Drilling Small Holes in guards and such....

Patrice Lemée

Patrice Lemée

Joined
Aug 13, 2002
Messages
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I was drilling small holes for alignment pins in spacers and guard and as always, I break a bit or just mess up the holes altogether. :( Especially with smaller holes like this (1/16th of an inch and smaller). And of course in harder material like Stainless Steel it gets worst.

Any tips on this:

1) Do you use a smaller drill press or is the Big One just fine
2) Any preferred bits for small hole drilling?
3) Speed, I feel the need for speed!
4) Any “Why didn't I think of that” tips?

Again this is pertaining to the difference if any between small holes (alignment pins for me) and larger ones.

Thanks for your help.
 
I never use a drill press with the small bits. I use a flexible shaft machine, and drill by hand.
 
What kind of material are you drilling?

Do you have center drills(combo drill/countersink)?
I've always found drilling to be easier when started with a center drill. If you don't have one small enough, just barely touch the part with the one you have to put a tiny angled hole to help the drill keep from wandering.

Have you done any calculations to know how fast you should be drilling? Small bits(endmills, drills, etc...) typically need to be screaming to cut properly.

Use extremely light pressure. Let the drill do the work.

I go up and down a lot while drilling to let the drill throw any accumulated chips out. Drill a bit, then lift out of the hole, and continue.

You can also chuck up on the flutes of the drill. If you are only drilling 1/4" there is no reason to have 1" of fragile <1/16" bit hanging out of the chuck.

I occasionally have to drill the heads of AN or grade 8 bolts with <.0625" drills for safety wire and everything seems to go ok if I take my time and follow these tips. Most of my drilling gets done on a mill so I don't see any reason you should have to use a smaller drill press unless it is capable of spinning the drills at the RPM they need.
 
I would go with cobalt, drill slow with tapping fluid , clearing the bit often. I would use the besr press you have without regard for its size. Frank
 
I would go with HSS or cobalt HSS, I'd spin a 1/16" bit fast as hell, perhaps 4,000 RPM, I'd feed it regular - probably 4 IPM or better (look at the the chip coming off, it should look right), I'd do it dry (because oil is smoky and coolant is still messy, no other reason) I'd peck every 1/8 - 1/4". I'd use your mill. (Okay, I'd use my mill, but if I were you, I'd use your mill).

So - many ways to skin that cat. In many ways they're all correct. But in a much more literal way - my way is correct... :D

I'm guessing you're breaking little bits because you're turning too slow, causing you to feed them uneven, or overfeed when it exits. The mill will have less runout - keeping things straight and true is helpful.
 
alignment is critical so a drill press is good, a milling machine better, however it is really easy to put too much pressure on a tiny bit. Use quality bits, harbor freight and hobbyist bits are worthless. centerpunch your hole locations to get the bit started in the right spot and make sure you are starting aligned. I have found lubricant essential when drilling. Everytime you progress more than twice the diameter of the drill back it out and clear the chips

-Page
 
I drill a lot of tiny holes. Regularly as small as a 0.5mm.......that is .020" .

General tips:
When the bit is small, the general rule is - fast is good and faster is better.
I use a flex shaft at work and the mill at home. In either case, I frequently lift the bit to clear the hole. I use burr lube (solid wax like lube) when drilling with a flex shaft and tapping fluid when drilling on the mill. The mill is far better than the flex shaft.

Universal tip:
Regardless of the tool or the speed, sharp bits are a must. If it is the least bit dull, replace it or sharpen it. Small bits come in 10 packs and 100 packs for a reason.

Super Shop Work Tip - Bordering on - "Dang, I Wish I Had done That":
What kills most small bits (and many big bits) when you are drilling is the exit. The drill cuts through the metal and the flutes grab the two tiny burrs formed and tries to screw through instead of cutting the burrs off. This throws a huge torque down the flutes and often breaks the bit. Slow can't save you here. For example, the bit is spinning at only100 RPM, and the feed is 1/2 IPM, when the bit exits and tries to screw through the hole it is momentarily trying to feed at something like 25 IPM. That just tears it in half. A backing piece of metal is the way to prevent this over-run. Place a piece of metal similar to what you are drilling behind the work piece. Set the stop or watch the depth readout to know when you have drilled through the work.

Higher speed, using a mill, and a backer plate will prevent 99% of most small drill breaks.
 
Thanks for your help guys.

I did not think of using my mill because I was under the impression that you needed something smaller for such small holes. :o

I would have tried with the flex-shaft but this was for alignment pins so I needed to keep things straight. Well as straight as I can make them anyway.

I will try all these good advices.

PS: Are the "jobber" drill bits they sell at Enco the same as hobbyist drill bits that Page mentions?
 
Patrice Lemée;8754174 said:
PS: Are the "jobber" drill bits they sell at Enco the same as hobbyist drill bits that Page mentions?
Click to expand...

For most knifemaking tasks I tend to stay away from jobber bits. Try sticking with screw-machine bits. The difference is in the length. Screw machine bits are shorter. You can get these as Enco or MSC. I also recommend cobalt for most tasks.
 
Jobber refers to the length. Usually Enco sells reasonABLE quality stuff, also look at Rutland tools, I get a lot of bits from them
-Page
 
For example, the Machinery's Handbook recommends a cutting speed between 70-85 feet per minute for annealed 1095.

Using those cutting speeds for 1/16" drill tells us that our spindle speed should be between 4278 RPM and 5195 RPM.

I just used an online machining calculator to come up with those numbers. There are ones for milling, drilling, turning, etc... in various places on the web.

Pick up a Machinery's Handbook. It has all kinds of good info in it.


Machinery's Handbook:

http://books.google.com/books?id=pPoNZB4xqHoC&pg=PA112&lpg=PA112&dq=speeds+and+feeds+for+1095&source=bl&ots=oQQaf7lvD-&sig=puTY6D8Ml9Y_dmo4v1aENt7FDMs&hl=en&ei=ll-zTIPlIYS8lQfpssWVDg&sa=X&oi=book_result&ct=result&resnum=6&ved=0CDAQ6AEwBQ#v=onepage&q=speeds%20and%20feeds%20for%201095&f=false


Machining Calculator
http://www.mapal.us/calculators/drilling/CalculatorDrilling.htm
 
Forgot to say thanks for the info on the jobber drill bits.

dillon, thanks for the calculator link. I do have a Machinery handbook that a friend gave me but I am not the brightest one and I sometimes have a hard time making sense of it all.
 
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