Giving up on Strip Casting (for now)

After several unsuccessful attempts at casting strip material on my Monotype Composition Caster, I’m giving up for a while.

The problems I’ve been fighting with include:

  • Unfused strip material, which easily breaks up into pieces
  • Blowback through the nozzle seat
  • Mould jams (strip material doesn’t advance)
  • Difficulty adjusting the mould clamp
  • Incomplete filling when using wider (6pt) moulds
  • Under-table squirts which foul the nozzle and its seat
  • Temporary misplacement of my collection of rule matrices, reducing the utility of strip casting in general

The first two can be attributed to the temperature of the metal and the mould. Unfused strip material occurs when there is not enough heat to partially melt the end of the previous cast so it can fuse to the new cast. Blowback occurs if the metal and/or mould are too hot and the metal is still molten when the pump disengages from the mould, allowing the pressurized air bubble in the mould cavity to blow the molten metal back out of the nozzle port. I have also recently made some improvements to the cooling water system on the caster, which should help with temperature control.

I found myself sort of thrashing trying to solve these interacting issues and decided it was time to take a step back and think about the problems more rationally. In the meantime I’ve removed the strip-casting attachment and converted the caster back to type casting.

Since then I’ve already found possible (and even likely) causes for some of the problems:

I had already determined how to deal with poor fusion and/or blowback but it is impossible to find the sweet spot between these extremes unless the rest of the casting is going smoothly.

Close examination of the pump piston has revealed that the ports on it which admit the metal into the pump chamber were pretty much completely plugged up, explaining the poor filling on larger moulds. These have now been cleaned.

I had not noticed that the caster was running with one of the gag plates installed (under the pot bracket). These plates cause the pump to start pumping a little earlier in the cycle. This could potentially lead to leakage around the nozzle if the pump trip latch is not also in use. I had tried casting with the trip latch both on and off and neither position seemed to make much difference given the randomness from all the other problems. It should be noted that although the trip latch delays the onset of pumping until the nozzle is seated (producing a burst of metal flow instead of the slow onset of flow with no plates or latch), it does nothing about the delayed end of the pump return stroke. Thus if the mould cavity is very small, or still contains unejected metal from a previous cast, there can still be pump pressure when the nozzle disengages, leading to the under-table squirt. The mould I had squirting problems with was a 2-point strip mould; with a ½″ mould blade stroke that amounts to about the same volume of metal as an 8- or 9-point em quad. Clearly I should not have any of the plates engaged for this. So this might explain the under-table squirting.

The mould jams and clamp adjustment sort of go hand-in-hand. The manuals seem to imply that the spring on the vertical rod that operates the clamp should compress a tiny bit (1/16″ seems to be the target value) during the casting part of the cycle. I was finding, though, that this was preventing the cast material from advancing out of the mould. I have since realized that there are two things that resist the clamp screw: One is the stiffness of the mould cavity sides, the other is the previously-cast material already in that area of the mould. If the clamp is adjusted with too-thin material preset in the mould, the prescribed amount of clamp pressure will close the clamp too far (as only the flex of the mould side resists the clamp force). More importantly, the clamp will not open far enough to freely admit the next cast piece, since the caster only rotates the clamp screw about a tenth of a turn. Next time I’ll have to experiment with this adjustment more. I’m not entirely sure what the effects are of not closing the clamp enough (or not closing it at all), partly because I don’t know if the mould cavity naturally has some taper to it, which the clamping is supposed to take up. Perhaps fixing the squirt issues will allow me the freedom to do such experiments in an effective manner. The mould jams could also be because my home-made spring box does not contain sufficiently stiff springs. Yet another cause could be some dirt incursion when I serviced the mould, so I’ll have to take it apart and re-assemble it again in a cleaner (and cat-hair-free) environment.

I seem to always have something around the shop that I’ve lost (after having stored it in a “safe”/”obvious” place!) and don’t find until long after I’ve given up, and am searching for the next unfindable object. I had a mat holder in this state of limbo, and recently my collection of rule matrices has been unfindable. In the process of looking for my latest unfindable (some large cuts, still not found), I have located the matrices so I can try them with the 6-point mould next time I’m trying strip casting.

