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Drilling problem in stainless steel

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  • #16
    Originally posted by Black Forest View Post

    That sounds great. What size do you have and how much do you want for them or it? Postage is no problem. Post a picture so I know what you are talking about. Thanks.
    Pm on its way

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    • #17
      5 or 6 years back I made stainless steel bolt lock pens using space pen refills for everybody for Christmass presents. (Jeremy Schmidt did a nice video on it several years ago.) I don't recall for sure, but I think I made 15-16 finished pens and a few failures. For every pen body I had to deep drill for clearance for the ink cartridge, bolt lock, etc twice (both halves). I was using 304 because I had it on hand. I started with a brand new fresh out of the index Precision Twist Drill for the deep drilling and it was brutally difficult. After a couple pen bodies were done I walked that Precision Twist Drill back to the bench grinder and hand sharpened it. The next dozen pens were drilled hard and fast to depth with long knifes of stainless shooting out of the hole towards my hand. Multiple times diameter in a single peck. Insane crazy it shouldn't work drilling. I put that drill back in the index without sharpening it a second time.

      That taught me horsepower, sharp tools, and fairly aggressive cuts. Either that or I just got lucky. If hardens throw it away and grab another piece.

      I finally filled that lathe with coolant a couple weeks ago for the first time. I was doing light finish passes on 304 stainless chasing a dimension with carbide turning tools and a decent stream of coolant keeping the insert and the cut area buried in coolant. It never seemed to work harden on me, but carbide can cut hardened stainless depending on how hard.

      From that (and other sources) I learned that heat may be a component of work hardening. Coolant is your friend if you don't mind it sprayed on you when you get close to the chuck.

      A couple years ago I made a tapered extension for fishing rod making mandrels (so the rod maker could make longer rods to put in the curing oven). I ordered in a piece of 416 for the strength and easier turning than 3(04/08/16). It really does turn easier than 304 in my opinion. I struggled and scrapped the first part. I struggled and used a vertical shear to semi finish the second part oversize, and chased final dimensions with finer and finer emery cloth. I was humbled by that piece of metal. Finally I finished and called my customer. Shortly afterwards I walked to the back of the shop to take the rest of the bar off the roller table that feeds that saw. When the piece rolled over as I picked it up I saw a paper label on the far end I had not noticed before. The paper label said 316SS.

      From this I learned two things. Make sure you know what you are turning if at all possible, and don't trust the metal yard guy to give you what you ordered.

      Good luck.
      Last edited by Bob La Londe; 07-17-2022, 11:12 PM.
      *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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      • #18
        Get a masonry drill, a good quality one, and sharpen up the cutting edges. I use them to drill hard sh*t all the time.
        I just need one more tool,just one!

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        • #19
          Originally posted by wierdscience View Post
          Get a masonry drill, a good quality one, and sharpen up the cutting edges. I use them to drill hard sh*t all the time.
          I did that and the bit disintegrated right away. I have done that many times and it always has worked in the past. This time no love.
          Location: The Black Forest in Germany

          How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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          • #20
            Originally posted by Black Forest View Post

            I did that and the bit disintegrated right away. I have done that many times and it always has worked in the past. This time no love.
            Edit: If you can get yer hands on a pint bottle buy it. Then use it.

            You might be surprised. JR



            No shat. I have cooked some nice cobault bits. in SS, That was not good. JR
            Last edited by JRouche; 07-18-2022, 02:48 AM.

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            • #21
              Originally posted by Black Forest View Post
              ...I first started with 8mm HSS split point drill..:
              That is where you went wrong--work hardened it right from the start. I would have started slower, with a smaller cobalt bit, and with heavy sulfur-based pipe cutting oil.
              12" x 35" Logan 2557V lathe
              Index "Super 55" mill
              18" Vectrax vertical bandsaw
              7" x 10" Vectrax mitering bandsaw
              24" State disc sander

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