| Name and Model Number | Belcher Brothers Hatter's Slide Rule |
| Country of Origin | USA, New York |
| Date of Manufacture | 1850-1860 |
| Front Scales | Inches to measure the diameter of a hat |
| Back Scales | Table of hat sizes, diameters and circumferences of the hat or head |
| Scale Length | 12 cm (5 in) |
| Type of Rule | Slide Rule |
| Construction | Boxwood and bound grass end pieces – brass slide |
| Area of Use | Conversion |
| Comment | Used for the hat trade of the mid 1800’s, unusual to have the maker's brand on a hatters slide rule |
| Rarity | RRR |
| Donor | Collection of Clay Castleberry |
| Match Number | 350 |
| Thumbnail (Click Picture for Details) |  |
| In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen |
| (1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD. |
| • RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace. |
| • RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale. |
| • RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale. |