Barrel Reamers - home edition

[crazy insane]

if the idea of buying a piloted drill bit was to expensive, then he might as well forget about buying a gun drill bit

 

[winchester_070]

what you need is a series of bore reamers which you can take about .006 per pass but that would be cost prohibitive , remember though if you dont ream to size as your final move you will not get a consistant round or smooth bore and all will be for nothing (that is only my oppinion others may differ)

 

[crazydave]

See if you can find a 3 stage step drill bit with a long shank, i have seen 3 stage step bits but if they make long shank ones it won't wander. stages wanted would ideally be
1/4-3/8-1/2

 

[Papaclaude]

A friend of mine had made something up several years ago. It was pulled through the pilot rather than pushed.IIRC, it used replaceable carbide cutters.

 

[mooncoon]

I have drilled barrels out for liners using spade bits pulled through the bore but there are several caveats.
Important to bevel the back corner of the bit to prevent the bit digging in and jamming when withdrawing. (I speak from experience)
important to remove the bit every 1/4" or so to clear chips
important to go up in small increments of around .020" per step to prevent breaking the bit off of the shaft.

A spade bit pulled through the bore will follow the bore but you are almost force to do the work in a lathe. You also require the lathe for making the bits in the first place.

cheers mooncoon