Tap and Die, need help.

[sandy]

I'm having to tap into a jackplate and use<br />a 1/4" bolt (20-thread) and I need to know what size hole to drill. Im unable to find a chart on the website, thought maybe one of<br />the mechanics could help.<br />Many Thanks

 

[petryshyn]

Re: Tap and Die, need help.

13/64"<br />

 

[sandy]

Re: Tap and Die, need help.

Schematic, thanks for the help (ref:13/64)<br />I'm drilling in the jackplate that holds a<br />Johnson 150 for my bass boat.

 

[2vincent]

Re: Tap and Die, need help.

a good thing is use nut any sise, and<br />find drill who fit in nut.never use bigger than nut hole cause they have 75% of trheads<br /><br />also u can use any oil for cutting threads<br /> <br />happy new year 2002

 

[Rex]

Re: Tap and Die, need help.

USE A #3 DRILL<br />IF YOU LOOK AT THE CHART 55% IS AS GOOD AS<br />75%. CHECK IT OUT.<br />REX A. HUBBLE.<br />IF IT IN SOMETHING THAT TAKES ALOT OF USE<br />MAKE THE HOLE 3 TIMES THE DIA. THAT IS DEEP.

 

[wippb]

Re: Tap and Die, need help.

Hey Sandy<br />Not that I know much about anything but I work in a machine shop and they have the charts hanging all over the place. For 1/4 x 20 bolt, the charts say # 7 drill which is .201". Schematics 13/64 drill is equivalent to .203". Close enough in my books and probably more readily available. Rex's #3 is .213" and will work but will make the thread a little sloppy as it is the drill recomended for 1/4 x 28 which is the fine thread. But like I said what do I know, just my $.02 worth.

 

[FNG]

Re: Tap and Die, need help.

Isn't the drill size labeled right on the tap?

 

[Lanier8]

Re: Tap and Die, need help.

I'M A TOOLMAKE.<br />READ THE FINE PRINT ON THE CHART AND YOU WILL<br />SEE WHAT I'M TALKING ABOUT.<br />REX A.<br />OR READ THE MACHINE HAND BOOK AND IT WILL TELL YOU.

 

[wippb]

Re: Tap and Die, need help.

My experience has been that some times it is but most of the time it isn't. <br /><br /><br />What do I know. Just my $.02 worth