I think I have some things to try for all the problems I’ve encountered so another attempt at strip casting is on the to-do list.

Troublesome Monotype Water Valves

The Monotype Composition Caster uses water to keep the mould and surrounding area cool, and the caster is fitted with two valves to control the water flow. The main valve just controls the overall flow. Most of the water flows through a passage in the caster’s table under the mould and then runs through a diverter valve and into the coolant drain. By restricting the diverter valve, some of the outflow from the table passage is forced through the mould itself, and from there goes to the same drain.

These valves are weir valves, meaning that they have a barrier (the weir) between the inlet and outlet which the flow must go around. A rubbery diaphragm is pressed against the weir to pinch off the flow of water. As you tighten the stem this pinches harder ultimately cutting off the flow entirely, and as you open the valve the water pressure raises the diaphragm to allow flow. As you open the valve further, a button that forms part of the diaphragm is pulled up to further increase the flow.

The body of the diverter valve. The water enters on the right, passes over the weir (vertical bar in the center) and leaves through the outlet on the left.

The valve cap disassembled. Left to right: diaphragm, plunger, stem, cap, lock nut, handwheel and retaining pin

These valves are between 60 and about 110 years old and the diaphragms have become very hard, to the point that the low water pressure in the cooling system is not enough to open the flow up, and the stem has to pull on the button to allow flow.

The diverter valve on my caster was stuck shut. It turns out that the diaphragm had hardened in the closed position, and trying to open the valve just pulled the button off the diaphragm.

I replaced the diaphragm with disc of plain 1/16″ silicone rubber. I also made a washer from boxboard to add some thickness to ensure the perimeter would seal. This has no button on it, so I made a plug of epoxy putty to fill the socket in the end of the plunger and smoothed it off to a dome shape with files/sandpaper. The valve can no longer pull the diaphragm open, but the diaphragm is soft enough that the water pressure should be enough to open it (unless it sticks, do not store with the valve closed tight!).

End of plunger with epoxy filler in place and smoothed down

The assembled cap with the plunger filler button and boxboard washer in place, and new diaphragm below

I had previously had problems with the main coolant valve being hard to adjust, and was also frustrated that I could not turn off the water without losing its setting, so I had replaced these with a combination of a ball valve (to turn the water on and off) and a needle value (to regulate the flow). The needle valve unfortunately had compression fittings and everything else here was pipe thread, so I made some adapters and soldered then into the compression sockets of the value. The adapters were made from standard 1/4MPT unions, using my lathe to turn one end to fit the compression socket.

New fittings as purchased

Needle valve and custom adapters, ready for soldering in

Now the diverter valve operates easily, and I can use the needle valve and ball valve to independently adjust the overall flow and shut the water off completely.

Updated valve system. Main shutoff and flow control on the right, diverter upper left

Here is a bit more information on the valves:

The valves are “SAUDERS” weir valves, type ‘A’.
The body appears to be zinc or perhaps aluminum though some parts (like the stem) are plated brass.
These have the “rising handwheel” style of cap.
The diaphragm is round, about 1.08″ diameter, and the button is about 0.375″ diameter.
The cover screw rectangle is about 0.9×1.03″. Note that the diaphragm is round and pinches in a recess in the valve, and does not engage the cover flange or screws.
The ports are FPT perhaps 1/4″ or perhaps smaller.

The brand still exists and similar valves are still made. There is a website for them but it does not appear to cover this particular product. Considering the sorts of environments these valves are designed for, they are way over-built for their use in these casters.

Lanston Monotype Pump Cleaning

I recently tried to get strip casting working on my Monotype Composition Caster but gave up after several failures. One suspect was the pump; the strip-casting moulds use a different pump than composition and display casting, and I had never used this particular pump before. One possible cause of (some of) my strip-casting problems could be explained by poor pump performance.

