What is this tool?

[Clint Ormosen]

This compass looking thingy was in a box of stuff passed on to me years ago from a fellow modelers widow. I have no idea what it's for, but it's such a nice piece that I keep it around. Maybe I'm missing out on a great modeling tool?

[Pat Chewning]

Dividers.   Used on maps to set a distance between two points, then apply this to the scale and get the distance.

Or:  Set the dividers for 150 miles (for example) and "walk" them across the map 4 times to get 600 miles, which might show you how far your airplane can go, deliver some bombs, and then return.

OR:  Set the dividers on a scale drawing of the model airplane between ribs.  Then take the dividers to the scale to see how far apart the ribs should be.

OR: Set the dividers to a distance according to the plans and then scribe that distance on the part to be cut or drilled.

https://en.wikipedia.org/wiki/Calipers#Divider_caliper

[SDF]

They are proportional dividers. Used to transfer measurements from a scaled drawing onto the full size piece or vice versa. The position of the pivot sets the scale factor.

[Dan McEntee]

   Yup, proportional dividers. If you were going to hand enlarge a set of model plans from a magazine, you needed a pair of these to complete the job. In either an old Air Trails or Flying Models there was an article on how to make a simple set from Popsicle sticks and pins. I think I have a similar pair from my collecting drafting supplies and tools. These were used in conjunction with a pentograph (spelling?) which you traced the original drawing with a stylus and it made an enlarged tracing to the size required. I have an old wooden set in a box also.
   Type at you later,
   Dan McEntee

[Trostle]

    pentograph (spelling?)   Dan McEntee

pantograph

Keith

[Gerald Arana]

This compass looking thingy was in a box of stuff passed on to me years ago from a fellow modelers widow. I have no idea what it's for, but it's such a nice piece that I keep it around. Maybe I'm missing out on a great modeling tool?

I remember my drafting teacher using those to check my plates (drawings) and I always got "A's" on the project and a B or C on my printing. Worked out well as I got a A for the course!

Jerry

[Clint Ormosen]

U/C guys are so smart. I knew somebody here would know what they were. Thanks guys. Now I just need instruction on how to use them.

[Phil Spillman]

As a High School student in 1955/6 I used one of these and a parallelogram to scale up a Utility Racing boat from a set of plans! The boat was powered by a 20cu. in. Mercury outboard motor and went 55 mph with me in it! Next to having raised two children and being married for 54 years to the same lady, this was my most significant accomplishment in my 78 years of life to date! Naturally flying Ringmasters ranks up there as well!

Phil Spillman

[Mark Scarborough]

U/C guys are so smart. I knew somebody here would know what they were. Thanks guys. Now I just need instruction on how to use them.

basically, you set the ratio using position of the pivot point, lock it down, then if you are scaling bigger, you set the points on the small drawing, and the proportion scaled up dimension is on the other end now,, which you transfer to the drawing you are creating

[frank mccune]

     Hi All:

     Wow! As a young person, I was taught that this tool was called a divider and was used for dividing a distance into equal parts hence the name.  I later learned that they could also be used for many other purposes.  Like many tools, their uses ae only limited buy ones imagination.

                                                                                                                             Be well,

                                                                                                                              Frank McCune

[Steve Helmick]

They are proportional dividers. Used to transfer measurements from a scaled drawing onto the full size piece or vice versa. The position of the pivot sets the scale factor.

First correct answer, and the WINNER!

These  are simply "dividers".     Steve