Rebuilding the Blade Welder, Parts Repair
My first step was to separate all the parts to be sandblasted and get them primed and painted. Shown in the photo are the motor and transformer brackets, the lamp shade, grinder guard, and contactor bracket.
Here's the weld control handle. Can you count the different colors?
I see:
Bright Green
Dark Green
Yellow
White
Red
Not for long!
Next up, I made a trip to the local motor shop and hit the industrial supply along the way. I picked up some .018" 5-10-5 Dacron-Mylar-Dacron insulating sheet (blue), 1/16" Phenolic (tan), and 3/8" Delrin rod (white). All this is to make the old insulators shown in the left of the photo. Most of these insulators are to protect the "hot" stationary jaw from grounding to the frame.
The 5-10-5 material came from the motor shop. It is used to insulate the windings of electric motors during rebuild. Thanks, Kurt, for the free "sample"!. It is tough to cut with an X-acto knife, but works readily with sharp scissors. I traced the outline of each insulator on the material and cut them out:
Then, I punched the necessary holes, just like if it was gasket material:
You'll recall that when I disassembled the welder, I damaged the cardboard insulator tubes that insulate the "hot" jaw copper bolts where they pass though the slide frame and main frame. The Delrin rod was used to make new bushings which should be more durable. I love machining Delrin, it machines beautifully and always leaves a perfect finish.
I neglected to take any photos of the machining process, but here's the finished product, next to the old bushings:
All the finished insulators, next to the originals:
I intended to use the 1/16" phenolic to build a new insulating block for the weld stop contactor, but I decided the existing block was in suitable condition for re-use. Plus, my Unisaw is disassembed in a corner where I can't easily get to it. Making the new phenolic block would require sawing a number of perfectly sized squares, which is best accomplished on the table saw. Should the insulator block ever break down, it is an easy to reach part. Yes, even I have to stop *somewhere*!
After finishing the insulators, I got to work on the welder jaws. These are machined bronze castings. Here, I'm removing the set screw that locks the clamp cam adjustment:
After sandblasting, I dressed up the back side of the movable jaw. This is important, as the two gibs ride on this surface. 600-grit sandpaper made quick work of things. Notice, the jaw was originally machined on a lathe, probably a turret lathe.
Then, I disassembled the grinder motor and cleaned everything up. This motor uses journal bearings and the rear journal was running dry. However, the grinder sees little use, so the bearings were still in excellent shape. Beyond cleaning, re-oiling the bearings and dressing the centrifugal starter contacts there was little to do here:
SIDENOTE: You'll recall when I first disassembled the saw, the welder was mounted on a piece of 3/8" plywood. I finally figured out why! The grinder motor is not original to the machine. The original motor is actually somewhat shorter, probably around 1/2" or more. Because the new motor is longer, the welder is actually too "deep" to fit in the cavity provided in the saw!
Good thing I haven't been able to finish-paint the machine yet... I'll have to build out the welder cavity with a custom 1/2" plate frame so that the welder will "fit".
Having just finished the motor and being in an "electrical mood", I decided to have a go at the main power contactor:
Again, like the grinder motor, it was in good shape. I cleaned everything up and dressed the points down and called it "good 'nuff". I couldn't quite dress out all the pitting, but I did get most of it:
Putting it back together took five attempts to make a video that actually made sense. Due to the miracle of television, you'll only be seeing attempt #5.
Fresh from futzing with the contactor rebuild, I decided to do something easy, and it doesn't get any easier than degreasing. Here's most of the hardware about ready to get a bath in degreaser:
While waiting on the degreaser, I quickly cleaned up the blade thickness gauge. This gauge mounts above the grinding wheel. It's purpose is to act as a go-no-go gauge for grinding the upset weld down to thickness. Without the gauge, it would be impossible to tell if the weld was too thick to pass between the saw's guides.
The gauge is really just a couple pieces of ground tool steel, with a couple punched pieces of shim stock in-between. A little Scotch Brite cleaned things right up. Then, I used some white paint to highlight the stamped lettering:
About here, I called it a day and closed up for the night.
Day Two
The next morning, I took a trip down to the Ace Hardware store a few towns over to find new control knobs. I knew they had a rather "vintage" collection of knobs in their hardware bins. I was hoping they had something close.
For the welder width control, what I found was better than close, but an actual NOS knob from "Daka-Ware" in Chicago, IL! Unfortunately, they didn't have any spherical knobs of the appropriate size. Back at the shop, I thought about ordering a few before I remembered that Bakelite works readily with abrasives...
Here are the welder clamp knobs before:
I found a 1/4" by 5" bolt which I promptly threaded into the base of one of the knobs. Then, I chucked the bolt in my small lathe where I sanded down the exterior of the knob and polished it:
It turned out so well, I did the other one. You can't tell the difference from new!
That pretty well covers cleaning up and repairing the welder's parts. While the welder transformer was drying off from it's motor cleaner bath, I took this photo of the components, ready to go back together:
In addition to the new blade width control knob near the upper right, you'll also notice some new switches and switch boots in the lower left. These will replace the annealing heat control switch as well as the grinder and lamp switch. Both of the original switches were worn beyond repair.