I’ve converted my caster back to its type-casting configuration, and have since been taking a close look at the pump. My caster normally uses an English Monotype design pump which has one-way valves on both the inlet and outlet of the pump chamber. The pump for strip casting was, however, a Lanston (American-made) pump, where the inlet to the pump chamber is opened or closed solely through the position of the piston in the cylinder: When the piston is at the top of its travel, the inlet port on the side of the cylinder aligns with the gap between the two bottom-most rings of the piston, and from there molten metal can enter the cylinder through two small holes drilled from this gap to the center of the piston. Once the piston starts its downward stroke, the second ring closes off the inlet port so metal can no longer enter (or, more importantly at this point, exit) through this port. The molten metal is instead forced out the bottom of the pump into the mould cavity, where it solidifies almost instantly. When the piston rises again, the now-solid metal cannot flow back into the pump chamber, so a vacuum forms there, and this vacuum is not relieved until the piston returns to the top of its stroke, again opening the inlet port.

These holes in the piston end are crucial to pump operation; if they are clogged the only metal that can enter the pump chamber is whatever can leak by the bottom piston ring.

Today I had a close look at this piston, and found that I could barely even tell where the holes were. I cleaned them out by putting the piston in a vise, using a torch to melt any type metal on the head of the piston, and using a set of welding torch tip cleaners to clean out these holes. I started with the finest cleaning wire and worked my way up until the hole would not open up any further, at which point I had run out of slag to clean out and was now trying to remove the metal of the piston itself.

With the holes properly cleaned, the torch tip cleaner can run through-and-through.

The cleaned hole is obvious when the piston is held up to the light.

Based on the size of the largest tip cleaner that would fit, it appears that these holes are about a #56 drill, or about 0.047″ (1.2mm) in diameter.

I suspect that many Monotype owners don’t even know about these holes. The need to keep them clear certainly never came up at Monotype University.

 

Are ‘sign’ and ‘sine’ homophones?

At the dinner table last night the conversation wandered into homophones, and at one point ‘sine’ and ‘sign’ were offered as an example, to which I objected. I felt that they are (very subtly) different, but my family and, as it turns out, most of the Internet (including Wiktionary) disagrees with me.

When I say the words, my tongue definitely does distinct motions for either word, though I really can’t be sure whether the result is a different sound.

When I say ‘sine’, the ‘n’ sound is formed by the tip of my tongue pressing against my palate just behind my front teeth. The action and sound are the same as in most ‘-ine’ words like ‘nine’ and ‘fine’.

But when I say ‘sign’ the ‘gn’ is formed by my tongue pressing against the sides and middle-rear of my palate as if I were trying to form a hard ‘g’ sound but the latter never finishes with the vocalized ‘-guh’ typical of hard ‘g’ at the end of a word.

I’m not sure if the resulting sounds are actually different… The only way to tell would be for me to record myself saying a randomized sequence of the two words, replay it, and see if I can actually tell them apart. It would be difficult, though, to prevent myself from over-emphasizing the differences in the sound.

Making a phone adapter for a tripod

There are a couple of videos I’d like to record. My current camera is 14 years old; it still works fine, but its video quality is poor by modern standards, so until I decide to buy a new camera I thought I could use my phone to record some video. That, however, requires some way of aiming the phone and holding it steady.

A year or two ago I bought a “Steelie” mount for my phone from Lee Valley Tools. This consists of a ring-shaped magnet that is adhered to the back of the phone, and a steel ball that attaches elsewhere (clipping to the heating vent on my truck in this case). The magnet clings to the steel ball allowing the phone to be oriented any way you desire.

Although Lee Valley sells some other Steelie accessories, they don’t have a tripod mount. So I made one.

I started with a 25mm steel ball bearing, into which I tried to drill a hole. Well, ball bearings are really hard steel. Even after trying to anneal the ball by heating it to red heat and cooling it slowly, I was barely able to drill a hole in it. I destroyed a few drill bits before finding that I could use a 1/8″ solid carbide endmill to make the hole.

I turned the end of a short piece of 1/4-20 threaded rod to fit the hole I had hacked into the ball, and brazed the two together. I also polished off most of the scale left on the ball from the annealing attempt along with the flux residue from brazing.

