I have a couple wrenches that came with my mini air powered die grinder. I want to put a hole into the top so that I can attach a wire or string so I don't lose them.
I used a punch to put a dimple into the wrench. I am trying to drill a pretty small hole maybe a bit bitter than 1/8". I put a cobalt drill bit into my drill press but it just doesn't seem to make any progress. I don't have a cutting liquid – was thinking of getting one. The wrenches are probably 1/8" thick.
Any other thoughts? What are the best bits for drill metal? What type do they use in heavy industry to drill through hard metal? Carbide? I probably have the drill press going too fast but I got it used and have never adjusted the speed. Given the size of the hole I am trying to drill it just seems like I shouldn't need the perfect setup to get a hole.
I adjusted the drill press speed to 620 rpm ( the slowest it can go – it was set at 3100 ) and I tried using a new cobalt bit with some spit on the wrench I had not previously tried to drill but it didn't seem to make any more progress than my previous attempt. I have some cutting oil and the HI-Molybdenum M7 Drill Bit Set on order so either I'll give those a try or next up I might try diamond or carbide bits.
I tried cutting oil – oatey 30201 -, setting the drill press at 3100 rpm, using a new cobalt bit, using a new spot and apply significant downward force – ending up breaking the bit.
I used my MAP torch to heat one of the wrenches to red hot and let it cool over night. The next day I used the same 3100, new cobalt bit, cutting oil and similar force. The drill bit went through ! You can see the line of the heat on the wrench. I didn't get around to trying a few of the other options yet. I'll probably give the diamond option a try on the wrench I haven't heated. Nice to have more than one trick in my bag.
Thanks for all the suggestions! I feel like I used a bit from each answer.
Best Answer
Anneal The Butt of the Wrench First
When you view this question in the general since of "how to I drill steel that is too hard to drill with the tools I have", annealing it first is one possible solution.
Depending on how steel is cooled, it can form different kinds of crystalline structures that give it its unique properties. In the case of the steel in your wrench, it was likely heated and cooled to different temperatures and at different speeds in a kiln until finally being quenched to give it that nice combination of hardness and toughness that makes it so good at applying force without breaking. The hardness part that you are having a difficult time overcoming comes from that final quenching where it is cooled quickly in oil or water (depending on the exact alloy).
So, to make the steel softer, you just need to heat the butt of the wrench with a blowtorch until it glows a bright red. If it gets too hot you risk decarbonizing and/or melting the steel which will ruin it; so, be careful not to let it get to being white hot. You also do not want to heat the head or neck of the wrench as this may ruin the original temper and make your wrench bend next time you try to use it, but since the butt experiences the least amount of stress in use, softening that steel will generally not be a problem. Then you want to let it air cool. You don't want to cool it in water as this will just re-harden the steel. You also don't want to fully anneal it by kiln cooling it either as you only need it to be soft enough to drill... not soft enough to bend in your hands.
... or if you just want to solve the actual problem (hanging metal tools that are otherwise hard to hang), you could just try a magnetic wall strip. If cost is an issue, you could instead put two nails in your wall that are far enough apart for the handle to fit, but closer together than the width of the head. Then you can hang the wrench upright between the nails instead of upside down on 1 nail.
These methods requires no actual modification of your tools, just your work space.