You could build from scratch with a motor, a pile of pulleys and v-belts, some "pillow block" bearings, and some keyed shafting (so you don't have to try and mill your own keyways). For a final shaft with a 1/2-20 end, use a fine thread bolt, or get a buffer adapter. The pillow block bearings will be designed for the side loads from the belts and cutting tools.
For slowing down a motor to working speed, put a small pulley on the motor, and a big pulley on the next shaft. That shaft will be slower by the ratio of the pulley sizes. Then keep adding pulleys and shafts until the last shaft is going the speed you want. You can swap out pulleys to change speeds, or get a set of step pulleys to go between two of your shafts (or between the motor and one shaft). You can put the step pulley pairs at each belt if you want more speeds to pick from.
But by the time you do all that, you might be money ahead to have bought a used wood lathe. The advantage would be being able to make just what you want. Also, if you are a good scrounge, you can find pulleys, belts, bearings and shafts from other sources such as appliances. If you are going to be working wet, you could have the shaft come up from below into a cut-off bucket or barrel to contain the spray, as long as you had another pipe sealed to the bottom at the middle for the shaft to come up through, so water wouldn't drip onto your belts.
Shafting:
1/2" x 36" Keyed Shafting | Keyed Shafting | Shafting | Power Transmission | www.surpluscenter.com
Buffer Adapter:
Eazypower 81 42 5/8" or 1/2" Motor Arbor Adaptor RH Thread (1-Pack) - Motor Shaft - Amazon.com
For slowing down a motor to working speed, put a small pulley on the motor, and a big pulley on the next shaft. That shaft will be slower by the ratio of the pulley sizes. Then keep adding pulleys and shafts until the last shaft is going the speed you want. You can swap out pulleys to change speeds, or get a set of step pulleys to go between two of your shafts (or between the motor and one shaft). You can put the step pulley pairs at each belt if you want more speeds to pick from.
But by the time you do all that, you might be money ahead to have bought a used wood lathe. The advantage would be being able to make just what you want. Also, if you are a good scrounge, you can find pulleys, belts, bearings and shafts from other sources such as appliances. If you are going to be working wet, you could have the shaft come up from below into a cut-off bucket or barrel to contain the spray, as long as you had another pipe sealed to the bottom at the middle for the shaft to come up through, so water wouldn't drip onto your belts.
Shafting:
1/2" x 36" Keyed Shafting | Keyed Shafting | Shafting | Power Transmission | www.surpluscenter.com
Buffer Adapter:
Eazypower 81 42 5/8" or 1/2" Motor Arbor Adaptor RH Thread (1-Pack) - Motor Shaft - Amazon.com