TIG Welder Foot-Pedal and Torch-Mounted Controls


What can you say about a foot pedal?

It works like a car's gas pedal. Push on the pedal and the foot movement rotates a potentiometer shaft. The reference voltage supplied to the welder power controller is changed and the power level is increased. This pedal also has a micro switch that can be toggled on and off by a sideways motion of the foot. The microswitch toggles the logic in the power controller to turn welding current on and off.

There is even less you can say about a torch-mounted control. It is a potentiometer and a snap-action switch in a box mounted to the torch handle.

Foot-Pedal Layout

Dimensional diagram
Back to Top

Foot Pedal Construction

The pedal is made from aluminum plate as it is easy to machine and it doesn't rust, which is important because the pedal gets kicked around a lot making painting a waste of time. Without a mill, the fit and finish leave a little bit to be desired. After a couple of weeks in the shop getting knocked around on concrete, I am sure no one will notice. To keep the pedal from sliding around when trying to actuate the microswitch, a piece of polycarbonate plastic was attached to the bottom plate.

Using a linear-taper, slide potentiometer would make construction simpler and actually make the control repeatability better. I couldn't find a 10k ohm linear slide pot, so I had to use what is shown here. The linear-to-rotational translation is simply a loop of woven fishing line wrapped around the 1/4-inch diameter rotating pot shaft.

Most of the construction is pretty evident from the drawing and pictures. Just a few words about the pot assembly may be in order.

The pot shaft has a #43 hole drilled through it on the centerline of the cord yoke. It has a 3/32-inch diameter hole drilled into the shaft rotational axis. All edges that the cord can contact are rounded and polished with rubbing compound. The cord has a metal ring tied onto the center of the cord to prevent it from slipping into the shaft centerline hole, then the cord ends are fed into the shaft centerline hole and one end comes out of each side hole

The cord makes a turn around the pot shaft and goes into the groove on the top of the cord yoke. It then goes down a #43 hole to a 1/8-inch diameter hole drilled in the side of the yoke. The side hole is to allow rounding and polishing of the cord contact surfaces, and to make it possible to feed the cord through the remaining hole towards the attachment screw. The attachment screw holds the ends of the cord and is tightened to clamp the cord at the ends of shaft travel.

A caution about the microswitch. You can see the microswitch is mounted on a bracket attached to the side wall. Make sure the bottom plate contacts the bracket before the switch housing. The housing is made of brittle plastic and will not take the impact of a heavy foot dropped on it. I didn't show the bottom plate return spring on the layout drawing. It got in the way of showing more important details. Besides it is not likely that anyone else will have the exact same spring so some changes would be necessary anyway.
Back to Top

Foot-Pedal Pictures

View of finished footpedal

Finished footpedal
before cable attachment.

View of finished footpedal

Footpedal inside.

View of finished footpedal

Footpedal inside.

View of ON-Off microswitch

ON-Off microswitch.

View of Linear-to-rotational motion transformer

motion transformer.
View of drilled potentiometer shaft

Drilled potentiometer shaft.

Back to Top

Torch-Mounted Controls

View of torch controls

Level control knob and ON-Off switch.

View of torch controls

Bottomside of box.

I added an aluminum box to the torch handle. The box is just big enough to put in a miniature potentiometer and a micro toggle switch,
Back to Top

Cable Sheath Splitter

View of hose splitter

Hose splitter.

To make a spiral cable wrap from garden hose I drilled a 5/8-inch diameter hole through a piece of 2x4, cut a 45-degree section out, and mounted a utility knife blade. The hose is split as it is rotated in and through the hole. This makes a very cheap cable wrap if you use Walmart's lowest price hose: $5.43 per 50 feet.

Back to Top


None. It is all original.
Back to Top

Copyright Dale Thompson.
Last revised: March 21, 2009.