Finishing the refurbishment of a Dalton Adding Machine

The surplus wreck Dalton is now refurbished, quite the transformation from what it was :)

The machine was cleaned inside and outside. The brightwork was de-rusted and all outer parts re-painted. With a few small repairs to its mechanism too, it can now be properly called: refurbished.

To complete the refurbishment (or restoration), the front and rear panels were re-painted and new gold decals applied. The number-keys were replaced, and as final-step fitted with new rubber feet.

Panels with decals

After some hesitation, also the front and rear panels were stripped down to bare metal. 

These panels have the gold lettering with the Dalton logo. The front decal had been severely degraded, but the rear had fared a bit better. Both in the end were removed to re-paint the panels in gloss black.

There is some variation in the exact shape of the Dalton script logo on machines. Suppliers of these decals maybe made their own cliches for this - or the Dalton company was simply 'vague' on an exact script. 

Just picked one design of the mid 1920s and created reproduction decals. The lettering on this front decal should have been a tad smaller, and the second-line should've been slightly smaller than the first. But as Dalton varied their decals too, deemed good-enough.

The yellow part of the image of course done in gold, not yellow. And the rear-decal design:

Decals printed on waterslide transfer paper as previous projects, filled with gold-paint and then applied. More softening-liquid and a lacquer clear-coat will make the film less visible. Viewed from the front it is already quite passable.

New number-keys

The wreck had ended up with the worn and damaged keys. To complete the refurbishment, a new set of number-keys were manufactured. Copies of the designs were modelled in CAD (FreeCAD). 

These designs were then 3D printed in FDM with a 0.4 mm nozzle, so fairly rough and fast prints - printing with a fine nozzle or printing in resin would create much finer detail. Even though these are relatively 'cheap-n-cheerful' replacement keys, they do look the part already.

Visible layering at the top-surface was of course sanded smooth and the keys were painted off-white. They were already printed in white PLA material, but an extra layer or two of paint makes them more opaque and also smoothens any remaining layering. The lettering was filled with red and black paint.

There are some minor mistakes in these keys so they may yet be replaced with slightly better copies, but for now they'll do.

(The 'clear-signal' indicator just above the keyboard here shows that 4 digits have been entered. This indicator was also given a new, laser-printed legend and the yellowed celluloid window replaced with a clear acrylic reproduction.)

New feet

From images in contemporary publications, these Dalton Super Model machines would have come with rubber feet. 

These feet were a little larger than the metal 'stub' and look as if less than half their diameter in height. The 'stub' at ~23 mm diameter, the factory-fitted feet were likely one inch diameter and, say, perhaps 7/16" in height.

Online there's a wide range of rubber feet - a set of 25 mm x 10 mm feet were sourced and screwed to the machine. It sits very solid, no skidding! It also transmits the sound very well into a table; definitely louder than the makeshift cork feet. Dalton's are loud machines. (Cork could've been a good choice for feet after all!)

Refurbished Dalton Adding Machine

This is the simplest, lowest cost 100-dollar 'Special' of the Super Model range. As such it is a fairly common and perhaps not very interesting machine. Indeed, these Daltons are today not very desirable or valuable; it's debatable if this was 'worth the effort'

Nevertheless it's historic digital-technology and an example of the state of office automation of 100 years ago. More than a photograph or document, it can be experienced and operated. As such it perhaps is worth preserving - plus of course that it simply was an enjoyable project!

(As always; after completing the process, then there is the insight in how it should have been done. A next Dalton refurbishment will be done better ;-)

Good advice for the Hammond typewriter

When delivered new in the 1910s, a Hammond typewriter would have had a 'Special Notice' card placed on its keyboard-card tray. It contains some useful advice for typing on the Hammond and especially on where to oil it occasionally (and where not).

From a couple of pictures found online of miraculously surviving specimens of this card, a quick re-creation was made and printed on heavy, ivory paper. Dimensions approximately 23 by 5 cm or about 9 by 2 inch:

Unlikely to remain on the machine, but good advice nonetheless :-)

Folding Corona - as simple as closing a book

(Full-page advertisement from the February 1920 issue of Popular Science, page 153.)

Or is it.

It's intuitive and folding over works. Just like closing a book. Unlike a book however, the Corona should ideally have its carriage locked in the correct position and its shift locked.

The many images of folded Corona 3 typewriters, both online and in print, suggest that often the shift is not locked - and the rear folding-beams pop back up.

When the shift is locked however, the Corona 3 typewriter folds very neatly flat.

The locks also reduce strain on the machine when it's in the carrying-case. 

