View Full Version : Welder Repair Question

01-16-2005, 10:24 PM
This is a Craftsman 295 amp stick welding machine purchased in 1976. It has become difficult to move the amp pointer which moves the core/shunt to set the desired amperage and when I strike an arc it jumps to a lesser amp setting. Parts are no longer available. Does anyone know how a repair facility might address this problem OR if this can be corrected?

01-17-2005, 01:23 AM
you can get an electrical lubricant from radio shack, i would clean and lube all the moving electrical controls myself

01-17-2005, 01:25 AM
I don't know about yours but on a couple welders I've had there is an adjustment on a type of brake that holds the setting where you put it. As far as turning hard, it's supposed to have a certain amount of friction to hold the setting.

01-17-2005, 09:55 AM
I'll pull the housing off today. The amount of friction far exceeds what's needed to stay in place. It actually takes two hands and some body weight behind those hands to move the amp selector. I hope it's going to be just a matter of heavy dirt and debris collected over the life of being in an auto repair facility. I'll make a trip to Radio Shack.

01-17-2005, 10:35 AM
Don't be afraid to open up the case on the stick welder you have. The mechanics are pretty simple. Especially if it is a 1976 vintage. There should be just a big transformer and a mechanical core that moves in and out of the transformer. The physical position of the core in the transformer will change the magnetic flux between the primary and secondary windings. This, in turn, changes the voltage and current ratios from input to output.

I had a stick welder given to me where the adjustment would turn easily, but the amperage setting wouldn't change at all. In this case the amperage wouldn't increase. Being the Curious George that I am, I opened the case to find the problem.

For the welder given to me, the means for moving the core was a big threaded rod. The rod was attached to a couple of phenolic guides that where attached to the core. One of the guides had cracked apart. Probably from some kind of abuse like being dropped. The screw adjustment would turn really easilyy. But, the core wouldn't budge at all. We even hit it with a hammer and couldn't get it to move. I think it got welded to the transformer!

Anyway, I through the think in the garbage because it wasn't worth my time to mess with it any more.

What I did notice was the amount of dirt build-up accumulated in it. So, take the lid off your welder and see if you just need to clean things up. Maybe there is a bunch of gunk on the some screw adjustment.

I'm curious to know what the problem was. Post a picture or two of what you find.

01-17-2005, 03:54 PM
The welder is working is working as good as new again.

"embeddedguy" had all the answers! I found a lot of dirt that had accumulated over the last 30 years, but the culprit that prevented the core from moving easily in the transformer was aluminum shavings. The shavings came from a stripped hole in the core's carrier. I tapped the hole for a 3/8-16 threaded rod and all is good again.

Couple of photos at:


01-19-2005, 12:19 AM

I love it when a plan come together!

Happy Welding!