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Hagerty Employee

Wrenchin' Wednesday: How to make your own thread-chaser

We've all made the discovery, proof that someone has been here before. Every bolt except one comes out easily, and sure enough, extracting it carefully reveals damaged threads. Ouch—one too many ugga-duggas! One of the realities of a project car is that often times things have been torn down and slapped together so many times that the threads become damaged over time. There's always the sin of cross-threading, but dirt and rust can also cause the female threads of a fastener to become to chewed up that a bolt will no longer fit.


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Clever way to do it if you lack the proper taps. I'd be hesitant to leave that bolt in, though, if it was holding anything more than an accessory, which you addressed as "Structural Use".


Been notching bolts for 35 years. With a nick name as difficult to live down as "Jack the Stripper" I felt it to be my duty to come up with face saving ways to repair my own damages just as quickly as they happened. Another good repair tip is to notch a flare nut from a discarded P/S hose especially for 85 and beyond Ford Taurus power rack n pinions. Made of aluminum + port location made for some easy damage. If not to severe

my notched flare nut was a life saver. The secret to the save though is when to stop turning the wrench. Still have that little nut too circa 1985.

Intermediate Driver

What cleans the threads on the thread chaser?


You might want to spin a nut or die on that bolt before hacking away. That way you can use it to clean up the threads as it comes back off. I also taper the first couple of threads to ensure a smooth start. 


Certainly a worthy trick when in that situation and in a rush, but consider "investing" in Harbor Freight tap & die sets. None of them will cut new threads in steel but they start at $10/set (before coupons!) and are fine chasers. Also come with a poorly made but useful thread gage.


Years ago I found a thread file in an antique store.  I don't know if they are still available but it has been very useful over the years. It has four different thread sizes.


Years ago I found a thread file.  It has four different thread sizes and has been very useful over the years. I don't know if they are still available, I think I found this one at an antique storel

New Driver

You sure it doesn't have 8 different tpi?  The one I bought back in the 70s has 4 on each end.  Each one is a different thread per inch.  Bought a metric one as well(being in Canada, mechanics all fell for the "world is going metric" crap and bought metric tools) that I haven't used but a couple of times.  They are most useful for wheel studs.