single plan 2

7/30/2019 Single Plan 2

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UntitledCONTRUCTION DETAILSThe first step is to get your barrel and a 1 inch x 1 1/2 inch x 5 inch pieceof metal for the frame. My barrel was 3/4 inch, much smaller and it getstoo thin for the screw holes in the bottom lug and the extractor gets reallysmall.

The next step is to mark the frame for the center hole and pivit pin,trigger pin, hammer pin and lock pin. The barrel hole/channel is firstdrilled 1/4 inch all the way through. I made a bunch of piloted boreingbars and ran them in the lathe while the frame was bolted to the carriagewith an angle plate. The easy way would be to use a piloted counter-bore3/4 inch with 1/4 inch pilot because the bottom of the hole must be flat for

the firing pin assembly to bear against it and you must have enoughmetal/strength to accept this load.22 Long Rifle max 26,000 PSI22 Mag max 28,000 PSI5 mm rem mag or 5mm craig 37,000 PSIThere are conversions for 22 mag to 17 HMR so figure at least 28,000 PSIfor the 17 HMT. Measure the inside diameter of the rear of the case thatyour going to chamber for: pie x radius squared to get square inch of theback of the cartridge. Divide the PSI of the cartridge by the squareinches of the cartridge. Double that for suddenly applied shock loads andthat will give you the amount of pounds per square inch that the framemust bear.Trim the frame and mill the slots for trigger and trigger guard, hammer

and bottom lug. Bottom lug is 1/4 inch, trigger is 3/16 inch, triggerguard is 3/8 inch and hammer is 3/8 inch.Drill the pivot pin hole, lock pin hole, trigger pin hole and hammer pinhole all 1/8 inch for now. When you make the hammer and trigger, drillthe holes 1/8 inch first. Put some 1/8 inch pins in the frame and thehammer and trigger on the pins on the outside of the frame to final fit

these parts.The firing pin assembly is made the same diameter as the barrel, 1/4 inchthick and threaded 5/16 - 18 for 3/8 inch or so. It gets trimmed later.Make sure it sets flush in the pocket.Mill a 1/4 inch wide slot in the barrel for the bottom lug. Make thebottom lug from 1/4 inch steel. Don't drill for the pivot pin or lock pinyet. Drill four holes in the lug, deep enough into the barrel for fivethreads. I used 4 - 40 allen head bolts. Mill a slot in the top rear of thelug for the extractor and drill a 1/16 inch hole for the retaining pin.Set the barrel in the channel, snug to the bottom and snug to the firing


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single plan 2

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