Goudy's Cutter Grinding Devices

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1. Introduction

Goudy employed two kinds of devices for matrix cutter making and sharpening:

Of course, he had at least two of each, one set before and then one set after the 1939 Deepdene fire.

2. The Cutter Grinder (Pre-1939)

The best published photograph of the style of cutter grinder that Goudy used prior to 1939 is in Bruckner's biography, p. 93. [1] [2] Kinematically, it is very much like Benton's second style of cutter grinder. [3] In terms of construction, however, it is a fascinating hack. It is build around a standard watchmaker's or jeweler's lathe turned backwards. That is, it has the standard and bed of a watchmaker's lathe, but where the headstock would normally be fitted there is nothing (Goudy's hand is resting there in the Bruckner/Cary photograph). Instead, at the far end of the lathe bed where the tailstock normally would be, a sort of clamping device has been fitted around the bed. On this the matrix engraver's spindle has been placed for grinding its cutter. As this spindle is itself basically a watchmaker's lathe headstock, the whole arrangement, while perfectly sensible, cannot help but look to be backwards.

To understand the operation of Goudy's cutter grinder, go to the photograph on p. 93 of Bruckner and get out a magnifying glass. (I cannot reproduce it here, unfortunately.) The Typologia photograph, though fuzzier, is also useful because it shows the grinder from the operator's side. Then compare these with the image below, extracted from Benton's 1904 patent.

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(Clicking on the image above will bring up a PDF version of it, which, if it loads in a separate window on your browser, may be easier to scale than a raw image. Here's a link to the PNG image, if you'd prefer: us-0774030-1.png . Here's a link to the entire patent as a PDF: us-patent-0774030-1904-11-01-benton-matrix-cutter-grinding-machine.pdf )

On the left in the Benton patent drawing is the matrix engraver's spindle, removed from the engraver and placed in the cutter grinder (in Benton's patent it is shown as a sort of cartridge spindle; in Goudy's machine it has the earlier form which resembles a watchmaker's lathe headstock). The cutter grinder has a grinding wheel, C, mounted on a spindle of its own, D. This spindle D rotates (of course, that's what spindles do) but also slides longitudinally on its own axis. This means that if you place the engraving machine's spindle (K) in the same place each time, you can advance the cutting tool forward in its collet (to get more material to sharpen) and then slide the cutter C on its axis to generate exactly the same cutting tool facet (relative to its own spindle) every time.

The matrix engraver's spindle may be indexed using an index wheel fixed to the spindle (j) and a pin fixed to the grinder (j').

Goudy's machine has these same basic features.

(Benton's machine has an additional feature which Goudy's lacks: a diamond dressing point at O which allows you to use a brand new grinding wheel each time and have it automatically dressed to exactly the same diameter as the previous wheel. This compensates for the minute wear on the wheel when grinding this tiny cutter. Benton was a bit of a perfectionist.)

Goudy devotes a rather confusing paragraph at the bottom of p. 117 of Typologia to this machine. So far as I can figure, all he says in it is that when placed in his cutter grinder the matrix engraver spindle may be indexed to fixed points to generate the cutter geometry.

Both the Bruckner/Cary and the Typologia photographs show a wooden vertical piece behind the cutter grinder (behind from the operator's point of view) with some kind of three-part fixture at the top. I have no idea what this is, and do not know if it is relevant to the cutter grinder.

3. The Cutter Grinder (Post-1939)

Boone's article shows the state of Goudy's tooling after the 1939 fire. The cutter grinder appears in two photographs, on pp. 118 and 119. It is a machine which differs in appearance from his earlier machine (it is built around a bedplate, not a watchmaker's lathe) but which is functionally identical.

Note: I do not believe that the caption in Boone's article for the photograph of the cutter grinder on p. 118 is correct. Boone says "To keep it [the cutter head] in perfect cutting condition, its assembly can be removed from its place on the top of the pantograph and placed in a special tool for grinding as shown below. [so far this is correct; it is the following that I believe is wrong] The knurled knob gives fine adjustment in grinding as in cutting."

The implication of this, I believe, is that the knob on the top of the cutting spindle (which Goudy has his left hand on in the photograph) gives fine longitudinal adjustment of the spindle. There are two reasons why this cannot be correct.

First, if this were the case then the cutter grinder would not in fact embody Benton's principle of the removable spindle. Benton's idea was that the entire spindle assembly would bank on the cutter grinder [4] and that this would establish the relationship of the ground cutter to the spindle. Having a "fine [longitudinal] ajustment" on the spindle destroys this relationship.

