Thread: slow turning/revolving

Originally Posted by brainstrust

Is there such a thing as a cheap or 2nd hand slow turning/revolving lathe that can be used for applying resin finishes and the like?

Or does anyone have any tips on setting up the bbq rotisserie motors either within a lathe or as a stand alone contraption?


Thanks!

I would possibly think about setting up a faceplate on the BBQ rotisserie independent of my main lathe.

Manly just to remove the mess of applying resin on the main lathe.

Cheers Matt.

Originally Posted by brainstrust

Is there such a thing as a cheap or 2nd hand slow turning/revolving lathe that can be used for applying resin finishes and the like?

Or does anyone have any tips on setting up the bbq rotisserie motors either within a lathe or as a stand alone contraption?
Thanks!

If you put a Vector Drive VFD and 3P motor on a wood lathe and run it on its lowest gear eg 300 RPM, and the VFD at say 10Hz (1/5th of the 300rpm) the headstock would be running at 60 rpm. This is the speed at which I run the my lathe while forming bell mouth hoods. This forming process is a "loaded operation" ie some force is being applied while turning the workpiece, and as the motor has much less power at these slow speeds this is why I don't run it any slower.

IMG_1877.jpg

As applying resin finishes is an unloaded operation you could probably run the the VFD as slow as 5Hz ie lathe headstock now at 30 RPM. You would need to monitor the motor temperature because at that speed the motor fan is not doing much cooling. If it does get warm you can always add an Auxiliary fan - something like a 4" Computer fan would be good enough.

If you wanted slower rpms then you could perhaps
- organise a pair pulleys with a greater speed reduction ratio
- purchase a slower speed 3P motore (6 pole motor) although these will not be cheap.
- replace the motor with a geared DC stepper motor and controller which will then very slow speeds to be obtained eg minutes per rev. .

Originally Posted by brainstrust

Is there such a thing as a cheap or 2nd hand slow turning/revolving lathe that can be used for applying resin finishes and the like?

Or does anyone have any tips on setting up the bbq rotisserie motors either within a lathe or as a stand alone contraption?


Thanks!

If it wasn't raining I would go out to the shed and photograph the gadget I just built using a supposedly "dead" cheap battery drill powered by a 12V plug pack and speed-controlled by a "Jaycar" 12V speed controller kit. There was enough room in the battery housing to fit the speed controller and the switches as well as a socket for the output from the plug pack.
It's only good for doing light weight stuff like pen blanks but the idea could be expanded using a bigger drill. The only problem with electric motors going slowly is that they often overheat due to decreased air flow from the fan going so slow. I made something similar out of a windscreen wiper motor mechanism and had to fit a fan in a duct over the motor. That was used to rotate firearm barrelled actions when they were painted with an exotic coating that was waterproof and tough as nails but needed a while to cure so we had the while thing turning like a turkey on a spit.

I just tried out to see how lows speed affected motor temperature on my ww lathe.
Running the VFD as low a 2.5Hz, (headstock spindle 18 rpm) the motor temp rose by about 2º over 10 minutes of unloaded operation - this is unlikely to be the case under load.
BTW even at this slow speed I couldn't stop the headstock spindle turning with one hand.
This is a 1 HP motor.

I guess it all depends on your budget and what you want to rotate. 3 phase motors and VFDs are not cheap and if you buy the things off evilbay and they die an early death you are snookered. Plus you may need a sparky to wire it all up. My electric drill gadget cost me under $50.00 at Jaycar plus an offset of 7mm ply, 4 small bolts and an offset of 6mm threaded rod from my scrap bin. For pen bodies, it's all I need.

Originally Posted by Old Hilly

I guess it all depends on your budget and what you want to rotate. 3 phase motors and VFDs are not cheap and if you buy the things off evilbay and they die an early death you are snookered. Plus you may need a sparky to wire it all up. My electric drill gadget cost me under $50.00 at Jaycar plus an offset of 7mm ply, 4 small bolts and an offset of 6mm threaded rod from my scrap bin. For pen bodies, it's all I need.

Sure, but a lathe with a 3P motor on a VFD is going to be a lot more useful for other things.

