[GreenKeys] Model 33 punch unit

[Jones, Douglas W]

On Jan 28, 2016, at 3:53 PM, Michael Zahorik wrote:

> Today, I began work on my Model 33 tape punch. It was pretty well gummed up.

Very likely the result of someone using the wrong oil.  3-in-1 oil is notorious for having a component that slowly evaporates, leaving behind a film that can build up to become gum.  The 3 functions of 3 in 1 oil are "clean lubricate and protect", and it does those, but the protect part is the gummy film, while the clean part is the light fraction that evaporates.

So, what you want is some kind of oil that leaves no deposit and does not evaporate.  Teletype said you should use KS7470 oil, and there are small amounts of this available as new-old-stock, but it is very rare.

I did some research and concluded that Starrett 1620 Tool and Instrument Oil is very close to the right specs.  According to one MSDS, this is really Nye 113 delecate machinery oil.  Starrett 1620 is widely available on the internet on places like eBay and Amazon.

I've recently become convinced that sewing machine oil should be just as good, and you can get it over the counter at any sewing store.

> I thought that I'd try punching something. Since I don't have any paper tape, yet. I cut a strip of my own. And it worked, well kinda. See picture.

Yours works better than mine at this point.

		Doug Jones
		jones at cs.uiowa.edu