Where to buy cnc drills in UK

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Roderick Jenkins on 02/01/2017 20:46:44:

Not to destruction

They seem fine, look nicely made and finished but only time will tell. I think they are good enough for my use – < etc. >

.

That'll do for me, Rod

Thanks

MichaelG.

[HopperParticipant @hopper]

For drilling brass you might want to look for some 2mm fast helix drill bits. The lesser angle on the helix means a lesser clearance angle at the cutting edge, so it does not tend to dig into the brass so much, which is what can snap small drills in brass. Or with so many holes to drill, how about straight flute carbide drill bits?

[Anonymous]

Posted by Hopper on 03/01/2017 04:08:38:

For drilling brass you might want to look for some 2mm fast helix drill bits.

That's odd, I use slow helix drills for brass.

Andrew

[Ian S CParticipant @iansc]

I think that's what he means Andrew. Once apon a time you could buy straight fluted drills just as easy as helical ones.

Ian S C

[Anonymous]

Posted by Ian S C on 03/01/2017 11:27:24:

Once apon a time you could buy straight fluted drills just as easy as helical ones.

I have a vague recollection of straight flute drills as a kid, but sadly they don't seem to be available now; pity. To be precise, you can buy straight flute drills, but they seem to be carbide, stub, and intended to drill hardened steels up to 65Rc.

Andrew

[john dakinParticipant @johndakin59277]

So what sort of speed should I be running at to drill 2mm holes into 3mm thick brass

[Tony Pratt 1Participant @tonypratt1]

Plenty of info on Google, one calculator says 10K plus [HSS drill], not many M/C's will do this straight out of the box so just run as fast as you can

Tony

Edited By Tony Pratt 1 on 03/01/2017 12:50:16

[Mike PooleParticipant @mikepoole82104]

14,000rpm for HSS, 50,000rpm for carbide, flat out unless you some exotic high speed spindle.

Mike

[john dakinParticipant @johndakin59277]

Thanks, my max rpm is 25,000

[MWParticipant @mw27036]

Posted by john dakin on 03/01/2017 12:26:17:

So what sort of speed should I be running at to drill 2mm holes into 3mm thick brass

As fast as you can get the machine, but I have had a small mill designed for small work and that usually used 10,000rpm.

The formula I have calculated for a conservative estimate on brass at 90 metres per minute, for a 2mm drill was around 14,500rpm.

I would say this only really shows how fast you can get the drill into the workpiece, you could go very slow but you'd need less pressure on the drill. Too much pressure and you're going to be forcing a very fragile bit into the face of the work with little cutting action taking place, that's why it breaks. You could grind a steeper lead angle onto the drill, which is what sheet metal workers used to do in the past to relieve pressure on the cutting tip. The angle on most drills is around 112-115 degrees, which is only a general purpose angle, a steeper angle of say 80 degrees might be more suitable for softer materials.

PS.everyone beat me to it 😛

Michael W

Edited By Michael-w on 03/01/2017 12:57:20

[john dakinParticipant @johndakin59277]

80 metres per minute seems too fast, did you mean feet per minute

[john dakinParticipant @johndakin59277]

I meant 90 metres per minute

[John ReeseParticipant @johnreese12848]

Brass has a tendency to pull the drill into the work unless the drill is modified for zero rake. Could that be contributing to your problem? To modify a drill stone the cutting edges. See video.

[Author]

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