The No. 55 Benton matrix engraver

The famous Benton matrix engraving machine.

Linn Boyd Benton’s No. 55 matrix engraver, as described in the American Machinist for December 16, 1909, consists of “two housings between which swings a long pendulum or arm … delicately suspended in a compound yoke by means of gimbal screws which gives it a toggle-joint effect.”


At the Dale Type Foundry last Saturday, the No. 55 was in the middle of a job. The grease around the machine’s cutting tool (which spins like a dentist’s drill at a speed of 8,000 to 10,000 revolutions per minute) seemed ready to splash onto the empty cutting platform (the matrix jig had been removed), and had even spilled over into the bowl of the yoke above the pendulum arm. “Wow,” I thought. “This machine is really being used. It really works.”

The empty cutting platform.

The empty cutting platform.

I visited the Dale Type Foundry on a Saturday, which was great because no one was working and it was quiet enough to talk to Theo Rehak about the machines. Here were the inventions I had been thinking about for years. I went around the foundry announcing to my son Roger what they were. “Here is a stereotyping set-up; this is a fitting machine; there’s the horizontal Benton engraving machine.” Even though I had visited ATF in 1984 and taken photographs of a row of matrix engravers at that time, last Saturday was completely different. I held a follower in my own hand and traced around the outline of a 16-point Tory Text “H,” designed by Frederic Goudy in 1935. That’s a complicated letter!

I held a “quill” assembly (they hold the cutting tools), and then looked at the point of its cutting tool through the foundry’s Louis Pasteur-type measuring microscope from the 1890s (all cast iron). The measuring microscope magnifies the point of a cutting tool so that you can tell whether it needs to be re-ground.

“Across the center of the face or lens of the microscope, is arranged a fine scale [ruled] in [increments of] 0.0005 of an inch,” the American Machinist explained. This is about half the thickness of a cigarette paper. A cutting tool looks like a heavy nail under this microscope, and so the cutting tools can easily be gauged by eye—the 0.080-inch tool covers 160 lines on the scale, and the 0.001-inch tool covers two lines. The point of the cutting tool we looked at covered seven lines.

More later …

 

 


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