Another Bad Casting day

Yesterday, I tried to cast another font of 12-point Caslon Old Style (Lanston 12-337E). The computer and pneumatics worked flawlessly, but the type kept misbehaving in the type channel.

The caster seemed to be doing something known as a “second shot”, where a bit of molten metal squirts up and adheres to the foot of the type after the jet is cut off.

This metal causes the type to ride high in the type channel, not pack tightly to the adjacent type, or force the (spring-loaded) type channel to open up a bit and so allow the other properly-cast type to fall over or turn sideways. The type also jams as it transfers from the type channel to the galley. Sometimes the metal breaks off and is dragged into the type channel area where it prevents the type of lining up neatly.

There are actually two causes of extra metal at the foot of the type. The other cause is known as “bleeding feet” which occurs when the jet is cut off before the metal has solidified completely, and a bit of metal oozes out through the still-molten part of the foot of the type.I have several reasons to think this is second shot and not bleeding feet:

  • The caster is running borderline too cold as evidenced by the fact that in the same line as the bad feet I was also getting nozzle freezes. Bleeding feet occur when things are too hot.
  • The extra metal almost peels off completely with only a tiny patch left adhering (though still enough to affect height-to-paper). I think bleeding feet would produce a solid well-adhered blob of metal.
  • The metal looks like a squirt; it has the appearance you would expect from the “splat” of molten metal and looks like all the other metal decorating the floor and walls around the caster. Bleeding feet would tend to produce a compact, nearly round, blob of metal.
  • The amount of metal exceeds what I would ever expect could ooze out of the foot of the type.

That being said, I’m at a loss to explain how this is happening. It has to be occurring after the type carrier and mould crossblock have moved completely to the right, exposing the foot of the type. By that time the pump has completely returned to its idle position. I only found one troubleshooting hint in the manuals relating to second shot, and it was a rather hand-wavy explanation of the source of the problem which did not really fit with how the mechanism moves. I’ll have to re-read that in detail to see if I can make sense of it. I’ll also review the timing diagrams I found in a (very old) manual to see the exact timing between the pump motion and the type carrier motion.

One strange though I just had, related to the caster running borderline too cold, is that before the nozzle drops away from the mould, it (the nozzle) freezes just enough to seal it. After the nozzle drops away, heat conducted up from the nozzle base re-melts the metal, so any residual pressure in the area would cause a little squirt of metal. Again, I’d have to take a close look at timings to see if this is plausible (and still would need a theory on the source of the residual pressure).

Perhaps I could also take a slow-motion video of the pump operating to see if anything odd happens when a second shot occurs. The problem here would be identifying which pump cycles in the video had a second shot and which did not. Murphy’s law will of course dictate that if I try doing this the problem will go away!

The problem perhaps seemed to be worse when casting narrower type.

One problem analysis technique I sometimes use is to consider what has changed since last time (when the problem did not occur). Before this casting run I removed the pump body, cleaned the piston, chased oxides out from around the heating elements, drossed and cleaned the metal, and reinstalled the pump. I also topped up the metal, giving a very full pot. Serves me right for trying to run things sparkly clean!

A Little Monotype Alignment Conundrum

I recently cast a font of 12-337E Caslon Old Style from a 15×15 matcase using my Monotype computer interface.

Upon rummaging around I also found that I had loose cellular matrices for the quaints in this font. That would be mostly the long-s and its several ligatures, but also include matrices for ‘ct’ and ‘st’ ligatures, so I decided to cast some of these to include with the font.

Rather than opening up the diecase to add these two matrices (and finding an appropriate location for them to get the correct width), I chose to use my 40A single cellular matrix holder (illustrated on page 104 of the Lanston Plate Book).This replaces the composition diecase, and the caster was manually positioned to H 6 to position the matrix under the centering pin (I could have used the computer interface and pneumatics to position this but I didn’t want to fire up the noisy compressor). By consulting a table in the rear of The Monotype Casting Machine Manual I found the settings for the justification wedges to allow casting these 14- and 15-unit types in row position 6 (normally 9 units). I engaged the dog (normally used for display casting) to force use of the justification wedges even without compressed air and cast the type.

