Modified Stock Gearing - Boston Gear

Engineering Information
Sleeve Bearing Wear Life (Continued)
For optimum performance of BostonE F-1 bearings, the
mating surface should be as hard as possible. Mild steel,
however, will give satisfactory results.
A surface finish range of 8-16 micro-inches is preferred;
however, good results will be obtained with finishes to 32
micro-inches.
Figures 1 through 6 apply to BostonE F-1 material only.
TIME (HRS)
1000
800
600
400
200
FIGURE 1 — TIME VS. RADIAL WEAR
(UNLUBRICATED)
Load Deformation (%)
(psi) 78°F 300°F
250 .1 .4
500 .3 1.4
750 .5 2.9
1000 .8 —
1250 1.1 —
1500 1.6 —
FIGURE 2 — DEFORMATION
UNDER LOAD
LOAD (P.S.I.)
0 .0020 .0040 .0060
2000
1500
1000
500
10,000
PV
15,000
PV
RADIAL WEAR (IN.)
0 .05 .10 .15
20,000
PV
.20
COEFFICIENT OF FRICTION (F)
FIGURE 3 — LOAD VS. FRICTION
SLIDING SPEED (F.P.M.)
500
400
300
200
100
0 0.1 0.2 0.3
COEFFICIENT OF FRICTION (F)
FIGURE 4 — SPEED VS. FRICTION
Coefficient of Friction
Shaft Material
Hardened Steel 0.15
Stainless Steel 0.15
Chromium Plated Steel 0.16
Cast Iron 0.19
Hard Anodized Aluminum 0.20
Monel 0.23
Cold Rolled Steel 0.25
*Brass 0.33
*Aluminum 0.35
*High rate of shaft wear
FIGURE 5 — EFFECT OF MATING SURFACES
WITH BOSTONE F-1
Coefficient of Expansion
Temperature C.D. M.D.
Range (all values are x 10 -5 )
+68°F. to – 400° –1.8 –3.5
+68°F. to – 300° –2.3 –4.0
+68°F. to – 200° –2.9 –4.3
+68°F. to – 100° –3.5 –4.8
+68°F. to 0° –4.4 –5.9
+68°F. to +78° 12 25
(approximate data)
+78°F. to +100° 3.5 6.0
+78°F. to +200° 3.5 6.2
+78°F. to +300° 3.6 7.0
+78°F. to +400° 4.2 7.8
+78°F. to +500° 5.0 8.5
M.D. = Molded Direction (parallel to length of molded or
extruded rod or tube)
C.D. = Cross Direction (perpendicular to length of molded or
extruded rod or tube)
All tubes are approximately ± 5%.
FIGURE 6 — COEFFICIENT OF LINEAR THERMAL
EXPANSION
0.4
F
P-1930-BG 04/10 Boston Gear 800-825-6544 177