Reply To: Hardness of steel rod…

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Bob Tascione
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Hi David,
Ha…Ahhh yes. I was 43 when I made those clock videos 17 years ago. Have a few more greys now at 60. The hair’s still all there though…just tied back and hidden for the pic.
Yes you are absolutely correct about S7 not being a good choice for ‘balance’ staff pivots. Wear would be too much for that application. I will be testing S7 for something much different though. I think I had mentioned the project I’m working on when we spoke on the phone a while back. They (the staffs/arbors) will rarely be in operation and then only briefly when manually activated. Wear will not be a factor. There is the possibility of shock though and this is where S7 may prove itself a worthy metal. Using S7 should allow me to scale down the pivot size a little and also go from a typical squared pivot to a lesser dia. conical staff pivot and at the same time reduce the parts mass. IF I can get a decent finish then friction should be reduced significantly. Friction is the big enemy here but I think it will be an improvement overall. I’ve managed to successfully heat treat tiny S7 parts with flame using both oil and water. Water’s difficult. Any sharp corners will usually result in cracks. The shape of the staff though has no sharp shoulders or edges. S7 get’s up into the mid 50s rc which is plenty hard enough for these parts. I had to pull the high carbon arbors back to at least this hardness to keep the parts tough enough. I’ve experimented with the shape and all’s well so far. It’s the surface finish I’ll be dealing with next. If all turns out well I’ll replace the arbors that I’ve already made with S7 staffs and will run some tests. I have one length of 1/8″ dia. left to mess with down here with me. We probably didn’t use S7 in our toolroom as much as you did as it’s not needed that often for jigs and fixtures so if you know of any trick or have any ideas that might work for polishing this stuff I’m all ears…as you can clearly see in my Avatar pic.!
Thanks David,