This gave me a male 1/4″ thread mount for the phone, but to fit a standard tripod mount, a female thread is required. I also wanted to elevate the phone so it could face forward in portrait orientation with the tripod in its normal position. I made a sort of mounting post by tapping 1/4-20 threads into both ends of a short piece of 13mm (½″+) aluminum round rod. The ball end screwed into one end of the post and the tripod’s camera mount screwed into the other end.

This particular tripod, though, had a rather wide slot for the camera screw to slide around in, and the rod I had made was very close to dropping into that slot and jamming, so I added a wider base to the rod (it is just a press fit).

Here’s what it looks like with the phone attached, from the subject’s viewpoint and from behind the camera:

Because the ball mount is so easy to turn, a remote (Bluetooth) shutter release is a must. The mounting magnet is also not quite at the phone’s center of gravity, so if you jostle the tripod one end of the phone will drop, giving crooked images. I am still considering ways to increase the friction of the magnet mount—it has a rubbery pad in the center to provide some grip but it isn’t really sufficient.

A Parchment Supplier in France

We don’t carry parchment for sale, but we recently received this message from a producer of parchment in France. We can’t vouch for them or their products, but parchment is hard to find so I thought I would pass this on in case you want to follow up on it.

CLASS’ CUIR 

Parcheminerie artisanale

Patrice HEBRARD

16 Grand’ Rue – 81220 VITERBE – France

06.73.88.24.87

class-cuir@wanadoo.fr / www.class-cuir.com

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An Extended Drill Press Table

The table on my drill press is more or less a 12″/30cm square which is fine for drilling smaller objects but once the workpiece is large enough that its center of gravity is more than 6″/15cm from the hole you want to drill, you either have to fight with the work to keep it on the table or clamp it down.

Sometimes clamping just isn’t practical so there are times where just having a larger table would be useful.

I made this extended table for my drill press from 1/4″/6mm MDF. It is 23″/58cm square (8″/20cm in front of the drill and 15″/38cm behind the drill) with a notch to clear the column. I used epoxy cement to attach four flat-head 7/16NC bolts into countersunk holes so they would line up with the slots in the main table.

Four washers and 7/16NC wingnuts hold the table in place for use.

I find it particularly useful when I’m drilling the holes for the screws that hold our ribbed papermaking moulds together. The mould has to lay face-down on the table and the holes drill quickly so clamping really wouldn’t work but with this large table even our 12×18″ moulds hold comfortably by hand on the table, and the wood surface won’t damage the mould screen.

An old video of commercial hand papermaking in 1976

I just stumbled across this YouTube video of a a 1976 documentary segment which shows the hand papermaking process at Hayle Mill in England. Note that the video ends with about 4 minutes of black screen for some reason. This mill ceased production in 1987.

Despite the age of the film, the picture and sound quality are very good, and they also do a good job of explaining the process and the jobs of the various people involved: the vatman who forms the sheets using a mould and deckle, the coucher who transfers the sheets from the mould to the post and interleaves the felts (couches), and the layer who, after pressing the post, removes and stacks the damp pressed sheets, returning the felts to the coucher.

The clip also shows some details of watermark construction using soldered wire, pulp preparation, and other steps in the process.

At the recent North American Hand Papermakers e-conference Simon Barcham Green, who is the fourth (or fifth?) generation member of the Green family who operated this mill since it was built in the early 1800’s, gave the inaugural Elaine Koretsky Memorial Presentation wherein he spoke about Hayle Mill’s history and operation. That might actually be Simon in the video explaining some of the processes.

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First try at strip casting

I have my Monotype composition caster converted to produce strip material—leading and rule—and this is my first try at running this setup. You can see the inauspicious results in my accompanying YouTube video.

I am using a pump body which I got from Rich Hopkins, with its nozzle specially positioned to mate with the strip material moulds. The piston was from my own parts stock, and I had to make the special nozzle for use with the strip material mould. The levers which operate the pump were given to me by Ed Rayher from Swamp Press. I needed these because the pump body dimensions are different for Lanston (American-made) and English-made pumps and the only levers I has were for English pumps (as my caster is an English one).

