Smithy Midas 1220 XL - Manual (Page 53)

Figure 11.5 When you revolve the headstock against a piece of chalk,
The chalk should just touch the high spots.
6.
Next, drill and countersink the centers to conform to the profile of the lathe centers.
This is best done with a combination center drill/countersink held in the tailstock arbor
chuck. The centers now will take the lathe centers without play or chatter.
If a combination drill is not available, you can drill centers with a small drill and
countersink them with a drill of sufficient diameter ground to a 60° point. A 60° taper is
standard for lathe center points. Correct center depth is given in Figure 11.6. Take care
to get an accurate 60° countersink in the center (Figure 11.7).
Figure 11.6 The correct depth of center is illustrated above. If it's too deep (bottom)
only sharp outer edges will contact the center.
Figure 11.7 Counterbore centers with a drill to a 60° point so they fit the lathe centers (A).
Too obtuse (B) or too acute (C) a counterbore will give insufficient bearing
and destroy the lathe centers.
Chalk Marks
Compound
Chalk
Too Shallow Correct Path Too Deep
Work Work
Center
Hole
A B C
Lathe
Center
Point
Work
11-3 Or Visit www.smithy.com
Setting Up with Centers, Collets, and Chucks