Dividers With Exchangeable Points

For several hundred years some dividers have been constructed so that the lower legs or points can be switched. One tool can serve as dividers as well as inside or outside calipers and other functions. The earliest pair of dividers with this option that I’ve come across on line belonged to Michelangelo and are in the Museo Galileo in Florence. These would likely date from the early 1500’s. Notice that this tool comes with several leg options including pen holder and marking wheel as well as caliper points. 

                                                   

Michelangelo's Compass, Museo Galileo

 Michelangelo’s dividers show what is likely the earliest form of point attachment to the body of the tool. In this method the point has a “tenon” on the end that fits into a socket in the upper leg and is held in place by a locking nut. Below is an example from my collection likely dating from the 18^th century. It includes outside caliper, inside caliper (only one), short points and a holder for a crayon or other marker. The tool is unmarked.

                                                            

 A second, later method of attachment is similar to the above, but in this case the lower, solid legs slip entirely into the hollow, upper leg section and are again fixed in place by lock nuts. The J. Stevens Arms & Tool example (No. 64) below is an example of this technique.

 

                                                  

These dividers are marked with a patent date of 14 Feb. 1888, but that Stevens patent does not apply to this tool. The correct Stevens patent is 22 Jul. 1890.

Two other examples of this arrangement are shown next.

                                                   

Lt: Unmarked, but similarities to Stoddard.    Rt. Starrett No. 90 (not marked)

                                   

 A third and possibly the most recent method of leg attachment is to set the lower legs  into grooves that run along the upper legs. The lower leg is held in the grove by an encircling band with a wing nut. 

                                            

J. Stevens Arms & Tools, No. 61

Sometimes this involves both legs or just one. Instead of a metal lower a leg, a pencil can be inserted converting dividers into compasses. Here are five examples of this method.

                                            

Top lt: Stanly #58, Top rt. Unmarked

                               Center: Cook's 18 Feb. 1873 pat. Bottom lt. Peck, Stowe & Wilcox                                                                                   Bottom rt. Miller's 11 Nov. 1873 pat.    

 

Not surprisingly, it is easy to lose the original lower leg pieces so complete sets are uncommon. Another issue that arises is dividers turning up with lower legs that fit into or along side the upper legs, but may not be original to the tool. This situation can be hard to identify.                                             

   

U.S. Patents for Dividers & Calipers

- The folowing information was taken from the "Directory of American Tool and Machinery                  Patents" (DATAMP) website. Patents where the tool was "not known to have been                   produced" are not included. 

- Updated November, 2025

- Approx.10% of patents for dividers and calipers were actually manufactured

- Patents for calipers often apply to dividers and vice-versa

- The following list is no doubt incomplete and likely contains errors

- I currently have examples of 66% of the 72 patents below in my collection (the search goes     on)

- u.m. = unknown manufacturer (according to DATAMP) 

- Every year patents listed by DATAMP as "not known to have been produced" turn up in sales

Date                             Patentee                               Manufacturer                           

Nov. 21, 1848              Thorn & Rieffel                     Fessenden, Wilkenson & Co.

Oct. 1, 1850                 W. W. Smith                           W. W. Smith

Jan. 3, 1860                  C. D. Sutton                           u.m.

Jan. 27, 1863                D. C.Talbot                            Kimball & Talbot

Jul, 21, 1863                C. A. Fairfield                         u.m.

Jan. 26, 1864                W. A. Morse                           u.m.

Aug. 16, 1864              C. Jilson                                  J & E

Dec. 12, 1865               B. G. Martin                           u.m.

Jan. 9, 1866                 Phleghar & Schollhorn           u.m.

May 28, 1867              G. L. McKnight                      G. L. McKnight

Sept. 24, 1867             E. Wright                                 Wright Machine Co. 

Jul. 7, 1868                  S. Sawyer                                u.m.

Feb. 8, 1870                Hadley & Page                        Stevens & Co.

Feb. 14, 1871               T. Alteneder                            T. Alteneder

Dec. 12, 1871              A. A. Cook                              Copeland & Chamberlain                                        

Aug. 27, 1872             O. Stoddard                             u.m. (Stevens?) 

Feb. 18, 1873              O.E. Weatherhead                   u.m.  

