Checking the oil-level in an adding listing machine

An old Remington Portable adding listing machine (or Monarch, Torpedo or Dalton) may actually need its oil level checked. Like most mechanical lever-operated adding machines, the Portable has a dampener to control the return-stroke and prevent the machine's lever from 'snapping back'.

The dampener is the metal 'pot' visible at the back of the mechanism on the right-hand side.

The metal 'pot' contains oil, the damper-rod rotates a vane inside the pot against this oil (and a baffle) to regulate (dampen) the speed of the machine. After 80+ years, it may be that the oil-level inside the dampener is low - oil may have escaped (evaporated) via any small gap, e.g. the fit of the rod in the pot. When the vane is rotating in air instead of oil, it of course doesn't work as intended.

The dampener is fortunately designed to be topped-up. It has a filling-plug!

The screw on top of the top is the filling-plug - allowing a check on the oil-level (insert pin, dipstick) and for re-filling the dampener. This machine 'snapped back' with alarming speed, perhaps risking damage to the mechanism. The oil-level in the dampener was indeed low, perhaps half full. 

To re-fill the pot, new oil was inserted with a syringe.

After re-filling the dampener this Dalton (or Remington, Monarch, Torpedo) Portable adding machine no longer snaps the lever back when you let go on the return-stroke. It still returns quickly, but now controlled with an even speed to the rest-position - as designed.

Not an obvious thing to check and uncommon on e.g. typewriters; when an old mechanical adding machine's handle snaps back very fast and hits the end with a clear 'impact', it probably needs its oil-level checked :-)

C-key for the Remington Portable adding machine

The Remington Portable adding machine of the 1930s has a C-key protruding from the front. This C-key has a pointer to indicate the position of the next digit, pushing it to the right allows clearing an entered number from memory: marked C for Correction. These adding-listing machines can be branded Remington, Remington Rand, Monarch, Dalton, or Torpedo; and before the purchase by Remington of course Brennan. The C-key should all be identical, no matter what a particular machine is named.

(The C-key shown above is an original.)

The key itself is a press-fit onto a short stub of a stem. This stem slides into a pocket in the machine, attached to the machine's pin-bed memory. This key needs to be pulled-out to take off the machine's housing, it is only held in clamped by a spring. 

Being exposed on the front and also very easily pulled-out, these keys and/or stems are frequently missing from these adding machines.

A missing stem could be re-manufactured from a bit of mild-steel or brass of ~1.3 mm thick (probably 1/10th of an inch, but 1mm brass would also be fine). The tab that holds the key is bent 1 or 2 degrees up, tilting the top of the key slightly towards the operator. The V-shaped indents on the main ~11mm wide length that goes into the slot is where it is gripped by a spring. Below scan shows the overall shape of this stem with the main dimensions:

To replace a missing key itself, a CAD-model was made of this C-key's pointy-design:

With this 3D-model of the key and a good FDM-printer, this little pointy-key can be 3D-printed without any supports:

Printing with a small layer-height (0.1mm or less), the amount of visible layering is not too great. One or two layers of hobby-paint will mask any layering and will create a smooth, glossy key. The lettering then  picked out with white (or cream) latex paint.

(The C-key show above is a reproduction.)

Now the entry can be cleared again also on this 1930s Dalton-branded Remington Portable adding machine.

With their catalogue picture (calipers were expensive)

Browsing, noticed that both my calipers are shown on this same page of a 1950s workshop tool-catalogue. The illustrations show pretty much the exact, same instruments.

This catalogue also showed that also the little brass pocket-caliper was a fairly expensive item back in the 50ies - listed at Hfl 4.43.

The larger vernier-caliper was even more expensive at Hfl 14.29 -that's a significant amount of money (or rather, it was back then). A loaf of bread would have been around 20 cents; so using the loaves-index the vernier-caliper was a little over 70 loaves. With today's price for a loaf of 2 to 3 Euro, that translates to around 175 Euro (or Dollar) in today's money. And that's the plain steel version, nickelled it was 2 guilders more; around 200 Euro.

These two calipers were expensive instruments when new. But as now proven, these instruments can last decades. The vernier's scale is adjustable and the instrument is still quite serviceable. Expensive, but probably good value for the money :-)

Octagonal complement-key (for the Burroughs Class 5 machine)

A fancy shaped octagonal keytop without any text, a blank key.

