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How to Fix a Stripped Screw

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How to Fix a Stripped Screw


Stripping the threads on a screw or machine bolt may seem like the end of that piece of equipment, but the problem can be repaired without too much trouble. What we are going to do is increase the size of the threaded hole by 1/16" in diameter. In this article, we will assume that the original bolt was 1/4" x 20 x 1". Check the "Things You'll Need" section below for necessary tools and parts for replacing the threaded hole and bolt with a 5/16" x 24 x 1".

Steps

Place the part or equipment containing the internal thread in a vise, or clamp it to a table.
Insert the 1/4" bit in the drill and drill down the internal thread parallel with the original hole.
Clean out any shavings with a vacuum, or turn it upside down and tap out the debris.
Place the tap in the tap wrench and oil the cutting part of the tap.
Keeping the tap parallel to the hole, press slightly downward and rotate the tap. The tap is usually tapered so that it will go into the hole before it starts to bite into the metal sides of the hole.
Once the tap is biting into the metal, release the downward pressure and let the tap direct it down.
Every two or three turns, reverse the tap to remove shavings, and add some oil.
When the thread is completed to the desired depth, clean out the hole and test the new bolt.


Tips

It is important to keep the drill and the tap parallel to the existing hole.
Make sure the tap's threads per inch are the same as the replacement bolt or screw.
Warnings
If the object you are repairing is a motor or complicated equipment, you should mask off any areas that might catch metal debris from the drilling or tapping.
Things You'll Need
1/4" drill bit
5/16-24 tap
5/16-24 x 1" bolt (replacement)
Tap wrench