David G. Posted September 9, 2021 Share Posted September 9, 2021 Dear community members! Some days ago I got a bunch of old bent big drill bits from my grandpa. Are these good to make bushcraft knives? If u have any other ideas let me know. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Frazer Posted September 9, 2021 Share Posted September 9, 2021 It depends on what they're made of. I don't know how old these are, but most drill bits are made of high speed steel. However, there are many different kinds of HSS. I would do some testing to make sure you can even forge them and then decide what to use them for. If you're considering making a knife I would also harden and temper some test pieces. Some HSSs are oil hardening, others are air hardening, others are air hardening with a stream of compressed air... You'll want to know what you have before you forge a knife out of one. Quote Link to comment Share on other sites More sharing options...
David G. Posted September 9, 2021 Author Share Posted September 9, 2021 By the time I tested one and it is hardening in water. Most of them are probably the same brand. Quote Link to comment Share on other sites More sharing options...
Frazer Posted September 9, 2021 Share Posted September 9, 2021 Was your test piece roughly the same cross-section as a knife or was it a piece cut off from one of the ends? Water might be too aggressive for a thin cross section. Quote Link to comment Share on other sites More sharing options...
David G. Posted September 9, 2021 Author Share Posted September 9, 2021 I took the drill bit, untwisted it and I drew it out to a long piece of 3mm thick and 20 mm wide. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted September 9, 2021 Share Posted September 9, 2021 What did the grain structure look like when you broke it after hardening? By "old" are we talking about over 100 years or over 20 years? Where in Europe did they come from? Spain, Germany, Czechoslovakia, Italy, Rumania, Switzerland? Quote Link to comment Share on other sites More sharing options...
David G. Posted September 9, 2021 Author Share Posted September 9, 2021 I did not broke it after quench but I could not file it at all. I think they are around 30-40 years old, made in Hungary or Romania. Quote Link to comment Share on other sites More sharing options...
Frazer Posted September 9, 2021 Share Posted September 9, 2021 It's always a good idea to break your test piece(s) to examine the grain structure. If the grains are too large then adjust the quench medium and/or temperature(s) of your normalization cycles until you end up with a small grain stricture. This is just a picture I found online, but it's a good example of what to look for. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted September 10, 2021 Share Posted September 10, 2021 16 hours ago, David G. said: Are these good to make bushcraft knives? To me 20 mm wide would be small for a bushcraft knife, especially after grinding & finishing. There are plenty of styles they would make though. Quote Link to comment Share on other sites More sharing options...
David G. Posted September 10, 2021 Author Share Posted September 10, 2021 (edited) Thanks I used the normalizing method, but I will keep in mind to break it too. I already have a wider knife made from coil spring. I would like this a little bit skinnier so I can eventually carve spoons or other things. Edited September 11, 2021 by Mod30 Remove excessive quote. Quote Link to comment Share on other sites More sharing options...
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