Friday, June 30, 2023

Clipless paper fastener, all-steel version

The all-steel version of the Ideal Clipless paper fastener.

Simply marked as 'Clipless' paper fastener. No longer marked Ideal or 'CK', not marked that it's made in Japan either. The construction and the same Japanese patent numbers however clearly make this the all-steel successor version of the 'Ideal'.

Noticeable corrosion, green felt can be seen in the seam around the edge of the base.

This remnant shows that the blackened steel base would have been covered with green felt originally.

This seems to be a less-common item. The wooden-cased product is described by American Stationer and there is e.g. a specimen in an Australian collection. There is however very little information about this later version, reported to be introduced in 1922.

This all-steel version is actually not so much steel, even though it does give this impression. There still is a wooden block inside as the base of the machine. The nickelled base and cover are actually made of brass, only the bottom-plate is made of blackened mild steel.

Despite its more industrial, mass-production appearance, the manufacturing-methods used in this device suggest hand-work in relatively small numbers.

After a cleaning and oiling, this Japanese version of the ingenious Bump-method fastener works fine. New, green felt of a similar shade again covers the base, fitted in the same way with a draw-string - elegant, that.

Sunday, June 25, 2023

Columbus bilateral letter-scale - repaint and polish

After a repaint and a polish, this little bilateral Columbus letter-scale is very shiny.

This one, like many, looked rather dejected. The brass was severely tarnished from old attempts at cleaning that removed the old lacquer and the cast-iron base was rusty. The pins that hold it all together can however be pulled-out fairly easily to be able to clean-up the individual parts.

The base got to join in the paint-stripping session last week:

The decorations of the base are best visible in the grey primer, just before getting a new coat of glossy black. 

The brass was polished-up, with the remnants of the original lacquer finish removed from the front-face of parts. After polishing, the brass parts were again given a coat of clear varnish to seal the surface as was done originally. Lacquer closes-off the surface to oxygen, stopping or at least slowing down tarnishing.

These small bilateral scales still show up on local classified sites - many were made and they are of course really durable. This Columbus letter-scale was made by the Ph. J. Maul company of Hamburg, Germany. The Maul company made many and diverse scales for over a century - and also made this one, as seen from their trademark on the linkages.

These bilateral scales don't need adjusting against a sloping desk. Because the weights move out symmetrically, it is automatically compensated. This bilateral scale is made to a design that was patented in Germany in 1904. 

This German patent 167,192 was however not by Maul, but by Automat AG in Berlin. The drawings in the patent do illustrate the design, as does the claim of two symmetrical weights rotating on a single axis. 

Possibly that Maul either took a license, or more likely completely took over the production of the Columbus-brand scales of this design from Automat.

Most of these have a brass weighing platform, this one however had a brassed mild-steel platform. The plating was partly gone and the metal rusted. The whole platform was sanded smooth and also painted gloss-black. This is not the original finish but it looks ok again. More importantly, the weight of the platform is not changed too much, so it still weighs correctly.

Perhaps the plated platform is a hint that it was made when brass was relatively costly, perhaps around 1917 to '19 or perhaps during the chaos of 1923. At any rate, it likely is at least a century old.

With small dabs of red paint on the pointers this little device is again good for another century of use. (It has a good chance to outlive the existence of actual letters and postage stamps, but will still weigh things just fine :-)

Tuesday, June 20, 2023

An old refurbishment - stripping off the paint

It looked quite awful, so the housing was taken completely apart. A mottled greyish-brown paint was all over the machine, almost certainly applied during an overhaul in the 1940s or early 1950s. At that time, many old Comptometers were re-furbished (scroll down to 'refurbed machines'), both by Felt & Tarrant distributors and by others. (Oh, and I can confirm that the four sides were not separated for the spray-painting on this one.)

The cork that is glued to the inside of the side-panels (sound-dampening) can be removed - using a sharp putty-knife to break the brittle glue and carefully bending the cork sheets to release them from the fold-over flanges. The top-plate cork is riveted, so that is left on the panel.

To strip-off the old refurbishing paint, a set-up with lye is used. The stripping-tray is the first step; that is a baking-tray with lye or sodium hydroxide or drain-cleaner - on the right. The mixture is made with about 50 to 60 gram of NaOH pellets per litre of water (a bit over 1M) and stir gently with a plastic or wooden spoon. When the solution turns clear again, it's ready for the parts to be placed in the solution. 

The pliers are used to handle the parts, taking care to avoid any splashing or spilling of course. The lye is not too strong, but still best to not get it on skin. In case of mishap, the tub of water is right there. The brush is used to test for softened paint that's ready to come off. The lye solution may take a few hours, but old (pre-acrylic) paint will eventually succumb and come away.

The second process-step is a tub with plain water. This is to rinse and dilute any lye still clinging to the parts as they are taken out of the stripping-tray. The stiff brush is then used to scrubb softened paint from the part in the clean tub of water. If paint still remains, the part is returned to the lye. Parts usually get several repeats before all paint is gone. 

