|
If it is a top cover,getting a replacement to drill is a good plan.
What do you have for equiptment?
I suppose some good advise might be "Don't do your first drill and tap job on a firearm receiver" Get some 1/2 by 3/16 or so steel and drill and tap hole patterns in it to match your base.Don't drill the gun till you are good at it.Maybe you can even experience your first snapped tap in scrap steel.
Look at Enco or MSC's web page.One of them has a spring loaded tap center.
Or,some tap handles have a slip dowel out the top.Either goes in the drill chuck to guide the tap square and straight while allowing it to feed in.
Begin with a small center drill,follow with your tap drill,then tap,all on the same location unless you have a good milling machine to accurately reposition your work.
Use a good tapping fluid like Tap Magic for drilling and tapping.
If this is a through hole,use a 2 flute spiral point gun tap.If it is a blind hole,use a 4 flute plug tap followed by a bottom tap.Blind holes take great care with the chips.About every 1/2 turn,back up 1/4 turn to break the chip.Stop,back the tap out,blow the chips clear if you feel anything!
Follow that with the bottom tap.t is very easy to break a bottom tap.Take a little at a time,clear the chips,and feel carefully for any increase in torque.Do not jam it into the bottom of the hole
I hope you have some means to precisely locate your holes.A drill fixture,an x-y vise,a mill,something,and at least a quality drill press.
Good luck
|