I need to mill bunch of small holes in cast aluminum. Can I use single edge cutter like Onsrud 63-620 or go with 2/3 flute tools?.

Thanks

How small is small?
How many is a bunch?
What sort of machine do you have?

50 small holes like .25" to .40" on a 3 axis without drilling attachment

Thanks

You could,... preferably a 2 flute cutter though. Or you could rough drill the holes, then finish it with a mill. Lots of ways. How deep are the holes? If you're on a 3axis mill, why can't you drill it? What machine is this? Why do you need an "attachment"?

Are these thru or blind?
What sort of tolerance?
What sort of machine are you using that will spin a cutter but not a drill bit?

What sort of machine are you using that will spin a cutter but not a drill bit?

Probably some type of router, since Onsrud makes router tooling.

Yeah, but generally those same routers can also hold a drill as well...... mine do....

Unless its a home built cnc and he doesn't happen to have the "attachments" to accomodate shanks other than 1/4 or 1/8....

Ahhhhh
You can get drill bits sizing from 1/4 to 1/2 with a 1/4 shank, these will fit in the collet.
If you need the holes machined drill 1/64-1/32 undersize and machine with a 4 flute cutter.
If you need to machine the holes virgin then a 2 flute is probably the best, high grade coated carbide is also the best cutter choice (I prefer TiAln). It is usually best to remove as much material as possible with a drill first if doable.

That`s the answer. Drill undersize and then machine with 4 flute tool. Just wanted to avoid drill wandering...

Thanks for all the answers, this forum is a great place!

I suspect that you'll end up snapping a bunch of carbide end mills by pre-drilling and then milling. Is this under some CNC control....if so then you could use a spot drill and then follow up with the appropriate drill bit.

To prevent drill bit walking (when not using a spot drill) use a split point drill bit and get the short ones designed for use in a CNC machine.

Thanks ViperTX. How fast can you spin these CNC drill bits?

I guess I assumed this was on a CNC machine and the holes would be interpolated.
Viper - I fail to see any reason why the cutters will be breaking?

DaraBee....was actually thinking of steel....I suspect with a center cutting end mill there shouldn't be any problem.

The CNC drill bits are used in screw machines....not sure about the actual RPM

I suppose we all could have different mental pictures as well.
This could be a 2" deep blind hole or a through hole in 1/8" stock.
Walter never did clarify this or what sort of machine he is running - eh Walter

Sorry guys, I did not mean to confuse you. Just monkeying with stuff (flame2) in my garage and not feeling like browsing book for formulas- that usually kills the fun. You know how it goes, you need to mill something and no milling machine within miles. Or you want to drill stuff but spindle on your machine does 45000 rpm min, you know, the usual garage fun :violin:

A lot of people here are total pros, I`m proud to be member of this forum. But there are also some hobbysts, enthusiasts and maybe even maniacs, it`s great to see all this crowd together. I think I fit well here.

So basically, I just needed some newbie info. Like: "when drilling holes in aluminum try to keep your RPM below 45000...." :stickpoke

I guess there are multiple technics to do this, deep blind hole would be different than shallow through, etc. Either way it`s great to see here info on technics and tools from pros who know their stuff. Any hobbyst or enthisiast will benefit from good reading here, not just me. Thanks for all the input, and keep up the good work!

Walter

How about - 1/4" HSS drill run 3,000 RPM at 18 IPM
You got a fixed 45,000 RPM spindle you are SOL ol'boy
Take off the router and mount a hand drill in its place.

Will do. ;)

Thanks DareBee