The Archimedes drill have been used by jewellers for many years as a simple but very effective way of drilling small dia holes. I found this combo on e-bay.
ARCHIMEDES TWIST DRILL + 20PC MICRO HSS BITS JEWELLERY WATCH REPAIR MODEL CRAFT
( 303645024684 )
A nicely made bit of kit with one drawback, there is only one size of collet chuck, so basically useless. Until I found a miniature collet chuck with a range of collets also on e-bay
5pcs/Set 0.5-3mm Small Electric Drill Bit Collet Micro Twist Drill Chuck
( 383870283579 )
The original collet unscrews to reveal an M4 thread which is very similar to 4BA, so I drilled the new chuck body and tapped it 4BA, screwed it on the drill and hay ho I had a drill that will take the full range of drills in the pack.
Mike
ARCHIMEDES TWIST DRILL + 20PC MICRO HSS BITS JEWELLERY WATCH REPAIR MODEL CRAFT
( 303645024684 )
A nicely made bit of kit with one drawback, there is only one size of collet chuck, so basically useless. Until I found a miniature collet chuck with a range of collets also on e-bay
5pcs/Set 0.5-3mm Small Electric Drill Bit Collet Micro Twist Drill Chuck
( 383870283579 )
The original collet unscrews to reveal an M4 thread which is very similar to 4BA, so I drilled the new chuck body and tapped it 4BA, screwed it on the drill and hay ho I had a drill that will take the full range of drills in the pack.
Mike