The same general instructions given for making fluted hand reamers are applicable to this form, except that the shank may be finished to size before the reamer is hardened, unless the shank is to fit a collet or is to be held in a chuck.
Fig. 53. Diagram Showing Method of Grinding Reamer for Clearance.
The regular jobbing reamer used in the lathe is shown in Fig. 54; the form for the chucking lathe or drill press, where the shank is held in a collet or a chuck, is shown in Fig. 55. When making the latter style of reamer, B may be left .010 to .015 inch above size to allow for grinding. The portion C may be finished to size, and the dimension of the cutting part of the reamer stamped on it as shown; if the reamer is made for special work and is to be used on no other, the name of the piece or operation for which it is intended should also be stamped.
On account of the uncertainty of a reamer cutting exactly to size when used in a lathe, chucking reamers are frequently made somewhat under size. Standard hand reamers are used for finishing. The amount of stock left for the hand reamer varies. Some tool-makers consider .005 inch the proper amount for all reamers up to 3 inches in diameter; while others think that for 1 inch or less diameter, .004 inch is right, and that for sizes from 1 1/16 inches to 2 inches, .007 inch should be allowed. For reamers larger than 2 inches in diameter, an allowance of .010 inch should be made. The exact amount necessary for finishing with hand reamers depends on the nature of the work and the stock operated on. Fluted chucking reamers are made with either straight or spiral flutes.
Fig. 54. Rose Fluted Chucking Reamer Courtesy of Union Twist Drill Company, Athol, Massachusetts.
Fig. 55. Chucking Reamer with Straight Shank for Screw or Chucking Machines.
When a reamer is used in a screw machine or a turret lathe, on work where accuracy and straightness of hole are essential, it should be held in some form of special holder, which allows it to locate itself properly as to alignment. These holders will be described later.