Slide
Rules, Calculators & Scientific
Related Antiques
We
Can Help You Sell Your Antique
& Collectible Slide Rules and Calculation Devices!
Introduction
This webpage is a basic
primer describing the different and various types of scientific and
calculation devices we buy, sell, deal in, and can help you sell.
I am an antique dealer interested in antique and
collectible slide rules and other calculation devices that date from the
early 20th century and before. I am
primarily focused on earlier model calculation devices rather than trying to "buy back" my child hood or re-live the period when I was supposed to learn how to use
one of these.
I have a nice selection of calculators offered for sale at
our sister site
www.Patented-Antiques.com, and if you
are looking to buy calculators, slide rules or other scientific and
technology related antiques and collectibles we invite you to visit that
site as well.
Please Contact
me with any early and
unusual slide rule that you have for sale.
Slide Rules
A Basic K & E Slide Rule
Cursor Lesson or
Beginning Primer for the Curious
The next three pictures give views of different early cursors (the sliding window portion)
employed by Keuffel & Esser or K & E and represent the transition
or changes that slide rule cursors have gone through over the years. This
is by no means the full story, and there are variations and other designs
by other companies that are not covered in this basic primer. I am
not the final word on this, and this is probably not a completely accurate
description, but it is close.
The first
picture of the all brass cursor on the right is referred to
as the Christmas tre
e or chisel point and has no glass
window like later models do. You would work
off of one of the tips to do your calculations. Some are like this
one with the points going out to just one side and other K & E cursors have points on
both sides of the center post or upright. This style is the first model
cursor K & E used and dates
from a bit before to near the turn of the 20th century. It is considered
rare and very desirable. It can cause what is otherwise a $10.00 rule
to sell for several hundred to $1000.00 or more.
The second 
picture shows what is
known as a clamshell cursor. This was the second cursor employed by K &
E and was not used for very long. Some are pretty rare, others on
common rules are not. This design was shortly replaced by the interesting
looking and difficult to find column
cursor which is pictured below on the right. They can affect
values up on certain rules, but on some others it seems to have little or
no effect. 
The column cursors
still show in the 1913 catalogs, but were phased out shortly after that.
This cursor style was only used for a few short years and in some cases
can affect the value upward to levels in the hundreds of dollars.
The next cursor to be
used after the column cursor was the short lived frameless cursor,
(not pictured here) which I suppose was an attempt to save money and material over the earlier
designs. This design was a disaster as they were very fragile and
prone to break at the connection points in the corners that had holes
drilled through the glass. I have not seen this style cursor bring
any premium even though it is hard to find them not broken or damaged.
I suppose that is because they were being produced in large numbers by
this point.
K & E
shortly thereafter introduced the standard framed cursor that most slide rules found today have. All
three of these early models and
variations came during the early 1900's, after which K & E introduced
several different styles of framed cursors until production of slide rules ended in the
late 60's or early 70's.
Slide Rules Wanted
I am
interested in any slide rule with one of these early cursors that I
have pictured, or slide rules with any of the other unusual cursors that some other companies used. Some of these had small decimal keepers on
them or arrows, or in one case a small
abacus to help you along with your calculations and in keeping track of where the
decimal point belonged.
I am also
interested in any special use slide rules, such as those dealing with surveying,
chemicals, electrical calculations, aviation, and others. There were many many
different types of slide rules produced to help the scientist,
machinist, shopkeeper, workers and others with the daily computations that they were faced with
in performing their jobs.
Slide
rules are an emerging collector category, and different folks collect them for different reasons.
Each of these groups feels that different
ones are worth different amounts for different reasons. If that
seems confusing, it is, and prices and supposed values of these interesting
collectables fluctuate wildly depending on which group you are listening
to.
Slide Rule Values
The first picture is of a relatively common but very collectable
slide rule
put out by K & E or Keuffel & Esser. It
is known as
the Deci-Lon and was one of the last sliderules that they
made.
It is all plastic and was produced for a number of years, with
the last models being designated by the number 68-1100. Before the Internet and the beginning of their "known" or
documented popularity this rule could be had routinely for $20 or less and
was routinely passed over by those in the
"know" who were looking for earlier and rarer examples of slide rules.
Today this rule routinely brings $100 or so, not because they
are scarce, but rather because they are popular. The 5" version sells for
even more for the same reasons. The collecting frenzy over them and
the resulting prices they bring is largely driven by
the same impulse that has created a desire for collectibles like GI Joes
and Barbie dolls rather than anything resembling scarcity or the historical significance
associated with them.
The point is that there are many earlier and somewhat rarer slide rules
that are not having a lot of attention paid to them these days 
that have potential
to be worth more in the long run, and these are the rules that I am
interested in.
Please Contact
me with any early and
unusual slide rule that you have for sale. I am always interested in ones that I do not
have. On our sister site
www.patented-antiques.com I have a good sampling of slide rules available for sale. Please visit that site if you are looking to buy slide
rules.
I am also interested
in other scientific or technology related antiques, including surveying
instruments, other early calculation devices and early patented adders that
date from the 19th century and into the early 20th century as well as a
host of other related antiques.
Slide Rules and Calculators Previously Sold
The above slide rules are an
examples of the
caliber, condition and quality I am primarily interested in.
To see many other examples of slide rules and related scientific antiques
that I currently have for sale please go to our sister site
at www.Patented-Antiques.com.and
visit the numerous sale pages you will find there. Thanks!
Back
to Top
