The bolt is a 12x 1.25

I can't find a helicoil kit for it in stock anywhere, I can order one...but do you guys know how large of a hole needs to be drilled for these kits?

I'm trying to figure out if these stripped bolt holes are repairable with a helicoil.

The rear two are the ones that need to be repaired. The one closest to the engine is fine.

You can see how they are oblonged out a little. Looks like someone drilled the bolts out before.

Anybody know what size drill bit you predrill with for a 12 x 1.25 helicoil? I'm wondering if it's just big enough that these holes can be repaired!

 

google M12x1.25 HeliCoil and the link has the drill sizes for each kit...
http://www.emhart.com/products...tm#MF

Although expensive,time-serts are alot more durable...
http://www.timesert.com

If you can't find the proper size in metric,
You could always use a standard size...


Modified by 88DXCRX at 5:11 PM 11/9/2005

 

The drill size for a M12x1.25 HeliCoil is a 31/64".

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88DXCRX &raquo;</TD></TR><TR><TD CLASS="quote">google drill tap sizes.. </TD></TR></TABLE>

Tap drill sizes? Do you know that is completely different then a HeliCoil drill size?

 

opps..wasn't thinking clearly..sorry..

 

if you want to save money and time, try to get a tap and die set, the one that looks like a screw, and screw it in.
Tap and dies are always good for stripped lug nuts. the hexagon ones that is.
they sell screw drill bits with that twist in.

 

You would have an easier time switching to SAE threads. 1/2" fine or coarse would work well. Bolts will be easy to come by too.

Actually, if you really want to do it up right. Tap it for SAE and install 3 studs.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MugenHonda &raquo;</TD></TR><TR><TD CLASS="quote">if you want to save money and time, try to get a tap and die set, the one that looks like a screw, and screw it in.
Tap and dies are always good for stripped lug nuts. the hexagon ones that is.
they sell screw drill bits with that twist in.</TD></TR></TABLE>

I would do that...except the bolt hole is stripped out completely. There's no threads left at all. It's been slightly overbored.

Thanks for the help guys.

 

Yeah, those holes look a little too fubared to use helicoils. FWIW, helicoil taps are known as STI taps for Screw Thread Insert. We use an insert at work called a keysert, its like the timesert except the wall is thicker. Would probably work. Does not require an STI tap, just a larger standard or metric size.
http://mdmetric.com/pdf/keysert.pdf
HTH
chris

 

Chris,

It looks like the 12 x 1.25 kit should work for me.

Do you know any retail stores that sell these things?

 

Try McMaster-Carr. http://www.mcmaster.com/

Search for helicoil.

Looks like 12x1.25 are $3.00 per pack of 10.

 

if I went with helicoil kit, I'll need to double up on them.

The only problem with that is that I don't know what the external thread size is for a 12 x 1.25 kit. The hole is too large right now to accept a standard 12 x 1.25.

Maybe a 14 x 1.25?

 

Tap it for larger bolts I dunno, i just don't trust coil.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tyro &raquo;</TD></TR><TR><TD CLASS="quote">Try McMaster-Carr. http://www.mcmaster.com/

</TD></TR></TABLE>

search for threaded inserts
They do small orders with a credit card

Don't try to double up on helicoils, bad idea.

HTH
chris

 

So the hole is larger then 31/64"?

I have used helicoils on engine mounts and they worked fine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Surewin &raquo;</TD></TR><TR><TD CLASS="quote">So the hole is larger then 31/64"?

I have used helicoils on engine mounts and they worked fine.</TD></TR></TABLE>

I tried with a 1/2"...that's larger than a 31/64, so yes.