Ok to use Thread Tap for Thread Chaser?

Married2Allis

Well-known Member
I have a 1980 jap import tractor with a Toyosha motor, replacing the head gasket and need to clean the head bolt hole threads before reinstalling the head. Bolts are 12mm x 1.50 (odd size). The only 'thread chasers' I can find are too short. The threads are too deep into the bolt holes in the block for them to go all the way down. How else can I clean up the threads? Can I use a 12mm x 1.50 tap? - thanks.
 
Goi ahead and run the tap in there. Unless the threads are messed up you shouldn't cut anything out.

Donovan from Wisconsin
 
That's all I've ever used thread wise. With really garbage filled holes, I'll use a snug fitting drill bit by hand, tap, aerosol can, air pressure, and basically do everything I can to make sure holes are clean.
 
like don said, try a tap. if it starts cutting threads, stop!! you can also use a bolt and cut some slots down the sides with a dremel, use a blow gun and slowly run the bolt in and out. you can also use a wire brush to get in and clean them out. i use one that is for cleaning up distributor cap towers. its long enough to get in there quite a ways, and again, use a blow gun to clean out the debris.
 
It's hard on the taps but I do it all the time. Rusty holes are especially bad. If rusted I'll soak the hole with PB or Kroil for while and go a little at a time with the tap and back it off between advances. Start the tap carefully so you don't cut a new thread. If it feels the least bit like it's cutting stop an check it.
 
Keep in mind there are different size taps in the same pitch { G sizes] . If you remove any metal you need a smaller G size tap.
 
But what is the difference in how are they made? Does the chaser have the flutes to let the dirt out like the flutes on a tap to let the cut metal out, different type of steel or what?
 
Leroy: I never had any of the chasers that you would use like a tap. I do have the chasers to clean the threads like on head bolts. They will not cut new threads. Talk to a good tool man. I got my chasers from the Mac tool man over 45 years ago.
 
What do you call a good tool man? One that has used taps for 40 years or one that gets a commission for selling them?

If you have the correct size tap the only way you will cut a different thread is if you start the tap cross threaded. If a person tends to start taps cross threaded he maybe needs a bendable rubber tap or something.

Nothing wrong with using a thread chaser tap to clean a hole but a nothing wrong with using a regular tap either. I am not knocking them if that is what you have.

In building and repairing molds for over 40 years I have taped thousands of holes. When I tap a hole I blow it out and run the tap back down and out. It will not cut going in the second time. It just picks up the chips blowing it out didn't get. You can run the tap in 50 times and it will not change the hole.

A silly story by a good tool man to sell tools. If he sells you on it he is a good salesman.
 
I always used taps to clean the holes in the block, but my thread chasers that I have are like dies I have used them many times because they were sizes larger than say 3/4 inch plus some of the not so common sizes like was used on generators and 9/16th. I have them in both course and fine.
 
Thanks Bob, I know know what they look like. Never saw any. Have only ever used taps. Some taps are straight and will not enlarge the threads other taps are tapered and will so you need to know how deep you are running that tapered tap.
 
thanks for the link bob. i have a thread chaser set here at the shop that we use to clean up threads. they mostly get used during a restoration, where you are working on a hard to get part or very expensive part and the gentle approach will save considerable money in the long run.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top