In the following table is given the sizes of cutters as made by one company, the bores being 1 inch.

Width of
face.
Diameter of cutter.Width of
face.
Diameter of cutter.
inch.inch.inch.inch.inch.inch.inch.inch.
1821234 151621234
316212341 21234
142123411821234
5162123411421234
382123411221234
7162123413421234
12212342 21234
9162123421421234
582123421221234
1116212343 21234
342123431221234
1316212344 21234
7821234

The keyways are semicircular, the key being composed of a piece of No. 25 Stubbs steel wire.

The following is a table of the sizes of milling cutters made by another company.

Width of
face.
Diameter
of cutter.
Size of
hole.
Width of
face.
Diameter
of cutter.
Size of
hole.
inch.inch.inch.inch.inch.inch.
182141 342781
3162141 782781
1421211 2121
51621211142121
3825811122121
71625811342121
1223412 2121
91623412122121
5823413 2121
11162781

Cutters of 1 inch face and over have teeth of a spiral form.

The object of providing spiral teeth is to maintain a uniformity of cutting duty at each instant of time.

Fig. 1911.