Cutting Tool Shape For Alum Using A Shaper ?

[Scruffy]

i'm wanting to recut the top of a 7 by 12 by 1 inch thick piece of 6061 aluminum that I'm wanting to use as a fixture plate on a mill table. Wondering what the best tool shape would be best fo this for a nice finish ?
I'm using a 16 in cinn shaper and have everything from quarter inch to 1 inch hss blanks.

Thanks ron

 

[Bob Korves]

Something with a round nose, using a light finish pass with small step over.

 

[Ed ke6bnl]

got a question, it you have a fly cutter or shell mill and you can take a full with pass, is the any advantage to take the pass with tooling above the cut below the cut or down the center of the piece to be milled. Is there one position that is better then another???

 

[Wreck™Wreck]

got a question, it you have a fly cutter or shell mill and you can take a full with pass, is the any advantage to take the pass with tooling above the cut below the cut or down the center of the piece to be milled. Is there one position that is better then another???

He is using a shaper, difficult to use a fly cutter on such a machine (-:

 

[francist]

A shear tool would also give a very nice finish, if you can tolerate taking only a couple thou depth per pass.

-frank

 

[4GSR]

Frank is correct.
You need a tool with a shear action with a very high positive back rake to the tool with a large blunt nose on the tool. Make the blunt nose as wide as you can and you are willing to take off in one pass! Say about 5/8" to 3/4" wide. Be best to grind the blunt edge on a T & C grinder if you can. Once ground, hone the edge to a razor sharp edge. Indicate the blunt edge parallel to the table. Coat the surface of the aluminum with a good cutting oil, NOT WD-40! Take cuts of about .005-.010 deep and hand feed about two turns on the table feed, about 1/2", at a time. You should result in a very nice machined finish on your aluminum. Ken

 

[Scruffy]

Thanks for all the replies, I ground a 3/4 tool blank as James kilroy's utube video showed, he called it a shearing tool. 45 degree face with a very slight radius, a little back rake.
I'm happy with the finish, would have been better if I'd had a decent stone to do a little touch up, but for table plate it will be fine.
Going to try to post pics. First 2 inches on left was wetting surface with Wd-40, the rest was done using diesel fuel, it gave a little nicer finish.
Thanks Ron