More bottle stopper help

[sgimbel]

I got the bottle stopper mandrel and drill bit from Woodturnz. I then needed a tap so I ordered 1 from Rockler (free shipping). When I tap a hole it's to large and barely makes any threads. What size drill bit is recommended to go with the PSI bottle stop mandrel, or should I say with the Rockler bottle stopper tap?

 

[woodgraver]

There may be a couple of sizes, but the one I am using works perfectly with a 5/16" drill bit with a 3/8-16 tap.

 

[monophoto]

The PSI stopper mandrel is supposedly 3/6" x 16tpi. And the standard drill to use to drill a hole that will be tapped at 3/8" x16tpi is 5/16".

My PSI mandrel came with a 23/64" bit - that's too large if you are going to actually use a 3/6" x 16tpi tap to thread the hole. I suspect (but cannot prove) that PSI expected that the user would simply screw the mandrel into an unthreaded hole.

I've seen an on-line video on bottle stopper mandrels in which the maker mentioned that the stud on his PSI mandrel was an odd size. That was not the case for me, but it does suggest that there could be some orphan mandrels floating around with odd-size studs.

 

[sgimbel]

The drill bit was packaged with the mandrel. I'll try the 5/16", thanks