Big oops - rear shock studs

[KrazyKarl02]

what I did

I broke off a shock stud in a similar situation. What I did was cut the remaining stud out, go to the hardware store and find a big bolt that matched it. Drilled out the old stud, put the bolt in, and mig welded it up. Most of us do not have mig welders, but this worked, I then ground the head of the bolt off and welded that side too, the end result is you can not tell the difference!

[Anonymous]

I know what you mean but if you only drill & tap the absolute minimum depth you are still retaining the maximum strength of the stud. If you "flat bottom" drill the hole, and use a "plug" tap to finish threading the hole you will minimise the dead area at the bottom of the hole.

Two terms I'm not familiar with here -- "flat bottom" drilling, and "plug tap". I assume the latter refers to a tap which can be used to finish the thread right to the bottom of a flat hole -- can I find such a tap at most hardware stores? How do I "flat bottom" drill the hole? Special drill bit?

Also, how deep did you drill into the stud?

Thanks!

Michael

[Paul]

Two terms I'm not familiar with here -- "flat bottom" drilling, and "plug tap". I assume the latter refers to a tap which can be used to finish the thread right to the bottom of a flat hole -- can I find such a tap at most hardware stores? How do I "flat bottom" drill the hole? Special drill bit?

Also, how deep did you drill into the stud?

Thanks!

Michael

Flat bottom drilling - a normal drill has a point at the end, which leaves a pointed hole, a flat bottomed drill has been ground so that the end fo the drill is flat so it leaves a hole with a flat bottom. Normally you would drill with a standard drill, then follow through with a flat bottomed drill to produce the flat bottom oin the hole.

Plug tap - taps usually come in sets of 3, referred to as 1st, 2nd & 3rd or taper, 2nd & plug. The 1st (or taper) has a long tapered form so that it will tend to self-centre itself in the hole, the 2nd has less taper, while the plug has no taper so you can get maximum thread in hole.

I threaded about 12/15mm into stud, I think the depth of thread was dictated by what bolts I had to hand at the time!

The stud was hard to drill though.

[Anonymous]

I drilled the studs this weekend. First I cut off the old threaded parts, and filed the end so it was clean. Then I used a regular drill bit to start the holes, then used an end mill to finish off the bottom. I couldn't find the "plug tap" that Paul referred to -- found a tap which said it was "plug-style", but sounds like what Paul described as the "#2" tap, just less taper than a normal tap. Anyway, I bought two of them, and one I ground off at the end to make a tap without taper. I drilled about 14 mm into the stud, tapped first with one tap then the other, then installed a bolt and washer to secure the shock. The bolts bottomed out just as they took purchase on the washer, which is perfect I think. I put a bit of thread-lock on the bolts so they won't shake loose, although I was able to get them nice and tight, so I doubt it would have been a problem.

The finished mod looks great, and leaves most of the original stud in place. Thanks for all your help!

Michael