Folding Corona - almost as simple as closing a book ;-) 

Progress in refurbishing a Dalton Adding Machine

The 'surplus' machine is mostly assembled again - and the side-frames are back, painted black.

As the machine shows promise of turning out nice, decided to have another try at repairing the damper or dashpot. Especially because the manual even instructs to pull the lever forward and then let go. With an empty dashpot, the lever slams back - not nice and not great for the mechanism.

With the machine already mostly assembled, it was still possible to take out the damper. The sideframes can be left, but the top-cover and printing-mechanism and spool-plate are best taken off. Then remove the screwed pivot-rod that holds the top of the damper and at the bottom first loosen the lock-nut (fiddly) and then remove the screw. The damper can then be manoeuvred out of the mechanism. After another failed attempt with heat to unscrew the tubes, went the radical approach and drilled a hole in the side of the upper-tube of the damper. That spot should be still above the piston at the extreme extended-position, so relatively 'safe'.

After filling the dashpot with sewing machine oil, a light 'paraffin oil', it started to work quite well as a damper! The hole is above the oil-level too, so not critical. It was threaded and closed-off with a screw and washer+gasket. (Threaded with 5/32" Whitworth because that was the tap-set I had handy -and a new, brass Meccano 37b is the plug :-)

When again fitted in the machine with the top-cover in place, this filling-plug is not visible. Most importantly; it is now safe to let go of the lever after the forward pull, as per instructions. The lever will move back swiftly, but without the hard slamming.

Even though this 'wreck' Dalton appeared to be fully working, there are several small malfunctions only discovered during the refurbishing. Like e.g. the peg-board carriage making a half-movement at the 8th digit, or the non-print button failing to re-set after a stroke of the handle.

The non-print button can be pressed down with the thumb when starting to pull the lever (very ergonomic, well-designed!). When pressed-down it is latched in the down-position and should pop-up again after one stroke of the handle. 

This is achieved by the tip of a conical 'stud' that pushes the lever off the 'latching-notch'. Maybe this mechanism got deformed (this machine got knocked-about at some moment during its ~100 years), or worn down, but it didn't push the lever back enough. A few layers of copper-tape were wrapped about the tip, to give it an extra .3 mm or so.

With this little fix, the non-print is again pushed forward just enough to pop back up at the end of a stroke.

An obvious 'fail' that was also remedied, was a flat feed-roller. The front feed-roller of a Dalton is pretty small and after 90+ years the rubber will invariably be flat. The larger-diameter rear-roller was fairly round still, left as it was.

The front-roller was stripped to the metal core and given a few layers of heat-shrink tubing, per usual method. Re-assembling the 'carriage' is surprisingly tricky; the factory must've had a handy jig. After several tries it came together and now line-feeds as intended.

Overall, this new (in 1921) Super Model range is pretty impressive. It has a reassuring amount of interlocks and even this most-basic version looks fancy with that "Damaskeen finish", as Dalton called it.

Progressing to a refurbished, fully functioning Dalton :-)

Fall 2024 typewriter safari

Last week, we did a tour of the local thrift stores - and for the first time in ages there were interesting typewriters! Right at the start, first aisle, this spread of four machines immediately caught the eye.

The Olympia SM1 was the most appealing of the lot, probably an early 1950s machine. As a postwar drab-green (but with fancy chrome) it is out-of-scope for the collection. It also had minor rust all over, even a dusting of oxide on the segment. Its German keyboard then was the deciding factor to leave it there.

The fourth machine in the scene was the solid Olivetti 80, bashfully hiding behind a toy ironing board.

On another set of tables was the usual assembly of beige machines. These seem to be a fixture in the store, or of course they do sell and get replaced by similar-looking typewriters.

And then at the end of the aisle, another Olivetti Lexikon 80 with some damage and very stiff.

It was kept company by a massive Adler standard in a sorry state - painted all-over with a chalky white paint. It may perhaps find its spot as an interior decoration item (and cheaper than those modern 'typewriter' decor items, a lot heavier though) - scrap metal is a likelier destination though.

No machines were taken, but a reason to have an occasional look-round again :-)

New typeshuttles for the Hammond - How to make

After some experimenting (and many failures), the workflow for creating new Hammond typeshuttles is starting to form. 

A new Hammond typeshuttle is assembled from several parts, just like the original. The individual parts have to be modelled, manufactured, finished and then assembled.

The core of the original shuttles (above) were two nickelsilver strips; one as flange to ride in the slot of the anvil and one curved 'vertical' that was embedded in the vulcanised rubber. The vulcanised rubber is the actual black bit of the shuttle that contains the characters or typeslugs, impressed from the mold. A small metal 'grip' collar was fastened with two rivets to the flange as take-up for the machine's driver-arm. An original Hammond shuttle could thus be seen to be made up of 6 different parts. These parts and materials all have different properties - also needed for their function. 

