drilling question

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Hunterarrow

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Although I set my drill press to the lowest speed I seem to go through my bits pretty fast. (My drill press is a cheap bench top from Home Depot).
I've been using unibit to skeletonize the handle but the metal heats up very quickly so I have to quench it in water to keep it cool so I can keep drilling.
I think I ruined my unibit already after drilling for several knives. I can't drill holes larger than 3/8" with it any more.
What am I doing wrong? Is there a good unibit type bit you recommend for drilling large holes?
I exclusively use stainless steels such as 154cm, 14c28n, s30v, etc... I do use oil when drilling.
Thanks.
 
If you need to drill lots of larger holes it'd be a good idea to start with a smaller bit then finish it out with the unibit.
Feed rate is a big deal with drilling metal. Be sure to feed the bit hard enough for it to bite into the metal. You want nice long curls rather than small chips. If the bit isn't cutting then all it's doing is generating heat and the life of your bit goes downhill fast.

If you can, find cobalt bits or at least titanium nitride. They will last longer as long as you're drilling correctly.
 
Stepping up from simple bits to cobalt (co) bits was a huge improvement.
Also cutting fluid for cooling.
 
first of all using water to cool down the bit is what mess you drill bit up. when drilling something that tuff you need to go at a low speed and get a can of WD-40 to spray the drill bit down. when the WD-40 is gone spray it again so your drill bit is cool. I did construction and I had to drill the big metal beams at the airport. I did it with a 18volt dewalt drill and used a lot of WD-40. I had no problem. another electricain did it and did'nt have WD-40 and broke 2 drill bits. these bits where $80.00 apeace. I got the job of doing the drilling because I drilled all of my holes and did'nt break any bits.
 
I just drilled 30 holes from 3/8" to 3/4" in M390 with no problems. I used a titanium nitride coated bit from Harbor Freight.
Ran my drill press at 250 rpm, used plenty of pressure, and lubricated with thread cutting oil. Expect to get at least 50 more holes.
Tim
 
I do not think that the UniBit is made to cut knife steels. They are for soft metals and aluminum. Electricians use them for holes in electrical panels. On top of that they are supposed to be run at slow speeds, just a couple hundred RPM makes them last the longest.

Nathan the Machinist just did a thread on drilling, speed and feed are your friends and enemies. Run the bit fast enough to not get blue and purple chips, but slow enough that your drill press has enough power to do the work. Feed the bit hard enough to break the chips so you don't get stringers, but not so hard to overwork the motor. It is little bit of a love-hate give-n-take relationship. If you have enough power you can run a 1/2" drill at 600 RPM through annealed tool steel without coolant, speeds and feed.

Good Luck
 
when I drilled holes in the big red Ibeams at the airport I just used WD-40. I let the drill bit do the work. I am also drilling about 1 inch thick Ibeams so every once in a while I had to stop and clean out the hole. what are you drilling please??
 
Right now I'm working with 154cm. 0.156" thick. Drilling 1/2" to 5/8" holes.
Got a cobalt unibit today. I'll give it a try tomorrow.
 
You certainly should be using a pilot hole. It's size should be close to the web of the larger bit. Those are what I call huge holes and demand maximum from the drill press if it's a small one as you said. Frank
 
Big Chris said:
Nathan the Machinist just did a thread on drilling
Click to expand...

Anyone who has questions on drilling holes through steel should do a search and find Nathan's thread. Worth its weight in gold (although I'm not sure just how much an internet thread weighs?). :D
 
Yes you got to find a way to slow the drill press down. Most all bench drill presses are only slow enough to drill .250 max. with out burning up bits. Also be sure to keep the blade clamped or it will chatter like crazy with a bit like that as well. It is my opinion though you will have the same result with the colbolt bit as you had with the last one in less you get that speed down to less the 250 rpms and you give it plenty of feed. Good luck
 
a unibit is made so a electricain can drill out the proper hole size for a emt fitting can fit in it. that way he can run emt pipe for the wire.
 
Hunterarrow said:
Although I set my drill press to the lowest speed I seem to go through my bits pretty fast. (My drill press is a cheap bench top from Home Depot).
I've been using unibit to skeletonize the handle but the metal heats up very quickly so I have to quench it in water to keep it cool so I can keep drilling.
I think I ruined my unibit already after drilling for several knives. I can't drill holes larger than 3/8" with it any more.
What am I doing wrong? Is there a good unibit type bit you recommend for drilling large holes?
I exclusively use stainless steels such as 154cm, 14c28n, s30v, etc... I do use oil when drilling.
Thanks.
Click to expand...

Using one of these
I like the way they self pilot and don't tend to grab
962154_lg.jpg






What RPM is that and are you sure you are on the lowest setting ?

quenching that steel after it's hot may be giving you some unintended hardening.

See Nathan's video, it shouldn't take that long enough for you to drill though a blade for it to produce that much heat,
try more pressure.

http://www.youtube.com/watch?v=vAy11Fv4N7s
 
that unibit was not ment to drill harded steel. the knife is going to be made out of harded steel or it would breask the first time you tried to use it. now what did that unibit cost you please??
 
richard thurman said:
that unibit was not ment to drill harded steel. the knife is going to be made out of harded steel or it would breask the first time you tried to use it. now what did that unibit cost you please??
Click to expand...

Judging from his original post, his knife is not HARDENED yet. No drill bit will do good on hardened steel.
 
Broomhead said:
No drill bit will do good on hardened steel.
Click to expand...

Not true. Solid carbide spade bits will drill hardened cutlery steel. But they are even more touchy about feed/speed.

I third (fourth?) the motion to search out Nathan the Machinist's thread on making holes. Drilling is one of the topics where us cantankerous, largely self-taught knifemakers, who often tend to want to do things the "quick an' dirty" way (whether it makes any sense or not) really need to listen to our friends with more education and experience.
 
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