Second, it doesn't fit with the construction of the spindle. In all three of Goudy's E&PM Co. pantographs (and in the very early Benton machines as shown in his 1885 patent, as well) the cutting spindle is basically a watchmaker's lathe headstock. Since the introduction of the modern collet-based watchmaker's lathe by Webster-Whitcomb in the 19th century, their headstocks have been of remarkably standard design. The spindle within the headstock is hardened steel rotating in a hardened steel conical bearing in the front standard. There can be no longitudinal play or adjustment in it. This spindle receives a collet at its working end. The collet is drawn tight by a drawbar (draw-tube, really) operated by a small handwheel at the opposite end - this is the "knob" that Goudy's hand is on in the photograph. Once the collet is tight, this handwheel/knob may also be used to rotate the headstock (as Goudy will do to index it to its several cutting positions).

If a third reason is necessary, one might observe that in Typologia Goudy draws attention to the micrometer with which his "stoning device" is equipped. This micrometer is on the stoning device itself, and would not have been required if there were a "fine [longitudinal] adjustment" in the cutting spindle.

The pin used for indexing is just visible in these photographs; it is more clearly visible in the photograph of the same cutting spindle (lathe headstock) as placed in the "stoning device" (see below).

(Aside: The two L-shaped pieces on top of each of the standards of the cutting spindle are oiling points; they are also more clearly visible in the "stoning device" photo.)

4. The Stoning Device (Pre-1939)

In addition to grinding his matrix engraving cutter, Goudy polished it using a stone. The machine he used for this was patterned after Benton's first style of cutter grinder.

To understand it, examine the lower illustration on p. 119 of Typologia (magnification isn't so important here; even the online copy via Google Books will suffice). Compare it to this drawing of Benton's 1890 cutter grinding tool, from his patent. [5]

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(The image above links to a PDF version of the entire patent, which may be easier to scale (if it shows up in a separate window). Here's the full-resolution version of the PNG image: us-0422874-1-crop-fig-1-1520x1186.png Here's the entire patent as a PDF: us-patent-0422874-1890-03-04-benton-cutter-grinder.pdf

Benton's grinding tool looks very much like a watchmaker's lathe, and it is built out of watchmaker's lathe parts, but it does not function as a lathe. Rather, the headstock shown in the drawing is actually the cutting spindle removed from the matrix engraver and placed on the bed of the what Benton at this time thoguht of as his cutter grinder (Goudy's "stoning device").

The headstock and the table (D) for the stone are located in a mutually fixed relationship by stop F'. An indexing pin k allows the cutter in its spindle and collet to be indexed to and fixed at any desired rotational position.

Goudy's "stoning device" is very similar (although it is built around a bedplate rather than a lathe bed). It has a fixture much like the one shown at C-G-D in Benton's patent. This fixture is basically a way of setting a hardened steel plate, D, at specific angles relative to the tool. In the side view above, it looks as if the tool projects into this block D, but in fact there is a cut-away portion of it (see Fig. 5 of the patent, reproduced below). This allows the operator to slide an abrasive stone over the surface of D and grind the cutting tool to match that surface.

[click image to view larger]

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Much of the complexity of this fixture in Benton's patent has to do with means to vary its angle in operation. This is because Benton wanted to allow pyramidal cutters with both straight and longitudinally-curved cutting edges (think of a rubber pyramid over-inflated). Goudy's cutters all had straight cutting edges and planar cutting faces, so he merely had to fix table D at an angle with a pin.

Goudy's tool does add one feature not present in Benton's, however. The entire fixture with the table can be moved longitudinally toward or away from the cutter under the control of a micrometer screw. This feature conflicts with Benton's principle of the removable spindle. Indeed, if Goudy's device does not have a way of repeatably bringing the cutting spindle (lathe head) to a fixed location, then as much as it resembles Benton's device it is in principle different.

But Goudy is not using this device as a grinder to shape his cutter (as Benton was, at this time). Instead, he is using it to "stone" or polish the cutter. He is removing a (presumably) minute amount of material from the cutter.

5. The Stoning Device (Post-1939)

A stoning device, functionally identical to the pre-1939 device, is shown on p. 119 of Boone's article.

6. Notes

1. Bruckner credits the source of this photograph to the Melbert B. Cary Graphic Arts Collection at the Rochester Institute of Technology.

2. Another view of the "Matrix-Cutter Grinder" appears in Typologia , p. 119.

3. US patent 774,030, issued 1904-11-01 to Linn Boyd Benton, "Grinding Machine." See Benton's Second Cutter Grinder.

4. To be honest, I can't quite see how Goudy accomplishes this in his post-1939 cutter grinder.

5. US patent 422,874, issued 1890-04-04 to Linn Boyd Benton, "Tool-Grinder."


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