The first Torchmate ever made

[Tmate]

Here is a photo taken today (8/13/2020) of the first Torchmate shape cutting machine ever built. I fabricated it in my garage in Reston, VA in 1979, and I still have it. I put a picture of today's Wall Street Journal home page in the shot.

At that time, plasma cutters didn't exist except in huge manufacturing facilities, and most of us had to cut with an oxy-fuel torch or a saw. Primitive as this unit was, it was the first powered pantograph flame cutting machine available in the sub-$1,000 range. I sold them for $245.00 in a U-weld-it kit form.

It used a Ford Granada windshield wiper motor and an MRC model railroad transformer. I had not yet come up with a magnetic tracer, so the rotor had to be held against the edge of the template. The rotor, which was a rotary file, then walked around the template. A lever on the top of the pantograph controlled a rod that pressed the cutting oxygen lever on the torch, which was held in the clamps below. The torch tip was aligned with the rotor, and duplicated its movement. The machine was featured in a lot of car magazines at the time. Note that I sold the company about ten years ago, and no longer have any connection with it.

 

[gr8legs]

Very cool seeing a bit of equipment history!

Thanks for sharing!

Stu

 

[Tmate]

Speaking of equipment history -- while Torchmate may have been the first affordable powered pantograph flame cutting machine, it was far from being the first such machine. The first patent for this type of equipment was issued in 1917. A search of the U.S. Patent and Trademark Office's database produced the 1919 patent shown below. The drawing and first page of the patent are pictured here.

 

[Tmate]

In my first post in this thread, I mentioned that the first Torchmate didn't have a magnetic tracer, and the rotor had to be manually held against the template. For any of you with an interest in how the magnetic tracer was added, I offer this detailed explanation.

In 1979, when my first machine was introduced, rare earth magnets were just becoming commonly known. They were quite expensive at the time. The intensive attractive power of rare earth magnets made it possible to miniaturize them to the point of being able to mount them on the tip of a rotary file, essentially converting it into a magnetic follower. Previous magnetic tracers were generally large cylindrical assemblies with the rotor sticking out the top. Some used electro-magnets.

At that time no rotary files were produced with a sufficiently large diameter to mount the magnets, yet a thin enough shank to prevent the magnetic field from traveling down into the motor shaft. I contracted with a major manufacturer of rotary files to make me a run of several hundred 3/8" diameter rotary files with a 1/8" diameter shank. After 25 years, I still have 30 or 40 left.

The motor I used at that time was a Grainger gear motor. I disassembled the gearbox and center drilled a 1/8" hole in the shaft. I then drilled a hole in the flat of the shaft so that the set screw in a shaft collar could go through the shaft and tighten against the shank of the rotary file.

The addition of a reflector plate made of a 1 1/2" long piece of 3/4" cold roll round stock added maybe another 40 percent to the magnetic pull.

The second method I employed some years later was to knurl a short piece of 3/8" diameter cold roll round bar, center drill it with a 5/16" drill bit, and drill a hole through its side to allow a shaft collar set screw to lock against the motor shaft. This was not quite as effective as the first method, but eliminated the possibility of a 1/8" rotor shank snapping if banged against the template. The hollow motor shaft reduced the magnetic field travel to the motor, but not quite as effectively as the first method.

At first I used a stack of 3 or 4 Samarium Cobalt magnets. These cost about $20 each, and this many were needed to generate sufficient magnetic pull. Later, I switched to Iron Boron magnets which were twice as powerful and a third as expensive.

Ultimately, as CNC coordinate drive (x/y) cutting tables became affordable, the pantograph design joined the legions of outmoded but fascinating machines of yesterday.