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Pump/nozzle questions

Started by Val Lucas, January 07, 2023, 01:03:18 PM

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Val Lucas

Newbie questions here, sorry- I'm up with Jim Walzcak this week casting on the Sorts Caster and we came across some issues yesterday. I engraved a new snowflake mat for 14 comp, then we discovered that there is no true 14 pt comp mold (they are what Jim calls a doghouse- slanted to 12pt at the top opening.) So I re-engraved and we set up the 14pt display mold, according to his old notes tied to a mold using a display nozzle on a small pump. We got hollow type with this, despite adjusting speed, temp, pump pressure. We then switched back to the large display nozzle and everything was beautiful. My questions (and my apologies, I am sure they are in books but I am still wading through them,) are:

Should a small pump ever be used for 14pt or above? Or limited to 12 and under, for comp?

Should a large nozzle be used on a small pump for any reason?

I am hoping to set up this machine in my own shop someday, and I'm still learning the basics of what types of things to use when. I plan to mostly cast my own engraved designs (flat display mats) on display molds, but hope to also cast fonts from comp mats as needed. I think I missed some of the basic basics and just started learning as we cast.

John Cornelisse

There is a little problem casting 14pt... The size of the body is more than the with of the matrix... Certainly when the mould is used for casting 14pt Didot... 

That is the reason why the top of these 14pt-composition moulds is made less wide.

But with the nozzle there is no problem at all, you can still use a number 16 nozzle while casting 14 point type.

Val Lucas

Thanks, John- that makes sense! We ended up using the display 14pt mold instead, but I could have made the design work if I'd engraved it rotated 90 degrees!
I wonder why we were having nozzle problems. Something to investigate further.

John Cornelisse

Do you have a few spares of these nozzles ?

These parts need to be cleaned regularly inside. Be aware that the drill does not go to far inside...
Besides this, you sure need to clean the screw threat of the nozzle too.

Cleaning the pump piston, and the pump itself inside... this you need to do also on a regular basis. And the screw threat inside the pump is part of this.

Val Lucas

Jim has a handful of nozzles, and I think a task will be to give them all a good cleaning in the threads. We do drill them out pretty frequently to keep the nozzle clear. It's time to set aside some time for pump maintenance day.

John Cornelisse

It is also handy to control the adjustments of the pump, is it properly centered and does the nozzle stand perfectly vertical ?

When this is not perfectly done, that could cause air bubbles in the type cast, and the parts will wear off easily.

Val Lucas

I will add that to the list of things to check. This was a pump that had not been used in a while so perhaps there was some problem with it that was never fixed. Thanks!
So much to learn.

John Cornelisse

In the past, bridges bared the same number as the composition caster when they left the Monotype corporation. It is however possible to adjust other bridges to your machine, and that makes it possible to cast even different heights characters on your machine.


Changing a pump... than you need to adjust the position of the pump too. The nozzle should be in the centre of the mould-hole at the right time, and the nozzle should be perfectly vertical at that moment.


In the past Monotype would like to sent a mechanic to you when needed. Did cost some money and these mechanics did not like to show how to do their job...

With Dutch height, you also need to change the type-carrier and another part... But that you cannot find  in the manuals...


Val, In your original post, by "small pump" vs. "large pump" are you referring to the piston diameter, or to the extended-stroke piston? Are you using an American-style pump (with the adjusting screw on the pump body) or an English-style pump (with the separate piston on the pump plunger)?

Are you using the spacer plates (under the pump frame) and pump trigger latch, which speeds up filling of the mould cavity at the lower caster speeds required for larger type, as recommended for the size you are casting?

Val Lucas

I'm referring to the piston diameter- this was an American style pump. Jim also has an English comp caster, I think,  so there are English pumps and pistons floating around too. My next trip I hope to get things labeled better!

He does have an English bridge that he's used for English comp mats on the Sorts Caster, so I am all sorts of confused about that one.

I do not know what the spacer plates are so I assume we were not using them. Can you point me to a manual or book page about that? We did have trouble getting 36 quads to cast properly the last time I was there, and ran them on the Thompson instead. 

Thanks everyone for all your help and patience- I'm learning this all piecemeal every time I visit.  This was my 5th trip,  and I'm sure I will have many more questions as I go along!


You can use an English pump on an American caster and vice versa but you also have to change out the pair of levers that operate the pump because the body and plunger are different sizes where these levers engage them. The operation of the two pumps internally (how they "valve" the metal flow) is actually quite different.

The "plates" were originally just a single spacer that was engaged when casting larger type, with a spring toggle to hold it either engaged or in its idle position. This was later replaced by a set of four spacer plates held by a thumb screw to allow a range of adjustment rather than being just on/off.

To find these, look under the bottom of the frame that the pot hinges on when you swing it open, right next to the pivot. There is a rod sticking out the bottom of the casting with a pair of lock nuts on it. The spacer or plate should be located nearby, positioned so they can fit into the gap between the locknuts and the casting.

These locknuts stop the upwards motion of the lower pump crossblock to initiate compression of the pump spring and the pump stroke itself. The plates stop the upwards motion of the crosshead early so that the compression of the pump spring/plunger starts earlier; this is combined with a latch mechanism near the crossheads which hold off the pump motion (so all you get is spring compression) until after the nozzle is seated, then releases the pent-up spring pressure so the metal flows quickly even though the caster is running at a low speed. Without the latch the pump will pump metal before the nozzle is seated, causing squirting under the mould.

