Changing Gears For Screw Cutting - Eastwood 32497 Instructions Manual

CHANGING GEARS FOR SCREW CUTTING

The Leadscrew is driven, via a Gear Train, by a Pinion Gear on the Spindle. The gear ratio will therefore determine the rotational speed of the Leadscrew with
relation to the Spindle. Conversely, one turn of the Spindle will turn the Leadscrew a corresponding amount determined by the gear ratio.
By setting the gears to a known ratio, threads can be cut to a known size, and as the Leadscrew supplied produces SAE threads, the known values will be in
Threads Per Inch (TPI), or if the Leadscrew supplied produces Metric threads , the known values will be in mm pitch.
As previously mentioned, the actual thread produced will be totally dependent upon the profile of the cutting tool. It is not within the scope of this manual to
provide detailed information regarding types of cutting tool, cutting speeds and working with various types of material etc., and it is strongly advised that you
consult appropriate handbooks or seek advice from a qualified person.
The chart below shows the thread sizes that may be cut using the gear configuration shown in the corresponding columns.
NOTE: The factory default setup for the lathe provides for normal turning using the power or auto feed, and the gear configuration is as follows:
- Gear A = 20T
- Gear B = 80T
- Gear C = 20T
- Gear D = 80T
SAE Gear Train Examples :
1. (FIG 15)
To cut 12 TPI, use:
• 40T in position A
• 30T in position D
• Any gear that fits as an idler to connect A and D
2. (FIG 16)
To cut 13 TPI, use:
• 40T in position A
• 65T in position B
• 60T in position C
• 30T in position D
METRIC Gear Train Examples:
1. (Fig 15)
To cut 0.5mm/T, use:
• 20T in position A
• 50T in position B
• 60T in position D
• Any gear that fits as an idler in position C
2. (Fig 16)
To cut 0.4mm/T, use:
• 20T in position A
• 50T in position B
• 40T in position C
• 60T in position D
16
FIG. 15
C
FIG. 16
B
C
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A
B
C
D D
A
B
C
D
A
B
A
D