Someone had asked me for some parts for their Monotype Compositon Caster. Like me, he has the pump latch mechanism but he’s missing the modified pump spring rod and spacer sleeve, so he asked me to make a set for him, following the model from when I made my own a year and a half ago (see here and here).
New parts are in general not available. They are not being made, and it is a very long shot to get some new-old-stock items from places like the Type Archive in London. As a result, caster parts are often obtained by stripping down surplus casters which have somehow been saved from a trip to the scrapper. The pump latch mechanism, as well as most of the other parts for display casting, are distinctively recognizable for what they are, and generally take up little storage space. The spacer sleeve and extended pump rod are less distinctive, and the rod is bulky to store, and people don’t think of these as parts that break and need replacement, so they are more likely to be scrapped or at least lost in a jumble of miscellaneous parts.
So it is not uncommon to be in the situation of having the pump latch but not the pump spring rod modifications required to use it. To get around this problem when I ran into it, I made my own parts. Now, I’ve made another set of the same parts for someone else in the same predicament.
I have posted a video of me explaining their purpose and test-fitting them to my own caster. It was a good thing I did this because at first, the rod extension would not screw all the way onto the standard spring rod. The female threaded hole on the extension was too shallow, and also was not counterbored to allow for the unthreaded area on the end of the rod. The video wasn’t turning out well either as I found myself babbling aimlessly without some notes to work from.
The video is less than ideal… For part of it I’m showing the relevant page from the parts manual and things are pretty hard to see because the video is only 320×240 resolution, and by the time I noticed how the page would look I was done editing the video. The editor I am using (VSDC video editor) does not allow you to change the basic resolution of a project; you have to choose it when you create the project and live with it. There was quite a bit of cutting and splicing of the video clips and there was no good way to copy all those editing decisions to a new higher-resolution project.
There is one magic spot where my hand vanishes from the picture, only to come in immediately from the side again.
That strange facial expression where I seem to be peering just to the side of the camera is because I had my laptop there acting as cue cards.
One other note about the video: I mention using a temporary thread locking compound when joining the extension to the spring rod. This is so that you don’t later find the extension left behind if you remove the rod (the extension by itself would be difficult to remove from the caster because it would be almost completely inaccessible with any form of wrench). Something like Loctite 248 (the blue stuff) would to the trick. I don’t recommend a permanent thread locking compound (like Loctite 263 red) because then you would never get the parts apart. Also, only use the thread locking compound to join the rod to the rod extension. Do not use it anywhere else, particularly where the rod screws into the rod eye below the upper crosshead!