Good day, Just wondering what head shape and shank length is working best for porting both cast iron heads and intake manifolds? Any type of rotary tool that works best for you? I'd like to purchase some but not too many. Got the double burrs for iron and single burrs for aluminum down. Thanks much, Matt
If you are on a budget and it's one or the other, get long shanks only. They can reach in where shorts can't, but you should have both, longs catch and bounce more than short ones.. Some of the sand grit type are nice for finish work.
Ideally, these are what you need for aluminum. A 3/8" VSR drill will massage that aluminum pretty easily too...Have a sharp HARDENED pick ready because the gummy aluminum will load up the cutters. A little spray oil goes a long way with these guys too. The cutters with a single edge don't load up as bad. We called them "rotary files". Also pretty easy to control. The multi directional cutters are really aggressive. A lot of porting (and polishing) takes some concentration and finesse to find the "sweet spot" on each cutter. Youll find yourself changing them frequently for the different contours. ws
On aluminum you really need the aluminum bits, those pictured are for iron. These are the Aluminum burrs
Its hard to tell from my pic but several are the single stage aluminum type bits. The multi-stage will load up especially if run at high speed. An oil mist will definitely help, but I had to use mine dry since the "blended" welds got faired with fiberglass and painted. Since I had no air at the dock, I had to use a cordless 19.2V drill which on "fast" is about maybe 1000 rpm. The conical burrs were the easiest to control, followed by the ball style. No.s 8 & 10 in the post above. An air grinder at 10,000+rpm will make short work outa the manifold, and cast iron for that matter. WEAR SAFTEY GLASSES and leather gloves for aluminum slivers. The cast iron makes dull chips. So now the boats ported and relieved and she stroked and bored, theres on more thing, I got the pink slip daddy! ws
That's a fine looking extension Marty! Gives you a "bearing" (gloved hand with a drop of oil) to hold it steady. I gotta make one of those. Ill bet that 3/4" (1" ?) burr does some damage! ws
I've never used the long ones for porting....I worry about the "high speed wobbles". I had the sand paper type get bent out of shape once and things almost got ugly real quick. Short burrs are much more stable...almost like using a paint brush.
That set I posted a picture of retails for $400 but it could be yours for $100 and I've only used one of those bits to deburr my 455 block.
