| Backlash
Measuring Backlash
| Backlash
can be measured using a gauge similar to the one shown in the
diagram below, using a dial indicator (A) at the correct distance
(L) from the center of the output (low speed) shaft. |
|
|
| Alternately,
a degree wheel may be attached to the output shaft and backlash
measured in degrees (D) using a fixed pointer. To obtain
the correct measurement, rock the output shaft while preventing
the input shaft from moving.
|
| All
gearing requires backlash clearance to allow the gears to operate
without binding or creating excessive friction and wear.
The acceptable range of backlash in a new Hampton worm gear unit
is shown in the table below.
|
| Size |
Meas.
Distance (L) |
Backlash
mm (A) |
Backlash
o (D) |
| 34 |
21.5mm |
0.03
to 0.1mm |
4'48"
to 16' |
| 45 |
30.5mm |
0.05
to 0.12mm |
5'38"
to 13'32" |
| 50 |
37.5mm |
0.05
to 0.12mm |
4'35"
to 11" |
| 60 |
45mm |
0.06
to 0.13mm |
4'35"
to 9'50" |
| 70 |
52.5mm |
0.07
to 0.15mm |
4'35"
to 9'50" |
| 80 |
60mm |
0.08
to 0.16mm |
4'35"
to 9'10" |
| 100 |
76mm |
0.09
to 0.18mm |
4'5"
to 8'10" |
| 120 |
90mm |
0.1
to 0.2mm |
3'50"
to 7'40" |
| 135 |
105mm |
0.12
to 0.23mm |
3'56"
to 7'32" |
| 155 |
116mm |
0.13
to 0.25mm |
3'51"
to 7'25" |
| 175 |
135mm |
0.14
to 0.28mm |
3'33"
to 7'6" |
| 200 |
155mm |
0.15
to 0.35mm |
3'20"
to 7'46" |
| 225 |
173mm |
0.18
to 0.4mm |
3'35"
to 7'57" |
|
