Lathe finished

May 01, 2011

I finally finished the lathe conversion. It ended up being a lot more work than I expected as I ran into problems in pretty much every area.

The lathe is a 1995 era Jet 9x20 lathe. It originally had an incredibly heavy 3/4 HP single phase motor.

  • The motor was not a drop in replacement. I had to move the motor mount over about 3/4". I had to chop off a chunk from the quick change gearbox mounting plate because the motor hit it. I also had to buy a new longer belt. Phew. In this case a Frame 56 motor was NOT a drop in replacement for the motor that it came with.

  • Building the pendant and wiring up the enclosure for the VFD took a fair amount of time. Probably 8-10 hours if you add in all the trips to Stoneway Hardware.

  • A single set screw is not enough. I had to put in two at 90 degrees to stop the motor pulley from loosening.

  • The motor is only good up to 70Hz, so my dream of running with never changing belts isn't true. I instead just use 3 ranges: 50-600 RPM, 80-1000 RPM, and 150 - 2000 RPM. Since I'm using the vector VFD the motor runs pretty well at the lower limits. It's also oversized at 1HP so it can absorb the heat.

Overall, I'm thrilled with the performance. I was able to finish a project that had been tripping the clutch. But had I known it was going to take 20-30 hours, I would have put it off for a while.

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Note the new holes to move the studs leftwards. If you look closely, you can also see where I hacked at the plate on the right side.

Closeup of Pendant showing custom calibration on speed knob

Pendant mounted via velcro for easy movement.
Pendant mounted via velcro for easy movement

Back shot showing overall layout of enclosure and wiring
The thing on bottom right is a 15A fused switch.

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two shots of the portal so I can see any fault codes, etc.
Access to see fault codes

Another portal shot

Yet another portal shot

Large grey 3 phase electric motor
This is a 1HP motor from Suplus Center. It is only balanced to 1800RPM :(.

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Written by Chris Prosser Data Science Engineer, Maker, Bad Sculpter, located in grey Seattle