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Insert or Helicoil on through hole

TXShelbyman

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Mar 17, 2013
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#1
I have tapped many holes freehanded and never gotten one really crooked. I wasn't so lucky this time. I tapped a 16mm hole in 3/8 aluminum plate, it is a bracket I am making, and I got it really crooked, not a little, a lot. :( What your be your suggestion on fixing this, redrill and helicoil or redrill and insert? I know, i should have used my mill to power tap it or at least start the tap. Thanks!
 

Randall Marx

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#2
I have no real preference except that solid inserts usually use standard threads instead of the Heli-coil threads.
 

T Bredehoft

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Dec 27, 2014
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#4
I concur with Jim, a Helicoil could not straighten out your hole, it's not that much larger than its internal diameter. Chuck a piece of 5/8 in your lathe, thread the OD, tap the ID while in the lathe with the tap in the tailstock, turn the chuck by hand, tap the 3/8 plate to fit the 5/8, locktite or pin the 5/8 threads.
 

TXShelbyman

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Mar 17, 2013
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#6
Thanks for all the replies! Looks like I will be drilling and using an insert. I had thought about welding, but alas I only have a mig without a spool gun.
 

mikey

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#7
You can also bore the hole so it will take a Time-sert. Boring will straighten it and bring it to the right dimension for the Time-sert, which is much stronger than a Helicoil repair.
 

outsider347

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Sep 3, 2012
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#10
Aluminum work piece?
Time -cert the only way to go. ....The insert of choice for anyone repairing a aluminum Porsche heads or case. I just repaired 6 Porsche heads with broken exhaust studs
 
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