Countersink the tube hole to fit 7030

[bertieng]

What should be the correct size drill bit to use to make the countersink on the tube hole to fit the 7030 tube?

Been doing the search but can't find the definite answer.

Experts please help to advise.

Thanks.

[Justasgood]

I use 5/32" but it depends on how low the hole is.

Often it can chew away the bottom if the position is too low. The older George MBW's worked out pretty well though.

good luck,

Kurt

[Martyd3]

I use 5/32" but it depends on how low the hole is.

Often it can chew away the bottom if the position is too low. The older George MBW's worked out pretty well though.

good luck,

Kurt

Ditto. As Kurt said, what the bottom of the hole or you will cut away the edge of the case.

Marty

[alligoat]

On cases like the noobmariner, it's about impossible to countersink w/o wallowing out a little bit on the underside. The position of the hole is too low on the case. Luckliy it doesn't affect the WR of the watch- or least it didn't in my two cases.

[HauteHippie]

Are you guys using regular 5/32" bits to do this, or actual countersink bits???

[Justasgood]

Are you guys using regular 5/32" bits to do this, or actual countersink bits???

Great question Chief.......The countersink bit for 5/32" will be a bit larger. I use the 5/32" drill bit and work it by hand to control how much cutting takes place. The I polish out the hole, re-tap and install the tube.

I have had no luck using the actual Countersink bit.

Kurt.

[Martyd3]

Same here. Just using a regular bit in a hand held drill. It takes a light touch and good control of the bit to do this. I would not attempt it using a drill press.

[alligoat]

I'm doing it the same way Kurt is, but next time I might try a countersink bit if it has a steeper pitch to the cutting edge. But you'd have to be careful not to make the hole too big/wide.