Thead Chaser

Category: General Tech Discussion 8 months ago
for 912ULS. I have a plug hole where the first couple of threads are just not right. I was told I can use a chaser. If I do, how do I keep the metal shards out of the cylinder?
  • Re: Thead Chaser

    by » 8 months ago


    I have heard of using a vacuum:Reduce the hose OD with an adaptor (make out of wood) with a small flexible hose run into the cylinder from the other spark plug hole.

  • Re: Thead Chaser

    by » 8 months ago


    Use the positive pressure side (outflow) of your vacuum to blow into the opposite spark plug hole or use compressed air. Also, use some grease on the chaser to hopefully capture any shards or debris.

  • Re: Thead Chaser

    by » 8 months ago


    This probably goes without saying, but if you use a vacuum to blow air into the cylinder, make sure it is clean air.

  • Re: Thead Chaser

    by » 8 months ago


    There is a difference between a 12mm thread tap vs a spark plug thread chaser. The tap has very sharp metal cutting edges and it will cut the threads and leave shavings verses a plug thread chaser that has a more dull rounded cutters that do more reshaping and conditioning than cutting. I would not use a standard 12mm thread tap. Apply a bit of white lithium grease to the cutter and it will work more smoothly, do a better job and catch any particles. Don't use it dry.
    Use the right tool.
    Like this:

    https://www.tooltopia.com/lang-tools-1013a.aspx?utm_source=google&utm_medium=cpc&utm_campaign=paid_search_google_pla&adpos=1o2&scid=scplpKAS1013A&sc_intid=KAS1013A&gclid=EAIaIQobChMI8OaluoTv3wIVwiCtBh12aAEZEAYYAiABEgJ5mvD_BwE

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-574-1080 Home (TRY HOME FIRST)
    520-349-7056 Cell

    Thank you said by: Ken Ryan

  • Re: Thead Chaser

    by » 8 months ago


    This is what I used: https://www.amazon.co.uk/Choice-Draper-XS17-24867-Expert-Recovery/dp/B06Y1XXQK4/ref=sr_1_1?s=diy&ie=UTF8&qid=1548016490&sr=1-1&keywords=draper+thread+recovery+m12

    You put it into the hole and gradually expand it, unscrewing it until you get the result you want. It doesn't create large shavings that fall into the cylinder as you can cut on the way out as it unscrews.

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