Fig. 2261.
[Fig. 2261] represents an ordinary solid hand reamer for parallel holes. The teeth are ground so that their tops form a true circle, this grinding being done after the reamer has been hardened and tempered, because in these processes the reamer is apt to get both out of round and out of straight.
Fig. 2262.
In some practice the reamers are formed as shown in [Fig. 2262], and are made in sets of three for each size; the first is slightly taper from end to end, the second is slightly tapered at the entering end for a length about or nearly equal to the diameter, and the third is parallel and rounded on the end like the second, and in many cases only three teeth are employed.
Fig. 2263.