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Slide Rule Collection

The rules which have been put on this site fall into two categories:

1. Rules which can be taken to represent standard types of rules.
2. Rules which have non-standard features.

Non-standard rules This includes some of more interesting rules.
5 inch rules Many of these were advertising gifts.
10 inch rules The most frequent size.
20 inch rules The monsters of the slide rule world
Circular rules Able to get longer scales in a shorter space.
Specialised rules Designed for very specific calculations
Books So far, just a few.


1. For the names used for scales and gauge points see A-to-Z.

2. I have used the following way of indicating the location of scales.
    (L),K,A[B,CI,D/ L1,L2,L3] {Eff,V}D,P (S,T)
   scales on edge of rule are in round brackets ()
   scales on stock are unbracketed
   scales on slider are in square brackets []: the forward slash (/) indicates scales on both faces of slider.
   scales in the well of the stock are in curly brackets {}.

For rules which do not follow the standard practice I give the label on the rule first then an equal sign and the standard nomenclature second, e.g. LU=LL1

For duplex rules I give two lines of information.

3. I have given the reference when dating the rule. P Hopp refers to "Slide Rules - Their History, Models, and Makers" Astragal Press, 1999.

4. Rules for which I have instructions are indicated. They fall into three categories:

  • Scanned from original documents.
  • Instructions in "Teach Yourself the Slide Rule"
  • My own experience.

5. I use small flags to indicate the country of origin. Where two flags are shown the first represents the origin of the company who marketed the rule and the second the origin of the company who manufactured the rule. The maps have all been adjusted to the same scale height (25 pixels) but have kept the correct length/height ratio.

6.  The overall views are at 50 dpi, and are about typically half full size; the detail views are at 150 dpi, and are about 1.5 time full size (depending on screen size and resolution). This is done to enable comparison between different rules.