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Discussion Starter #1
I have a 940-1 cylinder coming to do a 9mm convertable convertion on my 642 No Dash..
I want to fit it so that the yolk is undisturbed so the factory 38spl cylinder can be swapped back & forth..
Just wonder how this could be done? I assume the bottom of the cylinder were the yoke rides would have to be cut to exactly the dimentions needed while getting propper headspace & barrel cylinder gap..
Any advise that can be given would be helpfull..
I know then the ratchet would need to be fit to the existing hand as well.. + The center pin & ejector rod lenth made correct.. I've never filed a ratchet and would be terified to do so till I'm sure what I'm Doing.
I know that if the cylinder has some end shake I could shim it but what if there is none & the cylinder won't close then what?? Trim the yolk & then shim the other cylinder?? I only have two J frame end shake shims in my stash & they measure about .0015"ea not .002".
I may just work on making the 9mm cylinder fit but would love to just lay the 38spl cylinder to the side with the ability to return it to stock & do all the work to the new 9mm cylinder..
What else will I need to do??
Thanks in advance for any replies..
If this convertion works out It'll be my new pocket rocket backup to my two 940s...
I haven't read anything about removing material from the Cylinders Axis Bore bottom, If that's even a correct term..
500 Magnum Nut What Do You Think??
Gary/Hk
 

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I have a 940-1 cylinder coming to do a 9mm convertable convertion on my 642 No Dash..
I want to fit it so that the yolk is undisturbed so the factory 38spl cylinder can be swapped back & forth..
Just wonder how this could be done? I assume the bottom of the cylinder were the yoke rides would have to be cut to exactly the dimentions needed while getting propper headspace & barrel cylinder gap..

Might have to find someone at a machine shop to machine both cylinders so they are exactly the same length/ with extractors fit. Also on the inside where the yoke slides on (so the endshake matches up) Only thing the 9mm is a smaller bullet. so I don't think it will be very accurate. Ok for close range. Then the barrel will need to be turned to set the cylinder air gap. The yoke will need to be streched for the end shake. Your looking at a lot of work. But it would be cool to get it to work! You won't know until you start measuring the cylinders to see which one will need to be trimmed and where...

I've never filed a ratchet.
Will the new cylinder come with a extractor?


I may just work on making the 9mm cylinder fit but would love to just lay the 38spl cylinder to the side with the ability to return it to stock & do all the work to the new 9mm cylinder..

I haven't read anything about removing material from the Cylinders Axis Bore bottom, If that's even a correct term..

The frames are the same, so the cylinder stops are in the same location. That should not be a problem.
 

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Discussion Starter #3
Well I fit the 940-1 cylinder to my 642 No Dash..
It took some trial & error on getting the end shake right with one .002" shim then had to mark & file the ratchet very slowly checking ever couple of strokes just till the hammer would drop & then move on to the next tooth..
I have it set with almost zero end shake & have a barrel cylinder gap of .006" which I can live with.
Range report due..
Here's a pic of the "942" right after the convertion & one with it's Heavyweight brother "940" after I put the Spegels back on..
Thanks alot for any & all the info you suplied 500 Magnum Nut..
Gary/Hk
642/942 Convertable Airweight

940 & 942
 

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Discussion Starter #5
Thanks alot 500 Magnum Nut!!
That means alot to me coming from you Sir!!
Range Report Still Due & will be a while before I get a chance to test it with the 9mm cylinder, For Now it's a 38spl as it's my lightest carry Bug..
I know were to get a 940 barrel but would be tempting the fate of a cracked frame trying that on an aluminum frame even with a frame wrench..
Not Gonna Go There!!
Gary/Hk
 
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