In the next post, I'll cover putting it back together.
My first step was to separate all the parts to be sandblasted and get them primed and painted. Shown in the photo are the motor and transformer brackets, the lamp shade, grinder guard, and contactor bracket.
Here's the weld control handle. Can you count the different colors?
I see:
Bright Green
Dark Green
Yellow
White
Red
Not for long!
Next up, I made a trip to the local motor shop and hit the industrial supply along the way. I picked up some .018" 5-10-5 Dacron-Mylar-Dacron insulating sheet (blue), 1/16" Phenolic (tan), and 3/8" Delrin rod (white). All this is to make the old insulators shown in the left of the photo. Most of these insulators are to protect the "hot" stationary jaw from grounding to the frame.
The 5-10-5 material came from the motor shop. It is used to insulate the windings of electric motors during rebuild. Thanks, Kurt, for the free "sample"!. It is tough to cut with an X-acto knife, but works readily with sharp scissors. I traced the outline of each insulator on the material and cut them out:
Then, I punched the necessary holes, just like if it was gasket material:
You'll recall that when I disassembled the welder, I damaged the cardboard insulator tubes that insulate the "hot" jaw copper bolts where they pass though the slide frame and main frame. The Delrin rod was used to make new bushings which should be more durable. I love machining Delrin, it machines beautifully and always leaves a perfect finish.
I neglected to take any photos of the machining process, but here's the finished product, next to the old bushings:
All the finished insulators, next to the originals:
I intended to use the 1/16" phenolic to build a new insulating block for the weld stop contactor, but I decided the existing block was in suitable condition for re-use. Plus, my Unisaw is disassembed in a corner where I can't easily get to it. Making the new phenolic block would require sawing a number of perfectly sized squares, which is best accomplished on the table saw. Should the insulator block ever break down, it is an easy to reach part. Yes, even I have to stop *somewhere*!
After finishing the insulators, I got to work on the welder jaws. These are machined bronze castings. Here, I'm removing the set screw that locks the clamp cam adjustment:
After sandblasting, I dressed up the back side of the movable jaw. This is important, as the two gibs ride on this surface. 600-grit sandpaper made quick work of things. Notice, the jaw was originally machined on a lathe, probably a turret lathe.
Then, I disassembled the grinder motor and cleaned everything up. This motor uses journal bearings and the rear journal was running dry. However, the grinder sees little use, so the bearings were still in excellent shape. Beyond cleaning, re-oiling the bearings and dressing the centrifugal starter contacts there was little to do here:
SIDENOTE: You'll recall when I first disassembled the saw, the welder was mounted on a piece of 3/8" plywood. I finally figured out why! The grinder motor is not original to the machine. The original motor is actually somewhat shorter, probably around 1/2" or more. Because the new motor is longer, the welder is actually too "deep" to fit in the cavity provided in the saw!
Good thing I haven't been able to finish-paint the machine yet... I'll have to build out the welder cavity with a custom 1/2" plate frame so that the welder will "fit".
Having just finished the motor and being in an "electrical mood", I decided to have a go at the main power contactor:
Again, like the grinder motor, it was in good shape. I cleaned everything up and dressed the points down and called it "good 'nuff". I couldn't quite dress out all the pitting, but I did get most of it:
Putting it back together took five attempts to make a video that actually made sense. Due to the miracle of television, you'll only be seeing attempt #5.
Fresh from futzing with the contactor rebuild, I decided to do something easy, and it doesn't get any easier than degreasing. Here's most of the hardware about ready to get a bath in degreaser:
While waiting on the degreaser, I quickly cleaned up the blade thickness gauge. This gauge mounts above the grinding wheel. It's purpose is to act as a go-no-go gauge for grinding the upset weld down to thickness. Without the gauge, it would be impossible to tell if the weld was too thick to pass between the saw's guides.
The gauge is really just a couple pieces of ground tool steel, with a couple punched pieces of shim stock in-between. A little Scotch Brite cleaned things right up. Then, I used some white paint to highlight the stamped lettering:
About here, I called it a day and closed up for the night.
Day Two
The next morning, I took a trip down to the Ace Hardware store a few towns over to find new control knobs. I knew they had a rather "vintage" collection of knobs in their hardware bins. I was hoping they had something close.
For the welder width control, what I found was better than close, but an actual NOS knob from "Daka-Ware" in Chicago, IL! Unfortunately, they didn't have any spherical knobs of the appropriate size. Back at the shop, I thought about ordering a few before I remembered that Bakelite works readily with abrasives...
Here are the welder clamp knobs before:
I found a 1/4" by 5" bolt which I promptly threaded into the base of one of the knobs. Then, I chucked the bolt in my small lathe where I sanded down the exterior of the knob and polished it:
It turned out so well, I did the other one. You can't tell the difference from new!
That pretty well covers cleaning up and repairing the welder's parts. While the welder transformer was drying off from it's motor cleaner bath, I took this photo of the components, ready to go back together:
In addition to the new blade width control knob near the upper right, you'll also notice some new switches and switch boots in the lower left. These will replace the annealing heat control switch as well as the grinder and lamp switch. Both of the original switches were worn beyond repair.
In the next post, I'll cover putting it back together.