 Jun 17, 1873              W. Schollhorn                         u.m. (Schollhorn?)                                             

Nov. 11, 1873             G. C. Miller                             Detroit Bevel &  Divider

March 31, 1874           G. C. Miller                            Detroit Bevel & Divider

Feb 22, 1876               T. McDonough                        Star Tool 

Aug. 22, 1876             A. Gruber                                 L. Prang

Feb. 5, 1878                A. P. Freshman                        A. P. Freshman

June 25, 1878              H. C. Wight                            Copeland & Chamberlin

Mar. 9, 1880               J. F. Sullivan                             u.m. 

Mar. 22, 1881              F. J. Thomas                           C. F. Richardson                                                     

July 16, 1881              Hagerty                                   Osborne

Dec. 20, 1881              C. P. Fay                                 W. Fay & Co.

Apr. 4, 1882                E.C. Smith                              u.m.

July 24, 1884               W.P. Dodson                          u.m.

Jan. 6, 1885                 F.G. Lilja                                Starrett

Mar. 31, 1885             O. Stoddard                             u.m.

June 2, 1885                C. P. Fay                                 L. S. Starrett                       

Feb.23, 1886               G. M. Pratt                              J. Stevens Arms & Tool                                            

Mar. 9, 1886                J.Stevens                                J. Stevens Arms & Tool

Aug. 10, 1886              T. C. Hendey                         J. Stevens Arms & Tool

Oct. 26, 1886              Warfield & Stevens                J. Stevens Arms & Tool

Jan. 4, 1887                 J. D. Wright                          Wright Machine + Starrett

May 24, 1887              S. Copeland                           u.m.

Jun 7, 1887                  J. D. Wilkinson                       u.m.

Oct. 11, 1887               J. H. Culver                            Peck, Stow & Wilcox

Dec. 27, 1887              C. P. Fay                                  L. S. Starrett

Dec. 27, 1887              L. S. Starrett                            L. S. Starrett

Feb. 14, 1888              J. Stevens                                J. Stevens Arms & Tool

May 7, 1889                F. A. Welles                            F. A. Welles

Sept. 24, 1889             L. S. Starrett                           L. S. Starrett

Jul. 22, 1890                J. Stevens                               J. Stevens Arms & Tool

Jul. 19, 1892                W. A. Bernard                        W. Schollhorn

Dec. 11, 1894              H. Cole                                   Eagle Pencil

May 21, 1895              Starrett & Fay                        L. S. Starrett 

Sept. 15, 1896             C. Klaui                                  u.m.

Oct. 5, 1897                C. P. Fay                                 J. Stevens Arms & Tool

Mar. 28, 1899             W.C. Day                                National Drafting Tool

Jan. 30, 1900               L. S. Starrett                           L.S. Starrett 

Aug. 7, 1900               W. A. Bernard                         W. Schollhorn

Apr. 16, 1901               L. S. Starrett                           L. S. Starrett

Apr. 28, 1903               F. A. Hatch                             W. E. Trufant

Jun. 2, 1903                 C. Fosby                                 u.m.

Jun. 30, 1903              O. Stoddard                             u.m. (J. Stevens?)           

July 4, 1905                Simpson & Starrett                 L. S. Starrett

Oct. 17, 1905              W. A. Bernard                         W. Schollhorn

Dec. 5, 1905                W. A. Bernard                         W. Schollhorn

Jun. 12, 1906               Nadeau & Brias                       F. Brais

Oct. 2, 1906                 Petzold & Kohler                    Rochester Experimental

Jun. 30, 1914               E. E. Ellis                                Union Caliper

Apr. 13, 1915              Blake & Reidy                         u.m.

Mar. 20, 1917              A. W. Bjornstad                       u.m.

Feb. 25, 1919              L. Kaplan                                 Indicating Calipers

Jan. 18, 1921               T. E. Grove                              Grove Mfg.

May 23, 1922              Green & Schuh                        C. F. Pease  

Sep. 19, 1922               H. Perrot                                  H. Perrot (Germany)

Oct. 15, 1929                E. J. Tjurnlund                        Reiner & Campbell

Mar. 2, 1943                 F. G. Eubanks                           u.m.

Sep. 25, 1985               C. A. Emerson                          Creative Publications

Dividers: Curiosities and Questions

Let’s take a break from posts dealing with anatomical investigations of dividers and look at some curiosities and pose a question or two.  