That is the CAD-model for the top-left key of a Burroughs Class 5 Calculator. As is well-described elsewhere on the internet, this machine was a direct competitor to the Comptometer. It was cheaper and lacked the carry-suppression tabs. This means that when subtracting with the complement-method, zeroes (i.e. the 9-key) need to be added all the way to the left of the register. That is why the Class 5 has a lone 9-key over the 10th register position; as seen here in the image from 1927 advertising material (see the complete page at rechnerlexikon).

This key is only for chasing the overflowing, fugitive '1' out of the register. So it does not have any marking. It is a blank version of the same octagonal pattern as the rest of the keyboard 9-keys. This is more clearly visible in e.g. this snippet from a 1921 advertisement (see complete page at rechnerlexikon, a site btw well worth exploring!)

This key being a bit exposed at the edge of the machine probably contributed to many of these Burroughs Calculators missing this key. Or, as in the case of my specimen, the original replaced with any key that was available at the time - in this case a round, small key with the 9 legend sideways.

The original-pattern blank key is today well within capability of a regular FDM 3D-printer. So from the CAD model a mesh, then 3D printed in black PLA material. In the below image the 'raw' print straight out of the printer placed on the stem. The dimple is clearly showing the layers - printed at 0.12 mm.

With a little sanding to smoothen the dimple's layering and roughen the surface, it was painted black. With oil-based hobby-paint, the net-effect is a smooth surface that is also quite robust.

The STL is available in the Thingiverse here and the CAD-file with several mesh file-formats for printing is available here.

The finished, new key on the calculator - complete keyboard with a decently matching top-left key that is perhaps still looking a bit new and shiny:

Layers of history - 'excavating' a crusty Comptometer model F

A not-expensive local pick-up - it didn't look so bad in the pictures (dark, bad lighting). When seeing it at pick-up I did consider leaving it - it was not only rather dirty, but extremely rusty (crusty) and a whopping big iron carrying handle was mounted on the back.

But it was a century-old model F and did look a right 'project', so the sale went through and yet another Comptometer taken on. (Have been quietly acquiring more of these; fascinating machines.)

A solid steel handle riveted to the rear panel. That is not original.

Not subtle, that handle - though it actually is a good idea. It makes it so much easier to pick-up and transport the machine. Even the standing on its front panel isn't too much of a problem, it's fairly stable. This definitely is something that the Felt & Tarrant company could have done themselves (though perhaps not on the rear-panel or quite this crudely).

This Comptometer was handed down from the seller's grandfather, who'd worked with it at Smit, Slikkerveer - that was (is) a large industrial/electrical company founded in the 1880s. Smit was absorbed in Heemaf in '63 and after several corporate moves the Smit activities are now part of Alstom and produce electric-drive for trains. This Comptometer was made around 1918 and likely used for decades at Smit. It probably got its handle added when it was no longer 'new', but still actively used by perhaps a 'roaming' operator. And then taken home at retirement, to be kept as a memento. When it passed to the next generation it ended up in a damp shed. That's when it will have developed its 'patina' - especially the key-stems became very badly rusted. 

When cleaning out the shed of the father, the grandfather's old machine was put up for sale - there might be someone that'd still want it.  There was :)

After getting it home, it was first stored in the garage (much too dirty for taking indoors), before taking it out for a proper cleaning and repair over a a few days - an 'excavation' almost. 

There are minor differences between the models, but all 'shoebox' Comptometers can be taken out of the casing pretty much the same way. This gives access to the mechanism for a cleaning - this one was dusty even on the inside. The empty casing can then safely be given a good wash.

Fortunately the mechanism itself didn't need taking apart much (intimidating, quite beyond me). With liberal amounts of a light machine oil (sewing machine oil) and working the various parts, the whole mechanism slowly came to life again. At first a bit slow with 'sticky' carries, but after a while the full ripple carry from 099999999 to 100000000 again zips through the machine. Everything works and no broken or bent internal bits!

With the top-plate off, this also could be thoroughly scrubbed. One thing I'd not noticed before on Comptometers was that the key-stems had a gasket; every stem-slot had a fibre or card sleeve to act as an oil-soaked gasket. These were hard with old oil and/or crumbling and were all removed.

Considered replacing these with new, but did not want to risk one of these gaskets coming unstuck and then getting lost inside the mechanism. With the light use this machine will see, it should be fine without these oiling-gaskets. (Would the fact these gaskets were still present suggest this specimen hadn't ever had its top-plate removed for a full-overhaul maintenance?)

Another layer of its history were marks from a divider placed between column 2 and 3 (cents and guilders) and between row 5 and 6. The copper looks scratched/worn away by a divider, down to the plain steel. 

