If this procedure is done with with the machine hot, the VMB will be very hot and and, as it is covered in hot oil, very slippery. If it is dropped on the floor, it could easily be damaged and rendered useless. Before working on the VMB, make sure that you have prepared a place on the bench for it. Before removing the VMB from the machine (or lifting it from the bench) make sure tha you are handling it is such a way that you will not drop it.
The procedures shown here are those taught to me by Schuyler (Sky) Shipley at Skyline Type Foundry during my apprenticeship there. Thanks are due to Sky not only for teaching me this procedure but also for taking the time to help to document it. Most of the photographs here are of a machine at Skyline. Any errors which remain in this present document, though, are my own.
Note that when cleaning the VMB you are not only cleaning it but also the slot in which it travels. One side of this slot is the Bottom Block of the Mold. The Bottom Block of the Mold contains an important oil delivery hole as well as oil channels on its surface. These are frequently blocked by typemetal. So you're not cleaning just the VMB but also its oiling system as well.
4. A long, thin 1/2 inch open-end wrench. I am told by Michael Hurley (Titivilus Press) that wrenches of this kind are called "tappet wrenches" after their use in adjusting the tappets in early automobile engines. The wrench shown in the photographs here is the one used at Skyline Type Foundry; it is of unknown provenance and type, but is perfect for the job.
5. A pin wrench. The Lanston Monotype Pin Wrench p/n 49L1 cited in the 1956 Thompson manual is not illustrated. On my machine s/n 12,492, a 5/32 inch pin wrench works best. An inexpensive 5/32 inch solid pin punch makes a good substitute. The matter of pin wrenches is much more complicated than it really should be; see What Is a Pin Wrench?
7. An "L" shaped tool for removing the VMB ("L-Tool" in this writeup). This is a shop-made tool. No tool is listed for this purpose in the 1942 Parts Price List. See ../ Thompson Toolkit -> VMB L Tool.
10. If the work is done with the machine hot (Pot melted), you should be prepared for the possibility of a leaky Nozzle, and have available all standard Thompson Pot tools. See ../ Thompson Toolkit -> Pot Tools.
It is a good practice to lay out all of the tools necessary for the job before beginning, and to put these tools back during the job at the point after which they will no longer be needed. This way if you have a tool lying around at the end, unexpectedly, you know you forgot a step. There are steps in this procedure which are easy to forget, yet which, if omitted, will result in damage to the machine and possibly in injury.
Step 2. Stop the machine in the 12:00 position of the handwheel. We will later back the machine up, but it is always good practice to stop the machine in the same place, and 12:00 is the natural stopping point for the machine.
Step 4. Ensure that the Sight Feed Oiler is off. Failure to do this will mean that the oil in it will run uselessly through the mold while you're working on the VMB and will increase the likelihood that the Sight Feed Oiler will be empty when you resume.
The reason for this is that during this operation the pot will be swung back (and therefore disengaged from the Pump Lever). If a casting stroke were to occur in this situation, the Pump Lever would descend without the restraint of the Piston in the Pot. This could cause it to break.
It is not necessary to remove the Matrix Carrier from the machine in order to remove the VMB. Indeed, it is good practice to leave it in the machine. If you remove it, there is a chance that you will forget to put it back before casting and therefore potentially cause a very serious injury.
Leaving the Matrix Carrier in the machine during this procedure is also in line with the Skyline Type Foundry policy (and very good idea) that during operation (vs. maintenance) the operator should always keep the matrix carrier either properly secured in the machine or held in the hand. An operator may never set the Matrix Carrier down and release their grasp on it. Ever. Cleaning the VMB is an operating procedure, not a maintenance procedure, so this rule applies here. See the Notebook ../ Safety 2: The Matrix Carrier is Always In Your Hand or In the Machine.
This is discussed fully in ../ Swinging the Pot Back and In. This is just a summary here.
You are about to swing the pot back. If the pot is melted down and the Choker Valve is leaky (or, worse, stuck open) then this could result in an immediate flow of typemetal from the Nozzle. Be prepared to execute the standard emergency procedures for a leaky or stuck nozzle if this is the case. Never swing the Pot of a Thompson back when it is melted down unless you know exactly how to respond to this potential emergency and are prepared to do so.
After swinging the Pot back, it is a good practice to clean up the machine generally, paying special attention here to the area around the Mold and Receiving Plate/Shoe and to the "deck" of the machine. However, DO NOT at any time put your hand underneath the nozzle. It may at any time drip molten typemetal.
The direction the Handwheel turns to back up the machine is counterclockwise as viewed from the right side of the machine; that is, the top of the Handwheel moves toward the operator at the front of the machine.
The left one shows the Type Body Piece fully extended, having delivered the last piece of type under the Type Receiving Shoe. The Handwheel is at 12:00 in this position. The right one shows the Type Body Piece moving back into the Mold, but not yet clear of the VMB.