In re-creating a Hammond-compatible typeshuttle is is also necessary to build it up from different materials, with different properties.

Build-up of new shuttle

The new typeshuttles are built up of the shuttle-strip that contains the characters, a steel flange and a small take-up collar. The 3 parts are glued together, optionally held in a jig for correct shape and alignment.

 

Grip

The small take-up collar or grip is 3D-printed in PLA material on an FDM printer. Using a 0.2 mm nozzle, a precise and fine part is printed, with PLA being very strong at room-temperature and highly impact-resistant. The part is small, so even with a 0.2mm nozzle the printing is fairly fast. Optimal results from printing by-object, no finishing should be needed.

Flange

The steel flange is laser-cut from 0.2 mm stainless steel. These were ordered from a local shop, that does lots of laser-cutting. The parts are perfectly flat and were cut with an industrial-quality machine under protective gas so no cleaning or finishing is needed. Ordering a batch of these can make it quite reasonable and relatively affordable. (I.e. in the context of a Hammond typewriter :-)

Assembly jig

The assembly jig is optional; the grip, flange and strip have alignment features that enable correct assembly. For especially the resin-printed strips however, it may be essential to re-shape these with the jig. Resin-prints have residual tension and the curvature of the part as it emerges from the printer after cleaning off any supports is not reliably correct! The jig is not too critical and can be simply printed with a 0.4 nozzle on any FDM printer.

The model-files for these parts can be downloaded here.

Shuttle strip

The shuttle strips with characters are generated using a scripted 3D modeller. There are several of these programs, in this case OpenSCAD was used. The script was created for the current 'stable' release and everything was kept in one file without external dependancies (except of course the font-file). This should make it reasonably robust and easy to get working anywhere to generate a printable model. (Development-builds have some new features that could really help in creating better, nicely aligned, monospaced type.)

The script contains already a couple of layouts, selectable by uncommenting a single line further down. This selection-line also includes several extra parameters, optimized for that specific layout (the obvious one being number of rows). Some of the available layouts illustrated in 'preview', i.e. not yet with the type mirrored:

The script also contains lines for selecting a typeface, a font file that has to be present on the computer and available to OpenSCAD. This can be 'tricky' and may require tweaking to properly fit all the characters on the shuttle. Not every font contains all characters (glyphs) that are needed for a layout. Fontfiles also contain errors; the character may display fine on screen, but a small error can prevent the character from being able to be generated as a 3D typeslug.

Generating the actual, correct 3D model from the script is a computationally intensive task. Even on a fairly fast computer it will take several minutes, up to half an hour - depending on the complexity of the typeface. Every character is generated from the glyph in the fontfile with a tapered base. This taper is done for strength, naturally, and also to enable the 3D printing process to generate the shapes (limit overhang-angles).

There is the option in the script to generate a file for resin-printing - permitting fine detail - or for FDM printing with additional bed-adhesion features. The model generated for FDM also contains modifications to the 3D model geometry to compensate for limitations of the FDM process itself.

The shuttle strips will need some finishing after they've been printed; supports and adhesion-feet will need to be removed. Any remaining marks should be sanded smooth. Especially the inner curved surface must be made very smooth and clean; this has to slide over the anvil. FDM-printed strips in PLA are generally pretty good on dimensions and have the correct curvature, but resin-printed strips will need some time in the assembly jig to be 'bent' back into shape - the material does relax and settle in the correct shape after an hour or so.

The STL 3D-model file for an English Universal shuttle strip with a regular Roman typeface can be downloaded here for resin-printing and the file for FDM printing with a fine, 0.2 mm nozzle can be downloaded here.

The OpenSCAD script file has embedded comments that should help understanding what everything does, and what parameters to change when creating new shuttle models. It also should make is fairly easy to expand and adapt for new layouts or otherwise improve upon. The version of the shuttle strip script used to generate the above models can be downloaded here. (Whilst it is commented, the code itself is not very good. There is sloppy parameter-passing, many variables are global and used throughout. The code could do with re-factoring and probably be optimised for speed. I.e. options aplenty to tinker and improve - but it works. My Mignon type-cylinder code is much cleaner, having learned :-)

Assembly of the typeshuttle

Having a properly smoothened strip, a flange and a grip, these can be placed in the jig.

To fix the parts, a drop or two of cyanoacrylate glue are applied with a toothpick to where the flange sits in the strip's groove. 