The part I found odd was that the ‘t’ on the ligature hung over the edge of the finished type. I had to tweak the alignment by about 5 thousandths of an inch to remove the overhang so the ‘t’ in these ligatures would align just like a single ‘t’ in the regular font.

Looking at the matrices does not show any such misalignment. In these particular close-ups five thousandths of an inch would be about 10 pixels or 1/40th of the overall matrix size and would be clearly visible. Furthermore, the matrices are designed to be placed in the diecase with the regular font so you can do composition casting using the ligatures.

I’m at a bit of a loss as to why I got such poor alignment. Even if the matrix holder position needed some adjustment (by adjusting the draw rods), the matrix should still ultimately center on its cone hole (pushing the matrix jaw open if needed to allow the mat holder to shift). Such pushing around is of course in the long term rough on the centering pin and matrix cone holes (causing excessive wear), but the centering pin should be reliably strong enough to push the diecase around as needed. In any case I later checked the drawbar positions and they were fine—the centering pin was landing right in the middle of the matrix cone hole.

One thing, though, is that I was just finding the beard was overhanging the body of the type, so perhaps these mats have a wider beard than the regular ‘t’. I should cast some of these letters and proof them to see how the actual alignment turns out. If they truly have different alignment, in theory any computer program generating a ribbon file for composition casting could compensate for these matrices being out of alignment horizontally by kerning both sides, but that does not help when casting fonts.

Private Screening of Woodwriter

Last night we traveled to the Royal Cinema in downtown Toronto for a private screening of Woodwriter: The Wordless Art of George A. Walker. College Street in Toronto’s Little Italy was abuzz with pedestrians enjoying the wonderful warm spring evening.

This documentary film produced, directed, and edited by Jeff Winch, was partly funded through a Kickstarter campaign to which we contributed. The film presents George’s work, concentrating on his recent series of wordless biographies, along with a bit of his philosophy of life.

George is an old friend of ours from the letterpress/craft printing/book arts scene, and he has published a series of (so far) five wordless biographies of famous Canadians, illustrated entirely with his own wood engravings. These books are published by The Porcupine’s Quill and are available through their website as digital downloads or as physical copies sold through Abe Books.

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Wayzgoose 2022 Anthology

Well, it won’t be ready for distribution for several months, but this year’s Wayzgoose Anthology is on its way to the bookbinder.

This year our contribution is a bit of a farewell to Rhona Wenger, who just retired from the Grimsby Art Gallery, where she has been organizing Wayzgoose for so many years. It is based on cuts on a vegetation theme left from the now-dissolved Book Arts Guild of Richmond Hill (though one of the cuts might be a pair of serpents rather than intertwining branches).

Most of the blocks are lino cuts, but one, the nice “park” scene, is a copper engraving. Unfortunately, partway through the print run it was damaged by a bit of grit in one of the sheets of handmade paper. Bummer. I might try unmounting the plate and carefully hammering the pit out from the back; I suspect almost anything would look better than how it prints right now.

Especially with handmade paper, getting lino cuts and type to print well on the same page really requires two runs through the press, one normally inked with just the type and another very heavily inked with just the cuts to get the solids. Unfortunately I was running late getting this ready so I just compromised and got somewhat over-inked text and somewhat patchy blacks on the cuts.

Dundee Artisan Festival

We’ll be participating in the first annual Dundee Artisan Festival, next Saturday, May 7th, 2014, from 10am to 6pm. Most of the festival will take place in New Dundee Park, just a couple minutes’ walk from our shop, but in lieu of a booth at the park, we will be open that day for anyone who wants to visit.

The Festival will feature various artisans, as well as food and entertainment throughout the day.

 

For more details, see:

Now we just have to clean up the mess that has accumulated in our shop over two+ years of isolation!

