Can't find the right drill bit.

Mark Barone

Well-Known Member
Which type of bit will drill through steel. I keep buying the wrong ones even they say they are metal bits?
 
Cobalt bits are great but pricy. Really any QUALITY High Speed Steel bit should work. Unless your trying to drill hardened steel?
 
What speeds are you running them? if you run them too fast you'll just smoke them.
You need to run them slow, and oil helps if your drilling deep.
 
It's not hardened steel. Just 1/8 inch 1095 .
I just have a cheap
HArbour Freight drill press. Not super fast but I don't know the rpm. I was using 3:1 oil
I'll look for the cobalt. I think I used that before and lost track of which blades were which. I think I may spray paint the ends or something on any new ones I buy. I'm making my first knife . I'm on my 3rd blade already. I just can't keep going if I'm not happy with it. I kept screwing up the bevel with this crappy jig I made. I have improved the jig and also modified my 1x30 belt sander to make sure the belt over hangs a tiny bit on either side. The tracking in these sanders stink so I sanded down a little bit of the surface area in both sides. I'll post a picture where I'm at later . It's bad . I'm a bit addicted. I'm learning more and more from my mistakes and reading this forum.
 
If you have a HF 1X30 the tracking knob/adjuster may be sticking, also to get full range of motion I took mine apart and where the spring mount is on the Green body not the black handle where the knob is. I filed the casting back to give it a little more articulation. Mine tracks great now! YouTube has a bunch of vids on modifying them check them out that's where I found all the info for doing mine.
 
Much depends on the drill bits you purchase. If you're buy "local" go to Ace Hardware and by either Irwin High speed steel, or for a bit more money you can also get the Irwin Cobalt bits. If the drill press is adjustable for speed, put it on the lowest speed... generally that would mean the smallest pulley on the motor, and the largest on the drill arbor/shaft.

The method that you use to drill can make a major difference too. Most folks starting out tend to try to "cram" the drill bit through steel, like they would wood. That's NOT what you want to do with steel. Light pressure, and when a few chips come out, lift the bit out and let the flutes clear of steel, then go back into the hole until the same thing occurs....then lift the bit out and let the flutes clear. What I call "tap" drilling....just keep tapping away until you cut your hole(s). You can feel when the bit is about to break through the other side....your instinct is to pressure it harder, but DON'T! Lighten up as the bit goes throug (let the bit CUT it's way through, rather then "punching" it through). Drilling in that manner will give you cleaner/truer holes, make your bits last longer, and allowing the bit to "cut" through that last little bit versus "jamming" it through will prevent whatever you're drill from being sucked up the drill bit and likely causing injury. ;)
 
It's not hardened steel. Just 1/8 inch 1095 .
I just have a cheap HArbour Freight drill press. Not super fast but I don't know the rpm. I was using 3:1 oil I'll look for the cobalt..

don't feel bad, I have a Skil from Lowes. as Ed said, put on slowest speed. on mine slowest is about 50 rpm too fast, but close enough. I bought several 10 packs of M35(yes they are cobalt HSS) from here http://www.ebay.com/itm/3-32-Cobalt...hash=item1a201a1473:m:mx53WIcovqCKdG0CY4u-u2g about 3 years ago. still have 5 of each size left. practice speed and feed, Ed gave good description of what to do and how it should feel.
 
That's a really good deal of cobalt bits! Even imports from MSC and other outfits are more expensive then that!
 
I bought a large set of cobalt bits from Harbor Freight tool. Not the best im sure but thet got GREAT reviews and are resonable. They were on sale for $95 and I had a 25% of coupon with tax title and registration around $80! Another thing to consider to is to buy just the sizes you use in Cobalt.
 
OK I think I'll get the cobalts. I'm into this hobby about a million bucks anyway. Thanks for all the advice. @Ed I think I was trying to push through like wood. I do the up and down method.
 
