Hello Guys,
I was reading the article on MGB about Shortening a plug. I want to try this for my Gen 2 Insane Cat. Anyone have any idea on the size of the tap/die set that I need to re-thread the rod after cutting?

www.modelgasboats.com/Magazine..._Sparkplug.html

Thanks,
Anthoni

M4 or 6-32 should work fine. The electrode inside the sparkplug is 3.67mm or 0.145" diameter.

* this info is for a NGK CMR7H

Marc, thank very much.

Anthoni

I read you have to use a diamond blade to cut the ceramic, is this available as a Dremel wheel? I have the fiber wheels, and they are great but I've never seen a diamond one that I remember.

Yes the diamond cutting wheel IS required! And yes they are available for the Dremel 1/8" mandrel. They tend to be pretty expensive though. I got a few of them from a local shop here that had them really cheap at one time...

YEP! Marc's right! I've got a mini tabel saw from Harbor Freight. A diamond blade is an accessory for that unit. Thats what I used to cut the porcelan on my plugs. Can't remember the name of the place where I got this setup, but I used a 5-40 die to cut the threads on the electrode first, then followed it with a 4-40 die right over that. The tip of the plug was drilled and tapped 4-40 in a lathe. Brian

Found it! ;D This is what I used on the electrode. Brian
rodchuck.com/