Drill bit size for 3/16

[one more]

What size drill bit for 3/16 taps? Just ran some tubing and will tap tomorrow. The bit I used for my spiles looks as if it will be way to big. Thanks for any input.

[jimsudz]

CDL recommends 19/64 for their 3/16 taps

[one more]

Thanks. A wealth of knowledge on this forum, it's great!

[maple flats]

Either a 5/16 or 19/64 (1/64 under 5/16).

[DrTimPerkins]

What size drill bit for 3/16 taps?

Just to be clear, you are probably using 5/16" (or perhaps 19/64") spouts, but they have a 3/16" tubing connector. It is highly unlikely they are 3/16" spouts.

[one more]

Thanks for the clarification, I'm using CDL taps FYI. In a somewhat related topic, how are guys attaching vacuum gauges to 3/16? Can't find a barb that goes that small and fits the gauge?

[DANNY-L]

Found my barbed nipples at ace hardware and used my tubing tool to put the tubing on. Then screwed it onto the gauge.

[n8hutch]

The green CDL spouts for 3/16 tubing take a 19/64 drill bit , says it in the CDL catalog. That is what I used this year, last year I used a regular 5/16 bit, it worked but I found that I had to really bury the tap once things started to warm up to maintain my vaccum.

[jimsudz]

Thanks for the clarification, I'm using CDL taps FYI. In a somewhat related topic, how are guys attaching vacuum gauges to 3/16? Can't find a barb that goes that small and fits the gauge?

D&G sells a 3/16 barb to 1/4" female npt,reasonable also.

[katmike]

The green CDL spouts for 3/16 tubing take a 19/64 drill bit , says it in the CDL catalog. That is what I used this year, last year I used a regular 5/16 bit, it worked but I found that I had to really bury the tap once things started to warm up to maintain my vaccum.

Well I used the regular 5/16 bit with my CDL 3/16 spouts. I was not aware of CDLs recommendation. That might also explain why I max at only 18" vac and it does seem like I have more leakers. I also had to really bury some to get a seal..... Time to buy another bit.

[one more]

Thanks guys! Just finished putting in 50 taps, I used 5/16 bit so I will keep an eye on the taps. And thanks for the gauge answer. I'm excited to see how this all works out!