Principles and Operation of the Ludlow


Ludlow Slugs
Ludlow Slugs

In comparison with other typecasting methods, the Ludlow is very simple.  The Linotype and Intertype need around 6 feet square in which to operate and demand matrices and a mechanically complex machine; the Monotype needs a separate keyboard and caster.  Both need to stop the machine and make mechanical changes to change the type face and the length of the line; and both are expected to be supervised by a specialist.  By contrast the Ludlow was designed to be operated by any of the composing staff.

There are two main activities: assembling matrices and casting.  Matrices (or ‘mats’) are stored in special sloping cabinets, and are collected by hand.  Experienced users can gather more than one mat at a time and because each mat is a uniform size and easy to handle, this process is quicker than composing type from a case.  The mats are assembled in a ‘stick’: a metal frame with a moving end.  Different sticks are available for different purposes: ordinary sticks, justifying sticks, italic sticks, long sticks and self-centering sticks.  The moving end is brought tightly against the end of the matrices and this forms a single, solid line of moulds to receive hot metal.

The next step is to insert this in to the machine.  The Ludlow machine resembles a large table around 4 feet high with a pot of molten metal at the back.  The table lid opens up to reveal the workings of the machine, based around a main shaft driven by a small motor.  The cams on the shaft invoke a number of operations: including moving the pot, forcing hot metal in to the matrices through a mould, removing the pot, trimming the edges of the slug and ejecting it at the front of the machine.  At the same time, electric elements keep the pot of metal hot, and also circulate cool water to key parts of the machine.  The operator slides the stick in to the machine top and operates a catch to secure the stick but also to release the safety mechanism.  On pressing a lever under the machine lid, the cycle begins and a new slug of cast type is ejected at the front of the machine.  The stick is released and the operator can distribute the mats back in to the cabinet.  A setting on the machine front allows for repeat castings to be made: especially useful if printing two-up or other multiples on a single sheet in a single impression.

Because the most complex operation — the assembling of mats — is delegated to a human, it’s possible to achieve a much greater flexibility than other systems: multiple sizes and styles of type can be cast in one operation without a need to change the mechanism of the machine.

In terms of output, the machine produces everything on a single slug size, typically 21 or 22½ ems long by 12 points wide.  Other moulds are available, but this approach helps in handling the slugs during imposition and lockup; and avoids the need to change the machine while casting.  Types larger than 12pt will overhang in a ‘T’ shape: up to 144 pt will sit with just a 12pt support.  To help during printing, ‘blank’ slugs can be cast to go under the overhang and support the face.  The face is 0.153″ deep, and so much thicker than the equivalent from Linotype or Intertype.

For longer lines of text, special long sticks are available along with special stops.  Text is set with stops roughly where the slug would end.  The first slug is cast, the stick advanced to the next stop and the second slug cast and so on.  This produces slugs that might have the face of the text overhanging at the left or right, but a corresponding gap on the next slug.  When assembled, the gaps between slugs become invisible.

Operation of the Ludlow

When dealing with hot metal and powered machinery, I’d always prefer to call on the experts to demonstrate before I start work.  That said, there are some excellent guides to using the Ludlow, some online, some off-line.

Dr. David MacMillan has scanned and uploaded some excellent Ludlow material to the Internet Archive, they include:

Also available is the Ludlow Troubleshooting Guide from Dave Seat.

Repairs and Servicing

The Ludlow was designed to be easy to use and robust.  It’s crucial that the machine is kept clean and well lubricated to continue to perform.  In the US, Dave Seat is the pre-eminent Ludlow mechanic, and in the UK it is Keith Harding.

Video Guides from Don Black


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