Overhead Drive

Overhead Drive

The overhead drive is one of the most common methods used to drive the cutters used in ornamental turning. (Cutters would be held in either a cutting frame or a Drill Spindle.)

The benefits of using an overhead drive over a direct drive are :

  1. When the ornamental turner has a number of cutting or Drill Spindles, only one motor is needed for all of them, saving money for the craftsman.

  2. By having the motor separated from the cutting or Drill Spindle, there is a reduction in transfer of the motor's vibrations to the cutter.

  3. By having the motor further away from the craftsman :
    1. the motor's noise is further from the craftsman, and
    2. the craftsman has less obstruction to the visibility of his work.

Drive Motor

The motor to use for the overhead drive is the next thing to consider. It should be powerful enough to drive the cutter when cutting very hard woods, and turn it fast enough to make the cuts. But it can't be too fast or the belting will jump off the idler pulleys.

Generally, the guidelines recommended are :

  • 1/2 horsepower
  • variable speed

Jon Magill authored an article titled, "Build an Overhead Drive" that describes how to make one. That article was published in the AAW's magazine, "American Woodturner" in Spring 2008, pages 30-31.

One motor which is commonly used is from Penn State Industries - the Variable Speed Midi Lathe Conversion Kit. Another is the Sherline Variable speed motor.

If you chose to repurpose a router for this use, be sure to put a speed controller on the power feed. Rockler sells one, item number 25278.

These work by changing the frequency of the power. Be aware of these things if you incorporate this into your design :

  1. These motors were designed to operate at a certain speed, and changing that affects the power they can deliver. At too low a speed, they become ineffective.
  2. The cooling for these motors were designed for them running at a certain speed. If they run too slowly, the motor could overheat if used too long.
  3. Some speed controllers were designed for motors with brushes. I don't know what will happen if they are used with brushless motors.

Using a router is not recommended.

Cable Belting

Cable Belting

A belt is needed for the overhead drive motor to drive the cutter.

I used round belting from McMaster-Carr, part number 59725K729. It is made from polyurethane rubber, is 1/8" diameter, and is orange (because I liked the colour). It is sold by the foot.

Other types of belting are available, and they all have plusses and minuses, and varying costs. One common alternative is to use one which has a more rough texture. The argument made for this is that it doesn't slip as easily (though I've not had that problem, but others may have).

It will need to be replaced over time, but 20 or 30 feet will last quite a while.

A forum user (who goes by "Sherweld") posted directions on the Ornamental Turners International forum for a jig that makes it much easier to weld the cable into a continuous loop. The picture to the right shows the ends just before they were melted and joined. Melting the ends to join them is done using a soldering iron.

I made one of these jigs from a scrap piece of walnut and parts I bought at the local hardware store. The metal parts cost less than $10.

I've used this a number of times, and it has never failed me.

MDF Rose Engine Lathe : #7 - Overhead drive

This YouTube video is a quick overview of my overhead drive:

About this site
Disclaimer : eMail comments to me at OTBookOfKnowledge @ Gmail.com. The process of woodturning involves the use of tools, machinery and materials which could cause injury or be a health hazard unless proper precautions are taken, including the wearing of appropriate protective equipment.