USD $119
10″ Logarex/Koh-I-Noor Darmstadt Slide Rule VERY LATE MODEL, made in Czechoslovakia. Powerful, brand new full sized rule with front and back cm/inch edge rulers, smooth black scales, 3 log log scales on the slide reverse, pythagorean and trig scales, and 4 line cursor, and dual reverse side body cursors. Unusually marked, this rule contains ONLY scale equivalents, no arbitrary letters. Has a soft black padded leatherette case with top flap, and the name of the UK distributor for Logarex (Hellerman) embossed on one side. A very powerful and well-designed rule, but uncommon in North America. Like Pickett rules, this is lithographically made, not engraved, and has a shiny top coating for protection of the printed scales. A very nice desk rule to use for many purposes, thanks to the dual rulers. The 4 page Hellerman basic instructions are included.
(14 Scales, 4 cursor lines, 2 Rulers) (RH)
FRONT- cm/ log, sq rt(1-X2), X3, X2, [ X2, 1/X, X, ] X, sin, tg, s-t
BACK- inch/ [ e0.01X, e0.1X, eX ] Factors on the body area
Stock: 27
USD $65
A visually beautiful rule, complete with 2 part plastic case and factory box. The 544A features the trademark S/M blue slide and body braces, multi-line (5 line) cursor, plus two color (red/black) scale markings, and folded scales. The rule is self documenting on the right hand side for all scales. Staedtler-Mars rules are highly requested but quite uncommon in North America, and are very well made designs. Attractive blue slide and body braces, complement the bright blue and white two part plastic case. The folded scales are especially useful for mark-up/discount calculations, and a center index is well marked for this. The ‘invisible brace’ style with braces on the back gives the rule a very clean European look from the front.
Blank on the reverse side. These were still sealed in a factory bulk pack, so everything is in mint condition. We have included reprints of the S/M consolidated rule instructions because these came factory packed with no instructions.
(8 Scales, 5 Cursor Lines) (RH)
Front – K, DF, [ CF, CIF, CI, C, ] D, A
Back – Blank
Stock: 7
USD $110
While the box is a little worn, the rule itself is in mint/new condition and is still in its factory sealed plastic. Includes original instruction manual and case.
Front – T, K, P, S, C, D, +3 other scales, L, LL1, LL2, LL3
Back – Blank
Stock: 1
USD $65
This Hemmi pocket rule is in new/mint condition, and is still in its factory plastic sealed bag.
Scales include:
Front – C, D, + 7 other scales
Back – Instructions and unit conversion data
Stock: 1
USD $39
New and in mint condition, made in Czechoslovakia. A great beginner and student rule.
Basic Rietz format rule (has over-range scale extensions for easier operation) with added reference features. It has a black/red self-documenting scale arrangement and pale yellow slide. The slide reverse has trig (S, ST, T) scales, and the back has a treasure trove of useful data and factors. It has a slightly magnifying multi-line simplex cursor design that does area of a circle, plus some other interesting stuff like horsepower conversion. These are beautifully made rules, very well constructed. We will include basic instruction reprints, as these came bulk packed with with no manuals.
Stock: LOTS!
Sphere Research Corporation 
