Helicoil error found (PICS ADDED)

[suprarx7nut]

I recently looked at the bit, tap and studs used for my helicoil attempt again and I see a problem.

You must use the same thread on the tap and the bolt you plan on using. This seems like common sense, but I was fucking stupid.

THE TAP IN THE KIT WAS A 13 NC AND THE BOLTS WERE 14!!!

Now I'm no expert, but trying to put a 14 stud into a 13 tapped hole just wont work. I'm a little pissed off.


Now my confusion really set in:
1. The drill bit is a 29/64" and the tap is a 1/2". The only thread pitch for 1/2 seems to be 13. The only thread size for 7/16 is 14. WHAT THE FUCK?

I used the kit from Driftmotion, but the part that seems to be messed up is the tap which came with the helicoil kit. WTF?!?!


This is the EXACT tap I recieved: http://www.descotools.com/ProductInfo.aspx?productid=122138

This is the helicoil kit from OEM: http://oem-tools.com/product_info.php?cPath=27&products_id=1582

The studs are 7/16 - 14.


How should this have looked? What tap "should" I have gotten?


***EDIT***

Pics:

Here is the tap with one of the studs. The directions clearly state the threads must match exactly... they dont.

The helicoil does in fact match the stud. The helicoils are the 7/16-14 ones that the kit is labeled for.

Here is the helicoil next to the tap. I'm pushing it into the threads now. Notice how the coil has to spread out to fit into the thread of the tap.

Here you can see the tap and the label for the kit. The label of the tap reads:

DESCO USA
1/2 - 13 NC
HIGH SPEED

Directions just fo rthe hell of it:

At this point, I'm almost 100% certain that the tap is NOT the correct helicoil tap. Anyone disagree?

 

[Bill UK]

This may help Link

 

[Nick M]

You should have gotten Helicoil 10 x 1.25. It comes with the correct tap, which was 12 x 1.25.

 

[IJ.]

The included Tap with Helicoil kits isn't a standard thread form/size it's always a freak size (this is why you can't "nest" Coils to reduce a hole diameter)

 

[Poodles]

I have the DM upgrade in my head right now...it works fine

 

[suprarx7nut]

This may help Link

Doesn't really help because it does not list the tap size.

You should have gotten Helicoil 10 x 1.25. It comes with the correct tap, which was 12 x 1.25.

Ya, in retrospect, metric would have been MUCH easier to pair up taps/studs.

The included Tap with Helicoil kits isn't a standard thread form/size it's always a freak size (this is why you can't "nest" Coils to reduce a hole diameter)

But my question is why would they package a 13 tap with a 14 kit?

I have the DM upgrade in my head right now...it works fine

Can you please tell me what size tap you have? What brand is it? Is it desco?

I'm very perplexed as to why I ended up with a 13. I'm an idiot for not checking the thread properties of the tap.

 

[Kckazdude]

I am so confused. Are you putting the threaded insert in? You have to tap the hole bigger then install the insert then install your stud.

 

[isnms]

First: If you got the kit from Driftmotion, you should contact them on any questions you have.

Second: The stock size kit has Helicoil kit M10x1.25 & 13/32 drill bit

edit: It did not come with the drill bit, but that is the correct size.

 

[suprarx7nut]

I am so confused. Are you putting the threaded insert in? You have to tap the hole bigger then install the insert then install your stud.

I am familiar with the process. I did everything correctly, BUT the tap I used was the wrong size. I am not sure what the correct size should be.

First: If you got the kit from Driftmotion, you should contact them on any questions you have.

True. Although my problem is not with DM. Unlike some people I realize and accept that it was MY fault for not checking the tap like I should have. In the instructions they even set aside an ENTIRE step for making SURE that the tap and bolt/stud have the same threading.

Second: The stock size kit has Helicoil kit M10x1.25 & 13/32 drill bit

edit: It did not come with the drill bit, but that is the correct size.

The stock size has been known to rip out same as the original studs(not often, but it happens). I wanted to make sure my studs would hold so I got Aaron's 7/16 exhaust kit found here: http://www.supramania.com/forums/showthread.php?t=35682

Again, I dont really think DM is at fault in any way. Even if they shipped me the wrong part, I'm the fool who didn't check it before using it. :nono:

 

[suprarx7nut]

First post edited and pics added.

Does anyone think that is the right tap? I certainly dont.

 

[Nick M]

Either tap is wrong, or the bolt. Depends on how you look at it.

 

[Rennat]

nevermind, didnt realize you were pushing the helicoil into the tap...

my guess is the tap is wrong.

 

[suprarx7nut]

Either tap is wrong, or the bolt. Depends on how you look at it.

Ya. Given that the helicoil kit is labeled for the 7/16-14 and thats exactly what the bolt is and thats what size the coils are, I'm going with the tap being wrong.

you tap the holes for the helicoil, and the tap matches the helicoil. if the stud threads into the helicoil, your fine...


the threads inside the helicoil are probably different then the outside too, so it makes sense why the stud doesnt match the tap, because the tap is for the outside of the helicoil

Lol, no. The coil will form to the thread pattern of the tap. So when you tap a 13 hole, the coil becomes a 13 thread as well. The helicoil does NOT change the THREAD!!!

People keep saying that the helicoil taps are different. I dont doubt that, but the THREAD CANNOT BE ANY DIFFERENT!!!!!

 

[IJ.]

Done a bit of research and can't find mention of a 7/16-13 tpi tap.

The Helicoil part number is 91709A108 for the corrct tap.

I stand by my earlier post though the Helicoil taps AREN'T standard forms sizes meaning you CAN'T go and buy a 7/16-14 tap and use it for the inserts.

 

[suprarx7nut]

Done a bit of research and can't find mention of a 7/16-13 tpi tap.

Well the tap would be larger in diameter than 7/16. It needs to be about 1/2". And the tap MUST be a 14. NOT a 13.

Everything else is 14. The coils, the labeling of the kit, the studs... This has been done correctly before. I'm waiting to see what Aaron says because he has done this before.

 

[IJ.]

1/2-13 tpi IS a standard size so I'm not sure if someone thought the much cheaper "stock" tap would interchange or not.

 

[suprarx7nut]

1/2-13 tpi IS a standard size so I'm not sure if someone thought the much cheaper "stock" tap would interchange or not.

Ya, I think a standard tap very close to, but not exactly, the same as the helicoil one got swapped at some point. I just dont know where to get the special tap now. I think it only comes in the helicoil kit from OEM, but I dont know what the correct tap measurements are. I think I need to contact OEM unless Aaron has an extra lying around his shop or something.

 

[IJ.]

Mcmaster-Carr stock em using the part number I posted above.

 

[suprarx7nut]

Mcmaster-Carr stock em using the part number I posted above.

Wow, thanks Ian!!

25 bucks though... jeez. Maybe DM will hook me up.

I agree that a standard 7/16 tap wouldn't work because that would have an actual diameter of 7/16. The inserts are wider than the stud that will fit in them. The helicoil ones are some small amount wider than the stud/bolt that will fit into the inserts.

 

[IJ.]

Yep but Helicoil sneakily made it so the next size up tap is too small so you HAVE to use theirs!

This is what I meant earlier by you can't "nest" coils to reduce a hole size and the Inserts won't screw into each other.