"Finished" Low speed mod to Sieg C6B

Finally, it is is "finished" (I can now see improvements so I guess it
never will be!). Originally, I was going to use timing belt and cutting
the timing pulleys was a bit of a stumbling block, not having a dividing
head or similar. Poly-V (multi-rib) belt made that problem go away.
This is the new bottom end pulley to drive the countershaft and increase the
top end speed:
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The ribs were cut using an appropriate tap "tailored" with a slitting disk
and mounted in the toolpost.(same for the countershaft pulley)
This is the finished mod in "low gear":
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This is the high speed direct drive config:
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The countershaft pulley is 130mm x 20mm in cast iron, I think ally might
have been a better choice, its quite a flywheel.
I cheated by buying a C6 "banjo" and counter shaft spindle from Ketan at
Arcurotrade. The mod would have been cheaper if I'd fabricated the thing
from barstock, but I can't weld (yet) and don't have the gear to braze that
mass of steel.
The pulleys are home made.
The ratios available are roughly motor:spindle 8:1 and 1.7:1 instead of
the original 2:1.
It still won't take quarter inch cuts at 50revs, but it does have real
grunt now, so much so that I'm tempted to leave the drive belt a bit slack
so I don't get into serious trouble, particularly when parting off.
This picture shows the CD I made with 60 holes around the edge to drive a
rev counter:
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Next step is the electronics, because I used 60 holes, I can use a bench
frequency counter which will directly readout in rpm to set the lathe up,
before implementing a dedicated rev counter and display. I'm using infrared
TX/RX devices without modulation. They are completely enclosed so neither
dirt nor interfering light should be a problem.
This is what the stupid questions have been about over the past months -
thanks guys!
Steve
Reply to
Steve W
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