How long would a carbide drill last drilling steel

Probably 500-1000

Assuming proper speeds and feeds and everything was true and rigid.

This based on clients using this size range drill in CNC lathes on DEEPER material

Gunner

One could not be a successful Leftwinger without realizing that, in contrast to the popular conception supported by newspapers and mothers of Leftwingers, a goodly number of Leftwingers are not only narrow-minded and dull, but also just stupid. Gunner Asch

Iggy, no disrespect, but you'll likely break it. Carbide drill bits are brittle. HSS is far more forgiving. Till you've got a lot more experience, I'd stay away from carbide drills.

Just my 2 cents

Karl

I actually had good luck with carbide drill bits even on my manual bridgeport. None yet broke.

i

Trust me, you'll break s^&t on a CNC while learning.

Karl

Actually -- I would expect it to last until you bumped the plate while the bit was in the hole. (Assuming you are using it in a drill press -- if in a Mill, just make sure that the drilling cycle is complete before you move the table -- and clamp the plate to the table.

Solid carbide bits are *very* brittle. If you can keep the plate from moving until the bit is back out of the hole, it should last a large number of holes.

But why not use a high cobalt steel drill bit instead? As always, I suggest getting bits with a split point so you can drill with less feed force being needed. and since the plate is only 1/4" thick, get screw machine length bits instead of the usual jobbers' length so there is less flex in the bit.

You don't mention how long a run of holes you need to drill.

And I don't really see a need for carbide in 1018 -- it is more likely to clog the bit and break it that way than to wear out the cutting faces. Unless the 1018 has been case hardened, there is no need for the carbide. Carbide is the best for certain materials and states of hardness, but there are much better choices for something as mild as

1018 should be.

Enjoy, DoN.

It'll last 'til you break it or chip an edge.

1018 is very easy on HSS. I had my son drill 1400 accurately located 3/16" pilot holes in 1/4" and 1/2" 1018 last fall. He broke one bit, finished with the second. This summer I'm working on another part of the same system and he drilled 800 holes in 3/8" and 1/2" bars with a single bit.

If you're lloking for maximum speed as opposed to long life, that's another matter.

Don't carbide bits have a different geometry than HSS? I only use carbide on hard stuff. Does you mill have ball screws or ACME? Don't do any manual milling with ball screws, the other axis will move if not locked and break tools.

It is a real CNC mill, it has ball screws and no handles. It does not look like a retrofitted manual mill.

i

Tom...think about what you just wrote..and why its foolish.

Gunner, who dumped a box of rusty stuff on his foot 10 minutes ago and is still limping around

One could not be a successful Leftwinger without realizing that, in contrast to the popular conception supported by newspapers and mothers of Leftwingers, a goodly number of Leftwingers are not only narrow-minded and dull, but also just stupid. Gunner Asch

A cousin had replaced his acme with ball and the table would be "driven" by the tool. Acme screws don't do that. So, he had to lock whatever axis was not being used and make sure he had pressure on the handle of the axis being used. But, I say foolish things all the time and don't pretend to be smart.

Iggy is setting up a CNC mill not a manual one.

Manual mills with a ballscrew...are a dream to run..if as you say...you lock the not moving axis down like a rock. Ive never seen one..but Ive heard of them..and some horror stories.

Gunner

One could not be a successful Leftwinger without realizing that, in contrast to the popular conception supported by newspapers and mothers of Leftwingers, a goodly number of Leftwingers are not only narrow-minded and dull, but also just stupid. Gunner Asch

Having used "Wonder Bits" carbide bits in a rig for drilling safe containers, I can say "It Depends.."

Now, the hardplate is no 1018; it's a mix of soft, hard and really hard, including pieces of broken taps and carbide chunks....all mixed together.

Sometime 2 or three drills will do. On a bad day, the tip will break off and fuse onto the plate. Then you stop and try to crack it loose with a hammer and punch, get a new bit out and continue.

I keep seeing comments like this (and others) every now and again, and for the life of me cannot figure out where all the "theoretical" b.s. started.

Using 5 different Bridgeports (daily) fitted with lovely (and in great shape) ballscrews, very frequently, drilling and milling, taking some fairly respectable cuts, at fairly respectable feeds, and simply do not have such problems occur.

It's just not that big of a deal.

Ever.

Really.

Ever.

Can it move? Sure! Is it "all that"? Not really...

Is this, perchance, one of those, "... never done it myself, but sounds plausible, so I throw it out there to keep perpetuating the myth", kinds of instances?

Sorry to sound harsh, if I do, but it really is befuddling...

If it is servo controlled, then it will not move due to outside forces.

What about climb milling?

Sure, it should be better than a regular mill where the cutter can bite off a chunk the size of the backlash, but I thought the subject was manual handwheels on ballscrews without motors powered.

Ignoramus24043 fired this volley in news:qsWdncIdcaV1HNXRnZ2dnUVZ snipped-for-privacy@giganews.com:

Uh.... that's only true if you have _zero_ backlash. New, clean ball nuts are pretty darned tight, but not all designs are zero backlash. I don't know if those ball nuts are of the phase-shift loaded type, or not. Counting on no backlash might be chancy.

Any lost motion will become more apparent in heavy climb cuts.

LLoyd

What about it?

One locks the other axis when doing that, anyway. Don't you? It's the way I was taught, back when I was getting taught...

And by "lock", I don't mean "crank on the lock with a cheater bar", either. Simple finger pressure. Same for Acme and ball screws, alike.

Even when I'm in a hurry and don't do it, simply keeping my hand on the other axis' handwheel/crank keeps the table from creeping if it's wont to.

It simply just doesn't happen in the real world that it drags the table all around, spinning cranks like the end of the world is coming like one is warned about so many times...

Maybe I'm just ridiculously lucky... I keep hearing (reading) "might" and "could", and it just doesn't happen when I'm actually doing it.

I mean no offense, to be sure. There are people here whose posts I read regularly, and respect the experiences of, but this comes off very much as "The sky is falling! The sky is falling!"

It's just not a big deal in real life.

Typically they have split points -- which are also available on HSS bits, and which I prefer.

Hard or abrasive. My first use of them was with typically #70 bits drilling holes in G10 (fiberglass/epoxy) printed circuit boards. By my experience, a HSS #70 bit would turn into a needle shape in about

40 holes -- and just burn through the epoxy, leaving a fur-lined hole where the glass fibers were sticking out.

In comparison, the solid carbide ones would last forever in my use.

At the moment -- his answer should be "yes", because he has a manual mill and the CNC one.

No problem there -- his (and my) CNC machines do not have hand wheels -- just the servo motors driving the axes via toothed belts.

Enjoy, DoN.