Female Spark Plug Thread Chaser

weirdjim

weirdjim

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weirdjim
I've got all the male spark plug thread chasers I need. My compression checker adapter has taken a turn for the worse and doesn't like threading into the spark plug hole. I've examined it with a magnifying glass and I don't see the problem. I don't want to use the triangle file trick on it unless I can see the problem as it is a $75 oopsie if I mess the adapter up.

What sort of shop/operation has a female spark plug thread chaser?

Thanks,

Jim
 
Also known as a die? Harbor freight should have what you need, or any other auto / machine supply store. Bring the tester or a spark plug along to find the size, or look it up. Amazon should have them too, if not, then McMaster Carr.
 
All this gender language is so binary! Those aren't the only two options, you know.

Only kidding.....O'reilly's or Auto Zone will loan what you need.
 
an old spark plug with the ceramic and center electrode broken out
and a male quick disconnect fitting brazed on the harness end will make a cheap replacement.
 
I have a square file that's designed for cleaning up threads.. It has a few rows of teeth for each of eight thread pitches (two per side, one at each end). Mine is a jillion years old, but this one seems to be the same thing: https://www.matcotools.com/catalog/product/TR1A/THREAD-RESTORING-FILE/ It works great and, used gently, you will not ruin anything. The fact that the file engages several threads keeps it from wandering like a triangular file tends to do.
 
I think my spark gap adjuster (which threads onto spark plugs) could clean up dirt, very minor galling on male threads. Did you try it in several spark plug holes, to make sure its not the hole (you say you cannot see the problem; probably should be able to, is why I wonder about the hole)
 
Two votes for the thread file. The thread is probably just doinked at the end (It doesn't take much), seen it too many times. You can borrow mine, come get it.
 
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Let'sgoflying! said:
I think my spark gap adjuster (which threads onto spark plugs) could clean up dirt, very minor galling on male threads. Did you try it in several spark plug holes, to make sure its not the hole (you say you cannot see the problem; probably should be able to, is why I wonder about the hole)
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Several different holes, several different engines. But I have one of those gap adjusters; I had completely forgotten about it. I'll try that and if no joy I'll buy one of those thread files. By the way, none of the auto parts stores have that tool for loan. I almost called it a die, but the die is used to CREATE the thread, not clean it, although it would probably do the job. Just like the male plug thread chaser might be called a tap, which it is not.

Thanks for the help, gang, but I'm not going to Ohio to borrow a tool :cheerswine:
 
If you have a set of needle files there will be one or two that have a pretty sharp edge that would work better than your triangular one. Might want to try it, just a little bit, where the threads start.
 
Cooter said:
All this gender language is so binary! Those aren't the only two options, you know.
Click to expand...

I've got this odd vision of Jim sitting down and explaining the technical nature of the decision to the spark plugs. And then to you. :)
 
weirdjim said:
Several different holes, several different engines. But I have one of those gap adjusters; I had completely forgotten about it. I'll try that and if no joy I'll buy one of those thread files. By the way, none of the auto parts stores have that tool for loan. I almost called it a die, but the die is used to CREATE the thread, not clean it, although it would probably do the job. Just like the male plug thread chaser might be called a tap, which it is not.

Thanks for the help, gang, but I'm not going to Ohio to borrow a tool :cheerswine:
Click to expand...

A die is used to create threads as is a single point turning tool or a thread rolling tool. The thing about using a die is that it will clean up the thread by removing burrs and dents without distorting it or removing too much material. Of course if you are ham fisted with it, it can be cross threaded essentially destroying the thread. If you use a thread file, use a light touch and try to maintain alignment with the thread as you file. Hope you are able to fix it.
 
PaulS said:
A die is used to create threads as is a single point turning tool or a thread rolling tool. The thing about using a die is that it will clean up the thread by removing burrs and dents without distorting it or removing too much material. Of course if you are ham fisted with it, it can be cross threaded essentially destroying the thread. If you use a thread file, use a light touch and try to maintain alignment with the thread as you file. Hope you are able to fix it.
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Shucks, i teach tap and die techniques to my college mechatronics classes. if the old man bungs up a thread I'd never hear the end of it. I'll be REAL careful.

