skeeljc Posted November 12, 2014 Share Posted November 12, 2014 I have a EAA Witness Match. I need to drill and tap the frame for a Quinn III C-More mount. I know the screws are 4x0.7 (metric). Can someone give me the location of the four holes in the frame on the Limited or Gold? Height wise the holes appear to be in line with the slide stop pin. From photos the first hole (rear) looks to be just forward of the front of the trigger guard. Jim Skeel Link to comment Share on other sites More sharing options...
Glk21C Posted November 12, 2014 Share Posted November 12, 2014 Have you ever drilled and tapped holes in an EAA\Tanfoglio frame b4? Not for the faint at heart, really hard metal. Good luck Link to comment Share on other sites More sharing options...
skeeljc Posted November 12, 2014 Author Share Posted November 12, 2014 Have you ever drilled and tapped holes in an EAA\Tanfoglio frame b4? Not for the faint at heart, really hard metal. Good luck I know the frame is stainless steel. I have drills and taps for ss and a mill. Has anyone drilled one before? Link to comment Share on other sites More sharing options...
Glk21C Posted November 12, 2014 Share Posted November 12, 2014 I have, I am trying to warn you. Going slow and using appropriate cutting oils I broke MANY bits and taps. Can it be done? yes Link to comment Share on other sites More sharing options...
kneelingatlas Posted November 12, 2014 Share Posted November 12, 2014 I know the frame is stainless steel. Are you sure about that? Do you have a magnet? Link to comment Share on other sites More sharing options...
skeeljc Posted November 12, 2014 Author Share Posted November 12, 2014 I know the frame is stainless steel. Are you sure about that? Do you have a magnet? o.k. My bad! It is steel (contains iron). I suppose it could be surface hardened? I have drilled and tapped surface hardened parts before. You usually need to remove enough of the surface heat treat to clear the tap o.d. This can be done with a carbide center drill. Link to comment Share on other sites More sharing options...
skeeljc Posted November 15, 2014 Author Share Posted November 15, 2014 You guys were beginning to scare me. I purchased a good quality 3.3mm drill and a good spiral fluted M4x0.7 tap. The machining was very easy. I don't believe there is any heat treat on the frame. It was harder determining where to put the holes than the actual machining. I will post some pictures later Link to comment Share on other sites More sharing options...
skeeljc Posted November 15, 2014 Author Share Posted November 15, 2014 (edited) Here is how I proceeded. First I determined where to place the four holes in the frame. I set the height so there will be 0.050" clearance between the C-More and the slide. The Y-dimension I used is 0.300" down from the top of the frame. I placed the four hole pattern (10mm spacing) as far to the rear as possible keeping the rearmost hole in the frame channel so all the holes are through holes. I purchased a 3.3mm metric long life TIN-coated jobbers drill bit and a long life spiral fluted M4x0.7 metric tap. Spiral fluted taps push the chips ahead of the tap and can only be used for through holes. They need to be driven in a mill or a good drill press. They are not a "hand tap". I put the frame in the vice on my Enco mill. I used a carbide center drill to establish location. Then I drilled through the frame with the 3.3mm drill. I used 30 weight oil on for the center drill and the through drill. The frame was easy to drill so I knew it would be easy to tap. I used the mill to drive the M4x0.7 tap at 60 rpm and hand fed. I used TapMagic cutting fluid on the tap. Edited November 15, 2014 by skeeljc Link to comment Share on other sites More sharing options...
skeeljc Posted November 15, 2014 Author Share Posted November 15, 2014 (edited) I am waiting for a long Cheeley slide racker to complete the project. I just noticed that the thumb rest may block access to the C-More adjustments. I guess I can always just remove the thumb rest to change zero. My goal for this project is to use the pistol for bowling pins. The local pin matches place the pins at 2 feet for the .40 cal. as opposed to 3 feet for the .45 cal. I have some 200 grain plated flat point bullets which I will try. I run 230 grain FP cast bullets in my 1911 .45 ACP pushed to 900 fps. They take the pins off every time if I do my part. I just want to see how the .40 S&W will perform on pins. When you only get to load 6 rounds for 5 pins it becomes an accuracy contest instead of a speed contest! Edited November 15, 2014 by skeeljc Link to comment Share on other sites More sharing options...
skeeljc Posted November 16, 2014 Author Share Posted November 16, 2014 Decided against the long Cheeley slide racker. Made a short one for the right side. This way I do not have to remove the racker to remove the slide. Link to comment Share on other sites More sharing options...
NickD Posted November 16, 2014 Share Posted November 16, 2014 Wow, Great job! How nice to have the right tools, the skill to use them properly and the fortitude to dive right in. Love the racker!! Would you consider making another? Would gladly pay for your time. Regards, Nick Link to comment Share on other sites More sharing options...
skeeljc Posted November 16, 2014 Author Share Posted November 16, 2014 I noticed a similar racker in one of Henning's videos. I do not find it on his website. You might want to contact him. Link to comment Share on other sites More sharing options...
NickD Posted November 16, 2014 Share Posted November 16, 2014 I noticed a similar racker in one of Henning's videos. I do not find it on his website. You might want to contact him. Thanks, I wanted to try one I could install with two 8-32 spring loaded ball plungers for quick assembly/disassembly. They would align with the two existing counterbores in the dovetail. The ball plungers are .437" long so the racker would need to be at least .375 thick in that area. Link to comment Share on other sites More sharing options...
skeeljc Posted November 16, 2014 Author Share Posted November 16, 2014 My racker is just 0.150" thick where it fits in the sight dovetail. That way it will pass under the C-More when you take the slide off. Link to comment Share on other sites More sharing options...
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