Tapping Aluminum?
Tapping Aluminum?
(OP)
I have to retap new holes in an aluminum frame to attach an aluminum cover to seal a clearwell. Using 3/8 bolts, what size tap is required? Also, are there any good books on tapping?
Thanks.
Thanks.





RE: Tapping Aluminum?
http://www.emhart.com/products/helicoil.html
RE: Tapping Aluminum?
If your going to drill for a course thread a 5/16 drill is required for 70% thread.
RE: Tapping Aluminum?
Barry1961
RE: Tapping Aluminum?
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Tapping Aluminum?
RE: Tapping Aluminum?
Your post 21 Feb 06,
What!! Seek information from Machinery's Handbook as CoryPad said. Simple stuff... I would use thread inserts as indicated by "ajack1". All data is given and available for the required
thread size you want or need.
Wish you well
Best regards
pennpoint
RE: Tapping Aluminum?
Hope that helps.
RE: Tapping Aluminum?
On the subject of tapping threads in aluminium, the best cutting fluid I've used is metholated spirits.
RE: Tapping Aluminum?
RE: Tapping Aluminum?
RE: Tapping Aluminum?
Well good on you. I too hope you can get away with just tapping the aluminum material. But your question eluded to retaping and the best way and thats how many of us answered. If you want to get away with something why ask? Just do it!
Best regards
pennpoint
RE: Tapping Aluminum?
Perhaps a matter of corrosion or galling. Use a corrosion-resistant anti-seize compound (e.g., a Loctite or Permatex product) on the bolt threads. Avoid those containing graphite or copper in wet applications (galvanic problem).
RE: Tapping Aluminum?
RE: Tapping Aluminum?
"The original bolts weren't stainless and over time most had broken off in the frame."
If the original bolts didn't gall (cold weld), then corrosion products in the threaded area seized up the bolts. The advice to use corrosion-resistant, anti-seize compound (non-Cu, non-graphite) also applies for SS bolts in aluminum. Tefgel & blue Loctite are recommended in The Boatowner's Guide to Corrosion for SS/Al.
RE: Tapping Aluminum?