A while back I posted the use of a pin chuck for tapping small holes.
I have now made a more permanent device.
Using an inexpensive 1/4" hex drive chuck (I said inexpensive - not cheap and nasty - this is the best one of several to hand and at least has hardened parts and runs pretty true).
I turned down the hardened shank, leaving about 4mm of hexagon - so you've got something to hold with a 1/4" spanner for tightening / loosening - drilled it with a 3mm solid carbide drill (you can see it got hot) and made an extension shank which part press fitted / part locktite into the hole through a 10mm drill rod shank reamed to 5mm.
The whole assembly is free to rotate and has about 12mm vertical movement.
After drilling the hole to be tapped, I put this in the drill chuck and bring it to bear and then tap with the fingers.
Its bang on lined up, its impossible to apply side load and you get excellent "feel".
Ideal for small taps - up to about 3mm (4 if you've got really strong fingers or use a 1/4" spanner on the hex).
Ken
I have now made a more permanent device.
Using an inexpensive 1/4" hex drive chuck (I said inexpensive - not cheap and nasty - this is the best one of several to hand and at least has hardened parts and runs pretty true).
I turned down the hardened shank, leaving about 4mm of hexagon - so you've got something to hold with a 1/4" spanner for tightening / loosening - drilled it with a 3mm solid carbide drill (you can see it got hot) and made an extension shank which part press fitted / part locktite into the hole through a 10mm drill rod shank reamed to 5mm.
The whole assembly is free to rotate and has about 12mm vertical movement.
After drilling the hole to be tapped, I put this in the drill chuck and bring it to bear and then tap with the fingers.
Its bang on lined up, its impossible to apply side load and you get excellent "feel".
Ideal for small taps - up to about 3mm (4 if you've got really strong fingers or use a 1/4" spanner on the hex).
Ken
