Smithy Midas 1220 XL - Manual (Page 54)

Mounting Work Between Centers
Remove the chuck from the lathe, bolt the faceplate to the spindle if l angle (Figure 11.8),
and put in both headstock and tailstock centers. Fasten a lathe dog (Figure 11.9) to one
end of the work. For ease of operation, use a live or rotating center in the tailstock end
so you won't need lubrication.
Before centers starting the lathe, make sure the centers don't hold the workpiece too
tightly. Heat may cause the workpiece to expand, so watch for binding. Adjust the
tailstock center so the work turns freely but without end play.
If, after partially machining the workpiece, you find you must machine the stock under
the lathe dog, remove the workpiece from the lathe and place the lathe dog on the
machined end. Then turn this new tailstock center end of the shaft down to the desired
diameter or form.
Figure 11.8 Bolt the faceplate to the spindle flange
Using a Clamp Dog
Standard lathe dogs drive round, or near-round, shapes. Rectangular or near-rectangular
stock requires clamp dogs. In a properly made clamp dog, the under face of the heads
of tightening screws are convex and fit into concave seats, while the holes in the upper
bar are elongated. This design allows a firm grip of off-square shapes without bending
the screws. Top and bottom bars should also have V-notches to give a firm grip on
triangular or other odd-shaped stock. You can use clamp dogs or special V-jaw dogs also
to hold highly polished round bars.
Using faceplates
For work setup, faceplates serve two purposes. First, they drive workpieces held between
centers. Second, they hold workpieces shaped so you can't chuck them or mount them
on centers.
Faceplates for driving workpieces on centers are generally small. They're notched and
slotted to receive the tail of the lathe or clamp dog, bolt drive, or other driving tool
(Figure10.9). Faceplates for holding workpieces (irregularly shaped casting, machine, or
die parts, for example) are usually larger and have varied designs. They may be
T-slotted, drilled all over, or slotted and drilled. Workpieces mount on such faceplates with
T-slot or standard bolts, strap clamps, angle plates, or other standard setup tools.
11-4
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Midas 1220 XL Operator’s Manual