[mantisory]

Hi all. I am not a machinist by any means, but i have a (maybe) dumb question.
I have some 3/8" thick 6061 AL plate that i want to drill a 22mm hole through. Also, on the same center I'd like a 28mm hole halfway through, as the picture shows:

However, I only have limited tools - a handdrill, a drill press, etc...
Question: is it possible to do this with the tools i have, assuming i am will to spend a few bucks on bits or whatever? Would a combination of spade buits work? Also, it is not necessary to have it super accurate.
Thanks,
Byron

[Geof]

Here you go.

http://www.cnczone.com/forums/showthread.php?t=16696

[mantisory]

hmm..for some reason my search yielded no fruit - thanks a lot!
Byron

[shiney66]

Hi all. I am not a machinist by any means, but i have a (maybe) dumb question.
I have some 3/8" thick 6061 AL plate that i want to drill a 22mm hole through. Also, on the same center I'd like a 28mm hole halfway through, as the picture shows:

However, I only have limited tools - a handdrill, a drill press, etc...
Question: is it possible to do this with the tools i have, assuming i am will to spend a few bucks on bits or whatever? Would a combination of spade buits work? Also, it is not necessary to have it super accurate.
Thanks,
Byron

If you clamp workpiece down to drill table you should be able to drill a pilot hole say 5mm then drill out to 22mm dia try and use the bright finish drills as the alum sticks to black(steam finished drills)you will need a counterbore with a 22 dia pilot for a one off you could get a piece of 22 dia round and cross drill say a 5mm hole to take a brocken centre drill and sharpen this to give a single point cutting tool its easy for me as I was a toolmaker send me your email address I will draw up a sketch of what I mean regards shiney

[rustamd]

you could get forenster bit to do big hole, works pretty good on aluminum, just use some lubricant(wd 40 or similar).

[davereagan]

Send it to me with return postage and a $5 bill. I'll CNC it dead on. I'm slow right now. Priority mail flat rate is $4.20.

[mantisory]

davereagan, thanks for the offer, but i will be trying the Forstner bit this weekend i think - i need to finish up this project soon