Drill and tap trans pan- Question:

[Banjer Picker]

Alright gang, this may be a dumb question but it’s new territory for me:

I need to drill and tap my aluminum transmission pan for the 1/8” NPT temperature sender for my Autometer transmission temperature gauge.

Do I need to use a drill bit that is smaller than 1/8”

I tried to do a search and couldn’t seem to find any definitive answers.

Thanks!

Brandon

 

[Yeller]

The easy size to find and remember is a 5/16 drill bit will do the trick for 1/8" NPT. I know someone will get out a machinist guide book and call out an "R" or 21/64th bit but 5/16 is readily available and works just fine.

When running the tap in use plenty of lubricant, WD40 or similar is sufficient. Pipe threads are tapered (like a wedge or "v")so run the tap 1/2 way in the length of its threads, remove it and thread the sending unit into the threads, you should be able to easily turn 3 revolutions with your fingers, if it won't go 3 use the tap again but go farther this time and try again. If you just run the tap all the way in the hole with threads may be too big and leak.

If in doubt shot me a PM and I'll give you a call.

Steve

 

[Banjer Picker]

The easy size to find and remember is a 5/16 drill bit will do the trick for 1/8" NPT. I know someone will get out a machinist guide book and call out an "R" or 27/64th bit but 5/16 is readily available and works just fine.

When running the tap in use plenty of lubricant, WD40 or similar is sufficient. Pipe threads are tapered (like a wedge or "v")so run the tap 1/2 way in the length of its threads, remove it and thread the sending unit into the threads, you should be able to easily turn 3 revolutions with your fingers, if it won't go 3 use the tap again but go farther this time and try again. If you just run the tap all the way in the hole with threads may be too big and leak.

If in doubt shot me a PM and I'll give you a call.

Steve

Awesome! Thanks Steve. Will we see you in HotSprings next month?

 

[Yeller]

Awesome! Thanks Steve. Will we see you in HotSprings next month?

Any time Brandon, always glad to help out. Unfortunately I think I'm out for Hot Springs, got a lot of personal and work stuff happening between now and the end of the year. Time and resources are really spread thin, its all good and will be better for it in the future so hopefully the sacrifice of breaking my life rules about going and doing pays off so I can do more going and doing;D

 

[surfer-b]

I'm not sure what pan you have but I doubt it will be think enough to use NPT on it, sure it will tap but will not be thick enough for the proper taper, you need to weld in a NPT pipe bung.

run the tap 1/2 way in the length of its threads, remove it and thread the sending unit into the threads, you should be able to easily turn 3 revolutions with your fingers, if it won't go 3 use the tap again but go farther this time and try again. If you just run the tap all the way in the hole with threads may be too big and leak.

sounds like Yeller has done it with success, try it and if it works great, if not you will have to weld in a bung

 

[Apogee]

Good reference.

https://www.brokenbolt.com/images/starrett-inch-metric-tap-drill.pdf

 

[68rockcrawler]

If it's not thick enough to tap you could add a drain plug kit. Same threading as the temp sender. I just did this on my steel pan. Maybe your aluminum pan will be thick enough.
https://www.summitracing.com/parts/sum-g1380/overview/

 

[Banjer Picker]

I'm not sure what pan you have but I doubt it will be think enough to use NPT on it, sure it will tap but will not be thick enough for the proper taper, you need to weld in a NPT pipe bung.



sounds like Yeller has done it with success, try it and if it works great, if not you will have to weld in a bung

Here’s the pan. It’s almost as thick as the sensor is long directly under the hole for the dipstick

https://www.jegs.com/i/Speedmaster/...MIzIzZopqI5AIVGh6tBh3z6wyMEAQYASABEgLZHfD_BwE

 

[Banjer Picker]

Any time Brandon, always glad to help out. Unfortunately I think I'm out for Hot Springs, got a lot of personal and work stuff happening between now and the end of the year. Time and resources are really spread thin, its all good and will be better for it in the future so hopefully the sacrifice of breaking my life rules about going and doing pays off so I can do more going and doing;D

Well that stinks. Hate that we won’t see you but I definitely understand. Good luck with everything and maybe we’ll see you at the LEBC Round Up in Texas in the Spring.

 

[Yeller]

Does stink but I think the end game will be worth it. I do try to live like tomorrow may never come but sometimes gotta plan and work the plan like it’s a guarantee

That pan will tap just fine.

You never know where I might show up