marking the face of the ring with a marker. If so, you can remove material from the feet to center the ring. (Obviously, check progress often)

Mike
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Old January 5, 2020, 07:34 PM   #5
Catman42
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this maybe too simple but when i install mine i have to have it on 1/2 cock or it wont go together. krist is well designed but to be honest their quality control is lacking.fireing pins came loos on mine twice. a new cover was sent twice quickly. i emailed the owner and designer and it was impossible to talk to him. he would not listen to me on any of the problems i had with his converter. insisted someone was sabotaging his product before it left the shop. i finally had to hang up on him. how ever he kept calling back and yelling at me. he made no sense as to what he was talking about. i never replied and just hung up each time. im old but he is a lot older than me and he sounded to me like a man who may have reality problems. again he designed a wonderful product but quality control is none at all. would i buy a kirst converter again. yes. however i know how to fix or where to go if i cant do it to them. VIT will back them 100 percent. or it may be VTI. anyways it can be found on the internet.
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Old January 5, 2020, 11:06 PM   #6
woodnbow
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You might contact kirst... I’d be inclined to buy Mike’s explanation since he’s done this a time or two. I would not automatically guess that the arbor is out of square with the frame or not parallel to the water table. If that were the case you wouldn’t be able to mount the cylinder and the barrel.
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Old January 6, 2020, 01:02 PM   #7
Head Tomcat
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Am back at the converter...maybe found the problem

Guys,

I coated the ring with red layout fluid and also the pad on the bottom of the ring to see if that was part of the issue.

After slowly pushing the ring/cylinder onto the arbor and very, very carefully watching it go on, it appears that 45 Dragoon may well have been correct. As the unit got closer to the recoil shield I saw the pad on the bottom of the ring gradually come into contact with the frame until about 1/8" from the recoil shield it was in full contact. The unit could not push on any further without undue force.

Taking it back off, the pad had two clear lines etched into the layout fluid showing where the frame had contacted it.

Now, to me this is not a bad thing (I hope!) as it should allow me to very carefully remove material from the pad on the bottom of the ring to get a close fit with my specific Uberti 1851 Navy. The end result will allow the Kirst converter to be a solid fit to the arbor without binding up while it rotates.

Will let you know how this turns out!

Head Tomcat with tail slightly coming back up
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Old January 6, 2020, 01:45 PM   #8
Head Tomcat
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Solution!

Guys...it was the pad on the converter ring causing the interference issue!

After about 10 minutes of judicious filing and fitting, I got the converter ring/cylinder unit to neatly slide all the way down the arbor and seat against the recoil shield. The cylinder rotated crisply and without any friction being felt during rotation.

Thanks for the advice as it worked!!!

Head Tomcat (feeling a lot better now)

PS: Now to start the overall deburring of the pistol, polishing of some surfaces, and sorting out the final timing.
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Old January 6, 2020, 06:19 PM   #9
45 Dragoon
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Well, not sure if a "thank you" or "apparent" thank you is in order (from me for mentioning my "apparent" diagnosis ( I'd say NAILED IT !!! ) but thanks anyway and glad you got this far!
Good luck with the "polishing" and timing stuff.

Mike

Last edited by 45 Dragoon; January 8, 2020 at 11:24 AM.
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