Todays Project - What did you do today?

[Mayhem]

Your lathe will give you a much more controlled chamfer. That is how I did the chamfers on my draw bars.

[TomG]

You can't case harden 4140, but you can temper it to nice durable Rc46 by heating it to a light blue after heat treat (Heat to a blood red and oil quench).

Tom

[schor]

I did this on Saturday, brought the new old grinder into the shop. Got a screaming deal. $50. I just got some new bulbs today and put some of the rest pieces into evaporust.

[Pete O]

(06-06-2016, 06:18 PM)TomG Wrote: You can't case harden 4140, but you can temper it to nice durable Rc46 by heating it to a light blue after heat treat (Heat to a blood red and oil quench).

Tom

Thanks for that Tom. I'll do the same with the arbor spacers.

[Pete O]

Well I'm glad you all insisted...
I used the arbor to centre the nut in the 4-jaw, then left the arbor in place to steady the nut
   

A spinoff project was to mill my MTGNR 32x32 carbide insert holder to fit in a QCTP toolholder.
   

   

Chamfered the nut at 45 degrees.
   

Hope you're all happier now .
   

[awemawson]

Looks much better!

The reason I say don't through harden it is you'll get brittle threads, and there is a risk of marring them by oxidisation while heating. If you do harden, then as Tom says temper afterwards, but pack the threaded hole with something to keep the oxygen at bay, fire clay or whiting.

[Pete O]

(06-07-2016, 01:44 AM)awemawson Wrote: Looks much better!

The reason I say don't through harden it is you'll get brittle threads, and there is a risk of marring them by oxidisation while heating. If you do harden, then as Tom says temper afterwards, but pack the threaded hole with something to keep the oxygen at bay, fire clay or whiting.

Thanks very much for the valuable tip. So much to learn!

[Mayhem]

Looks much better Pete. Nice job.

[Dr Stan]

not only looks better, but your hands will appreciate the fewer sharp corners.

[Pete O]

It's been nuts around here lately...

This one for the QCTP.
Turned the outer and inner diameter for the hex then set it up in the mill for indexing.
I didn't show how I set this up for the previous job; I have a limited selection pf parrallels so I put 2 of them under the dividing head so the work cleared the base of the mill vise, then used a jack to maintain the height between cuts.
   

Tighten vise, cut, loosen vise, rotate, tighten vise, check level (my chinese vise has an annoying amount of lift), cut, etc.
   

I took it back to the lathe this time before cutting off the nut from the stock, much easier to do the chamfering, also used a form tool to radius the top
   

Over to the bandsaw, then back to the lathe to face the bottom, drill, bore and thread. Had to do the threading on the lathe as I only have a starter tap in this size, no intermediate or bottoming ones. Forgot to take pics of the threading in progress but I'm sure they won't be missed.

I'm reasonably confident I won't hurt myself on this one.

   

   

Although this photo shows it does still need a little deburring before the heat treat.
   

Heat treating won't be happening until I've finished all the arbor spacers.

I'm thinking of making these nuts to sell. If I can get around $750.00 each for them, it should be a viable business plan...