
My smallest slide rule, actually a novelty slide rule but it works just fine and is more accurate than you might think.
D Scale length: 36 mm. Significant digits: 2.2 to 3.2. 

An early (late 1800's) hand stamped 24" two fold carpenter's rule incorporating a brassinlaid slide rule.
D Scale length: 140 mm. Significant digits: 2.7 to 3.3. 

Nice example of a carpenter's rule by Rabone incorporating a brass slide rule in the upper arm. Classic Coggleshall log scales on top. 1/4 and 1/2 scales on bottom with inches on bevelled edge, protractor in hinge marked with degrees 0180 x 5. Reverse is standard inches + square and line scales . The first widely used standard form for a logarithmic slide rule is the twofoot, twofold design devised by Henry Coggeshall around 1677. This one by John Rabone and Sons of Birmingham would have been made in the late 1800's.
D Scale length: 140 mm. Significant digits: 2.7 to 3.3. 

Issac Aston 4 Sided Box Slide Rule, c 1860. Made in England. Made by Issac Aston, 25 Old Compton Street, Soho, London. Everard type made of Boxwood. Length 12" (30.5 cm), Width 1.0625" (2.8 cm), Depth 0.75" (1.9 cm) approx.
D Scale length: 283 mm. Significant digits: 3 to 3.7. 

A Sun Hemmi 4" pocket slide rule with original leather case. Manufactured in Bamboo with a celluloid coating. Front scale A, B, CI, C & D. Rear scale S,L & T. Made in Occupied Japan date this to 1946  1952
D Scale length: 160 mm. Significant digits: 2.8 to 3.7. 

A small 5" pocket slide rule, no name on it.
D Scale length: 125 mm. Significant digits: 2.7 to 3.7. 

A compact pocket slide rule, famous as the slide rule carried by Apollo astronauts to the moon.
D Scale length: 125 mm. Significant digits: 2.7 to 3.7. 

American made wooden slide rule in good condition. Inscribed 'Lawrence engineering service, Wabash, Ind.' With original tin & cellophane cursor, all the numerals/ lettering are legible, as are the instructions printed on the back of the rule.
D Scale length: 188 mm. Significant digits: 2.9 to 3.9. 

Keuffel & Esser 40532, 8" slide rule, c. 1900 (N.Y. pat. June 5, 1900). This is one of a series of similar K&E slide rules in different lengths  K&E40532 (8"), K&E40533 (10"), K&E40533F (10" but with magnifier and finer scale divisions) and K&E40535 (14").
D Scale length: 200 mm. Significant digits: 2.9 to 4. 

Keuffel & Esser 40533, 10" slide rule. This is one of a series of similar K&E slide rules in different lengths  K&E40532 (8"), K&E40533 (10"), K&E40533F (10" but with magnifier and finer scale divisions) and K&E40535 (14").
D Scale length: 250 mm. Significant digits: 3 to 4. 

Keuffel & Esser 40533F, 10" slide rule. This is quite a scarce slide rule  the F stands for "Fine" because it has finely divided scales. Finely divided means that the scales are subdivided as closely as the 20inch slide rules. Combined with the included magnifier on the cursor, this means greater accurancy when reading the scale  it is almost as accurate as the K&E40535 (20") slide rule, but more compact. This is one of a series of similar K&E slide rules in different lengths  K&E40532 (8"), K&E40533 (10"), K&E40533F (10" but with magnifier and finer scale divisions) and K&E40535 (14").
D Scale length: 400 mm. Significant digits: 3.3 to 4.3. 

A.W. Faber slide rule with decimal keeping cursor. The slide rule is made of wood with celluloid overlays. It is marked A.W. FABER MADE IN BAVARIA D.R.G.M 116832. (D.R.G.M. 116832 is the German Registered Design number given in 1899 for a cursor with indicator). The slide rule has 7 scales, as well as a centimeter and inch scales. The only scales that are labeled are on the back of the slider. They are: S, L, T. The case is marked A.W. FABER'S CALCULATING RULE LONDON and MADE IN BAVARIA.
D Scale length: 250 mm. Significant digits: 3 to 4. 

Pickett & Eckel N803ES slide rule, 12 inches in length, made of aluminum. Labelled Pickett & Eckel, Inc., Chicago. Details..
D Scale length: 250 mm. Significant digits: 3 to 4. 

Pickett Model No. N4ES Log Log Vector Hyperbolic slide rule in good working condition with the original case. The "Big Guy" of Picket slide rules. It is a DualBase Speed Rule. It is about 12" long.
D Scale length: 250 mm. Significant digits: 3 to 4. 

Sun Hemmi Japan Student 1447 slide rule. It's a nice simple utilitarian slide rule in great condition. Slide Rule is marked "Sun Hemmi Japan Student Slide Rule Hughes Owens Since 1900".
D Scale length: 250 mm. Significant digits: 3 to 4. 

This is an old Faber Castell #375 slide rule, 10" long, c. 1920, marked "Bavaria Reitz". Mahogony base with celluloid.
D Scale length: 250 mm. Significant digits: 3 to 4. 

This is a very nice and quite rare Faber Castell slide rule with magnifying glass cursor. The rule is marked A.W. Faber "Castell" , "DRGM" and "Castell 1/98/398". Mahogony base with celluloid, early 1900's. The lens can fold flat when not in use.
D Scale length: 500 mm. Significant digits: 3.3 to 4. 

Faber Castell Slide Rule 52/82 "Duplo", made in Switzerland, with 15 page instruction booklet. This was a very popular work horse right up to the end of the slide rule era. It is the same model I used in first year engineering.
D Scale length: 250 mm. Significant digits: 3 to 4. 

A 500m long scale straight slide rule by Nestler.
D Scale length: 500 mm. Significant digits: 3.3 to 4.3. 

Size comparison of various linear slide rules.
D Scale length: 500 mm. Significant digits: 3.3 to 4.3. 