In addition to the plates and trigger latch, there is a third piece for this all to work: The upper crosshead is fitted with a threaded rod/stud and locknut, and this rod operates the pump raising/lowering lever instead of the underside of the lower pump operating lever. This is because using the plates changes the motion of the lower crosshead and lower pump operating lever making it unsuitable for operating the pump raising/lowering.

I know, clear as mud. Maybe we can do a Zoom session using phones so we can point at things...

Val Lucas

Thanks! This is all great info, but made hard by the fact that I'm now 7+ hours away from the machine, and won't be back till the summer. I'll save this and make a note to check it out next time I'm there.
I found a manual in the Library section that Jim didn't seem to have so I'm going to study that and make sure I have a better understanding of the basics. Thanks- I'm sure I'll have more questions later :)

I did get 7 new mats engraved and cast this trip, so I'm feeling pretty good about that!

Dave Hughes

Don't forget, avatar_Val Lucas ,  you can set up your own bookmarks for anything on the Forum by using the green heart icon under the posts.
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Pat Reagh

Hi Val,

There are 14pt. composition molds for large comp that aren't doghouse molds. I have one. Same for 16 & 18. Hope this helps.

Pat Reagh

Terrence Chouinard

Dear Val, I'm with Mike right now. He doesn't get to these forum posts often, but I opened it and read him your questions and everyone's comments. I typed up his reply and offer it below.

I routinely cast my 14-point doghouse mould with the standard comp nozzle redrilled with a standard 3/32nd drill from the hardware. In 14-point, you need a larger drill opening that 10, 11, or 12-point moulds. Monotype made a 14-point comp mold wherein the body was a full 14 points, the same as the display, and I always use a display nozzle. In 16-point and 18-point large comp, I routinely use the latch mechanism.

The only difference between an American small comp pump body and a display pump body is the length of the piston. The display piston is shorter to allow more metal into the pump well. Doghouse moulds were invented so that .2 by .2 comp mats could be run with a 14-point body. All our comp mats are .050 drive, the English drive, so ascenders and descenders that might kern a point would not break.

I drill all my American comp nozzles from the bottom with a number 29 drill which is a little bigger than the Lanston-recommended number 30 drill. I drill the tip of the nozzle with a 3/32nd drill, which is just under a 1/8th. I also drill the pump body port opening, the piston stem opening, and the hat valve to slightly larger sizes. Understand that my metal has extra antimony from scrap foundry type and requires a casting temperature close to 730 degrees.

On the English Supercaster there are four individual leaf plates. When engaged, they increase the volume of metal. We don't start engaging the plates until we have 24-point type; as the size increases we engage 2, 3, or 4 plates up to 72-point. On the American sorts caster, there is only one plate as the very bottom of the pump mechanism; it's about 3/16th of an inch thick--and is engaged only for large type like 30 or 36-point. If engaged for smaller sizes of type like 14, you usually will get a helluva squirt. There's just too much volume of metal. Again, consider using the latch mechanism routinely for 16-point and above. And always lubricate the nozzle and the piston with carnauba wax generously.

American and English bridges are interchangeable, with a few exceptions for achieving a low quad. The American large comp centering pin will also work for English mats in an American bridge. The centering pin in the English bridge, however, is quite different from the American centering pin. The  English centering pin is used for large and small comp mat sizes, regardless. If large comp American mats or any English mats are used with an American bridge, the centering pin must be an American display/large comp centering pin.

The 14-point Lanston large comp mould is known as a EN series mould. (That's the series that includes the 16 & 18-point Pat mentioned.) The 14-point doghouse mould, which opens at the top to only 12 points, is part of the EM series. The EN moulds take a display nozzle, but the EM moulds take a comp nozzle. That's why the 14-point EN doghouse mould runs better with a 3/32nd drilled hole and venting. Both are triumphs of engineering, hard to find and expensive.

One other thought is to check your cross-blocks for venting. Any American Monotype comp mould, wherein the cross-block is not vented can result in questionable type. Venting was discovered in the 1950s and allowed air to escape as metal entered the mould. You can vent your cross-blocks by yourself; it is not difficult. The shoe of the larger block in the cross-block is removed, and very carefully, with a Dremel grinder, a vent is ground into the edge of the shoe. If you attempt to do this, first, find a mould with a vented cross block so that you can see exactly what is required. It makes sense when you see it in your hands; you have to see this stuff to understand it.

After drilling out the arm of my American pump bodies and allowing them to cool, I ream the inside of the pump body with an expensive American machine shop reamer. I bought it second-hand for $20 forty years ago. Then I soak all the disassembled pump body parts in a plastic 5-gallon bucket filled with boiling hot water and just less than a cup of lye (sodium hydroxide) available at any plumbing supply. When you add the lye, stand back outdoors, and cover the bucket. Let it sit overnight, and you will be amazed that all cast iron pump body parts will be cleaned entirely of any crud, crap, grease, or paint. Wash these parts with a stiff brush and a garden hose. It's essential to use protective rubber gloves. The flesh will come off if you put your bare hands in the stuff. Some mobs use this process to get rid of bodies.

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