Introduction: Make a Tap From a Bolt

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A tap is used to either make new threads in a hole, or repair damaged threads. Taps can be purchased, but here is how to make one out of any bolt. After you repair the damaged threads, the bolt can still be used. When using it, apply light oil, and remove the metal shavings. Cut the grooves with a triangular file.


billsw (author)2016-10-22

This is a neat idea but unfortunately it's not a tap replacement. For one thing, a tap is usually made out of high carbon or high-speed steel (HSS). The higher carbon allows the tap to be heat treated to stay sharp while cutting into steel which is softer than itself. The picture above shows what looks like a zinc plated bolt made of mild steel. An attempt to cut threads with this would likely lead to simply mucking up the threads on the bolt. At best, this might be a way to clean up threads which are full of gunk and grime but any amount of grunge in the threads is going to quickly fill the pockets which have been filed in. Depending what's in the "gunk" you may end up spalling or galling whatever threads are left and possibly damaging things further. If you do a lot of fix-it stuff, invest in at least a cheap tap & die set. They can be had for under $20 bucks at They are cheap high carbon steel sets and won't put up to a lot of abuse, but they'll work OK for cleaning up spalled threads or maybe getting a couple extra turns into a blind hole you stripped out. Don't bother with the TiN coated sets. Unless you plan on spinning the tap at high speed, the TiN coating is just eye candy. If you want a tap and die set like the pros use, get one made of HSS.

hjjusa (author)2012-04-04

I woud suggest a high carbon bolt, then heat treat it, I have some I have been forging knives from, think I will try this, trouble is they are all the same thread diameter

georion (author)hjjusa2012-04-09

well,,,,,,,,,,,you could get some diff diameters to suit your 'needs,,couldnt you???

hjjusa (author)georion2012-04-09

Very true

finton (author)2011-10-17

Love the idea, but isn't this remarkably like the Instructable "Repair threads with a home made tap"? Perhaps you could combine these two with "Turn any nut into a die" and bring both great ideas into one Instructable.
Definitely going to remember these two ideas for my workshop.

heathbar64 (author)finton2011-12-28

I'm with finton on this. Seems like cheatin to make several ibles from the same idea.

georion (author)heathbar642012-04-09

i dont hear no cheatin songs,,maybe they are on another station with another JUDGE???????????

aaahotdog (author)2011-10-10

To speed things up in addition, use a dremel cutting wheel rather than a file to cut the threads. Thanks for the reminder, good tip

pfred2 (author)aaahotdog2012-02-02

So you want to speed things up a bit with an abrasive disc do you? Well then do I have an article for you!

About This Instructable




Bio: I am the author of "The Art of Fixing Things,"
More by Fixit guy:How to tighten things.Make a tap from a boltGet your hardware in order.
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