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self-tapping screw for Aluminum Housing
How are you?
We have a project which is assemble process of housing (aluminum casting) and plastic inside parts by using general machine screws (#6-32 x 7/16”).
We have problem with threading process (blind hole) of aluminum housing. It took lot of time and labor, so our manufacturing contract vendor suggest self-tapping screw for this project.
We never use self-tapping screw for aluminum casting part.
My questions are
1. Is self-tapping screw popular for aluminum casting part in this time?
2. Do you think self-tapping screw can be replaced our screw?
- Thread hole is blind hole, screw size #6-32 x 7/16”, Screwing toque 20 Lb-inch, one time assemble (never repair or replace)
3. If you know, please tell me proper self-tapping screw type, shape or PN with manufacture name.
Thank you in advance.
Best regards,
Paul
We have a project which is assemble process of housing (aluminum casting) and plastic inside parts by using general machine screws (#6-32 x 7/16”).
We have problem with threading process (blind hole) of aluminum housing. It took lot of time and labor, so our manufacturing contract vendor suggest self-tapping screw for this project.
We never use self-tapping screw for aluminum casting part.
My questions are
1. Is self-tapping screw popular for aluminum casting part in this time?
2. Do you think self-tapping screw can be replaced our screw?
- Thread hole is blind hole, screw size #6-32 x 7/16”, Screwing toque 20 Lb-inch, one time assemble (never repair or replace)
3. If you know, please tell me proper self-tapping screw type, shape or PN with manufacture name.
Thank you in advance.
Best regards,
Paul
Replies to This Discussion
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Permalink Reply by Sean Grape on -
We almost never tap into aluminum directly, we use an insert (like a helicoil) because the material is so soft and won't hold up to repeated fastener insertion. Sounds like there is an access issue going on here, so there might not be room for helicoil insertion tool either. Have you considered riveting or pressing in a stud?
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Permalink Reply by Richard Weinandy on -
Paul,
Look at this type of screw: It is self-tapping but the screw also has a point like a drill and grooves up the side of the screw for the fine chips to get out of the way; so you are both drilling the hole and self-tapping the thread as you thread it in.
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Permalink Reply by Scott Stearns on -
In most cases aluminum is best to either have a helicoil inserted as stated by Sean , if possible roll forming the thread would be a much stronger thread vs using a standard tap. This prevents pushing a chip into the bottom of the blind hole.
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Permalink Reply by Jude Jonas on
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We use a self taping #4-40 screw on a aluminum casting with a blind hole that has a draft. Alls the screw does is hold a PCB board, and no major force is applied to the part. I have personally removed the screw several times and the taps are fine.
go to Mcmaster.com and look for self taping screws...they usually run a little expensive than regular machine screws.
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Permalink Reply by Bill MacCracken on -
Bill MacCracken said:I would suggest a DOE with torque,hole dia and breakage as factors. One concern with self tapping screws is the chips created. If you have electronics in the area it may be of concern - even with a blind hole, because of rework The self tapper sounds like a cost reduction to me if you're tapping the holes now.
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