I plan on purchasing a few burrs for porting intake manifolds and cast iron housings. Should I buy burrs specifically for aluminum when doing the manifolds or will the burrs for cast iron suffice? I'm worried they may be too abrasive for the aluminum. Is that the case or will they simply cut much faster and work fine?

 

You just need a good set of carbide bits in a variety of shapes. My "tulip" point is the one I use the most but straight and rounds are very helpful too.
This is more than you asked for but if you are asking this question the rest may be helpful to you as well.
You have to watch the really aggressive (coarse cut) even on cast iron because they can kick back hard and really screw **** up fast including your body. Aluminum does not kick back *as bad* but it cuts so much faster as you indicated that you can screw up fast.
Use the least aggressive bit that will actually get the material cut and get everything as close as you are comfortable with. Then you can step down to finer cut bits to finish up.
Do not to buy cheap bits.
Aluminum gums bits and you may need to use a scribe or some other hard pointed tool to clear the cutter.
Another trick is to get plenty of light, a good bench, and chair to make yourself as comfortable as possible and where you can see very well. Shadows are a bitch so watch out for them too.
You really need to get some bad parts if possible and practice first. You need to get the feel of each bit on different material and turn them at different angles and then you will know what to expect.
I have seen some real catastrophes from people not doing that and frigg'n their good parts up

 

They do make ones especially for aluminum that dont "gum" up. A bit of grease will usually help as well.

 

Of course patience and a light touch help too. Don't try to do too much with too little (if that makes sense).

 

these burrs either come in single or double cut.

i perfer the double cut b/c they cut faster however the do make a slighty rougher cut. a combo(first double then go over w/a single cut) would be the best when porting

special bits are made for alum and it might be worth getting one for the rotor housings. they have less, farther spaces edges in comparision to the bits made for steel/cast. dipping the bit in oil to cool it usally helps when cuting alum.

justin

 

Once you get the port to the shape you want, smooth it with sandpaper "cones". They are basically sandpaper rolled into a cone shape. They screw onto a 1/4" threaded shaft. They will smooth out your work nicely.

 

Isn't there a wax that you spin the bit into to prevent clogging while cutting aluminum?

 

I've not seen that but it makes sense that it would work

 

The small rolled up sand paper things that push-screw on the 1/4 inch shaft, are called Hardrolls, They come in different grits .

 

Where can the Hard rolls be found?

 

my friend got the "hard rolls" from summit racing

 

Try McMaster.com for all your tooling needs.
If you can lay your hands on their catalog, you'll spend about 4 hours just thumbing through the 3000 pages of "stuff".
Pretty decent web site too. Good prices as well.

Frank

 

Here is a guy on Ebay selling sets http://cgi.ebay.com/ebaymotors/ws/eB...tem=2415156532