The motion of the VMB is controlled by one of the main cams, a2TC11 (Vertical Mold Blade Cam). The motion of this came is transferred to the VMB by a two-part lever. This lever is composed of a53TC1 (Vertical Mold Blade Cam Lever), which engages the Cam at its lower end, and 52TC1 (Vertical Mold Blade Lever), which engages the VMB at its far end.
In operation, these two levers are locked in a fixed relationship with each other. A tab on 52TC1 (VMB Lever) fits between two projections on a53TC1 (VMB Cam Lever). The exact position of this tab between these two projections is controlled by two screws: 53TC2 (Upper Adjusting Screw for VMB Lever) and 53TC4 (Lower Adjusting Screw for VMB Lever). In the colorful terminology of Skyline Type Foundry, 53TC4 is the Flying Saucer Screw, for reasons which are apparent when it is seen. The Upper screw, 53TC2, is secured with check Nut 53TC3. The Lower screw, 53TC4, is secured with a Clamping Screw a53TC5.
The purpose of the next few steps is to loosen this arrangement so that the VMB Lever may slide to the left. By loosening only one of the Screws, the existing relationship of the two Levers is preserved (though of course one should never count on this).
Step 9. Using the long 1/2 inch end wrench, loosen the check nut 53TC3 (Upper Adjusting Screw Nut) on 53TC2 (Upper Adjusting Screw for Vertical Mold Blade Lever). It is not necessary to restrain the Screw 53TC2 from turning while doing this (as we are not attempting here to preserve its adjustment).
Step 10. Using a pin wrench, loosen the knurled Upper Adjusting Screw 53TC2 itself. You don't need to loosen it very much; we're just trying to get enough clearance to allow the Vertical Mold Blade Lever 52TC1 to slide (as described later).
Step 11. Lift a76TC10, the Pump Cam Lever Yoke. This Yoke is just a spacing piece which helps to keep the VMB Lever in place. In the photo below left it is shown in its regular, lowered, position. In the photo below right it is shown raised.
Step 12. Slide the Vertical Mold Blade Lever to the left. It will probably take a bit of wiggling to do this. The purpose of sliding it to the left is to free up the VMB Lever Lifting Block (52TC2), which is a rectangular block at the far end of the Lever which engages a rectangular recess in the VMB. Once the VMB Lever Lifting Block is disengaged from the VMB, the VMB may be moved by hand up-and-down to any position.
The photo below left shows the VMB Lever moved leftward. It is of course taken from the front of the machine. The photo below right is taken from the back of the machine. It shows the rectangular block of the VMB Lever Lifting Block as attached to the end of the VMB Lever. As shown, the Block has just been moved free of the rectangular recess in the bottom of the VMB.
The vertical motion of the VMB is adjusted by three gibs. Two of these do not concern us here: 54TC30 Mold Stand Gib (for 47TC1 VMB), which bears on the front of the VMB, and the often overlooked 54TC27 Mold Stand Supporting Plug (for 47TC1 VMB) below the Mold on the right side of the VMB.
The gib which is important here is not actually called a "gib" in the Lanston documentation. It is 54TC21, Mold Stand Adjusting Shoe (for 47TC1). However, since it is the largest and the most frequently adjusted of these three, it is common to call it simply the "VMB Gib" despite official Lanston terminology. It is located on the left side of the VMB (left as viewed from the front of the machine)
The 54TC21 Mold Stand Adjusting Shoe is itself adjusted via an Adjusting Screw, a54TC23, which runs diagonally from the front of the machine to the left of the Matrix Carrier. This Adjusting Screw, once set, is retained by a Lock Nut (Knurled), a54TC24.
To allow the VMB to be moved freely by hand, it is necessary to loosen this Adjusting Screw. It will also prove useful later in the process to use this Adjusting Shoe / Screw to hold the VMB at intermediate positions.
The photo below shows this Adjusting Screw and Lock Nut (Knurled). As can be seen, it is a diagonal screw located just to the left of the Matrix Carrier and just under the two screws of the Type Receiving Shoe.
At this point, the VMB can be moved freely by hand. But if the machine is hot, do not just try to pull it out. There is a specific procedure for removing a hot VMB, and failure to follow it might result in burned fingers and a VMB flung to its destruction across the shop.
IMPORTANT: If the machine is in operation, the VMB will be too hot to hold or handle with bare hands - easily 500 degrees or more. It will also be oily and very slippery. As noted earlier, you should not just grab it and try to pull it out. Also, it is essential that you have a place prepared for it on the bench before you attempt to remove it, and that you have rags available to protect your hand when handling it. Do not wait to do these things until after you've started, because even with your hand protected by rags you will only want to hold the VMB for a short period of time before setting it on the bench.
Step 14. Using the L-Tool, lift the VMB partway up. To lift, hook the L-tool in the recess at the bottom of the VMB (see photo below left). Lift the VMB up high enough to expose the small circular hole in the back side of the VMB (see photo below right). Then secure the VMB in this position by tightening the Mold Stand Adjusting Shoe ("VMB Gib") Adjusting Screw. You need not use its Lock Nut, as this is just a temporary positioning.
