Insert or Helicoil on through hole

[TXShelbyman]

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]

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

 

[JimDawson]

Since you need to straighten out the hole, the threaded insert might be better since it requires a larger hole than a Heli-Coil. Would require removing more material so has a better chance of taking out all of the angle.

 

[T Bredehoft]

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.

 

[RandyM]

If you have a welder or access to one, I'd be inclined to just weld it up and re-tap it.

 

[TXShelbyman]

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]

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.

 

[Kernbigo]

make your own insert ,tap it to a taper pipe and use a pipe plug for a insert, works great

 

[Ulma Doctor]

I use Keenserts whenever a helicoil is insufficient

 

[outsider347]

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