Drilling o1 drill rod

[Madbob9]

I'm having limited success in drilling 2mm holes in 5mm stock.I've been using cobalt bits and 50% of the time after getting a straight start the drill wanders one side or the other and even for and aft.I guess my main question is what is the correct rpm to be using.
Also picked up a few t. carbide drills since they were cheap.Would they be any good for drilling this material?

[skmetal7]

u want to use one of these http://www.littlemachineshop.com/pro...1230&category= a center drill. 01 drill rod is just steel, easy to drill and no special rpms needed(unless u hardened it!), for a small drill like that just us a fast rpm and go slow!!! what are u using to hold the drill rod?

[Madbob9]

My setup is a V block mounted in a cross vise with a work piece clamp.I use a very small burr to make my starting point.
I think my problem is I'm using to slow a rpm and to much pressure.Can you give me a rpm # to get me close. Thanks

[DareBee]

1700 RPM .002 FPR
Use lots of cutting oil and keep the chips cleared out.
This is for cobalt SP drill

[Madbob9]

I'll give that a try.That's close to double the rpm that I've been using.That feed rate I'm going to just have to guess at.My arm isn't computerized.Thanks

[Surfacefeet]

I'd use 2185 RPM for the Cobalt drill.For Carbide use 7280 RPM.With the Cobalt drill definitely make sure you are center drilling or spotting first.You wont need to center drill for the Carbide drill.

[g-codeguy]

Originally Posted by Surfacefeet I'd use 2185 RPM for the Cobalt drill.For Carbide use 7280 RPM.With the Cobalt drill definitely make sure you are center drilling or spotting first.You wont need to center drill for the Carbide drill.

Sounds like the guy is using a drill press and lubing with a brush, if at all. I think those RPMs would burn the drills up fast if that is the case. I would definitely start the hole with a #1 center drill. Don't think "Cheap" when buying the drills. You will be wasting your money if you go for some of those Chinese drills. A more expensive drill will not only hold up longer, but should hold size better.

[One of Many]

Make sure the V-block is actually lined up to the spindle. If the table is not trammed in to the spindle or the seat the V-block is setting on, including the vise is not perpendicular to the spindle, it is unlikely it will ever drill straight. Some light duty drill presses are weak enough, that they mis-align while under drilling pressure.

One last thought. If the drill bit is not ground equally on each flute, it will tend to wander once inside the hole from cutting heavy on one flute. This is where spinning the part in the chuck and the drill bit stationary, should self center, but poorly ground bits still wander.

DC

[Madbob9]

Well I still had no luck with the cobalt bits.After about 4 holes they would start to wander even with the spotted starter hole.So I grabbed the cheap $2 a piece carbide drills and punched 25 holes with one drill and no spot drilling.And that one drill is still cutting well.Surprised me.
Thanks for all the info guys.This is a great site.

[g-codeguy]

Originally Posted by Madbob9 Well I still had no luck with the cobalt bits.After about 4 holes they would start to wander even with the spotted starter hole.So I grabbed the cheap $2 a piece carbide drills and punched 25 holes with one drill and no spot drilling.And that one drill is still cutting well.Surprised me. Thanks for all the info guys.This is a great site.

A $2 carbide drill is still a tad stiffer than the most expensive cobalt drill, especially when you start getting down to that size. I cross drill smaller that that with carbide drills in live tooling and no center drill. Just slow down the initial feed rate until you get a hole started. You have a small advantage as there is no "feel" on a cnc machine.

Glad you got it sorted out and working to your satisfaction. I agree...this is a good place to learn.