CrookedPath Posted February 5, 2015 Share Posted February 5, 2015 I have recently had some issues with drilling the pin holes for my full tang blades. I am using a 5 speed table mounted drill press, set to the slowest speed, cobalt drill bits, and oil to keep the temp down while drilling through the steel. My problem is I seem to be hitting a section in the steel, maybe 1mm deep that appears to be too hard for my drill bits to go through. Some times the hard spot is deeper, almost in the center of the 3/16 thick handle I am drilling through. I've taken to annealing my blades before I drill, and today it still happened. I went through 2 brand new drill bits just to get through this bugger. My annealing process is to heat the blank as evenly as possible to non-magnetic and stick it in a 5 gallon bucket of vermiculite over night. I am using NJ Steelbaron 1095. What am I doing wrong? I am ready to tear my hair out. Quote Link to comment Share on other sites More sharing options...
Crazy Ivan Posted February 5, 2015 Share Posted February 5, 2015 Did you pre heat the vermiculite before putting the blade in? A thin profile blade will not cool slowly enough often times. Try heating up some thick bar stock and putting it in the vermiculite with the blade to help the cooling process take longer. That or your drill speed could be no good which damages bits faster, but I would put my money on the annealing not being successful due to the cooling rate. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 5, 2015 Share Posted February 5, 2015 yup a helper bar during annealing was my first thought too. Also being careful to not quench the tang using a postvise or large set of tongs for a contact quench... Quote Link to comment Share on other sites More sharing options...
CrookedPath Posted February 5, 2015 Author Share Posted February 5, 2015 I live in Florida i didnt think those things were necessary. If this metal is so hard it beats a drill bit made for drilling metal even after a poor but mostly sound attempt at annealing, at the very least it's been air cooled, why the heck am I going through the bother of hardening at all!? I say that mostly in jest. I am just blown away that I have spent the better part of a year learning the how to make my steel tough and hard and springy and all that, only to find that its harder than a drill bit without me even doing anything to it. Seriously though for the helper bar. Just stick a heated chunk of rebar in the bucket along with the knife? Or stick it in before I put the knife in, kinda like I do for preheating my quench oil? Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted February 5, 2015 Share Posted February 5, 2015 A few seconds eitherside. A bar bent into a trough works well to. Also make sure you soke your blade a bit. I find that some "home" type drill presses just turn to fast. A jack shaft to futher reduce the speed my help as well. The issue, i think is that wood likes fast and steel slow, home presses are just fast enugh to turn wood working bits efficiently, threw their speed ranges, as to steel, i think its just slow enugh for low carbon and anealed medium carbon steel. Quote Link to comment Share on other sites More sharing options...
Rainbows Posted February 5, 2015 Share Posted February 5, 2015 Are your drill bits reputable and sharp-ish? A good brand (in my case Dromer) of simple HSS bits will beat a mystery china brand of cobalt bits on most days. Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted February 6, 2015 Share Posted February 6, 2015 I've found that new bits that are on the cheap side will have this problem. The steel you are working with is supposed to be properly annealed to begin with, I expect it from Admiral Steel (it's where I get my steel). When I'm having this issue I'll resharpen my bits, that usually does the trick. Even the cheap bits cut better when I do this. Quote Link to comment Share on other sites More sharing options...
arkie Posted February 6, 2015 Share Posted February 6, 2015 Did you pre heat the vermiculite before putting the blade in? A thin profile blade will not cool slowly enough often times. Try heating up some thick bar stock and putting it in the vermiculite with the blade to help the cooling process take longer. That or your drill speed could be no good which damages bits faster, but I would put my money on the annealing not being successful due to the cooling rate. I second the idea of putting a companion heated bar in the vermiculite with the blade. I had the same problem when just sticking the blade alone into the vermiculite, but the heated bar with the blade solved the problem. Without the heated bar, the blade was cool enough to handle after only 4-5 hours. As I recall, I used a bar about 1/2" thick by 8" long by 4" wide heated to red. Quote Link to comment Share on other sites More sharing options...
CrookedPath Posted February 6, 2015 Author Share Posted February 6, 2015 I use Dewalt cobalts. Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted February 6, 2015 Share Posted February 6, 2015 impressed with dewalt drills, darn things like to slip and get chewed up in the chuck. I wander, JM if you sharpen to a les acute angle? Wool likes a more acute angle and Steel a les acute angle. A lot of "box store" bits i think have a "unhappy medium" Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted February 6, 2015 Share Posted February 6, 2015 A chunk of rebar won't do it. You need a substantial piece to hold the heat against the knife. I have seen a thick chunk used with the knife wired to it on one side, or two thick pieces with the knife sandwiched between them. Quote Link to comment Share on other sites More sharing options...
jimmy seale Posted February 6, 2015 Share Posted February 6, 2015 if nothing else, hot punch it.. Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted February 6, 2015 Share Posted February 6, 2015 To easy Jim, lol Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted February 6, 2015 Share Posted February 6, 2015 if nothing else, hot punch it.. You know, I had some large band saw that wouldn't anneal for nothing. That was the only way to do it. Another thing I'll do is take a section of leaf spring, heat it up then heat the steel to be annealed and bury them. Quote Link to comment Share on other sites More sharing options...
gearhartironwerks Posted February 6, 2015 Share Posted February 6, 2015 try carbide drill bits. john Quote Link to comment Share on other sites More sharing options...
CrookedPath Posted February 7, 2015 Author Share Posted February 7, 2015 I thought about the hot punch, but I don't currently have punches in the sizes I need for the pins. I always drilled because it seemed easier, and more precise. It may be I will just start punching. Still this is a good lesson in proper annealing. Love this forum Quote Link to comment Share on other sites More sharing options...
llen Posted February 13, 2015 Share Posted February 13, 2015 I don't know much, but HSS bits works! he said that he tried cobalt already which are much harder than M2, and they did not work. Quote Link to comment Share on other sites More sharing options...
Kendall P Posted February 16, 2015 Share Posted February 16, 2015 I have the same problem with some mystery steels that i use when i am making knives out of old files - the last one i did was hell - i tried anneling several times, the only way i got it drilled was by hot drilling one hole and then annealing the blade something like 3 times for the seccond before it grudgingly went through not without breaking the bit. for two pins and my utter stubbournness it took a week of various things attempted. So my two cents - If you know what type of steel you have you can often find out the very accurate specifics of what temperature and timeing of cool down you will nead to anneal that particular steel. If you dont know what type it is then use a slow speed - carbide bits - cutting oil and patience with a solid anneal and a helper bar (nice red hot lump in the vermiculate) when you try your anneal, If it doesnt work and no matter what you do if failing you can try a hot drill - get it nice and cherry red and it should drill. If it still wont drill consider a pinless hidden tang design ;) You also plucked on my heart strings when you spoke of the stress of steel not drilling. I wonder how many other knife makers have had that particular bad day? Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted February 17, 2015 Share Posted February 17, 2015 I thought about the hot punch, but I don't currently have punches in the sizes I need for the pins. I always drilled because it seemed easier, and more precise. It may be I will just start punching. Still this is a good lesson in proper annealing. Love this forum I've got a set of cheap nail set punches for this. ;) Quote Link to comment Share on other sites More sharing options...
IanJ Posted February 24, 2015 Share Posted February 24, 2015 One thought that occurs to me is feed rate. With some kinds of stainless, if you drill too slowly (ie, too little pressure on the drill bit), it heats up enough to work harden, and exhibits a problem very like the one you're describing. It just gets diamond-hard, and no amount of drilling seems to work, or it takes forever and destroys the edge on drill bits. If you drill at lower speed and higher feed, it works like it should. Could that be happening here? Quote Link to comment Share on other sites More sharing options...
Michael Posted February 24, 2015 Share Posted February 24, 2015 When you get the thin crust of hard metal in the hole you are drilling, a tiny sprinkle of baking soda or chalk will give the bit just enough grip to drill thru the....not workhardened.....friction heated layer and keep cutting.Picked this trick up on a machinist forum a few years back, trying to drill 1/16 inch hole in thick music wire. Quote Link to comment Share on other sites More sharing options...
gearhartironwerks Posted February 26, 2015 Share Posted February 26, 2015 Try MSC for straight flute and die drill bits. Not inexpensive, but they work.john Quote Link to comment Share on other sites More sharing options...
CrookedPath Posted March 4, 2015 Author Share Posted March 4, 2015 I'm glad others feel my pain. Thanks for the good words Kendall. Micheal i am gonna try this. Baking soda, hmmmm Quote Link to comment Share on other sites More sharing options...
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