Thursday, September 13, 2018

5C Lathe Part II: Power Supply and ESC

450 w 12 v server power supply connected to 25 amp ESC. With this arrangement, I get a very compact 1/2 HP variable speed motor for $100 or so. The parts are all pretty high quality too-

I made the aluminum enclosure from .062" aluminum found in the remnants bin at local metal supplier. The top handle and aluminum for knob came from a dumpster, and the pushbutton switch on the top was recycled from my wooden computer case build.

Servo tester with 'mode' switch and potentiometer breakout.

Wednesday, September 12, 2018

Thin .040" Parting Tool Holder


The slot has a dovetail shape to pull the parting blade towards the tool holder. It's really helpful if the blade can go right up next to the chuck. The parting tool holder made by Taig is weak in this department:

I skimmed maybe .075" off the blade clamp, but it still gets in the way all the time. I'm excited to have a holder that can part almost flush with the chuck!

To cut the dovetail on the new holder, I ground a safe edge on a cheap triangular file and finished the slot with it. It might have been faster to grind a single-point cutter, but this worked fine

It takes up half of the AXA tool holder; the other half will get a piece to hold a 1/4" facing tool at matching height to the cutoff tool.

Made for my 5c lathe. Ideally this would be made of 4140 or something like it, but I used the cold-rolled steel I had. I parted a 1/2" stainless rod and it worked a treat. I have never used a parting tool so thin, and it's a good match for small work and light lathes. I can get real stingy with my bar stock now :)

Sunday, September 2, 2018

5C Lathe Part I: Motor Mount

I'm putting together a new manual desktop lathe to replace the one I put together two years ago. The old one has been awesome, despite its weaknesses and size it is the most useful tool I have ever had.

The new one is made with light production in mind, for making drawer pulls and hand tool parts. It has a 5C spindle, quick-change tool post, and slots for mounting five or more tools in a gang arrangement.

Above was boring out the hole for the motor using a fly cutter. I adjusted the cutter with my most precise hammer and ended up with a darn accurate bore, a snug slip fit over the motor. :) The motor is a 450 w brushless DC motor, pretty spicy for a motor that's smaller than the lathe spindle itself...

I wanted the fit to be close so that the pinch bolt wouldn't have to stress the aluminum much to clamp it (it does clamp easily). The outer edge of the plate is pretty sloppy though; I got tired of filing the gummy aluminum. A mill or router would have been nice for that.

I roughed out the plate shape with a wax-lubed coping saw, which was actually pretty quick. The 18" frame saw also cuts through it plenty fast. I made the plate to fit the vee belt I had on hand (standard Taig lathe belt), after I machined both pulleys. It pivots on the bottom mounting screw and locks with the screw on the top to tension the belt. I erred on the long side for the slot travel since the belt is heavily used.

Approx 1:6.5 reduction. Small pulley machined of steel and secured to shaft with setscrew bearing on flat portion. Also managed to bore a tight slip fit on the motor shaft with a little honed carbide boring bar.

Used steel shaft collar to mate the plywood pulley to the spindle--I often grab the pulley and rotate by hand to tap holes and do other high-torque stuff. Setscrew just seems hackish for this.

Stay posted for the base, tooling, electronics, and maybe even an electronic leadscrew-