Mass38S Posted February 16, 2005 Share Posted February 16, 2005 Built a new Steel gun about a year ago with a C-More serendity. Found out at a match (figures) that the screws were loose. Well... the screw holes in the dust cover are stripped. I could put a new mount on and modify the serendipity, or I could drill and tap bigger holes? If I drill and tap bigger holes (current are 6-40) am I going to compromise the strength of the dust cover and/or mount? Any help or suggestions would be appreciated. Thanks! Link to comment Share on other sites More sharing options...
benny hill Posted February 16, 2005 Share Posted February 16, 2005 standard 1911 frame or sti? Link to comment Share on other sites More sharing options...
EricW Posted February 16, 2005 Share Posted February 16, 2005 Why not just fill the holes with a little jb weld and retap? Link to comment Share on other sites More sharing options...
TDean Posted February 16, 2005 Share Posted February 16, 2005 Ever heard of a helicoil? "..Repair threads with these corrosion-resistant coil inserts to restore parts that would otherwise have to be scrapped. Once installed, each spring-like coil expands to permanently anchor the insert. These inserts provide a smooth free-running thread..." Link to comment Share on other sites More sharing options...
EricW Posted February 16, 2005 Share Posted February 16, 2005 Tom, Helicoils will hold in something that thin? I've helicoiled spark plug holes, but had no clue they were that versatile. Link to comment Share on other sites More sharing options...
TDean Posted February 17, 2005 Share Posted February 17, 2005 Oops, the title was stripped CMore holes. I thought he meant the dust cover on top of the C-More module itself. I see he means the frame. The 6-40 holes are .113" dia. The next size up ANSI would be 8-32 which is .136" dia. I suppose there's a metric screw somewhere in between? Let's see...3mm is .118", that shouldn't affect strength at all. Drill the holes to 3mm and run a M3 x 0.5 tap through them. Link to comment Share on other sites More sharing options...
Mass38S Posted February 17, 2005 Author Share Posted February 17, 2005 Benny, The frame is a Caspian single stack. I thought of heli coil, but I don't think it will work with these small holes. Link to comment Share on other sites More sharing options...
Jasonub Posted February 17, 2005 Share Posted February 17, 2005 how about trying industrial epoxy? the ones we use on grouts without the c part. its strength is about 12000-16000 psi Link to comment Share on other sites More sharing options...
v-comp Posted February 17, 2005 Share Posted February 17, 2005 Hi Tdean IIRC you'd need to drill the holes with a 2.5mm drill to tap a 3mm thread. Remember with metric to take the thread pitch off the diameter to get the size of the drill. EG: M3mm tap with a .5 pitch , 3.00-.5=2.5mm drill needed M4mm tap with a .7 pitch , 4.00-.7=3.3mm drill needed etc Also I think you'll find that the 6x40's are already twice the size of the 3mm tap Weld/silver solder it up and start again Link to comment Share on other sites More sharing options...
Mass38S Posted February 17, 2005 Author Share Posted February 17, 2005 Thanks to everyone so far. Might just have to weld and start over. Link to comment Share on other sites More sharing options...
Paul B Posted February 17, 2005 Share Posted February 17, 2005 I had this trouble continually with my open guns till I had my gunsmith braze a pad of thin steel on each side of the dustcover. The extra thickness let me have more threads and they never have stripped again. The pads look like they are about 1/16 to 3/32 thick and are on the sides of the dustcover permanently. You will have to thin the c-mores legs by about the same amount, but that is not too hard with a file and/or sand paper. Or you could just use the c-more mount for the sti as the legs are thinner. Good luck. Link to comment Share on other sites More sharing options...
benny hill Posted February 17, 2005 Share Posted February 17, 2005 Silver solder a pad on the side of the dust cover. The frame is to thin. The pad should be about .075 thick. Drill & tap it & it will hold like a sti frame. Link to comment Share on other sites More sharing options...
Mass38S Posted February 18, 2005 Author Share Posted February 18, 2005 Thanks to all for the information. Very Helpful Rich F. Link to comment Share on other sites More sharing options...
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