DIY Thread chaser

**TrailLeadr** · 07-26-2007, 12:24 PM

When I sent my heads out to the shop to be reworked they came back looking all pretty, but beauty was only surface deep. What I failed to realize was that all of my threaded holes were very much caked up with junk from the cleaning process.

Because of the condition of the threads I ended up breaking rocker studs in the heads. This worked out in the end because I replaced the stock rockers with full rollers.

However it's always a good idea to chase the threads and clean them out, before you stress the threads, and either stip the hole, or break a stud in the hole. anyone can do this, there are no special tools required.

If you have a tap and die set then you're ready to go, but if you don't own a tap and tie set, you still can get the job done. I have a tap, and die set, and I also have kids, which means at some point my tools have been scattered, lost, or used as toys. So my set isn't complete anymore.

So what do you do?? It's easy:

Pick up an old bolt that fits the current sized hole, and thread. Preferably one that came out of the hole in question.

Once you have the bolt selected, using a cut off wheel, a dremel type tool, or even a file, cut a notch starting at the bottom of the bolt going upward across the threads. You may wish to cut two notches, one opposite of the other on the bolt. I only cut one. (image below)

Try to keep your notch a little shallow. You could go deeper than I did, but not too much, as this will weaken the strength of the bolt. I definitely could have gone deeper, but I was only removing rust, so I didn't need a big notch to catch a lot of garbage.
Too deep may cause the bolt to snap in the hole, which would cause you a whole lot more work.

NOTE:It is important to cut your notch, just like this one pictured (Based on right hand thread). The red oval at the 12 o'clock position has a sharp right angle cut into the thread.
While the blue oval at the 10 o'clock position has a taper cut into the threads. When cut this way, it allows the hard cut 90deg angle to bite into the garbage in the thread and scrape it away. If not cut this way, the bolt will not be as effective. (image below)

Once you're past this point, you simply need to thread the bolt into the hole, and then back it out to remove the gunk. As you do, the build up of gunk, or whatever is in the hole will collect in the notch.
Depending on how full of debris the hole is you may have to back the bolt out a few times to completely chase the hole.

**Cableguy** · 07-26-2007, 12:39 PM

Originally Posted by TrailLeadr

which means at some point my tools have been scattered, lost, or used as toys. So my set isn't complete anymore.

Looks like his action figures have new weapons....

Sad really.

But on another note good job on the write up, good when you don't have time to go get another tap. WTG!

...which "T.O.D." should I put that under...

**phoebeisis** · 07-26-2007, 12:44 PM

Hey,great idea.This is better than a tap,since it won't cut any metal away from the threads like a tap almost always does because the material is so darn hard-carbide or whatever. You won't end up with a loose hole like running a tap thru causes.
Thanks,
Charlie

**dwill3015** · 07-26-2007, 12:54 PM

Nice job! Very informative DIY.

Way to go Patrick

**Davandy** · 07-26-2007, 01:47 PM

Good idea, way to go Patrick

**TrailLeadr** · 07-26-2007, 04:34 PM

Thanks guys

**84fiero123** · 07-26-2007, 06:03 PM

Great write up Patrick, and I don’t want to make the post any less important because it is a great idea, but I just use compressed air. And you don’t even need to own a compressor nowadays.

Just buy a can in the computer section of your local Wal Mart, or what ever.

**bjersr** · 08-03-2007, 01:54 PM

Thats a great idea but Summit has a set of thread chasing taps for $12.95 (part# SUM-900200). You should never use a regular tap to chase threads. It will remove material and make the hole weaker. I have a set of these and they work great. If you turn wrench's regularly get a set.

**Cableguy** · 08-03-2007, 10:04 PM

Originally Posted by bjersr

Thats a great idea but Summit has a set of thread chasing taps for $12.95 (part# SUM-900200). You should never use a regular tap to chase threads. It will remove material and make the hole weaker. I have a set of these and they work great. If you turn wrench's regularly get a set.

Nice work, Bjersr. Sounds like a good deal too.