Southbend 13" Heavy 13 Gearhead lathe SB - Manual (Page 82)

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For Machines Mfg. Since 5/11 13" Heavy 13 ® Gearhead Lathe S E R V I C E
Leadscrew Shear Pin
Replacement
Tools Needed: Qty
External Retaining Ring Pliers #1 ....................... 1
Magnet ................................................................... 1
Safety Goggles ....................................................... 1
Blow Gun w/Compressed Air ................................ 1
Light Machine Oil .................................. As needed
The leadscrew is secured to a connecting collar
that is part of the headstock drivetrain with
the use of a soft-metal shear pin. The shear pin
is designed to break and disengage the power
transfer to the leadscrew to help protect more
expensive lathe components in the case of a
carriage crash or the lathe is overloaded.
Contact South Bend to order a replacement shear
pin (Part Number PSB10121234) or use the
specifications in Figure 128 to fabricate your
own.
If you fabricate your own shear pin, make sure
to use the material and dimensions specified
in
Figure 128. Otherwise, the shear pin may
not provide the intended protection and lathe
damage could result.
9mm
7mm
5.8mm
0.5mm
0.2mm 0.2mm
3mm
NOTE: Shear Pin Material = S45C (SAE 1045)
Figure 128. Shear pin specifications.
To replace the shear pin:
1. DISCONNECT LATHE FROM POWER!
2. Rotate the shroud washer on the leadscrew
shown in Figure 129, so that the cutout
lines up with the shear pin head.
Figure 129. Shroud washer and shear pin alignment.
Cutout
Shear Pin
Head
Shroud
Washer
Figure 130. Shear pin access.
3. Put on safety glasses.
4. Move the retaining ring shown in Figure
130 away from the shroud washer.
5. To make enough room to remove the shear
pin, move the shroud washer away from the
shear pin and against the retaining ring, as
shown in Figure 130.