The first photo is of a pair of large, dual purpose dividers with outside caliper legs welded to the inside of the straight points. These are likely 18^th century or earlier. Also in the picture is a much smaller pair of flat stock dividers with basically the same design, but probably made 300 years later.   

 

 Converting one tool type into another by a creative handyman is not a new idea. Below, we have two pairs of pliers or diagonal cutters that have been modified to function as dividers. The amount of work that went into creating the pair on the left boggles the mind!  

 

The Swiss Army Knife of dividers. You can never have too many legs.

 

 Is the tool below a pair of flimsy dividers or does it have some other function?

 

 

Finally, a question of deep philosophical importance in the world of antique dividers. Why do some wing dividers have a wing that sweeps to the right while others have a wing that sweep to the left? I examined the 48 wing dividers from the 18^th and 19^th centuries in my collection and found that 60% have right sweeping wings and 40% left.

These 48 are predominantly English and continental examples. The 19^th and 20^th century patented dividers from the U.S. are all right sweeping. So……what’s going on here?

 Possible explanations include age, country of origin, handedness of the maker or, most likely, maker’s whim. 

Dividers With Hinged Lower Legs

 Sometimes you come across dividers or calipers where the lower section of one or both legs are jointed so they can swivel or rotate. This generally occurs for one of two reasons. In one case, it allows the points of the lower leg to remain vertical. Another use is to rotate another type of point into place. In this post we’ll look at examples of each of these applications. 

“Verticality”

In larger dividers, if the legs are widely separated, the points tend to slip as they cannot easily bite into the surface being measured. If the points face straight down this problem is reduced. The only downside to this is the degree of separation of the legs is reduced somewhat. What follows are several examples where this technique is used.

Sullivan's Mar. 9, 1880 patent. Unknown manufaturer. Machine screws holding lower legs likely   replacements.                        

Oscar Stoddard's Mar. 31, 1885 patent for dividers with lower legs that can swivel is similar in function to the Sullivan example above and the Copeland pair of dividers two photos down.

Stoddard 1885 patent

The dividers shown below are marked "S. Copeland Pat. May [24] 1887". Likely manufatured by Copeland and Chamberlain, Worchester MA. One removeable leg has a swivel point. A leg like this does not appear in the patent drawing and may not be original to the tool. It is similar to the legs in the Stoddard example above.

The example below is a Peck, Stowe and Wilcox No. 35. The add on, angled, fixed points are not marked in any way. They look like they may be patented, but I haven't located such a patent yet.

Finally a pair of wooden dividers (more precisely compasses) which have appeared in a previous post. The lower legs swivel and are held in place only by friction

 

Rotating in different points

A fairly common variation seen in calipers is the ability to rotate the lower legs to bring into position either inside or outside caliper points or standard straight points. An alternative method to achieve the same end is to have removable points that slide into or along side the upper section of the legs. This will be examined in a later post. 

None of the examples pictured below are marked with a manufacturer. All three are likely user made.

Until next time!

Dividers: Decorative Elements

 The design of tools is grounded in their function, but decorative elements add to their aesthetic appreciation. There are few antique tools that exceed early dividers in the degree to which artistic elements have been worked into what is ultimately a very simple tool. Tools from the 18^th century and earlier fall into two general categories. Everyday, utilitarian tools made by the user, or a local blacksmith are generally lacking in much decoration. Skilled craftsman and early, small shops produced pieces often showing a surprising amount of decorative detail. It’s probably safe to say that the more decorative elements a tool shows, the older it is. American made tools of any era show minimal decorations; English tools slightly more, while continental tools usually show the most. This applies to a range of tools such as wooden planes as well as marking and measuring devices such as dividers. Few sources highlight these ideas more impressively than Sandor Nagyszalanczy’s The Art of Fine Tools, 1998, Taunton Press. 

Decorative elements on dividers are generally focused on five areas of the tool:

-        Hinge joint

-        Wing nuts and thumb screws

-        Wing finials

-        Leg sculpting

-        Leg shape (mainly calipers)

-        Surface etching     

In this post I’ll give some examples of each of these from my collection. Far more impressive examples can be seen on sources highlighting museum collections (e.g. Museo Galileo) or web sites such as Jim Bode Tools, Fleaglass ,Tesseract and the wonderful French site Compas, dans toute leur diversite.  

Hinge Joints 

Not many examples exist in this category except for the concentric circles in the bullseye pattern characteristic of 18^th and early 19^th century “Lancashire pattern” English dividers (rt. below).

