arkie Posted February 2, 2018 Share Posted February 2, 2018 Background: I recently tried to drill a 5/16" hole in a Nicholson (Made in USA) file that I had annealed. I heated the file to non-magnetic in my coal forge, soaking for about 10 minutes, tested with a magnet, and imbedded it in a bucket of vermiculite overnight as I have done many times over. I tested the annealed file with a regular file the next day, and a regular file cut it just fine. I used a center punch to start the bit (metal cutting HSS bit, 118* angle) and liberal WD-40 for lube. My drill press was set for the proper speed by drill bit tables. Since I had drilled lots of holes (mostly mild steel) with that setup, I anticipated no problems with the annealed file. The bit was newly sharpened, BTW. After the bit cut about 1/4 of the way into the file, with good shavings, it abruptly quit cutting and just spun there. I flipped the file over and tried the other side with a new bit and the same thing happened. It appeared that the outside of the file was softened by "annealing", but the center never softened. With a file being only about 1/8" thick and soaking for the mentioned time, one would think the heating and annealing in the vermiculite should have occurred throughout the thickness. I tried to repeat the drilling with other newly sharpened HSS bits, same size, on other similar annealed files, but still found the very center still hard. Anyone else had problems like that? (BTW, I wanted drilled holes, not punched holes in these file sections. I punched some holes and they came out fine.) Quote Link to comment Share on other sites More sharing options...
DavidF Posted February 2, 2018 Share Posted February 2, 2018 One thing I wanted to mention, I have seen a similar issue. As I looked into it, one idea that could be an issue for me was using the spring punch multiple times. I intended to create a deeper starting point, but after some research, the multiple punches probably hardened the steel and reacted the opposite of what I intended. I haven’t been able to test this theory yet, so I am not sure if what I outlined is correct, but based on what I described, are you punching multiple times and hardening the steel? For anyone else that has experience, is the theory correct that multi0le punches will harden the spot you want to drill? Quote Link to comment Share on other sites More sharing options...
arkie Posted February 2, 2018 Author Share Posted February 2, 2018 One punch only. The punch holes are on the surface. The hard place is in the file center. If you read the post carefully, the outside drilled out normally. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted February 2, 2018 Share Posted February 2, 2018 Although I am more likely to anneal by leaving steel in the forge when I shut it down I have experienced this phenomenon as well. I'm not sure what causes it, but for the steel I was using I know what cures it. Heating to a dull glow (still magnetic) and letting it cool slowly has typically allowed me to drill afterwards without problems. If you don't want to heat the whole piece then you can get by with a torch or even chucking some round mild steel in a drill press and let the friction heat up the area you want to drill. Of course that will not work with certain alloys, but it should work ok with simple steels. Sorry I don't know the why of it though. Quote Link to comment Share on other sites More sharing options...
TwistedCustoms Posted February 2, 2018 Share Posted February 2, 2018 I have had the exact same issue with drilling files, Black Diamond and other "old" files. Sometimes after annealing I will get one or two holes that drill like butter and then hit a hard spot on the second or third. It is usually part way through and not consistent, just random hard spots. I always assumed it was some degree of air hardening. I have heated and punched holes as small as 3/16" and then drilled them out to 1/4" to clean up the holes but if you want smaller holes you can try "hot drilling" with a throw away drill bit or start over on the annealing. I don't know why it happens but the only time I ever have this come up is with files. Quote Quote Link to comment Share on other sites More sharing options...
arkie Posted February 3, 2018 Author Share Posted February 3, 2018 I'll probably just take the ones that didn't drill through and let them soak again, for maybe 15-20 minutes this time at cherry red (non-magnetic) then poke 'em back in the vermiculite, this time with a companion piece of hot steel to slow down the cooling a bit more. I don't know if soaking that long at non-magnetic will decarburize the file steel any or not. I'm making some small pocket flint strikers to give away so I need to keep them hardenable on the edges (and the holes are for lanyards). Don't want to punch at this time and don't want the curvy ends so as to keep them small. Quote Link to comment Share on other sites More sharing options...
