Threads in 6061 & 2024 Aluminum
Threads in 6061 & 2024 Aluminum
(OP)
What is the recomended full thread depth to diameter ratio for threads in 6061 & 2024 Aluminum? Would another common alloy and temper be better?
Thanks,
Sean
Thanks,
Sean





RE: Threads in 6061 & 2024 Aluminum
--Scott
RE: Threads in 6061 & 2024 Aluminum
Swertel's rule of thumb is good advice. You also asked about "better" alloys and tempers, by which I guess you mean stronger alloys and tempers. You didn't provide tempers for your 2024 and 6061 alloys, but there are stronger alloys available, 7075 being one of them.
Suggest you use the applied load to determine the strength you need in the joint, then select a combination of alloy, temper, and thread which will do the job. Be careful, also, that drilling and tapping, or other machining in the vicinity of the threaded holes, does not cause local annealing, which can result in a drastic loss of strength.
RE: Threads in 6061 & 2024 Aluminum
Don't tap Aluminium alloys, use helicoil inserts.
RE: Threads in 6061 & 2024 Aluminum
RE: Threads in 6061 & 2024 Aluminum
RE: Threads in 6061 & 2024 Aluminum
Cheers
Greg Locock
RE: Threads in 6061 & 2024 Aluminum
Nice answer or post!
Do you mean calculate or do you really
mean measure? I have seen calculations
in machineries handbook that calculate
strength based on the actual diameters.
It would nice to have a graph and post
the gain from 68 to 80 percent threads.
RE: Threads in 6061 & 2024 Aluminum
special taps roll form type that require
larger size hole as Greg Locock mentions
and does a nice job. The tap depth is
dependent greatly on the grade of bolts
that you are using. No one has mentioned
class of threads. I think this too would
be a factor not so much for strength but
for dynamic reasons.
RE: Threads in 6061 & 2024 Aluminum
Tapping into soft metals such as aluminum is a poor design practice:
A. Since most screws are steel, you end up with dissimilar metals (steel on aluminum) which will cause corrosion, pitting, galling, etc. at the threaded interface.
B. Aluminums are usually softer than the steel screws and are apt to strip.
Best practice is to use clinch nuts or helicoils where the contacting metals are galvanically similar.
RE: Threads in 6061 & 2024 Aluminum
The way we do it in practice is to tap the aluminium the first time and expect to helicoil if the bolt ever comes out.
Cheers
Greg Locock