Foot pedal issue/tweak.

[angular]

In total noob mode here and was practicing on some 304 stainless pipe and some aluminum pipe, having a hard time getting a good puddle, etc. Well, finally it dawned on me that I wasn't getting the amperage I dialed in on the front panel.

Turns out the foot pedal "rail" that drives the cog on the potentiometer was not pivoting as it should, so would quickly lose contact with the cog and stopped working. The pair of nuts on the far end of the pivot screw needed to be loosened up a bit so the thing can pivot freely. Squirted a little lube on both sides of the rail while I was at it.

The other thing I noticed is the stop screw was really loose and woobly. It appears to be a standard M6 thread so I rummaged around for some nuts to put on top and bottom to stabilize it against the foot pedal housing. BIG improvement!

Hope this helps some other poor dumb bastard (like me) who finds themselves struggling with the foot pedal. Also, be sure to adjust the stop screw so the pedal doesn't go too far down and put too much stress on the potentiometer (when it reaches it's limit).

[presure2]

like the fact that you included pics!
i'll have to check mine when the unit arrives.

[jakeru]

I tried Bradley's 250EX TIG setup out, and it seemed like the "new style" of Everlast footpedal required excessive force to operate. IMO, too much force required to operate the pedal = inability to press pedal down fully while maintaining fine control of your torch and filler rod.

Now subjectively, Bradley's new pedal seemed like it took somewhere on the order of 5-10x or so as much force to operate. Seems like it had an excessively strong return spring. I could use it at highly throttled positions, but not comfortably at any position over about 1/2 throttle.

So I just I tested my "old style" Everlast footpedal (see attached picture) to see how much force it required to operate. With the footpedal's weight zero'ed out on an electronic scale, and measuring the force applied to the pedal at my "ball of foot" position (~8" from the heel rest), here is what I got:
3.0 lbs @ ball of foot - gets the pedal moving
3.5 lbs @ ball of foot - pedal hits "wide open throttle"

It would be interesting to see what other people measure for the amount of force required to operate their footpedals? And also to hear other people's feedback about whether the force to operate the pedal is easily controllable, or excessive?

[angular]

Interesting. Your pedal is lower profile too. I'll see if I can get a measurement of the how much pressure it takes to operate my foot pedal when I get home tonight.

[jakeru]

I measured 3-7/8" - 4" above ground level @ the top pedal surface, immediately above the pivot. It might be just a little bit lower?

[angular]

Hard to get accurate readings with the bathroom scale, but I'm guestimating 7 pounds of force to get the pedal moving (where the contact switch clicks) and around 15 pounds at full travel. 6" height above the pivot point, about 4" at the heel, and 8" at the tippy top of the pedal.

[jakeru]

Good data, Bradley! OK I guess at 2" taller above the pivot, yours is more than a "little" taller than mine. But I was right about the high amount of force to make it move. Keep me/us posted if you try any tweaks to it.

I was thinking, one mod you could try that I think would give good results, would be to take the return spring out and using your bench grinder, grind the outer edge of the wire to change its cross section from an "O" into a "D". This would reduce its spring rate, which at 8 lbs to make it move throughout its working range, seems excessive. It would reduce the 7 lb pre-load as well, which also seems excessive.

I would grind off enough of the wire thickness to reduce the force at full depression down to around 5-8lbs or so. Obviously it would be a good idea to keep enough return force in the spring to make the footpedal always reliably return to zero, so if you say lost your balance or had your foot slip off the pedal while welding, the arc would reliably stop.