The horizontal mark suggests a divider to help practice/use the touch-method. Experienced (and fast) comptometrists only used the 1 to 5 keys in every column. All numbers were entered by touch without having to move the hand, never taking the eyes off the figures to be added made this a very fast method.

It was also revealed that the greasy dirt-layer between the keys had actually been protecting the copper finish of the machine - still closer to the original colour than the rest. The darkening of the 'clean' surfaces is probably due to decay of the clear lacquer and oxidation of the copper underneath.

Even though it was part of the machine's history, the rusty handle on the back was removed. The holes left by the 1/4" rivets (!) were plugged and made less obvious with copper-colour paint. The lighter, original colour where the handle had been also confirmed that the darkening (and rust) was probably from its time in the shed.

The patent dates again all readable, from the original 1887 to the most recent 1914 date for a model F.

All the stems were scrubbed clean with steelwool and the cellulose-nitrate keys were washed with soap and water. Kept in sets per column, to place them all back in their original spot. Bent stems (several!) all carefully straightened.

The case was cleaned with soapy water and 'crusty' areas were polished down to a smooth rust-finish. The case now has multiple shades of brown in interesting patterns that would be the envy of some modern 'industrial-look' decorative items. Sealed with a waxing, safe to touch and handle.

With clean keys and remarkably shiny key-stems, it all looks much better :)

The re-mounted, clean keys confirm that this machine was used by an experienced operator - the lower half of the keyboard is worn. This shows it was used mainly for addition of amounts up to 4 or 5 digits large using only the lower half of the keyboard with the right hand - fingers resting on the 3-keys, as per recommended method.

The machine was completed by re-fitting a red correction-key; again a proper well-used Comptometer model F. 

The model F was introduced in 1915 with a white Correction Button for re-setting the controlled-key mechanism and blank decimal-markers. Numbered-markers were available sometime before mid 1917 and the correction button had already changed to red before that. With serial number 135855 this Comptometer was probably made in 1918 so will have had numbered decimal-markers and a red key from new.

It was actually surprising how well this machine could be recovered back from its extremely rusty 'boat-anchor' condition. A nice (and cheap) addition to my modest collection of Comptometers :-)

With occasional 'exercise' this Comptometer should remain in good working order for decades to come as a 'collector-item' or historical technology-artefact; a new layer being added to its accumulated history.

Why do people keep wrecking these boxes?

Why is it, when a drawing-set case is in a thrift-store, the latch of the box is always destroyed?

Probably because nobody remembers these cases. I.e. that these have a little latch at the front-right corner (or sometimes have two, at both front corners). Pulling-out the latch will unlock the box and -voila- the lid can be opened. For anyone encountering one of these baffling boxes; that's how they open.

This was a decent late 1930s to perhaps 1950 set, made by the firm of E.O. Richter in Chemnitz, Germany. A medium-sized set with ink-pen, a large compass, extender and a drop-bow compass. These are pretty common, but are quality instruments; worth trying to fix. 

To repair the latch, an old 2mm knitting-needle was filed down replace the missing section. The combined part (cyanoacrylate) makes the assembled 'rod' have again the slot for the little nail that locks it in orientation and limits its travel in its channel in the wooden base.

After re-fitting the latch (slide in from the right), placing the locking-nail (through the slot and push firmly into the wood), the purple box-lining is carefully glued down again as is thin paper-edging. An almost invisible repair, this.

These larger Richter-type compasses have a little mechanism that keep the handle straight - this must not be forced; you can't open the legs by pulling one leg and holding the handle. If you do, then the small guiding-rod snaps. That's probably another bit of once-common knowledge that's no longer all that common: the compass should be opened by holding the legs, not the handle. Thrift-store: so a broken guiding-rod. This little guiding-rod is now replaced by a new 'rod' fashioned from a length of M1 threaded rod and two (relatively massive) M1 nuts. (In picture below, centre, they're really rather small :-)

Yet another thing with thrift-store drawing-sets is that bits go missing. The case gets opened (broken open), handled and something will accidentally drop out and is lost amongst the rest of the jumble. This set is only missing its needle-attachment for the large compass. I have a spare part for this, but no needle-screws yet, so this is something to hunt for (or re-create).

These fairly-common Richter sets are difficult to date reliably, but the black tapered plastic handles would make it not earlier than the mid 1930s. The old style of Richter-brand and absence of any GDR quality marks suggest it is earlier than 1950 and probably before 1945.

In any case, the latch-repair turned out well and even though these sets are common (and not expensive), it is a very nice and still usable drawing-set. (And at a fiver, no regrets about getting it :)

Standard Folding 2 Typewriter - restored

The barn-find from Jubbega; restored: