8/23/2023 0 Comments Guhring cobalt drill bit setI also drilled about another 20 holes in another piece of stainless with the damaged bit with no problems. Then I proceeded to drill holes in the SS with both bits. I cut the tip off the bent bit and sharpened it. Late that day the supervisor had a go at me for buying cheap drills from China so I brought a piece of the same SS and the bent drill bit and another new bit home. If you look really closely at the tip you will see a galled ball of metal. Instead the member did this to the Co bit. After many minutes of trying with a regular HSS bit he failed to get through even one hole so he spoke to the supervisor who told him to push harder but to no avail.Įventually the supervisor went to the sheds drill stash and took out a cobalt bit that I had bought in bulk from China. You must have good tool rests and well cared for grinding wheels.įor drilling in stuff like stainless bit survival can sometimes be be attributable to operator experience.Īt the mens shed a member needed to drill 3 holes in a bit of stainless. ![]() It is a good alternative and not hard to master. This year I have spent some time at 4 facet grinding. Sutton and Bordo are the brands I sell and surprisingly their cheaper sets are OK too. Standard HSS drills work well in SS if the speed is right. The drill manufactured won't change as it is a cheaper way to make them. Drill point thinning takes a bit of practice but get used to doing it. Most drills 4mm and over delivered today are wide web drills and have a notched, split point. Use a light hit on the punch or grind a pyramid shaped point on it. You have started the work hardening process. Also with SS if you whack it hard with a big center punch your off to a bad start. There are lots of speed charts on the net. SS requires about 40 SFM drilling speed compared to 100SFM for mild steel. Most tradesmen don't operate the drills at a correct speed for the more difficult material. ![]() I get asked for better drills for SS often. The cheap drill bit out performed the expensive drill and it is still going.so I am a bit skeptical on paying a lot of money for drill bits. So after I broke the very expensive drill on this stainless job I figured I would sacrifice one of these cheap drill bits to try and complete the job. So I popped down to the local bunnings and bought the cheapest hss set they had to complete the job at mums. Sure it was a nice bit but bugger me if I didn't break the thing after a few hundred holes.Īnyway, a week or two earlier I was at my old mums house doing a job and I forgot to take my drill set. One thing that does annoy me a little though, is recently I had to drill several hundred holes in stainless for a job, so I bought a very expensive cobalt drill bit to do the job. ![]() I would have spent more than that on drill sets over the years. At around $400 though its going to have to be a birthday or Xmas present.Ill have trouble convincing the rest of the household that I need a $400 set of drills. I am leaning towards the Sutton purple Cobalt set.
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