Phil,
A video:
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This is an example of a 24 volt DC motor with a DC motor speed controller and power box. The system was built with a reverse switch, a hand operated speed dial, useful for drying, as well as a foot pedal for power wrapping.
In this example, the power head is one of the New Alps improved chuck with the small DC motor placed under the chuck. The power is connected to the head stock by use of an XL cogged belt and XL cogged pulleys.
This was a unit that was built a few years ago.
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Here is another video of a unit that was built a couple of years ago, using a 32 rpm 24 volt DC motor with a variable speed controller and a 24 volt DC power supply. If one wished, one could add an appropriate foot pedal to replicate the speed changes that are observed with the hand dial. In this case, the unit was built for drying, using a flex coat chuck with an integrated clutch to stop the rod if needed when applying finish.
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The reason for the video is to demonstrate the simplicity and total control that one can achieve by using a DC gear motor to be rid of large and small speed changing pulleys as well as the use of a polarity reversing switch to easily reverse the direction of the motor when wrapping to correct a mistake or to reverse the motor to apply finish. I prefer to have the top of the rod turning toward me when wrapping. However, I prefer to have the top of the rod to turn away from me when applying finish.
By the way, with a DC gear motor, it is very difficult to turn the rod by hand, due to the gear reduction attached to the motor. But, with the excellent speed control and the ability to reverse direction under power, there is really no reason to wrap by hand.
Best wishes
p.p.s
When I first started building rods years ago, I wrapped one rod by hand. After that one rod, I made a vow to myself to never ever ever wrap another rod by hand and I haven't. But, I have built a very very large number of rods over the years and have always used a power wrapper of one sort or another to assist with the job. I started with the conventional AC sewing machine type motor and associated foot pedal. Then, I added a couple of jack shafts and various pulleys and belts to further slow the speed of the system. Then , I found a right angle drive with gear reduction, using the similar AC/DC universal motor with an appropriate AC motor speed controller that worked very well. But, there was one big downside. The right angle gears were very very very noisy and quite objectionable in a quiet rod shop wrapping for hours on ends. Then, I discovered the use of DC motors and in particular DC gear motors where the motor speed reduction is in the form of a very small compact set of gears on the end of the motor to give a slower maximum speed when the motor is running at its maximum speed. In today's world, DC gear motors are available with various supply voltages and various top speed ranging from sub 1 rpm to 5-500 rpm as well as 600-6000 rpm top speed. So, for the person who wishes to use a dc motor it is a matter of choosing the appropriate motor with a desired top speed, a power supply and speed controller along with an appropriate foot pedal that will instruct the speed to control to vary from its minimum to its maximum motor speed.
In past years, I thought that the maximum speed of a motor would be 1000 rpm. Then, I thought that an 800, down to a 600, down to a 400 rpm or less top speed would be functional for a 1;1 pulley system or direct drive system for a power wrapper.
Now, I find that in fact, that the typical rod wrapper would be very useful if the top speed of the motor and a 1:1 pulley system would work well at 100-200 rpm. i.e. the very majority of rod wrapping is done at speed of 1 rpm to 20 rpm. Once in a while for a long butt wrap,one might want to have a rod speed of 100-200 rpm. But, one finds that it is not often when a rod is needed to be turned at a speed that is greater than any type of rod wrapping.
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So, yes, to your original post. The typical AC/DC universal motor that has a top speed of 7,000 rpm is very very very very difficult to have a reliable low speed of 4-10 rpm which is likely to be the range of a lot of wrapping. Yes, one can use a bunch of pulleys and shafts to get the top speed of the wrapper down to 200 rpm, but it comes at the expense of a lot of bulk and construction to achieve this speed reduction. Then, when one uses an AC type dimmer to lower the power to the motor, it turns out that the AC motor when driven by low power, generates very little torque and very uneven speed. But, the fix is readily available by moving to a dc gear motor and controller system with an integrated reversing system and switch.
Best wishes.