Thanks,

Jim
 
weirdjim said:
I've got all the male spark plug thread chasers I need. My compression checker adapter has taken a turn for the worse and doesn't like threading into the spark plug hole. I've examined it with a magnifying glass and I don't see the problem. I don't want to use the triangle file trick on it unless I can see the problem as it is a $75 oopsie if I mess the adapter up.

What sort of shop/operation has a female spark plug thread chaser?

Thanks,

Jim
Click to expand...
Just wire brush it, Jim you should know how to clean a spark plug threads,---- its the same ..
 
For you guys, don't be using tools to cut new threads, all you will do is,, ruin the old ones.
 
weirdjim said:
Several different holes, several different engines. But I have one of those gap adjusters; I had completely forgotten about it. I'll try that and if no joy I'll buy one of those thread files. By the way, none of the auto parts stores have that tool for loan. I almost called it a die, but the die is used to CREATE the thread, not clean it, although it would probably do the job. Just like the male plug thread chaser might be called a tap, which it is not.

Thanks for the help, gang, but I'm not going to Ohio to borrow a tool :cheerswine:
Click to expand...
Remember Jim, these are AN threads, not your common pipe or automotive.
just wire brush them
 
Tom-D said:
Remember Jim, these are AN threads, not your common pipe or automotive.
just wire brush them
Click to expand...
Interesting. My old Ford pickup must use AN threads on it's sparkplugs. It's plugs are threaded the same as the ones in my Cherokee.
 
GlennAB1 said:
LOL, Maybe NF is NF
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Must be. The only sparkplugs that I've found to not be one of two standard sizes, are for the Model T Ford, which was Pipe thread. 3/4" IIRC.
and Fisk came out with an oddball size, which required you to buy their adaptor to install on your car. IIRC it was an 11mm 1.25. Was supposed to be the best sparkplug you could get, and the last one you'd ever need. (that was in the 30's)

Nowadays, everything is pretty much going to be one of two sizes, either 18mm, or 14mm. And believe it or not, sparkplugs have been metric sizes for nearly ever. (at least since the 19teens) And bearing sizes have allways been in inches.
 
Tom-D said:
When using thread cutting tools, that is what you do.
Click to expand...

Nope, wrong..... not if done properly on an existing thread, the only cutting it will do is removing the burr or the peened over portion of the thread that has been damaged. Used them all the time to clean up threads that had been bunged up.
 
GlennAB1 said:
Seriously? Yet you asked the initial question...
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Yeahhhh. We may teach world class methods but for whatever reason the department only has Imperial tools...not a metric tool in the shed.

Jim
Tom-D said:
Remember Jim, these are AN threads, not your common pipe or automotive.
just wire brush them
Click to expand...

All wire brushing will do is clean the crap out of the threads. THe threads are sparkle-clean, but still there is a cobbed-up thread burr. I'd use a thread file if I could find one but nobody up here in the boonies has a clue what I'm looking for.
 
Tom-D said:
Remember Jim, these are AN threads, not your common pipe or automotive.
just wire brush them
Click to expand...

They're 18 millimeter, the same as the 18 mm automotive plugs.
 
Checkout_my_Six said:
well.....we knew you were that kinda guy. :D
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For the cost of a thread file, would you loose a friend? I don't believe Jim would.
Problem being, the shipping will exceed the cost of a new file.
 
Let'sgoflying! said:
@weirdjim , what happened - how did you end up fixing?
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We have a facility on the field that does a lot of engine work. He had half a dozen cylinders that would never see service again (cracked, bent, etc.) that he normally just sells to the junkyard for metal scrap money. I borrowed one, took my male plug chaser, made sure that the plug hole threads were sparkly clean & lightly lubed, and used the plug hole for a female thread chaser. Gave the old jug back to the scrap pile along with a promise that if he ever had to chase a radio problem that he had full access to my electronics equipment (see attached) IMG_0423.JPG .
 
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