The most efficient speed for machine reaming is closely tied in with the type of material being reamed, the rigidity of the set-up, and the tolerance or finish required. Quite often the best speed is found to lie around two-thirds of the speed used for drilling the same material. The following table may be used for a guide:
| Material | Speed in Feet Per Minute (fpm) |
|---|---|
| Magnesium and its alloys | 170 - 270 |
| Aluminum and its alloys | 130 - 200 |
| Plastics | 70 - 100 |
| Brass and Bronze, ordinary | 130 - 200 |
| Bronze, high tensile | 50 - 70 |
| Monel Metal | 25 - 35 |
| Cast Iron, soft | 70 - 100 |
| Cast Iron, hard | 50 - 70 |
| Cast Iron, chilled | 20 - 30 |
| Malleable Iron | 50 - 60 |
| Steel, Machinery .2C to .3C | 50 - 70 |
| Steel, Annealed .4C to .5C | 40 - 50 |
| Steel, Tool 1.2C | 35 - 40 |
| Steel, Alloy | 35 - 40 |
| Steel, Automotive Forgings | 35 - 40 |
| Steel, Alloy 300 - 400 Brinell | 20 - 30 |
| Stainless Steel, A.I.S.I. 301, 304 | 15 - 35 |
| Stainless Steel, A.I.S.I. 302, 309, 314, 316, 325, 420 | 15 - 30 |
| Stainless Steel, A.I.S.I. 303, 321, 347, 414, 430, 431 | 20 - 40 |
| Stainless Steel, A.I.S.I. 310 | 15 - 40 |
| Stainless Steel, A.I.S.I. 403, 405, 406, 410 | 20 - 50 |
| Stainless Steel, A.I.S.I. 416F, 420F | 30 - 60 |
| Stainless Steel, A.I.S.I. 430F, 440F | 30 - 50 |
| Stainless Steel, A.I.S.I. 440A, B & C, 442, 443, 446 | 15 - 30 |
A lack of rigidity in the set-up may necessitate slower speeds, while a rigid operation may permit high speeds.
When close tolerances and a fine finish are required it is usually necessary to finish ream at considerably slower speeds.
In general, reamers do not work well when they chatter. Consequently the primary consideration is selecting a speed low enough to eliminate chatter.
