Saturday, January 3, 2015

Keypunch rehabilitation work and start of construction of the 'data center' shed

I skipped a day with the diary, including work from both Friday and Saturday in this posting. We are having a cold wave in California and it is hard to do much work when the work area is 42 degrees F inside. I lose part of the day waiting for it to warm up.


I polled some typewriter enthusiasts to see if anyone had a spare motor pulley to replace the part that was corroded on my I/O Selectric mechanism. So far, no luck. I will check with Grainger and other suppliers to see if I can find a suitable replacement to fit a 5/16" motor shaft.










I set up a repository for this interface on Github as KPgolem, public as of yesterday (Jan 2). Initially I will upload the Arduino source code, following it later with all the details of keypunch modification, cabling, and hardware construction advice for the interface box.

I worked on the keypunch all day trying to get the adjustment right to allow the card to register in the read station but be able to move through when released. I could get one or the other but not both. I need to disassemble more of the keypunch to see what I might be able to do as a fix.

The eject and read head, the part with the two roller arms that sits over the read station, determines the relative timing of dropping the gate that blocks card movement to the movement of the two roller arms. The arm that registers the card does not move down far enough, although it may partly be a problem with how much the running feed wheel sticks up through the card bed from inside the keypunch.

I will take the card bed off and look more closely at the feed wheel and any shims for card bed height. If I can drop the bed or move the feed wheel a bit more forward, that could solve the problem. If not, I might need a bigger diameter wheel, as wear and age may have dropped the diameter below its effective range.

Keypunch after removal of card bed and other parts, then removal of feed wheel

Alternatively, I have possible modifications to the roller arm, either increasing the effective diameter of the metal roller or changing the rotary position of the arm when engaged to push it closer to the feed wheel, while the gate the blocks card movement is not yet dropped into the card path.

I removed the feed wheel and measured it - exactly 1 3/16" diameter at the rubber rim - although I have no spec to compare this to. The shaft on which it is rotated can't be moved forward, nor can the card bed be moved deeper. The only adjustable items are the feed wheel diameter and the positioning of the metal roller.

Feed wheel for read station registration, after removal

Eject unit that pinches cards onto the read registration (and stacker eject) rollers
I will check the size of the spare wheels at CHM to see if it makes any sense to replace the drive wheel. This will take a few days of investigation and work before I can get the keypunch working as it should.


I spent much of today working on the 8 foot by 12.5 foot shed that will house the working system in the side yard of my home. I built part of the wood platform upon which it will sit. The platform itself sits on 12 concrete pilings, even though it is pressure treated wood that could have been put directly down.
Building the framing of the platform for the shed
The reason is the uneven area, 100 square feet of it, that I would have had to level if I wanted the shed to sit directly on the ground. This way I only have to dig and adjust the height of 12 pilings, about 11 square feet worth of digging would be involved.

I have more work to do on the platform, including cutting and screwing down the 3/4" plywood sheathing that completes the substrate, in addition to the digging and setting of the pilings. However, it is less than a day's additional work to get the platform itself complete and ready for installation on the pilings.

The plywood sheathing won't be installed until the framing is on the pilings, allowing me to pick up and move the framing onto the pilings. The total weight would be too much if it was completely screwed together first.

I began construction of the shed itself, those parts that don't require the platform to be ready, such as trusses, gables and doors. I have only one of the doors left to prepare, after which I will have to wait. The following step is to lay down the plastic floor of the shed atop the installed platform, then erect the walls.

Trusses and gables built and ready to install
Left door built and ready to install

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