SLAG Posted February 3, 2018 Share Posted February 3, 2018 You could allow the files to anneal in a depression in a container / "sand box" that is filled with carbon dioxide gas, in order to stop decarburizing. The CO2 would displace the air and it is heavier than air and will not rise into the atmosphere if the gas is in that depression, and the "air" is still. SLAG. Quote Link to comment Share on other sites More sharing options...
basher Posted February 4, 2018 Share Posted February 4, 2018 Try a sub critical anneal, or more specifically a very high temper .Taking the piece to below critical, dull red and still magnetic a couple of times. I find it works much better than a "blacksmiths " anneal. a full spheroidal anneal is often quite a rigmarole and needs to have controlled slow cooling (computerised oven) to do properly. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted February 4, 2018 Share Posted February 4, 2018 its covered Quote Link to comment Share on other sites More sharing options...
arkie Posted February 5, 2018 Author Share Posted February 5, 2018 On 2/4/2018 at 9:37 AM, Steve Sells said: its covered Steve, thanks for pointing out that section. I had read through the sections, but just wasn't sure which applied and why the inside would not anneal. I suppose the "Sub-Critical annealing" is something to try next...I have not done that before. Quote Link to comment Share on other sites More sharing options...
BeaverNZ Posted March 3, 2018 Share Posted March 3, 2018 I think its probably unlikely to have a hard part part way through, it maybe the workpiece work hardening from the drill going blunt by it being driven too fast or the drill having too much back clearance or rake this makes the cutting edge weaker as its not as well supported (I often reduce the clearance on new drills ). When drilling a high carbon or alloy steel reduce the speed to about half the recomended speed for mild steel or more is required sometimes for alloy steels and use a heavy cutting pressure to make the drill cut and not rub, this is important with stainless steels as they are really prone to work hardening. My big old drill pres goes right down to 28 rpm and thats too fast some times when driling with larger drills in wear resistant plate Cheers Beaver Ps good old kerosene makes a good lube for hard steel or Rocol RTD Quote Link to comment Share on other sites More sharing options...
DavidF Posted March 4, 2018 Share Posted March 4, 2018 I was looking at drilling titanium this week and one of the things I ran across was a mention of the work hardening for steel (although it was titanium research, it was used as a comparison) that @BeaverNZ is describing. I was so happy to see this resurrected because as I read that background, I recalled this post. I have ran into the issue of being able to easily drill through one part of,the handle and then not be able to dent a point 1” away. Even when switching to a brand new drill bit, it wouldn’t bite. My press has five speeds, but it requires opening the top and moving the belt. So my question becomes, if I don’t want to have multiple presses since I am a hobbyist, would the best setup be to set the press at the slowest speed? I use the same press for both the metal and wood work and I can use a handheld drill to start holes in the metal for pins, but now that I am getting some experience I realize that others have probably gone through this and have feedback. An important piece of background, when I describe having difficulty drilling the holes, it is after annealing and before hardening. And the stock indicates that it is shipped as annealed and ready to work, these are standard 1095 12” bars from the factory. So it isn’t a case where I don’t know the alloy or it is mystery steel from springs or files. I have experienced the same issue trying to drill it right out of the gate or after I have fired it up and let it cool in Perlite. It could be that 1095 is difficult, it work hardens, my drill speed is too high, etc. I feel like I may be onto something with drill speed, but I am new to working with steel, so feel free to assume I am missing the basics. I would rather figure out how to do it right and I am open to any ideas that help, including steel, drill speed, process, etc. and also recommendations for press setup, starting with a variable speed handheld before moving to the press, etc. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted March 4, 2018 Share Posted March 4, 2018 Be aware that steel hardens differently, as in backwards methods, than other metals, so what you do for steel wont work the same way as for titanium which is why we have a separate section for nonferrous metals Quote Link to comment Share on other sites More sharing options...
DavidF Posted March 4, 2018 Share Posted March 4, 2018 Thanks Steve. I agree. Although I found the information in a titanium article, it used the process of working with steel as an example. What I actually ended up caring about was the details for high speed drilling causing steel (not Ti) to work harden. So that is what I am actually asking about. I probably confused my point and question by mentioning the origin where I read this information. The writer was actually working with 1084 if I recall correctly And I think I will only decorate the titanium for my project and not attempt drilling. But if I do, I will consult the non-ferrous section you cited Quote Link to comment Share on other sites More sharing options...
BeaverNZ Posted March 4, 2018 Share Posted March 4, 2018 On 3/3/2018 at 9:17 PM, DavidF said: For drilling a problem steel you often have to run the drill at 150/200 rpm or slower if you have the chance thats when using a small drill 3mm or about 3/16 and i have found that a GOOD quality Ti coated drill is a good investment though once sharpened the coating is void. I have found that there are alot of gold coloured drills claiming to be Ti coated but just dont cut it. If you run a drill too slow it just takes longer to drill but too fast and it just stops Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted March 5, 2018 Share Posted March 5, 2018 All it takes is the outer edge of the drill to get dull and it will stop your progress. When I was a tool maker at a machine shop I usually didn't use drill speed charts, and went by what worked best by eye. In most cases it was far slower than what would have been suggested. Also ditch the WD-40 as a drill lube. Even the old baking soda and water mix is better than that. A good oil will do and keep the hole filled. I have also use the chlorinated carb cleaners for difficult holes, but you need good ventilation when doing so. The original Tap Majic used 1,1,1 TriChlor and it was great, but you definitely did not want to breath it. Quote Link to comment Share on other sites More sharing options...
Joël Mercier Posted March 5, 2018 Share Posted March 5, 2018 I did read in an interesting pdf about using file steel that slow cooling hypereutectoid steel can promote the formation of bainite. That's what's ruining your drill bits. The sub critical temper is definitely the best way. I'm just the kind of guy that needs to know the why of things. So I thought this might interest some folks. Quote Link to comment Share on other sites More sharing options...
Mike Scan-D Posted March 7, 2018 Share Posted March 7, 2018 On 2/2/2018 at 6:50 PM, TwistedCustoms said: I have had the exact same issue with drilling files, Black Diamond and other "old" files. Sometimes after annealing I will get one or two holes that drill like butter and then hit a hard spot on the second or third. It is usually part way through and not consistent, just random hard spots. Had this happen last night. drilling three holes in a knife handle before hardening and the third hole just wasn't having any of it. I reheated and punched the last hole due to the fact that she ate the sharp off my last 3/16 TiN cote. Quote Link to comment Share on other sites More sharing options...
arkie Posted March 7, 2018 Author Share Posted March 7, 2018 I've decided, as well, to forego any drilling of files. Bits are too expensive to ruin. I'll just punch from here on out and either drift or clean up with carbide bits/reamers. Cleaning out or enlarging a punched hole in a file with another file doesn't always work either. I had one punched hole (in an "annealed" file) that I tried to clean out with a rat tail file and it wouldn't cut. I have yet to try the sub-magnetic annealing. Quote Link to comment Share on other sites More sharing options...
Joël Mercier Posted March 8, 2018 Share Posted March 8, 2018 That's the thing, standard "annealing" creates bainite in file steel. Either do normalizing cycles and air cool or do a sub critical temper. File steel is shallow hardening, there's no way it's going to air harden. Here's an interesting document on file steel. Old_Files_New_Knives.pdf Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted March 8, 2018 Share Posted March 8, 2018 I will have to contact him because I got conflicting information from the materials guy at Nicholson. He told me that they have used the same alloys for the 46 years he has worked there. Quote Link to comment Share on other sites More sharing options...
arkie Posted March 8, 2018 Author Share Posted March 8, 2018 8 hours ago, Joël Mercier said: Here's an interesting document on file steel. Old_Files_New_Knives.pdf VERY interesting and informative article, Joel. Thanks for posting! Quote Link to comment Share on other sites More sharing options...
BeaverNZ Posted March 8, 2018 Share Posted March 8, 2018 I may stand corrected here but even just tempering should remove enough hardeness to allow an item to be drilled or filed if taken to a black/blue colour unless its a high speed steel alloy Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted March 8, 2018 Share Posted March 8, 2018 3 minutes ago, BeaverNZ said: I may stand corrected here but even just tempering should remove enough hardeness to allow an item to be drilled or filed if taken to a black/blue colour unless its a high speed steel alloy didnt you read the post? he did anneal it... thats the problem Quote Link to comment Share on other sites More sharing options...
BeaverNZ Posted March 8, 2018 Share Posted March 8, 2018 yes Steve I have read the whole story Im just thinking out loud, maybe he has very poor temp control? just putting out ideas why this is happening. Isnt all tempering regardless of the amount done at subcriticle temps? I was just rereading some of the other resent posts. I may be interesting to here back from Biggundoctor . Quote Link to comment Share on other sites More sharing options...
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