Motor Upgrade Question

you may not want to increase HP - my nova mini lathe has a 1 inch spindle (compared to your 3/4 inch) and it was not happy at 5 inch diameter, my larger lathe has a 1.25 inch spindle - it seems to me that the HP and lathe are well matched

Hi Harry, Without more info about your lathe, I'll make some assumptions that may not be true. I assume that since it can turn both metal and wood that there are no back gears and it has either a jack shaft or small drive pulley-large spindle pulley set-up. If so I would just try lowest existing speed and the present motor before doing anything else. If not substituting a larger motor will still run the lathe too fast. IOW, since you probably won't turn more than 12" diam blanks outboard, I think high speed not low hp might be your limiting factor, but I'm often wrong. :) Motors of that era listed honest hp, but I assume yours is split phase with low starting torque.

If the original set up seems too fast for wood blanks larger than the size designed for and the original motor's shaft extends at both ends, you could devise a jackshaft by adding a large diam. pulley to your present motor's unused end and drive it with another, say 1/2hp, motor having a small diam. pulley. The original motor is left unpowered and free running, of course.

As I remember Dunlap was Sears less expensive than Craftsman line, so I assume your lathe has sleeve bearings. If so and there is any slop, I'd change them. Otherwise I see nothing to be gained by changing.

Careful with what age you call antique. :)

Turn to Safety, Arch Fortiter

I'm just blue-skying here, so take my advice with a grain of salt.

I would think that you could as much HP on it as you want, provided that you get another 1750 RPM motor (shouldn't be too hard, IIRC, there are really only two common speeds) If your bearings are original, it may be getting near time to replace them anyways, so give it a try and see what happens- if the weight of the blank on the outboard side is too much for the bearings, you can always replace them with a more modern set. But, older stuff tended to be overbuilt, and if it is a metal/wood combo lathe, I can't see how the wood would be too heavy.

Thanks for the great advice. Much appreciated.

I had a chance to mount a large bowl blank (outboard) yesterday evening using my existing motor. I used a piece of walnut from one of my neighbors trees that was just under 12" diameter, trimmed to a reasonable round shape on my bandsaw. I was pleasantly surprised to see that the motor turned it just fine. Unfortunately the lathe stand is not anywhere heavy enough for such a large piece. Vibration would be an understatement. It was more like a bucking bronco :) I'm thinking I might just save my larger blanks for when I get a new lathe with a larger swing.

Thanks again and keep on turning! Cheers... harry

For Harry and others with older lathes designed for spindle turning, but have threaded outboard spindles.

For occasional outboard turning or as a permanent set up, would it be practical to mount a hardwood blank on an inboard faceplate and turn a large diam. wooden Vee belt pulley almost equal to the swing or get fancy and turn a multi-diam. pulley. Then drive the inboard spindle at a very slow speed for larger outboard work by remounting the present or another motor that has a small diam. pulley.

Inconvenient and inelegant maybe, but could this be a practical solution? If not, I'll go back to musing inside the box. :)

Turn to Safety, Arch Fortiter

aaah, Harry - 12 inches is a medium sized bowl - it seems really big if you have been doing only 4 inch pieces - your 3/4 inch spindle should be ok at