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Mat holders for the Super Caster

Started by Jason, May 17, 2022, 09:34:53 PM

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Hi everyone,

As my first official topic post to this new forum I thought I'd share some of the unique matrix holders I have for the Super Caster, most of them fabricated by the very talented Dan Jones in Toronto.

The first is a fairly simple but effective holder for foundry mats, which will accommodate pretty much any sized mat, as long as they're deep enough to seat firmly in the holder. I'm using wooden shims to raise the mat to the correct height, and to establish the fixed side-bearing. See the first three images below.

The second one is again made by Dan, this time for Giant mats.

The first related image here is of the original Monotype Giant mat holder assembly, but I don't have the various insets and shims that go with it, so what I have only allows me to cast the largest Giant mats.

So, Dan went to work. He took a standard British display mat holder, and a blank British display mat, and screwed the mat into a new fabricated holder, with sliding locators to position the matrix on an X/Y axis. The holder therefore uses the British matrix bridge. The added components require that the display matrix head be lifted, so Dan also fabricated an aluminum riser plate that fits between the matrix head base and the matrix head itself. I have an extra display matrix head (7SE) and a couple of spare matrix head bases (8SE), so I've fitted one set together (base, riser base, matrix head), so that I can easily swap the complete assembly on when I want to use this Giant holder. (The first image below shows the riser plate installed under the matrix head.)

Thanks to Dan, I can now cast all of the Giant mats that came with Jim Rimmer's equipment.

Dan has quite a few videos on his Flickr account of his efforts making these holders, which you can find here:

This last one (for now) is a holder that Jim Rimmer hacked together in order to cast large-comp mats using the display matrix head. Despite it's appearance, it actually works!

That's more than enough for one post, but I have others to share as well.
Does anyone else out there have any odd/unique mat holders for their Super?

Jason Dewinetz
Greenboathouse Press


Adding to the post above, I've just found that @John Cornelisse posted about a flat-mat holder for his Comp caster:,4314.0.html

I have a flat-mat holder for the Super Caster which no one else seems to have seen before, and it appears to be the exact same construction as the one that John showed in his post. I've posted a couple of images in reply to John's, but here are the images again.

This holder works great for flat-mats that are custom made and not quite to exact Monotype specs in terms of height/width of the mat, but the problem (on mine at least) is that the lock-screw has a tendency to work itself loose (as the holder is hammered down on the mould again and again) and the result is that I've had mats slip out of the holder, in one case badly damaging the mat.

I have one of the standard Super Caster flat-mat holders, but the release arm on mine broke (at some point before I got it) and it took a while to find a shop that could fabricate a new arm. It's now back together, so I tend to use that one, as the spring mechanism is more secure than the screw on this one.


Here's a rather poor photograph of almost all of the mat holders that I have (it's missing the Giant mat holder shown in my original post here, above).

The one holder I'm missing, which I'd very much like to find, is the 5SL (for .4" mats). I have the home-made Jim Rimmer holder, shown above, but I'd like to find an original for use with the Comp matrix head. If anyone has a spare, and needs one of the spare holders I have shown in this photo, let me know.


Dan Jones

Nice collection. For the record, here is the Super Caster holder and mould you got from South Africa, that being a holder for Ludlow mats in the Super Caster. Jason, thank you for trading it to me, much appreciated.

Dan Jones

Here is a picture of an English Monotype foundry matrix holder at the Type Archive, unused or "New Old Stock" as historic automotive restorers say. I believe the picture came from the web site, it is not my photo. Note the side clamping arrangement similar to the holders that I designed, the original was my inspiration.

Dan Jones

Here is a Super Caster holder for casting quotations. In this photo, it has the adaptor for wood inserts, meant for plate mounting.

Dan Jones

Jason, a close inspection of your Super Caster (SC) holder for American flat mats reveals something interesting. The number "7972" is the correct manufacturing number for the body of an SC holder made for an American flat matrix. However, there is a visible patent date of 1908 on the other half of the holder. The SC hit the market in 1929, so what you have appears to be an English Monotype part married to a Lanston (American) composition machine part. Why, who knows. Two thoughts, the original holder was damaged and parts were not available, so a fix was cobbled together. Alternatively, English Monotype kept an inventory of spares, so long after the actual machines were shipped, a customer could order spares. In this hypothetical case, they ordered the "7972" part however, other components were not available, so a fix was creatively made. Anyway, if it works, use it!

Dan Jones

A totally unique holder designed and made in India, it holds small foundry matrices in the Super Caster composition head. Very well designed and very useful. Since the comp head holds the matrix down against the mould with just a spring, it is not necessary to shim the head up to accomodate various thicknesses of foundry matrices, just 'plug and play'.