The following procedure is suggested if you are right-handed. First, have a good rag in your left hand so that you will be prepared to receive the VMB into your (protected) left hand. Then, using the L-Tool in your right hand, hook the tip of the L-Tool into the hole in the back of the VMB and raise it up into your waiting (protected) left hand. If it sticks on the way out, wiggle it a bit. Then carefully and quickly place the VMB on the place on the bench you have previously prepared for it.
The photo below left shows the L-Tool hooked into the VMB. Below, right, it is shown on the bench (in this case the top of a former Linotype operator's cabinet being used as a "Thompson tender"). Its temperature is still several hundred degrees; you can see the oil glistening on it.
Step 16a. If you have not already done so earlier in this procedure (or if it needs it again), clean the machine generally, paying particular attention to the area around and in back of the Mold and Type Receiving Plate/Shoe; also clean the "deck" of the machine (but do not ever put your hand under the nozzle, as it may drip typemetal at any time).
Step 16b. If you have not already done so, clean the Nozzle Plate (removed earlier) with a rag (and possibly scrape with reglet if anything on it is recalcitrant). Then dress with Mold Polish. (Take a very small amount of Mold Polish on a short piece of reglet and polish the Nozzle Plate with it. In time the reglet will become so charged with Mold Polish that it will be necessary to add more to it only occasionally.) Clean off the Mold Polish with a rag.
Step 16c. Clean the oil passage in the Bottom Block of the Mold (now accessible through the VMB's "slot"). Use a dental pick. This oil passage is the only way in which oil can get from the Sight Feed Oiler to the right side of the VMB. Clean the oil grooves on the Bottom Block of the Mold. Use a dental pick and toothbrush.
The two photos below show "before and after" views of the Bottom Block of a mold. (They're of a different mold photographed in a bench setup for a different project, but they show the issue clearly.) In the photo on the left you can see a mass of typemetal on the Bottom Block which completely obscures the oil passage. In the photo on the right everything has been cleaned up (and I've changed the body size to 36 point, but that isn't relevant here).
Step 16e. Clean the area under the VMB. Note that there is a screw directly under the VMB, held in place by a checknut. The position of this screw determines the lower travel of the VMB. It is very important that the top of this screw be clean. Note A: The clearance between the top of the VMB and the Type Body Piece as it slides above the VMB is 0.004 inches; accumulated swarf on top of this screw could raise the VMB in its lowest position so that it is struck, under power, by the Type Body Piece. Note B: There is no "give" in the VMB Levers as they bring the VMB to its lowest position; accumulated swarf on top of this screw will stress, and possibly damage, these Levers. It is a good practice as a last step in this cleaning to run a rag through the Mold Stand over this screw.
Step 17a: Hold it with a rag in your left hand (assuming you are right-handed) and use the L-Tool to lower it. When you have reaced the limit to which you can lower it with the L-Tool, tighten the Mold Stand Adjusting Shoe Adjusting Screw ("VMB Gib") to hold it in place.
Put the pin wrench and the 1/2 inch wrench away. This signifies that the VMB Lever has been returned to its correct position and secured. (Some of the other "tool return" steps may have seemed obvious - it's easy to see that you forgot to put the VMB back in. This step is not obvious, "hides" in the depths of the machine, and is easy to forget - yet failure to perform this step will result in damage to the machine. This is why the "tool return" regimen is important.)
Step 22. Tighten the Mold Stand Adjusting Shoe ("VMB Gib") by tighening its Adjusting Screw a54TC23 until it is "just tight." (Lanston Monotype's term for this is that it should be "brought to bearing.")
Step 25. If the machine turns over smoothly, adjust the tightness of the Mold Stand Adjusting Shoe Adjusting Screw. This is largely a matter of feel. It is easy to tighten this Screw so tightly that the machine cannot turn over by hand at all; this is too tight. Remember also that as the VMB heats up it will expand, which will tighten this adjustment further.
Step 26. Tighten the Lock Nut (Knurled) for the Mold Stand Adjusting Shoe Adjusting Screw. Sky emphasizes that this is an extremely important step. It is easy to forget, and there is no tool to correlate it with. Yet forgetting to do it will result in a squirt.
This is discussed fully in ../ Swinging the Pot Back and In. This is just a summary here.
Step 27c. Swing the Pot in, using an appropriate tool to ensure that the Pump Lever is correctly engaged. Ensure that the Pot is locked up properly. Ensure that the Nozzle Plate is firmly seated (wiggle it with the forceps/tweezers).
Note that if you are casting narrow set widths, the time taken by this entire procedure may have allowed the Mold to cool too much for casting. If this is the case, you have two options: You can simply wait for it to heat back up (but this may take some time). You can also change the set width to something sufficiently wide (e.g., Em width, or 12 point, whichever is larger) and cast a number of throwaway types on this measure with the existing matrix. The purpose here is just to heat up the Mold.
All portions of this document not noted otherwise are Copyright © 2012 by David M. MacMillan and Rollande Krandall.
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