Chase size vs. book size ?

By using bent metal strips (I use 18 point brass thin spaces) stuck into the tympan bales for gauge pins, I am able to print a sheet as large as or larger than the platen on my 6x9 Sigwalt Nonpareil (basically the same as the Sigwalt Ideal of the same size). An advantage of the Sigwalt/Golding Official/Craftsman Imperial (same essential shape and operating mechanism) is that the sheet can hang out the sides as well as stick out the top of the platen, so in theory you could print six 6x9 pages (one at a time) on each side of a 12x27 sheet and then fold it down to make a 12-page signature, all on a 6x9 tabletop press! Sad to say, you can’t do that sort of thing on a Superior or Pilot.

As far as type forme size, any of these tabletop presses is pretty much limited by the strength of the impression mechanism to a type forme printing about half the area of the chase inside dimensions. A lot depends on the surface qualities of the paper — smooth vellum finish or calendared book paper will give a better impression than textured or laid paper.

Generally a good estimate of the area a platen press will print is equal to 1/4 of the platen area. Some presses are better than others, and not all type areas are the same, ie., prose versus poetry, traditional layout versus abstract…
I have seen books printed on a 3 x 5 Kelsey. It takes a good understanding of the capability of the particular press you are using and the overall area of type coverage.

Thank you both for the great information although the two of you seem to disagree as to the usable print area for the forme size . One question, utilizing the pin arrangement you mention to hold on your Siswalt, are you able to get precise registration if you want to do two colors ?

Thanks
Mike

Useable print area would be corner to corner in the chase, it doesn’t mean that you can fill the chase full of type and expect it to print. The size of the paper does not equal the size of the form and the size of the form depends on how much surface area there is to print. For example, I had a old series 7” x 11” C&P that could not print a wood engraving that was a nearly solid 4” x 4”, but could run a solid matter legal form (7 1/4” x 9 1/2”) on a 10” x 15” C&P Craftsman. I repeat: a good estimate of the area a platen press will print is equal to 1/4 of the platen area, however it is distributed around the chase.

I was only printing a single color. You would have difficulty with close register since you only would be able to use guides on one edge of an oversize sheet as I described. I made pencil marks on the edge of the sheet for left-right alignment and that might be OK for placement of, for example, a color border or initial letter.

I assume that a 4x6 type forme would have less than half the actual surface area of a 4x6 white-line wood engraving and therefore could be printed on a smaller press.

Bob

Thanks again to you both. Am I to assume the size of the platen is equal to the outside dimensions of the chase or does it vary by press? It’s clear to me I need to get some time on these type of presses to fully understand the process. Thanks again to you out there with the patience to explain bonehead fundamentals to people. It’s very encouraging that you’ll take the time to do it.

Mike

The size of the platen is usually the inside dimension of the chase and you have to take into account the guides for the paper (gauge pins) and the paper hold-downs (bales). Like AdLib said there are ways of working the paper outside of the impression area, but that doesn’t necessarily mean you can work the type out of that area (unless you run multiple impressions or multiple colors). Simple ain’t it.

My God,

No wonder Bill Morris wandered around mumbling to himself and fondling type in his pockets. There’s a press here in Olympia I’m visiting today to see about being a press grunt for experience.

Thanks

Mike