rotarysmp

Machining the pulley

Rating: 3 votes, 4.33 average.
I have finishing turning the pulley from one side, inclusing the bore and drive key slot. I use the lathes old top slide for shaping slots.

A pivot is bolted to the end of the slide, and an anchor pivot bolted to the cross slide t-slots, behind the shaper slide.




To lock the spindle, I just use a bolt wit nuts as a machinist's jack.


The casting has come out really crappy, with a lot of voids. This alloy has turned out to be pretty abrasive, and dirty. I it not very nice to machine, and is differcult to get a decent surface finish with.

It came from die cast industrial transformer covers, and had a thick strong paint on it. This Alloy is a mix of about 65% which had already been skimmed and made into ingots, and 35% which was still painted. I skimmed a lot, and used soda, then salt, but still need to improve my technique in this area a lot.


The mill motor I will use is only 1/2 HP, so I doubt the defects will cause a failure, but if it does frature, the next will be better

Now I just need to turn it around and remount it to so the 100mm pulley step. For this I regret not having the 2 speed gears in my lathe. The slowest speed is currently 250 rpm, and I have to turn faster than that to get enough torque to avoid stalling, but then get edge buildup on the cut off tool used to make the pulley grooves.
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Comments

  1. TRYPHON974's Avatar
    I like much your keyway cutter . Maybe you should only use ingot for casting , my 2 cents
  2. rotarysmp's Avatar
    I think you are right. As the scrap is quite thin section diecast, the thick paint makes for a large percentage of contaminants and slag. I will need to pig the whole lot, and use it in ingot form.
  3. Metal Hero's Avatar
    Try a little WD40 lube, might help with the galling. I also like your keyway cutter.
  4. rotarysmp's Avatar
    Thanks MH. I used a spray cutting oil. It helped, but the surface finish was still not close to that which I normally get with these TMCT0802's and wrought alloys.

    That big scar around the first step isn't a durface finish issue. It was a G01 Z-53 command, when that step was at Z-43. I drove the tool into a shoulder till the spindle stalled. Oops.