drill bit cutter

hi all i need to make a hole for a 1/2'' stainless ball to fit in, its in a block of ally now i havent got the money to buy a ball nose cutter or material to make a cutter so i was wondering.......

would using a 1/2'' drill work that will be ground with the correct radi and a cutting edge ground on work for this one off hole

manythanks mike

Yes

Although it might be easier to make a d-bit by rounding the end of a bit of 1/2" silver steel, milling away just under half the thickness and hardening & tempering it.

Neil

Mike, you could make a cutter from a bit of 1/2" silver steel. Mill or file down to a couple of thou.more than half the diameter and file the end half round. A 1/2" hole drilled in a piece of sheet can be used as a gauge to get the shape. Remove most of the metal with a standard drill and you your home made one to finish it off.

you could try a (wood working) carbide router bit.

alleged to work in Al.

-russ

But fot this job, NOT IN A ROUTER!

Should be no problem in a pre-drilled dimple at slow speed with plenty pressure, in a pillar drill.

Ian

A ball nosed end mill is only a pound or two dearer than the same size drill !

If you use a drill bit , it can be put back to normal with little loss of length. Ian S C

Does it realy need hemisphere seat?

why not use 1/2" drill to depth as required? maybe with pilot hole ( 1/2" center drill ?)

Lots of good suggestions, but we have only half a story. What is the finished article going to do?

Regards Bear..

A half inch diameter ball nosed end mill is £10.30 from ArcEuro. If you genuinly cannot afford a tenner (?) then regrind a 1/2" drill to give a 90 degree included angle and allow the ball to sit on that. Alternatively put your block of aluminium in a chuck and gring a boring bar bit to create the radius form and simply bore it to size and form. However as GB says we could all do with more information to give accurate advice.

hi all i looked in my tray of milling cutters and lurking in the amungst them all was a 1/2'' round nose cutter perfect for the job

which represents the biggest problem of all - remembering what one actually has! (not to mention where one put it...)