As last process-step the parts are given a final rinse in clean water, dried off with an old towel and placed on the rack to dry in the sun.

On these particular Comptometer panels, the greyish-brown paint came off to reveal the original dark-copper finish. With a quick waxing, the side-panels actually look too good to be re-painted (as originally planned). The rivets in the front S-panel suggest a dealer-plate and the scratching of the rear-panel probably is from removing an inventory label before re-painting. Likely this was a trade-in that got refurbished to be re-sold.

Unexpectedly however, the top-panel was plain steel and not copper-plated. Very likely then that this top-plate is a replacement - after heavy use, the slots can be worn-out to become wider and need to be replaced.

The original plan had been to completely refurbish the machine including re-spraying it in bronze/copper, but with the decent condition of the side-panels, perhaps only the top panels will get a re-paint.

This was a local, low-cost pick-up purchase, that seemed to have all keys still present in the listing. When we picked-up the machine, it indeed had all keys. Unfortunately, at the time of refurbishing this ±1920 model H, the keys were replaced by a then-modern green-ivory set. These are made of very badly aging plastic, the ivory keys basically crumble under so much as a hard stare; it no longer has all keys.

It's all turning into more effort than it's worth for a pretty common 8-column model H Comptometer, but a fun project anyways. This 1920 calculator will get another overhaul now in 2023 similar to the one it got in the 1940s. The housing will be re-finished, mechanism adjusted and all the keytops will be replaced by new-manufactured black-white keytops. (It just won't be used quite as much as it was after the previous refurbishing of the 1940s.)

Wednesday, June 7, 2023

Making new spools for the Hammond typewriter

Spools for the older models of the Hammond typewriter are quite large and made of hard-rubber flanges and a brass hub. Being as exposed on the machine as they are, and brittle too, many spools are broken with sometimes shards missing. That the paper-rest folds down right onto the edges of the spools also won't have helped.

They have a very distinctive design with textured and smooth areas and text around the hub - the spools are a noticeable element in the overall appearance of the Hammond.

Although one of the spools of the Multiplex was 'fixed' with card sections to make it usable, also wanted to try making 'whole' reproduction spools. One way is to make a press-mould from a good original side and then cast new flanges from e.g. sealing-wax or polymer clay - as shown in this video. However, first wanted to try 3D printing a new spool.

Taking measurements from an original, the flanges and hub were modelled in CAD. The lettering was traced manually over a scan of the spool in a vector-editing program. This traced drawing was then exported to CAD to create the raised lettering on the inner plane. A feature not (yet) modelled is the textures. (There is one extra difference between the CAD model and originals, one that'll make them readily identifiable as reproduction :-)

The parts were then ordered 3D printed in black resin. After getting the parts, they needed only minor sanding of the flange-holes to make the flanges a press-fit on the hub: a new Hammond typewriter spool!

With some more sanding, also the hub is a proper press-fit onto the capstans of the machine. In the image below, the reproduction spool is placed on the Hammond Multiplex (right capstan). Compared to the original spools there are differences, but overall the printed spool 'fits the machine'.

The resin printing process created a fine weaved-cloth-like texture over the whole part that actually works quite well. The outer and third 'rings' were lightly sanded. These 'rings' were then given a single coat of black paint to further smoothen and create a visual contrast with the texture of the second ring. This contrast is not as distinct as on the originals, but on the whole it's a credible impression of a Hammond ribbon spool.

This was a proof-of-concept for 3D printing reproduction spools. So far, conclusion of this test-print is that 3D-printing in resin seems to be a viable way to equip Hammond machines with replacement spools - and shortly will give this Multiplex spare spools :)

Monday, June 5, 2023

Sighting of a couple of Sholes and Glidden's and a Writing Ball

Sightings; seen last weekend - Sholes and Glidden typewriter serial number 1681:

Right next to it, another Sholes and Glidden typewriter (or type writer), this machine with serial number 2698:

And only a few feet away an original Malling Hansen Writing Ball. 

These rare machines are part of the typewriter section of the HNF, the Heinz Nixdorf MuseumsForum in Paderborn, Germany. Even though only a small selection of their typewriters (over 500) is on display, there are several rare and grand machines to be seen on display, many in great condition with shiny nickel.

The museum showcases the development of information technology in the broadest sense, from early beginnings all the way up to modern computing. (From clay-tablet to a Cray2 :-) On show are a.o. several beautiful examples of the early stages of mechanisation of calculating, such as this ornate 1855 Arithmometer.

A visit to the HNF had been on the wish-list for some time. The IFHB meeting around the 400th anniversary of Schickard's calculator (calculating clock) held at the museum in Paderborn gave the push to now really go there for meeting and museum both.

Easily spent two days exploring the museum's collection - well worthwhile :-)