Interesting printing base.

Hello all, i just purchased this from Dave Churchman, and he confirmed what i thought, this is a base that could be used for unmounted metal (magnesium?) dies, and they can be locked on this base with the special clips it has on the base.

I cleaned off the bottom of this base, and it looks like it was made by Rookstro (sp?) manufacturing of New York….?

I want to test this base out and it looks like i can order unmounted dies in various gauges, and i think that 11pt. ( 11pt (.153”/3.86mm) ) is the way to go. If anyone out there might have knowledge of this, i would love to know what gauge to order to try this out.

Any information on what gauge (or thickness?) plates this would use would be greatly appreciated. I would love to use this in addition to the boxcar base that i already use.


Don Kilpatrick

image: unique_base.jpg


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you should mike the base, then order the mag dies to make the total .918. Good Luck Dick G.

11 pt. was the industry standard for duplicate plates (stereotype, electrotype) and most patent bases were made specifically for that. The only other height I have seen for patent base is for 1/4” dies. There were lots of different base designs but I haven’t seen this one before.
The standard thickness for original photoengravings was 16-gauge, and they were put on backing plates to use them with patent bases. People are doing this with photopolymer plates today.

Thanks dickg and paralell_imp for the information. Today i used a micrometer and the base seems to measure out at .754, and .85 if i include the height of the bevel hook on the base for securing the plates. I figure that i will need the 11 pt gauge plates for this base. I laid an old 16 gauge plate on the base and the height didn’t go above the hooks, so even if i were to pack it i am almost 100 percent sure it would print alongside the plate…

I have heard from a couple of different people that magnesium is horrible, copper expensive as hell, and zinc plates aren’t being made anymore.

Not that i want to start a debate or something like that, but does anyone here have strong opinions on this? I have been using photo-polymer just because of convenience, but i want to explore the possibilties of magnesium for this base.

It looks like Owosso offers magnesium unmounted in 11 pt. Will this be strong enough to not depress into the grooves on this base?

Thanks again everyone for the information, and a big thanks to Dave Churchman for letting me take time from his busy schedule to buy this.


Don Kilpatrick

Hi Don,

I don’t have a lot of experience here, but I’ve used Owosso 11-point magnesium plates on a honeycomb base and they’re plenty strong. I think magnesium has the reputation of being “horrible” because it corrodes so quickly and so dramatically. For storage, I slather my magnesium plates with Vaseline and seal them in a Ziploc bag with all the air squeezed out. I haven’t experienced any corrosion after many months.

I’m going to try the 16-gauge copper, though. I don’t think it’s that much more than the magnesium, and it sure is prettier and less bother to store. You need a 0.854” base for the 16-gauge, which is 0.064”.

I’m going to take a leap and have my Boxcar standard base milled down to 0.854” and then use tape to affix the plate to it. This method was developed by Richard Tautenhahn, who demonstrated it at the International Printing Museum on Saturday. I was pretty impressed.

I asked Rich if one could use the tape method on a honeycomb base, built up to the proper height (my honeycomb is 0.759”). He said that the tape probably would not get enough purchase on the base because of the holey pattern. Your base looks like it has about the same solid-to-space ratio, so that’s probably the case for you, too. Might be worth an experiment, though.

This is an interesting subject. I would like to hear more from the seasoned printers.



You may want to mount the 16ga. plates to an intermediate base if you try to mount to the honeycomb, and use the actual honeycomb hooks to hold the intermediate bases in place, not adhesive. You may mount the 16ga. to the intermediate base with adhesive, but if you mounted directly to the honeycomb, you would lose the capability of re-positioning the plates on the base, one of the great features of the honeycomb base.

I cut many sizes of intermediate base and leave the plates attached to it for reuse. Works well for me, but I have some shop equipment for beveling the bases, etc. Since I use polyester-backed photopolymer plates, and removeable adhesive, the plates bend on removal and return to the flat state after use.

If you mount the 16ga. copper plates on the Boxcar base, you must be very careful in removing them as they will have a tendency to bend, and you will have a very difficult time getting them to lay flat again for reuse. Maybe the adhesive will just pop off, but I’ll bet it retains its adhesion enough to cause you some difficulty. You could soak in solvent to loosen the adhesive, but I’ve done that, and it’s not pleasant cleaning up the mess afterward.

Don, i use mag dies, and have since the early 1970’s, i store them on galleys, yes i have had some rot away, buy very few, i must have 3 or 500 and only lost about 10 or 15 over the years, i have a customer who uese copper dies, they are nice, and last a long time, but so do mag. dies. Some of my dies i foil with, some i print with, for printing i mount them on my wooden furniture with double sided tape then run masking tape around the four sides of the die to make sure it don’t move, i get 1/4” dies and use 2 pieces of chipboard under the furniture. Good Luck Dick G.

Hi John,

Thanks for the excellent suggestion of mounting the copper plates to an intermediate base for use on the honeycomb. What do you use for your intermediate base, and why does it need to be beveled? The mag plates I’ve used on the honeycomb are beveled, but it seems as though the hooks (Sterling) would work okay without the bevel, maybe better.

Richard doesn’t use double-stick adhesive to mount plates to his solid aluminum base. He uses 7/8-inch Intertape PG-21, which he applies around the edges of the plate. (You need to have the platemaker leave a 3/8-inch margin around your image.) This way all you do is peel off the tape; you don’t need to do any prying at all. He researched many tapes, and the PG-21 is very strong and leaves absolutely no residue.


Hi Barbara-

Where can one purchase the PG-21 tape? Sounds interesting.

Thanks again everyone for this informative thread!


Don Kilpatrick

Hi Don,

Richard said you’re not likely to find that tape at the hardware store. It’s generally used for automotive or marine paint masking. I checked online. Here’s the first Google hit:


Check with NA Graphics, if he don’t have it you probably don’t need it, he might be able to tell you where to get the tape. Dick G.