Drill size for 10-40 Tap in Aluminum

[65arboc]

I bought a mini spark plug and it came with a 10-40 tap/ All the charts I have only list to 10-32. What # size drill should I use for taping in aluminum?

Thank you,

Jim

 

[charlesfitton]

http://www.harveytool.com/secure/Content/Documents/Tap_Drill_Chart.pdf

 

[65arboc]

http://www.harveytool.com/secure/Content/Documents/Tap_Drill_Chart.pdf

Thank you very much, I had not seen that before.

Jim

 

[Philipintexas]

I hadn't seen that chart either, I'll print it for future needs. Thanks for the info.

 

[purpleknif]

Major dia. minus lead (.025") = drill size.

 

[kquiggle]

You can find more charts at the link below; I particularly like the Little Machine Shop chart for tap sizes.

https://sites.google.com/site/lagadoacademy/useful-links#charts

 

[Capt,n John]

I never seen any glow plug that had 10-40 threads. All I have seen have 10-32 threads. Check the threads per inch on the plug you are going to use. Good Luck

 

[65arboc]

I never seen any glow plug that had 10-40 threads. All I have seen have 10-32 threads. Check the threads per inch on the plug you are going to use. Good Luck

It's not a Glow Plug, It's a Spark Plug