From our Magna-Lock USA archives, a discussion of rotary electromagnetic chuck types and comparison of Mattison and Blanchard chucks.
To illustrate a point I wish to make, let’s for a moment assume we were asked to engage in an in-depth study of the clothing industry. Of the many types of clothing on the market, how would you prepare a simple logical outline of the many classifications applicable to clothing? Should our major divisions be woman’s clothing vs. men’s clothing? Or should our major divisions be outerwear vs underwear? Or should we start with formal vs. casual wear? Or we might consider groupings on the basis of fabrics, or colors, or many other characteristics. I’m sure you’re ready to admit the outlining of the broad product category “clothing” would be horrendous task.
It seems necessary to touch on the history of the electromagnetic rotary chuck product line and I’d like to think this helps us understand why we do or don’t do certain things with the products under consideration. I’ll go back to somewhere around the late 1930’s or early 1940’s, the early World War II days. At that particular time—and it still holds true today—the leading manufacturer of vertical spindle, rotary table surface grinders in the USA was the Blanchard Company. In fact, their machines were so widely accepted that this type of grinding was commonly referred to as “Blanchard Grinding,” a misnomer which persists to this very day. At this same point in time a similar grinder was also manufactured right in Big Rapids, Michigan by the Hanchett Manufacturing Company. Incidentally, both Blanchard and Hanchett manufactured their own concentric ring rotary electromagnetic chucks used on the work tables of their machines. Previously, I’ve explained how in late 1948, the Hanchett rotary table surface grinder business was sold to Mattison Machine Works in Rockford, Illinois, where the machines were continued to be manufactured until the 1990’s when Mattison closed. You’ll remember that it was also at the same time in late 1948 that the Hanchett Company sold their magnetic chuck line to result in the formation of Hanchett Magna-Lock, the forerunner of the present Magna-Lock USA brand. And Magna-Lock had been virtually the sole supplier of rotary magnetic chucks for Mattison’s grinders.
The differences in the chucks of the 1980’s and the chucks of the 1940’s for Mattison grinders would be barely discernible to the naked eye, except that the most popular size in the 1980’s was the 42” diameter chuck. Back in the 1940’s, the most popular size jumped back and forth between the 30” and 36” diameter chucks. Other familiar popular Mattison sizes include 48”, 54”, 60”, 84”, and 96” diameter; and on occasion we have supplied 90”, 108”, 120”, 144”, and 168” diameter chucks.
Magna-Lock had been virtually the sole supplier of rotary magnetic chucks for Mattison’s grinders.
The Mattison chucks are designed with removable top plates.
Removal of Mattison chucks is simple.
The Mattison chucks are complete units, integral assemblies which are then simply mounted on the round table of the grinder.
Other Rotary Chuck Patterns
Rotary electromagnetic chucks are by no means limited to concentric ring top plate patterns. Magna- Lock USA have manufactured a variety of other designs and modifications. Time does not permit an in-depth study of each of these concepts, but some of the better-known types have been included in the following list:
A. Radial Pole – a pattern of radial spoke-like non-magnetic separators dividing the pole pieces into pie-shaped segments.
B. Heavy-Duty Crossover – a modification of the conventional radial pole pattern, generally with one pair of parallel non-magnetic separators at right angles to a similar second pair of parallel separators. The cross shaped area between the two pairs of separators becomes one magnetic polarity, while the four remaining circular segments are of the opposite magnetic polarity.
C. Clover-Leaf – still another form of radial pole pattern in which the path of the single non- magnetic separator describes the outline of a multi-leaf clover. The area within the separator is one magnetic polarity and the area outside the separator is the opposite polarity.
D. Tear Drop – a modification of clover-leaf pattern, except there is a symmetrical pattern of lobed pole pieces each with its individual non-magnetic separator totally enclosing it.
E. Staggered Pole – commonly used on Arter grinders. Can be considered another of the clover- leaf modifications, except that the separators’ outlining the clover leaves describe a severely accented serpentine pattern. You could say the clover leaf becomes a maple leaf.
F. Straight Chordal Laminated – with a parallel laminated pole pieces and separators, resembling a circular piece sawed out of a conventional rectangular laminated chuck.
G. Grid Style – grids and fingers (like those in rectangular grid style chucks) arranged in a geometric pattern.