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How to Repair Snap/broken Bolt/Stud Using Hand Tapping

Posted on Monday, January 21st, 2013 at 4:13 pm

This is nightmare for some people, including me, do you recognize this special stud? The 10mm bolt/stud is easily over-torque.

DISCLAIMER: I can not say this is the best or safest way to do. I am not
responsible for any thing you damage, or what ever harm you cause to
yourself or others. This is how I did it and it worked for me.

Grinding the surface.

For 10mm bolt, using the M6x1.0 (M6 mean the major (nominal) diameter of the thread and 1.0 is the pitch of the thread) tap and 5mm (the major (nominal) diameter of the thread – is the pitch of the thread = 5). From left, drill, taper tap, plug tap and bottom tap.

You also need the tap wrench. There are two main types of tap wrenches: double-end adjustable wrenches and T-handle wrenches. Double-end adjustable wrenches, also known as bar wrenches, have one threaded handle which is attached to one of the clamps. The clamp is opened to insert the tool and then tightened down against the tool to secure it. This type of tap wrench is used with larger taps and where there is room for a larger wrench, because a T-handle is more compact.

Before drilling, punch the stud center to keeps the drill bit from wandering around when you start drilling.

Make sure the hole is 90° and deep enough.

Tips before and during tapping :

1. Make sure the cutting teeth is always stand straight 90° around (left, right, front, back).

2. Use lubricant, example : Tapping fluid, WD-40, engine or machine oil or even your blood (just kidding) to reduce friction binding and aid in chip removal.

3. Take the time, taps are brittle (make from HSS – High Speed Steel) go slow, or you will need another tool, broken tap removal!

4. After 1 – 3 thread(s) (you will feel a little bit tight), move the tap counterclockwise and anticlockwise to remove the chips of loose material.

5. Be patient.

For starting, use the tapper tap, make several threads (usually the first 3-5 threads), then use the plug tap for further threads, and bottom tap for finishing.


Bolt in tightly and cut the bold head.

Look like an original right?

And after several day, my friend found this at the junkyard. My super friend!

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2 Responses to “How to Repair Snap/broken Bolt/Stud Using Hand Tapping”

  1. Abu hurairah ariff says:

    Can you sell me one of those…mine snapped as well. Cannot find it at autopart.

  2. Raz Veinz says:

    Hi, Im sorry, not for sell, I only have two of this, need to spare.

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