Drill Bushing Search
Click on following link Drill Chart for decimal sizing.
Bushing Search - Inch
- 1 Input letter of bushing style type (P = Press Fit) and a dash...P-
- 2 Input bushing O.D. in 64th's of an inch (20=5/16") and a dash...P-20-
- 3 Input bushing length in 16th's of an inch (8=1/2") and a dash... P-20-8-
- 4 Input bushing I.D. in 10,000th's of an inch (.1250=1/8")... P-20-8-.1250
Bushing Search - Metric
- 1 Input letter of bushing style type (PM = Press Fit) and a dash...PM-
- 2 Input bushing O.D. in mm's (8) and a dash...PM-8-
- 3 Input bushing length in mm's (12) and a dash... PM-8-12-
- 4 Input bushing I.D. in two decimal mm's (4.50)... PM-8-12-4.50
Drill Bushing General Spec's
Material
Standard drill bushings are manufactured from either C1144 Stressproof steel or other high carbon steels. The bushings are heat treated to achieve an ID Rockwell hardness of C62-64. Optional materials such as tungsten carbide, 52100 steel, A2 tool steel, D2 tool steel, M2 tool steel, 416 stainless, 440C stainless, 17-4PH stainless, 303 stainless, 660 bronze, Ampco 18 bronze, Oilite, and brass are available as specials.
Counterbores
Upon request, bushings can be ordered with or without counterbores. Long bushings with small ID's are slightly counterbored for proper drill-bearing length and chip clearance. Counterbores prevent binding and heat build up due to excessive bearing length. Counterbore diameters are generally 1/32 inch larger than the inside bearing diameter.
Concentricity
The bushing OD is ground concentric to the ID to within .0003 TIR (total indicator reading) for ID sizes from 1/8 inch to 1/2 inch (3mm to 12mm). For larger or smaller sizes, concentricity is within .0005 TIR. Unground bushings are concentric to within .006 TIR. On counterbore bushings, concentricity applies only to the drill-bearing length.
Installation Hole Size
To avoid jig-plate or bushing distortion, do not use excessive interference fits on press fit type bushings. The table below is for recommended hole sizes in unhardened steel or cast iron jig plates. Use of a jig borer or reamer is recommended for bushing installation holes. Standard chucking reamers with a plus tolerance should give the required hole tolerance needed. Other factors to consider regarding installation hole preparation are: (1) headed bushings require less interference to resist drill thrust, (2) longer bushings into thicker plates require less interference, (3) thinwall bushings are more prone to distortion, (4) less ductile jig-plate materials require less interference.
Press Fit OD Nominal |
Press Fit OD Actual |
Recommended Hole Size |
|---|---|---|
| 5/32 | .1578-.1575 | .1565-.1570 |
| 3/16 | .1891-.1888 | .1880-.1883 |
| 13/64 | .2046-.2043 | .2037-.2040 |
| 1/4 | .2516-.2513 | .2507-.2510 |
| 5/16 | .3141-.3138 | .3132-.3135 |
| 3/8 | .3766-.3763 | .3757-.3760 |
| 13/32 | .4078-.4075 | .4069-.4072 |
| 7/16 | .4392-.4389 | .4382-.4385 |
| 1/2 | .5017-.5014 | .5007-.5010 |
| 9/16 | .5642-.5639 | .5632-.5635 |
| 5/8 | .6267-.6264 | .6257-.6260 |
| 3/4 | .7518-.7515 | .7507-.7510 |
| 7/8 | .8768-.8765 | .8757-.8760 |
| 1 | 1.0018-1.0015 | 1.0007-1.0010 |
| 1-1/8 | 1.1270-1.1267 | 1.1257-1.1260 |
| 1-1/4 | 1.2520-1.2517 | 1.2507-1.2510 |
| 1-3/8 | 1.3772-1.3760 | 1.3757-1.3760 |
| 1-1/2 | 1.5021-1.5018 | 1.5007-1.5010 |
| 1-3/4 | 1.7523-1.7519 | 1.7507-1.7510 |
| 2-1/4 | 2.2525-2.2521 | 2.2507-2.2510 |
| 2-3/4 | 2.7526-2.7522 | 2.7507-2.7510 |
Press Fit OD Nominal |
Press Fit OD Actual |
Recommended Hole Size |
|---|---|---|
| 3mm | 3.020-3.014 | 3.000-3.010 |
| 4mm | 4.027-4.019 | 4.000-4.012 |
| 5mm | 5.027-5.019 | 5.000-5.012 |
| 6mm | 6.027-6.019 | 6.000-6.012 |
| 7mm | 7.032-7.023 | 7.000-7.015 |
| 8mm | 8.032-8.023 | 8.000-8.015 |
| 10mm | 10.032-10.023 | 10.000-10.015 |
| 12mm | 12.039-12.028 | 12.000-12.018 |
| 15mm | 15.039-15.028 | 15.000-15.018 |
| 18mm | 18.039-18.028 | 18.000-18.018 |
| 22mm | 22.048-22.035 | 22.000-22.021 |
| 26mm | 26.048-26.035 | 26.000-26.021 |
| 30mm | 30.048-30.035 | 30.000-30.021 |
| 35mm | 35.059-35.043 | 35.000-35.025 |
| 42mm | 42.059-42.043 | 42.000-42.025 |
| 48mm | 48.059-48.043 | 48.000-48.025 |
| 55mm | 55.072-55.053 | 55.000-55.030 |
| 62mm | 62.072-62.053 | 62.000-62.030 |
| 70mm | 70.078-70.059 | 70.000-70.030 |
| 78mm | 78.078-78.059 | 78.000-78.030 |
| 85mm | 85.093-85.071 | 85.000-85.035 |
| 95mm | 95.093-95.071 | 95.000-95.035 |
| 105mm | 105.101-105.079 | 105.000-105.035 |
| 115mm | 115.101-115.079 | 115.000-115.035 |
| 125mm | 125.117-125.092 | 125.000-125.040 |
