I stopped actively collecting comic books in my very late teens. But I held onto my collection, and hope to keep it to the end of my life. And for many years it had a gap in it that greatly annoyed me; specifically, I needed Giant-Sized Conan #3, in mint condition, to plug a hole. Whenever I would go into comic book stores, and the couple of times that I went to San Diego Comic-Con, I would look for that specific issue, in that condition. A few weeks ago, I finally managed to obtain a copy.

At the end of April of last year, I announced

I have secured at least one complete exemplar of every variety of [working Mannheim slide-rule tie-clips] that was made for resale.

but retracted that claim about a week later. I am going to be so bold as to make the claim again. Actually, I obtained an exemplar of the missing sort some time ago, but its indicator wasn't in the best condition. The exemplar that arrived to-day was as-new, in its original box (whose exterior is a bit abraded) and with its original instructions (as-new).

I'm not sure how to count the sorts of clips in this collection, as there are minor variations, but I'd say that I have thirteen or fourteen sorts.

Readers of this 'blog might recall that I collect working slide-rule tie-clips, and readers of my defunct LJ might recall that I have a collection of ordinary slide rules (to which I almost never make additions, because I had limited ambitions and most of these have been met).

Recently, the Woman of Interest mentioned the slide-rule tie-clip collection to her maternal grandmother, who volunteered that her late husband (grandfather to the Woman of Interest) had had one, and offered to give it to me. I was happy to accept, as none of my other such tie-clips has a family significance for me. I also learned that this man had had a slide rule, a Pickett & Eckel of unknown composition, but that it was not in working order; the rules wouldn't slide, and there was a lot of white powder on the device. I offered to fix it and return it, but the outcome of that offer was that it was given to the Woman of Interest, for whom I was to fix it.

The slide rule arrived on Monday (along with a bag of premium salt-water taffy, perhaps to sustain me as I worked on the device). It proved to be a Model 500, and I decided that it were of a light-weight metal with plastic laminate for the scales, and that the white-stuff were probably corrosion product. Some of Pickett's later slide rules were definitely made of aluminum, and aluminum oxide powder is typically white, but I didn't find confirmation on-line that this model were made of aluminum. Nor was I sure that other metal parts wouldn't be damaged by water; the braces, bolts, and rivets might be of a different metal, and the indicator spring was surely not aluminum. Meanwhile, I had to be careful about that plastic laminate as well.

Having gone to the local drug-store for something else, I wandered around the aisles looking for something to use to clean the slide rule, and saw jars of petroleum jelly. That seemed a great choice; it could be used to wet areas without water, loosening and suspending the oxide and other dirt. Any residue could function as a lubricant and water repellent, and it shouldn't reäct significantly with the metal, plastic or marking colorant. There would be no odor. The only down-side is that the residue will tend to hold onto particulates with which it has come into contact, but occasional wiping should fix that. (Unfortunately for the store, I already had a tub of petroleum jelly at home, but I'd bought that from them, years ago.)

Anyway, I carefully disassembled the slide rule, cleaned it with the petroleum jelly (and the indicator plates with hot water), reässembled it, and made sure that the scales and indicator plates were in good alignment. The slide rule is back in working order.

Uh, er….

At the end of April, I reported

A few years ago, I got it into my head to collect working Mannheim slide-rule tie-clips. I believe that, as of to-day, I have secured at least one complete exemplar of every variety of such that was made for resale.

Yester-day, the clip whose acquisition I was celebrating arrived. It is of a somewhat different variety than any of my previous acquisitions, which is in-and-of-itself a good thing. But I had used the word complete advisedly. I have a slide-rule tie-clip that is missing the indicator (the clear, sliding thing used to check just how the graduated pieces line-up) with which it was originally sold. I was expecting a complete exemplar of the same variety. Instead, I have one that is altogether new to my collection.

So there is at least one sort of which I continue to lack a satisfactory example.

Decades ago, before the typical scientist or engineer had a hand-held, electronic calculator, they used slide rules. And, at some point, jewelers had the thought of making men's jewelry — tie-clips, cuff-links, and what-not — designed to look like slide rules. Well, actually, several designs didn't just look like slide rules; they were slide rules, not very precise, but able to make actual calculations.

A few years ago, I got it into my head to collect working Mannheim slide-rule tie-clips. I believe that, as of to-day, I have secured at least one complete exemplar of every variety of such that was made for resale. You can see some of these sorts included in the Jewelry Slide Rule Archive of Sphere Research's Slide Rule Universe The one sort of working Mannheim slide-rule tie-clip of which I do not have an exemplar was not made for resale, but was given to staff at K&E (an example is in the aforementioned archive). It is sufficiently rare that I have little expectation of getting one.

(BTW, some time ago, the Woman of Interest gave to me a jewelry box specifically so that I would have one suitable for storing and displaying my collection.)

[Addendum (2009:09/23): On 6 May 2008, I retracted this claim, as the slide-ruler tie-clip that I received was actually somewhat different from those that I had seen before (though I have since seen more like it). On 20 July 2009, I made the claim again, and have not felt a need to again withdraw it.]