Bull'seye pattern on right

 Large eighteenth ccentury dividers, often called French armorer's dividers, can have very fancy extended hinge decorations.

French "Armorer's Dividers"

Closer view of above 

 Wing nuts and thumb screws 

A common and often whimsical design element in wing dividers. 

 

Heart, ram's horn and mouse ears thumb screws

Wing finials

Generally, a small artistic twist.  

Leg sculpting 

Usually, gouge-like chamfers in the upper legs, often file cut. Also, inscribed lines in thicker leg bosses (characteristic of Lancashire dividers).

 

A fine example with a range of filed elements

 Leg shape 

Most often seen in flat stock calipers. The best examples are “lady leg” or “dancing master” calipers. Those with detailed designs can be pricey.  

 

Lady leg calipers

Surface etching

 Not very common given the limited surface area on which to work. Etched owner’s names, as on one of the pairs of dividers below, can be quite fancy.

 

Dividers With Fine Adjustment

 For hundreds of years dividers and calipers relied on a single adjustment process to hold the legs in place. This usually involved friction at the main joint or a thumb screw bearing down on a wing. It’s unclear when a second adjustment step was added to the tool whereby the user could fine tune the spacing of the points once they were roughly set. This is almost always seen in wing dividers. My guess is this option became more common during the 1600’s. A 1709 print by Nicholas Bion shows a pair of wing dividers (“d” below rt.) with a fine adjustment wing nut attached to the end of the wing. If you look at the wing dividers in the painting “God the Geometer” from c.1250 there is a wing nut on the outside of one leg which could have been for fine adjustment. As you might predict, there are numerous ways that  fine adjustments were carried out. The focus of this post is to look at some of the ways this occurred. 

       

God the Geometer

                         

Bion: Mathematical Instruments

                          

                                           

Likely the earliest and most widespread technique to fine tune the points was to extend a rounded section of the otherwise flat wing through the leg opposite the leg with the locking wing thumb screw. If this protruding end was threaded, the wing could be moved a small distance in or out with a wing nut. For this technique to work effectively there needed to be a way to put pressure on the wing on the  inside of the fine adjustment leg. Typically, this was done by attaching a slightly curved piece of spring steel on the inside of the fine adjustment leg near the joint with the other end pulling on the wing, exerting a force opposite that of the thumb screw on the outside of the leg. This style has been in use for several hundred years. It’s common to find examples of dividers where this piece is missing or broken. 

                                                    

Sullivan's 1880 pat.
The most common form of fine adjustment

In some early dividers a second locking wing nut passes through the fine adjustment leg and presses on the wing extension within the leg and locks the wing in place once the fine adjustment is complete. In the second photo below the main wing locking screw is on the left leg and not visible.

                                                                     J. Stevens #61

J. Fenn, London, 1821-1873

A later development was to replace the curved spring steel piece with a small, coiled spring wrapped around the end of the thin wing extension which pressed against the inside of the leg and against a stop on the wider part of the wing. These variations are best understood by referring to the photos rather than my convoluted descriptions.                             

Starrett #85

                                                                                                                            

Stanley #57

                                             

What follows are a number of examples with various kinds of fine tuning mechanisms.

Unmarked with "roller nut"

W. Schollhorn "Pat. Appplied For"
The fine adjustment is on the left leg.

W. Schollhorn 1866 pat. +
1890 pat. for fine tuning on right leg + patented pencil holder

            

                                                                    Starrett #62

Early example with threaded insert in top leg

                                

           An interesting unmarked piece with an internal spring in the main joint to maintain tension.

        

               Likely a user made caliper with Rube Goldberg fine adjustment in the upper left

Rare to find wooden dividers with a fine tuning option
(doesn't work very well)

  

                                                                Starrett 1885 pat.

                                  Top thumb screw locks legs. Central knurled knob fine adjusts.

A final technique I'll mention for fine tuning dividers utilizes eccentric lower leg points. Since the points are not in a direct line with the legs above them, by rotating a lower leg one can change the separation of the points slightly. This can only work on dividers where the lower legs can rotate freely from the upper legs and lock . In the Stevens # 62 below the eccentric points provode a second fine tuning option that supplements the primary mechanism in the upper left leg.       

Eccentric points on a J. Stevens # 62, 1890 pat.