Spark Plug Thread Chaser

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Part# 12-01683
MFR Model# 20200


Chaser cleans threads in spark plug hole of dirt, carbon build-up, and metal particles. Double ended for both 14mm and 18mm threads. Neoprene band on hex drive holds tool securely in any 13/16" deep-well spark plug socket. 1lbs shipping weight.
California Prop 65 Warning Symbol

WARNING: The product may contain and/or expose you to a chemical(s) or substance(s) which are known to the State of California to cause cancer and/or birth defects or other reproductive harm.

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Daniel E Verified Purchase


December 2, 2022

No problem.

Kenneth L Verified Purchase


September 26, 2022

Jerry J Verified Purchase


July 23, 2021

Part arrived on time and was as was expected

Bill H
September 30, 2019

I had a 18 mm spark plug helicoil that had a tiny tip that broke off (fatigue failure I believe). I couldn’t get the spark plug to start threading no matter what I did. A fellow A & P had this item, I borrowed it & GENTLY chased the threads with it. Viola, spark plug threaded first try. I haven’t used the one I purchased yet but it is the same item my buddy bought. Works way better than the Champion spark plug chaser. Good for cleaning up threads but improperly used could also cross thread & damage them.

Gary S
February 18, 2018

I purchased this for cleaning the threads on a 3D printed spark plug caddy and it works fine for that and is much cheaper than an M18x1.5 tap. The description said it fit a 13/16 socket but it actually fits a 3/4 socket.

Joel U Verified Purchase


February 4, 2023

It is a solid tool and priced right. Performs as expected.

Paul B
April 21, 2018

I thought this little tool would be good but when I used it, it resulted in a damage thread so I had to replace the thread in the cylinder. I may have used the tool improperly, so I wont put the whole blame on it. But I would suggest users to be very careful when using it.
April 17, 2017

Tool works but if youre not careful, it may thread past short reach spark plug threads and become near impossible to engage the reads upon removal. Had to replace a cylinder due to this flaw in the tool.

Hangar X
December 15, 2022

Purchased this some time ago, only used it for first time today. Will not fit 18 mm x 1.5 pitch spark plug hole. Thread profile verified under microscope and with threat gauge as ok but there is some sort of anomaly that doesnt allow it to engage properly. Three A&P/IAs tried it on three different cylinders and still cant get it to work. If you buy this be very caeful when you use it to assure yours doesnt ruin the helicoil of the spark plug hole.

Gary S
October 11, 2022


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: I am curious about what happens to the debris that this tool removes from the threads? On the bottom plug threads, gravity would help keep it from falling into the cylinder but the top seems as if the debris would fall inside pretty easily. What method is or can be used to keep this from happening?

The ATS 20200 Thread Chaser is intended to straighten out deformed threads without cutting. The "without cutting" part is very important as this tool is not a tap -- it is not intended to cut metal, but to reshape the threads and clean out residue such as carbon and dirt. The usual technique is to cover the threads of the tool with a layer of grease prior to using it so that the grease will capture the dirt and debris as it cleans up the threads.

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