Your gizmo reminds me a bit of my chainsaw chain cleaner.
If the vid is a tad slow, skip to the 1:20 mark and you can see it working and me touching the moving chain with no problems


Yes - the chain is moving backwards

A rotisserie motor from a domestic (2nd hand oven) will turn a ~2kg lump of meat for hours.

Many years ago I made fishing lures that were coated with two pack epoxy. I made a box and fitted a rotisserie motor in one end, with an extension bar attached to the rotisserie motor. A small bearing supported the shaft aot the other end. A small light globe was fitted to the bottom to apply gentle heat to hasten the epoxy set. The whole set up was contained in a box preventing contamination with dust and insects. I could do up to 60 lures at a time.

With a bit of ingenuity, I can see no reason why it wouldn't work for a turned object.

I can get a photo of the set up in the morning if required.

Jim

I think the easiest, cheapest solution is a rotisserie motor. Turner Philip Moulthrop of Georgia, USA made a device for rotating bowls while epoxy set, using a small motor and pulleys & V-belts to get the required rpm. I can't find a photo that I have seen.

Bowl made by making a shape, gluing on end grain branch pieces, slowly rotating while applying epoxy, turning the outside, then hollowing. https://mk0centerforartp11xx.kinstac...osaic-Bowl.jpg

Get yourself a small, easily handled motor. Could be off a sewing machine, could be just a complete old corded drill or even an angle grinder.

Work out the speed of the motor, the speed you want the item to rotate and thus what pulley ratio you'd need to achieve the target speed.

On the lathe, make up a pair of pulleys from thin (10mm-ish) ply with a sharp v-groove. Make the one for the lathe fit behind the chuck, and t'other to suit the little motor.

How you fit the pulleys is normally pretty trivial, really. eg. Add an arbor for a drill, drill a hole for an angle grinder

While fitting a thick 'washer' behind a chuck is generally frowned upon forr actual turning (it increases chuck run-out) it won't matter when running as a rotisserie. So long as the re's still enough thread left to securely mount the chuck afterwards, of course.

Mount the pulleys, loop a bit of string around both and rig up some way to clamp the small motor to the lathe bed with the string under tension. Again, it's fairly trivial to make an mdf jig for this.

Et voila! A rotisserie for your lathe.

Could be prettied up quite considerably and lots of improvements can be made (eg. adding a small spring to the string to aid in maintaining tension.) but the basic form should be cheap, relatively reliable and easily mad by anyone who already has a wood lathe.

This is the gadget I made for spray-finishing pen bodies. I had the "dead" drill, just needed a speed control and power supply. 3-jaw chuck solves connection problems. It turns the pen bodies while I spray them and they sit in the sun for a little while to let the finish harden. Cheap and cheerful.
DSCN0746.jpg

This is a "rotisserie" I set up to coat lures with a two pack epoxy. It was capable of holding up to 60 lures. Would be useless in it's present form to hold wood turned pieces.
The rotisserie motor has a hexagonal shaft. I would remove the lure gear and make a driving spur with a grub screw for the motor end. The other end could be supported by a 12mm rod sharpened to a point for a dead centre. For bowl, a face plate like the end plates in the box, can be fitted to the rotisserie motor and the box stood on it's end.
A small low wattage globe will provide a rise in temperature to help curing and with the box closed, problems with dust can be avoided.
Initially the box got too hot and the epoxy blistered, took a few attempts to get the bulb size right.
I used the box for many years, (about 12years) without any problems.


This is the inside. The rotisserie motor is on the right with a "face plate" fitted to the shaft. The centre is an aluminium boss fitted to the motor shaft and extended to take the central rod. All that stuff would simply be left out.
RotisserieS.jpg

One switch controls the rotisserie and the second switch controls the light. The lid is closed here.

SwitchS.jpg

I took a video of it in operation nut can't seem to upload it.

Jim

I had the need to keep some rings moving while that Luci-clear epoxy dried on them last year and dug out a turntable motor (24V) from an old microwave oven - did the job perfectly - about 8 rpm for about 18 hours - that stuff takes forever in cool weather!!. Depends on how heavy your items are I suppose

dryer.jpg

Have not tried it but a drill with var speed either mains or battery could be made to turn a lathe if you remove the belt from the lathe motor. Any size pulley wheels can be turned up to get the required speed if thats what it takes. It's only rotating the work so no great torque involved.
Regards
John