With a quick glance type 1 & 2 cancels look very similar, however differences in these two versions are found in the diameter of the circles and also the shape ("pointy-ness") of the cogs. The cancel types (i.e. 1, 2 & 3) were identified long ago, by Ashbrook & Jessup in the 1940’s, and are not something I personally created. Oddly enough, type 2 actually was the earliest used type, not type 1, although their "debuts" were only weeks apart.

**Characteristics of the type 1 cogwheel:**

Smallest diameter circles; 9-9.5 mm outer circle, 5-5.5 mm inner circle (measuring outer diameter).

Many cogs have pointy-tips (not squared or blunt), and appear wedge shaped (not rectangular).

**Characteristics of the type 2 cogwheel:**

Larger diameter circles compared to type 1, 10-10.5 mm outer circle, 5.5-6 mm inner circle.

Nearly all cogs (16 total) have squared-tips (not pointy or wedge shaped).

Take a quick glance at the cancel, specifically look around the circle for multiple pointy cog tips.
Do you see several cogs with wedge shapes or not? If you find yourself saying yes, this is type 1...if no, then type 2.
Several times I have used this approach and started out immediately counting out what I thought was one wedge,
and then that was all I found! Type 2 in these cases.

Another key that can be used for type 1 is that the two longest arms are diametrically opposite each other.
A line drawn thru the center of the circles will align along these arms. This approach is only viable however if the
strike is full and clear.

If you have the item in your possession, the circle diameter is the biggest identifier.
It is easy to measure the circles using a template to determine types. Note, you can make your own template
(clear plastic with circles of various sizes drawn on it, staggered in 0.5 mm diameters) using basic drafting
software such as Claris or Corel Draw, or even Power Point. This software can draw circles of the size desired,
then you can print on a plastic vugraph sheet instead of a sheet of paper. Obviously, if you do not have the item
and are trying to determine the type from a picture or webite, then looking at the cogs, per above, is required.

If using a measuring template, a type 1 outer circle diameter (9.5 mm) will not "cover" the type 2 outer circle
and a portion of the cancel will extend outside the template (conversely a type 2 outer circle diameter (10.5 mm)
will leave a gap when applied to a type 1 cancel). So you can easily determine the cancel type simply by
laying a 9.5 mm circle template on the cancel. If the cancel still pokes out and is not covered, the cancel is type 2,
if it hugs the outer circle nicely, it is type 1.

See the figure(s) below for a pictorial representation of this.

Details of the type 1 cancel are shown in the figure below (the "easiest to find" wedge shapes are circled).

Items englarged to show detail.

Details of the type 1 & 2 cancel relative sizes are shown in the figure below. Items to scale. The following figure is a zoom.

Here is a very good side by side example of type 1 (right) vs. 2 (left). It's easy to see the differences in this figure.

Rick Mingee (rmingee@frii.com) email Copyright © 2009 Rick Mingee. All rights reserved.