What is it? LXI

If that fails, try an ebay search on:

K&E slide rule log-log

I found a page full of them at not bad prices.

The best of them (of that brand) should be marked:

K&E log-log duplex decitrig

and you should be able to find one with the manual. I don't remember the names applied to the best of the Pickett and other makers' rules. Each had its own complex name. :-)

The older ones were thin ivory over mahogany bodies. (Including my 20" one.)

More recent ones were moulded plastic, but still engraved instead of simply hot stamped, so the accuracy remains excellent.

I presume that this is one on image processing and recognition, not on decorating a bathroom or kitchen. :-)

I think that I'll skip on this, but others may be interested -- and may even have a spare slide rule of good quality to trade.

Good Luck, DoN.

And, according to an old old olllllllldd joke, "Pie are round, cornbread are square."

Steve, who used a Pickett slide rule in high school physics, chemistry, and calculus, and still has it.

No -- this is not a planimiter nor a map measuring device. I have one of each, and know the difference. It is a circular sliderule, made in Russia, and the size of a pocket watch.

Note the two knobs on it.

When looking at it from the busier side (more scales), with one knob at 12:00, and the other at about 10:30, the one at 10:30 moves the pointers on *both* sides of the device. They are equivalent to the cursor on a normal straight slide rule.

The one at 12:00 appears to do nothing when viewed from that side. However, when you flip it over, the 12:00 one (the other is now at about 01:30) rotates the entire scale (equivalent to moving the slide on a slide rule), Directly under that knob is a short index mark, which reaches just past the circle on which both scales are based.

Starting with the sparse side (with the sort of lightning-bolt maker's logo), the inner scale is clearly marked as the 'C' scale. This makes the outer scale the 'A' scale, since it covers two decades (1-10 &

On the flip side, the outermost scale must be the 'D' scale, and in conjunction with the 'C' scale, you can multiply and divide.

The next scale inward goes from 0 through a full circle to 90, so it is for setting angles, and a quick check with setting it to 30 degrees, and reading on the 'D' scale a value of 0.5, it must be for getting sines of the set angle.

The next one inward from that is a spiral, which makes 1-3/4 full turns from 1 to 90 with 45 in line with 90. A little experimentation verifies that it is for determining the tangent of angles. (Aside from it being marked 'T'. :-)

Enjoy, DoN.

"DoN. Nichols"

It is a circular sliderule,

A search on ebay brought up a circular slide rule that was up to $200 this afternoon.

Steve

Hmm ... has it already closed? I don't see one in that price range.

And it wants me to sign in to search on completed auctions, and since my wife is the one with an account, that won't happen. :-)

But a duplicate of the one which started this dicussion is being sold under auction #6178947080 -- with a buy it now. ($44.99/$50.00). And it is complete with directions, so I didn't have to spend that time re-figuring out how to use it. (My version has only a folded piece of paper in Russian, which is no help at all to me. :-)

Enjoy, DoN.

In the comments section on my site someone left a link to a page containing many Russian slide rules, one that looks like yours has a pdf of the instructions translated to English. It can be seen here if you are interested:

Rob

Got it! Thanks (to you and to whoever posted the link).

Enjoy, DoN.

Very much like one of these:

In the US, Radio Shack. They sell a pack of 3 sizes on small spools. It's called "magnet wire", just in case nobody's mentioned that yet.

Cheers! Rich

You can pull a few rare earth magnets from most junk hard drives. Probably scrounge the wire too.

That's what I used for the coil wire, the heaviest gauge wire that came in the pack didn't work for some reason, but the next size worked great.

Rob

Depends on how pre-packaged the kit is. I'm an electrical engineer, and when I was young my dad bought me one of the electronic kits with a couple of transistors, resistors, and capacitors, complete with a peg-board affair where you could assemble circuits with a type of Fahnestock clip.

I had a blast with this kit, and the components later became my first parts stash. :) However, there was a contemporary kit where the components were enclosed in lucite cubes with metal ends and a schematic on top. The idea was to build circuits by joining the cubes together. Somehow this kit struck me as just Not Right. I don't think it would have held my interest as long not being able to handle the actual components themselves.

I also had one of those little motor kits where you wound your own armature. I have to say I think this home-made battery bazinga tops that. :)

Certainly not for the very young, but a great book for kitchen table experiments is the collection(s) of Amateur Scientist articles from Scientific American magazine. One of these articles got me building Van de Graafs as a kid.

Good picture. My Galvanometer (it is older) model used a Horseshoe magnet that is set and the coil is very long with a pointer. It is a very, very low current device and was used to measure charge storage (flow) thus current. It was built by GR - General Radio and mounted in a Fine wood case with a black plastic-like top. Lab grade. The box is now on display at Department of Energy as an instrument to measure the current delivered by a Hydrogen Fuel Cell that I did the tech work for a local group (My wife was the Primary Teacher at a private school that had a grant!).

Martin