Capillary action and some help from a scrap bit of card will spread the glue over the entire length of the shuttle. (Picture below was taken when the ends still needed a proper push into the groove.)  Despite its reputation as fast-setting, allow several minutes (hours!) for the cyanoacrylate to properly harden out.

If everything went fine, then the newly assembled typeshuttle should fit on the anvil on a Hammond typewriter. It should slide around freely without any binding. If there is binding, the shuttle strip may be a bit deformed and need further sanding - this is actually fairly likely with resin-printed strips, FDM strips usually are fine as are. The grip may also need a bit of smoothing on the side it runs against the inside of the anvil - e.g. run a bit of sandpaper (180 grit) through the shuttle against the sides to smoothen all surfaces.

With all this done, the Hammond typewriter has another typeface added to its repertoire ;-)

As warned by the Hammond company; do not use oil on the shuttles - if wanting to lubricate, perhaps apply a little talcum powder. It should run fine without any lubrication though.

In conclusion

With the above workflow, new typeshuttles can be made for the Hammond typewriter. It thus becomes possible to use the antique machine without risk of damaging an old, original typeshuttle. The original shuttle's hard-rubber is relatively brittle and can easily crumble or chip. It's also possible to re-create shuttles with otherwise rare typefaces or layouts - or make shuttles with completely new layouts and typefaces.

Creating these new typeshuttles was only possible by building on top of the awe-inspiring work done in making new Selectrix typeballs; especially the work and example code of Dave Hayden of selectricrescue.org was instrumental in getting things this far. Sharing experiences and discussing designs with Leonard Chao really helped getting it all to work. He's been doing amazing work on 3D printing new Blickensderfer cylinders and Hammond shuttles too!

And of course made possible by open-software design tools OpenSCAD and FreeCAD.

The ability to make new shuttles should enable Hammond typewriters to continue typing far into the 21st century; usable Hammond typewriters! :-)

Dalton Adding Machine serial numbers, estimated agelist

An estimated, approximate agelist for Dalton Adding Machines; serial numbers are start-at for the year.

The ~1927 issue of Business Machines and Equipment Digest contains an estimated serial numbers agelist. This list with details about changes over the years was likely provided by the Dalton company itself. 

Taking this list as a starting point, a full agelist with serial numbers from the start of production in ~1907 to the end around 1933 was estimated.

Added were any hints from period literature (e.g. start of active marketing), advertising and competition. E.g. the introduction of the Special 100-dollar Dalton was very likely the direct consequence of the Burroughs Portable being introduced in 1925 for 100 dollar.

The Dalton machine was probably also expensive to manufacture, relative to the Burroughs Portable. Even after the re-design into the Super Model range; this replaced many castings with stamped parts, but the machine was still very heavy for its capability and remained fairly complex in assembly. The Special being offered for 74 dollar via Sears in late 1929 must have been bad for margins - Dalton was likely losing badly from Burroughs by then and perhaps 'desperate measures'. 

The Brennan, despite its unfortunate launch-timing in 1929 was a 'better' machine than the Dalton. It will have been significantly cheaper to manufacture, was more compact and offered roughly the same functionality. Even though adding machine sales overall probably 'tanked' the years after the Wall Street Crash, the Brennan would have been a competitive 10-key offering versus the by-then aged (old-fashioned?) Dalton. (Notable that Remington-Rand hardly used the Dalton brand for their new Portable adding machine, but instead mostly marketed these from around '32 as Monarch or Remington-Rand.)

The published agelist in the Digest shows an overlap of Old Style and Super Model production - putting this in a graph gives a good impression of average annual volume of Dalton. It also suggests that annual sales of the Dalton company were probably around USD 20M at its peak.

The serial numbers after ~1929 become more uncertain and rough estimates. The company probably struggled as part of Remington-Rand, but would surely have continued to manufacture and sell machines right up to the switch-over to the Brennan-derived machine. Doing a quick inventory of machines that can be 'sighted'; the serial numbers probably did not go much beyond 212,000.

The sightings also give a clue to the different color-schemes of Dalton machines. From the start of production up to around 1926 the machines are lacquered plain black. In 1926, there was a switch to a crackle black and for the Special machines a 'crystalline green' finish. The Specials were finished in green for several years, but not all Specials - there are also crackle black specimens.

Then in 1928 Dalton switched to the brown woodgrain finish - judging from typewriters in woodgrain finish, that was just about then becoming very fashionable (and practical for manufacturing).

With more data and analysis, the agelist and e.g. the chronology of finishes can certainly be corrected and improved upon - this is a quick, first guess/estimate.

Anyways distilling all this; an estimated (!) agelist for Dalton Adding Machines :)