Towards a better casting day

After analyzing the problems from my bad casting day, I’ve managed, with some success, to address all the problems (numbered to match the previous post):

  1. I disassembled, cleaned, and reassembled the mould, and checked the carrying frame height on the caster bridge. I got a little lost doing the latter so I’m not sure if there turned out to be any net change in the adjustment. The result was that the type came out cleaner with little flash. A close inspection of both the matrices and the mould show little wear on either.
  2. The airpins sticking either up or down were addressed by adding a better air regulator to the interface.
  3. I didn’t address the wear on the normal wedge, but one other possible source of wrong-length lines could be stuck airpins in the front pin block. This would select a cast whose width is different from what the line length was calculated for.
  4. A few days after the bad casting run I noticed that the tank on my closed-loop cooling system was empty, so I may have had insufficient cooling water during the failed casting run. This new run did not encounter any such problems.
  5. See #4 above.
  6. The communications issues turned out to be a failing clock on the laptop. After an hour had elapsed, the time would jump back an hour, causing the computer to relive the same hour forever. Some changes to the software or a new laptop resolved this issue (yes, “or”… see the linked post).

The new casting run went much better, but still not perfectly. There are still issues with airpins sticking either up or down, so I have to look further into air supply problems. I haven’t looked at the line length variation yet, which seems a bit pointless as long as the wrong matrix row is being cast. Other than the casting not containing the diphthongs ‘æ’ and ‘œ’, which is a software problem with the MCA and font scheme, the sticking airpins are the only problem left. Perhaps contamination in the air is causing the pneumatic valves to operate improperly, and I need a filter/water trap right at the caster.

Solving caster communications the expensive way

During my Bad Casting Day, I was having problems with the communications between my caster computer interface and the 14-year-old Windows laptop I was using to drive it. They connect using a USB cable, and I thought electrical noise might be the source of the problem. The computer would apparently randomly stop receiving status from the caster interface, or would stop some of its internal test cycles that are there to exercise the caster.

I eventually determined that the problem was the clock in this aging laptop. It no longer remembers the time on power-up (and replacing the internal battery did not help) so I have to set the time when I boot it, especially if I want to browse to any secure websites (using https instead of http). As it turns out, once I set the clock, after an hour has passed it jumps back to the time I set it, so the laptop keeps reliving the same hour over and over again, reminiscent of the movie Groundhog Day.

The caster-control application on the laptop is written in Java (so it should port trivially to MacOS and many Unix clones), and uses the java.awt.Timer class to run its internal timers. This class turns out to be sensitive to unstable computer clocks. It schedules the next thing to do based on the clock, so if it schedules something for 10ms in the future, then the clock jumps back an hour, that event does not occur for 1:00:00.010. If the clock continually jumps back the event never occurs.

My code did not need most of the features of this Timer class (such as a thread pool) so I changed the code to use the lock-with-timeout builtin language support instead. This is the feature that Timer uses to wait until its (mis-calculated) next-event time anyway. This seems to be insensitive to the irregular clock so I prepared the package with the new code.

I returned to the workshop to find that the caster cooling loop (which I had just refilled after finding it dry) had blown off one of its hoses and drenched, amongst other things, the laptop. I did not think the pump developed enough pressure to blow off the hoses, and it had seemed fine up until that time. Perhaps having the tank run dry warmed up the pump, pipe fittings, and hose enough to loosen the hose.

I tried to dry out the laptop over several days, and inspected it inside for visible damage, but it was dead.

So now I have a new laptop, I’m getting used to Windows 11, and the clock works properly, and the software wouldn’t care even if it didn’t. So the problem has been fixed by correcting the software or replacing the computer (or both), your choice.

I’ve also put hose clamps on the cooling loop and a more secure cover over the pump and tank.

 

More updated caster pneumatics

One of the conclusions of my Bad Casting Day was that I needed better regulation of the pressure of the compressed air which controls the caster operation. The caster has about 30 pins about 3/8″ (1cm) in diameter which must be raised by the air pressure, or drop down under the force of a return spring, in a fraction of a second when the caster is running at full speed.

Read more ›

Rebuilding composition mould 12-pt 3E3618R

After my Bad Casting Day, one thing on the to-do list was to tear down the mould because the type being cast had a lot of flash at some of the edges. Read more ›

A slightly better casting day

After the really bad casting day a few weeks ago, almost anything would be an improvement. I had taken steps to resolve some of the problems, and here is the result:

The casting run. The top twelve lines were attempts at re-casting other lines that had mistakes. Some of the lines might have odd casts at the left end where the line came up short and I manually inserted whatever odd sorts I had to fill the line.

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