Southbend SB1059F owner manual Leadscrew Shear Pin Replacement, To replace the shear pin

EVS Toolroom Lathe w/DRO S E R V I C E For Machines Mfg. Since 3/11

Leadscrew Shear Pin Replacement

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 PSB1042PF0927) or use the specifications in Figure 130 to fabricate your own.

	10.54mm
	8.75mm
5.8mm	3.74mm
	0.5mm
0.2mm	0.2mm
NOTE: Shear Pin Material = S45C (SAE 1045)

Figure 130. Shear pin specifications.

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

To replace the shear pin:

1.DISCONNECT LATHE FROM POWER!

2.Clean debris and grime from the shear pin area (see Figure 131).

Location of

Shear Pin

Figure 131. Location of shear pin.

3.Rotate the shroud washer on the leadscrew (see Figure 132) so that the cutout lines up with the shear pin head.

Shear Pin

Shroud

Head

Washer

Cutout

Figure 132. Shroud washer and shear pin alignment.

4.Put on safety glasses.

If you fabricate your own shear pin, make sure to use the material and dimensions specified in Figure 130. Otherwise, the shear pin may not provide the intended protection and lathe damage could result.

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