If it is making chips it is cutting, if its smoking its done!! LOL
My Dad use to have a drill (brain fart can't think of the proper name for it) like the one in this pic.
jason-edwards-antique-hand-drill-used-for-turning-wood-in-a-remote-homestead-australia.jpg
It The one he hadlooked simalar to this one except his had a large nut that advanced the feed. He used it when he had to drill a large hole in heavy duty metal or any hardened metal. It had a large wrench and only a time or two did I ever see him use that wrench on it and that was hardened metal. Most of the time you advanced the pressure by hand turning the nut! Someone at some time had put to much pressure on it and cracked the yoke. It had been welded. He use to tell me if you have to use the wrench to put pressure on the bit you are probably cutting something you shouldn't be!! As you can imagine the speed of the bit was pretty slow with the hand crank!

IMO 90% of drilling is the speed of the feed and the other 10% pressure!!! If you are smoking a bit, then usually that bit is done until resharpened to get past the burned area!! Most store bought bits are 118 degrees, as that angle is good for use in wood, metal, plastic, and most other materials! When using strictly for metal 135 degrees works better. Here is a link that kind of explains why!
http://www.practicalmachinist.com/vb/general/why-118-why-135-drill-angle-152137/
 
I use to use a machine that worked on the same principle for tapping cast iron gas mains, it was made by Mueller. you would screw the fixture into a saddle tap on the main and use a 1 1/4"socket wrench to turn the bit, slow is a relative term here, and occasionally turn a hand wheel a little bit at a time to put pressure on the bit. as long as the bit was sharp it actually worked great and didn't take all that long.
It sure seemed like an old timey way to do it though.
 
Most cobalt drills are split point. That means they have zero thickness at the web. Most high speed steel drills have a much thicker web and therefore require more pressure and create more heat that a cobalt. Not a function of the different alloys just geometry. If you have a grinder with a nice sharp corner on it you can learn to thin the web on the high speed steel drills. They are much cheaper. Also thinner material appreciates a thinner web and a shallower included angle (135 over 118) If you hand sharpen drills you may want to drill a little under size and ream to final desired diameter.(hand sharpened drills are not as accurate and can cut oversize depending on the skill of the guy sharpening) Reamers last and make a real nice finish hole. A sacrificial backer of aluminum(brass or mild steel) is a good idea under whatever you are drilling. It will greatly reduce the burr on the bottom side.
 
IInteresting posts. I see other bits that say 2x faster ...6 x 10 x. Does that play into any of this?
It is advertising. Faster how? faster speed or higher feed rate or faster drilling 100 holes because you didn't have to change bits? Cutting speed does depend on type of drill bit. go here and look at page 6, it gives speed and feed recommendations for 3 different drill bit materials when drilling O1. (http://www.uddeholm.com/files/PB_Uddeholm_arne_english.pdf) I think it safe to assume that these numbers would work for all high carbon, low alloy steels(1084,1095, 80CrV2, 52100.....) to find cutting speed, = 0.2618 x Diameter of drill bit in inches x RPM find other drilling formulas here http://www.guhring.com/documents/Tech/Formulas/Drilling.pdf
most of the time we are drilling in thin steel, rarely more than 3/8" thick, in low volume. so does possibly saving 20 or 30 seconds of time per blade out weigh breaking or dulling a $5 drill bit?
 
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Keep in mind that there is a lot of hype out there, for just about any type of product. When it comes to quality drill bits, my experience has always been that the best ones, whether is be HSS, Cobalt, or Solid Carbide, for what we do in knifemaker are, "Made in USA" bits. When you see things such as "2x faster", etc. they are usually referring to using them in wood, and are throwing you a ploy in an attempt to get your $$.

Ted mentioned "split point".... these are bits with a 135 degree point angle, with a relief built/ground in..... these are the bits I most often purchase for knifemaking duty, and for those bits that don't have it, I change them to a 135 degree split point.

Long story short, you life in the knife shop is much nicer when you purchase quality drill bits, and use them correctly for the material you're drilling.
 
final note, buy "Screw Machine" bits, they are usually half as long as a standard or jobber bit so the chances of drilling a round hole increase.
 
Like I said before I bought a huge set of import Cobalt bits. I have to admit they work pretty good. I also have a Milwaukee set of Cobalts that were around $60. But I drill under sized holes and ream them up to size with HSS reamers. I only have a few of these for pins 1/4", 3/16" and 1/8". Thats all i need for pins the reamer is by far a superior fit and finish for pin holes.
 
Ok I'm am going to start a new post with the progress of my neck knife. I would appreciate any help. I'll name it Neck Knife Help.
 
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