Porting tools for .21 engines

[niggle]

I want to try my hand at porting a spare (but serviceable) 3-port that I have lying around here.

I intend to cut some grooves in the outside of the sleeve leading to the transfer (schneurle) ports. I bought a couple of 3.2mm (1/8") tungsten carbide cutters for this but after practising on some scrap material I now suspect the grooves will be too large if I use these cutters.

Would some 2.4mm cutters be more suitable? What size cutters/stones are other people using for performing these kinds of modifications on .21 size engines?

 

[Plaidfish]

Carbide blades or real sharp exacto heavy blades actually work well....or sanding stones and polish after the grind....

 

[markallen]

Here is one that works great for me..It's 3/32 or 2.4 mm
The dremel part # is 9904..

Mark