Some new developments on the mat-holder front.
In other threads I've been discussing engraving new mats, and the initial trials have been promising. I'm engraving foundry-style mats, like this one (not a great photo, and this was my first engraved mat, so it's not perfect):

This is a custom mat-holder that Dan Jones made, and while it's very simple in its operation, it was (I can only imagine) quite a job to machine, as it's made to slip right into the display type bridge with only the small key slot to be added on (and the handle). Here I'm using wood shims to lock in the mat, in conjunction with set screws available all the way around the holder. I have a thin steel shim on the right edge so that those set screws don't eat into the wooden shim.

This worked just fine for the 18pt ornament shown in the photo, but I've recently engraved the first letter of a titling (all caps) alphabet I've designed (engraved to .065 for large type moulds), and after very carefully engraving and fitting the mat I discovered a serious problem. The large type moulds have the casting surface sunk below the top plate of the mould:

Also notice that the two main screws for tightening down the mould into its base stick up just a bit above that top plate.

After roughing out where the mat needed to be positioned to land over the casting cavity, I then discovered that my mat is too long, and the lower end of the mat was hitting that top plate of the mould. Not a huge problem, it just means I had to cut the mat, and will need to make my planchets smaller going forward.

However, I had to make sure the mat holder and my shims weren't making contact with the top plate of the mould, while the mat itself had to seat firmly on the casting surface.

The first step was to fabricate shims from hard wood that would sit just below the edges of the mat holder, and then to fabricate a new metal shim for the right side that the set screws would tighten against. I also had to raise the mat itself so that its higher than everything else, and at the right height to seat firmly on the mould surface, but not have too much pressure on it.

[Again, this is my first mat of an actual letter, so there are some serious flaws. I'm slowly refining my engraving process, so don't judge just yet!]

I then set the mat holder, with the mat, onto the mould and used a .002 feeler gauge to check that nothing but the mat was making contact.

Everything was clear except for that screw just above the feeler gauge in the photo. Luckily, these screws have very deep slots, so I ground down the heads until they sat below the surface of the mould's top plate. After that, the feeler gauge cleared all the way around the mat holder.

The next step (so far) was to install the mould, with its bridge, insert the mat holder, and turn the machine to casting position to see how firmly my mat was seated on the mould. In this photo I have a slip of wax paper (.001) under the mat, and when in position I can't pull the slip out (in fact I ripped 3 of them doing this test just to make sure).

So, I think I'm good to try casting. No time today, but from what I can tell I now have the mat in position, seating well on the mould, and the mat holder isn't making contact anywhere. We'll see what happens when I heat up the pot on Friday.

Dan Jones

Jason, nice work! First, as a comment, the original foundry holder by English Monotype did not go over 36 pt. I had to look at a work-around and came up with a method to grind down the top of a spare inset (for each size). See the attached videos and pictures:


Take 0.100" from the top of each plate, up to about the screw opening, as shown.

When you drive the tapered pins out, they go from front to back.

If you don't have a spare pin to shorten, grind down the one it the mould.

BE CAREFUL GRINDING, the plate is HARDENED and will warp if done aggressively. Either go very slow or use coolant with a surface grinder.


Hey Dan,

Oh, if only I had a surface grinder! As it is, I don't have any reliable way to grind down the top plates of my moulds (although I certainly have spare insets). Are yours ground down enough to be level (or slightly below) the casting surface? That would certainly make things simpler around here. I'm not sure I trust my local machine shop to do the job, so I may be stuck with my work-around detailed above.


Dan, I pulled a top plate off of one of my spare insets, but the taper pins didn't fit. I have quite a few spares, so I'll see if any of the top plates match up. Otherwise, if I had the plates milled down as you suggest, would I just grind down the taper pins so they don't actually reach the top plate?

Also, do you know what purpose these two screws serve? They don't actually make contact with the top plate, so I can't figure out what they do.


On other fronts, the various tweaks I outlined above seem to be working!

Keep in mind this mat is still pretty crude, as it's an early attempt. The counter-depth cut shows a lot of swirl, as I was using a relatively large cutter to that depth, but the face is reasonably clean, with decently sharp corners on the serifs, and the type is right on .918. I'm now going to go ink up the press and pull some proofs to see how it prints.


The holes for taper pins are often drilled and reamed after the parts have been factory-asssembled and aligned, but the holes themselves are not particularly accurately placed from one assembly to the next. As a result, parts aligned with taper pins cannot generally be swapped around from one assembly to another. In this case it would mean you can only use the cover plate on the mould on which it was originally installed.

But then, I have to wonder... If this is just a cover, does it really need to be so carefully aligned? Could you skip the taper pins (but put in some sort of putty so you don't get type metal in the taper pin holes) and just rely on the fixing screws for position? Perhaps it has a slot in its underside which guides the top of the blade, in which case alignment would be important?


Quote from: Jason on September 09, 2022, 08:22:16 PMAlso, do you know what purpose these two screws serve? They don't actually make contact with the top plate, so I can't figure out what they do.

The two screws are for the bridge used when casting standard height spacing. They only appear on the 42 to 72 point mould insets. 

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