© All rights reserved G W Howe 2017
Gear making site
the Gear Generating Machine
specification
Gear Blank Diameter
min. 0.625” dia. max. 8” dia.
Gear Blank Bore Diameter
Large arbor
min. 0.5” dia. max. 1.0”
Small arbor
min 0.25”dia. max. 0.5”
Gear Thickness
max. 0.625”
Number of Teeth in Gear
Dependent on method/gear set configuration
Teeth cut per cycle
1 or more, dependent on DP
Cutter Stroke
1"
Cutter Thickness/Teeth
0.25” thick, 4-5 teeth
DP Range
20 - 48
Arbor Rotation
rack & gear method
Gear Profile
Generated
involute
Generation Method
Sunderland
Cutter Strokes per min
circ. 40-50
Castings used
none
Framework
steel plate (0.5” or 12mm thick)
Operation
fully automatic after setting for first gear tooth
Bearings
ball bearing and phosphor bronze
Drive Reduction
motor – belt then compound gear train (basic high ratio)
Cutter Lubrication
mech. recirculated pumped system
Scope:
Number of Teeth
The number of teeth that can be machined is only dependent upon the method used to rotate the gear blank fixed to the arbor. All methods
make use of a rack and gear(s) in mesh. The gears can be single or configured as a simple or compound train. Some gear teeth numbers will
not possible unless a direct copy of the gear is available.
For convenience, a set of gears has been selected to form a standard set and this set will provide a large range of numbers dependent on the
configuration devised. The standard gear set comprises: 20, 25, 30, 35, 38, 40, 45, 50, 55, 60, 65, and 70 teeth gears, all of DP20 and these
actually came from a Myford ML7 lathe (14.5PA, DP20)
Methods
The numbers shown below are by way of example and make use of the standard gear set.
Direct Gear Rotation Method - uses the standard gear set where the DP is the same as the standard set (DP20).
20, 25, 30, 35, 38, 40, 45, 50, 55, 60, 65, 70 (‘n’ teeth)
Indirect Gear Rotation Method - uses the standard gear set configured as a gear train to provide teeth numbers different from those in the
standard set but the DP is the same as the standard set (DP20). For example, in the range 18-57 the following are possible:
18, 19, 21, 22, 24, 26, 27, 28, 32, 33, 36, 38, 39, 42, 44, 48, 49, 52, 54, 56, 57
Gears not possible - 23, 29, 31, 34, 37, 41, 43, 46, 47, 51, 53
Different Gear DP/Mod Method - This method incorporates both the direct and indirect rotation methods above and uses the standard gear
set but significantly, enables the generation of gears having a different DP or Mod to that of the standard set.
using the standard lever attachment
- DP 24, 30, 34, 40, 48
- MOD 1.0, 0.9, 0.8, 0.7, 0.6, 0.5
note: additional lever attachments can be easily made to cater for other requirements as long as DP required is > standard set (DP20)
Direct Copy Rotation Method - A direct copy of a gear can be made for any gear having DP or Module notation, within the size limitations of
the machine. This method requires a corresponding cutter rack and a rotation rack which meshes to the gear being copied.