Tap drill size

In metric the tap would be 11.9 x .794 mm; charts like at

show

11.25 mm drill for 12 x 0.75, and taking off 0.1 mm would give 11.15, which is 0.0015 over 7/16". The metric calculator at gives 11.20 for a 12 x 0.8 mm thread at 77% thread.

"Christopher Tidy" wrote in message news: snipped-for-privacy@googlegroups.com... Hi folks, Can anyone tell me the correct drill size for use with this tap?

am guessing 7/16" or very close, but does anyone know for sure? Thanks! Chris ================================== This gives 80% thread for a 7/16" hole. jsw

Great. Thanks for the answers!

Chris

Great. Thanks for the answers!

Chris

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15/32-32 is the US standard for toggle switches. 1/4-32, 5/16-32 and 3/8-32 are also electronic thread standards. I used a 3/8-32 tap to make a heatsink that screws onto the F connector on a USB TV tuner that ran hot. 5/16-32 fits a Schrader tire valve, loosely.

A toggle switch is exactly what I want the tap for. The problem is that the plate is 10 mm thick, so there isn't enough axial length for the retaining nut and washer.

By the way, what size is the Schrader valve thread officially?

Thanks!

Chris

A toggle switch is exactly what I want the tap for. The problem is that the plate is 10 mm thick, so there isn't enough axial length for the retaining nut and washer.

By the way, what size is the Schrader valve thread officially?

Thanks!

Chris ===================

've also seen 0.302" / 7.7mm specified.

The "Leica" thread is a mix of metric diameter and British pitch and form.

Strangely, the rim + tire on a Soviet artillery piece captured in Iraq that I saw at an air show was sized in inches. The tire was Russian, made in Moscow (Mockba).