I had a few other odds and ends from my parts stock: The stroke adjustment mechanism, one of the levers that operates the mould blade, and the adapter that connects the centering pin arm to the clamp lever on the side of the mould. The rest I had to make: various push-rods, levers, linkages, a spring box, and a base to provide mounting points for everything.

In this video I have everything put together and trying to cast some 3-point low leading. It sort of works, but it is not filling the mould properly, the casts are not fusing to each other properly, and the casting keeps jamming where the trimmer blade is removing the side jet from the strip.

My mould has a two-part trimmer setup. One knife cuts close to the side of the strip to remove all traces of the jet. Another curved piece before this knife seems to be intended to break off most of the jet but I’m finding that it just jams on the cut-off jet material. At that point the strip stops advancing and the spring box compresses since the mould blade can’t advance. My copy of The Monotype Casting Machine Manual doesn’t show this second cutter so I’m not sure what to do with it.

Well, it turned out that I had this installed on the wrong screw. There are two screws holding the trimming knife in place, and this should be mounted on the screw to the right. Once mounted here this part becomes a smooth extension to the knife, ensuring that any cut-off jet gets pushed down back into the pot to be remelted.

The jet deflector, properly installed.

This deflector may not serve much purpose. I don’t see it mentioned in the manual, and I only have one on my 3-point mould, not the other two moulds. This is probably used when you are also using the guide tube which supports the cast strip as it crosses above the pot on its way to the stacker. When there is no guide tube the regular trimmer blade should deflect the jet down enough to not cause problems, but with the guide tube in place this extra deflector might be needed to force the jet quickly into the pot so it doesn’t butt up against the end of the guide tube.

I’m hoping a bit more tuning will get me casting solid and properly-fused strip material. Then I’ll try out the other two strip moulds I have (2-point and 6-point) and maybe play with casting some rule. I have several rule matrices but I can’t use them with the 3-point mould because I don’t have the “high” mould blade for it.

For my test I had the blade stroke stop set for its short-stroke position, used for ½″ stroke when casting rule. When I repositioned it for a ¾″ stroke (which can only be used for casting leading, not rule) I found that my spring box wasn’t compressing at both ends of its stroke. It would appear that I’ll have to alter my linkage a bit to change its lever arm ratio to provide a tiny bit more stroke. I’m hoping I can do this just by drilling a new hole in one end of the first lever; this is fine if the hole moves far enough (more than its own diameter) but for a smaller shift, I’d have to either weld the old holes closed or make a brand new lever.

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A novel motorcycle air filter (not!)

We’ve had a week of beautiful warm (for November) weather here and I took advantage of this to take my motorcycle (a 1987 Kawasaki EX500) out on several rides. Unfortunately on the last ride the bike decided that it wouldn’t idle unless I constantly blipped the throttle. If I released the throttle the engine would go to idle speed but then over a few seconds gradually slow down and stall. Restarting the engine required opening the throttle a bit, something I don’t normally have to do.

This is a symptom of the pilot (idle) system in the carburetor not working properly. This system supplies the fuel needed to run the engine at idle, when the throttle is completely closed.

To fix this I had to remove the carburetors to clean them and one of the first steps is to remove the air filter. They don’t make that easy: I had to remove the fuel tank (including disconnecting its hoses) and the fuel tank bracket. Once I removed the air filter cover this is what I saw:

The airbox was almost completely filled with what was probably a mouse nest, containing a mix of fibreglass insulation (mice love that stuff), shredded paper, sunflower seeds, acorns, and other junk. The foam element of the air filter was completely gone.

I’m not sure how long this has been this way; it could have been fairly new, or it may have been like this for years.

To get this cleaned out I had to remove the airbox completely, disassemble it, and wash everything out.

I also removed and cleaned the carbs, and now have things partly reassembled. The engine will idle now, but only with the idle speed turned up a bit. I don’t have the replacement filter yet (it is due later this week) so that might be affecting things a bit.

As it turns out removing the air filter is one of the few things I didn’t actually have to do to remove the carbs. But I did have to remove the side covers of the airbox so it would be able to lift up a bit. Taking those off would have revealed the mouse nest as well.

But now the nice weather is coming to an end so I probably won’t ride again until spring.

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