[Illustration]
The scale used in Valicourt is which is that here quoted.
[Illustration]
If bed-plate and slide rest are both equally diminished at each cut, a
shell results, with the close part internal. If bed-plate is increased
and slide rest diminished, the close part of the shell is external.
SPECIMEN I.--Tools 25, 32, 36; Click-plate 96 or 288.
Bed-plate moved. Slide rest moved. Circles done. Tool.
3 2 12* (1 done 7 missed) 25
6 1 12* (1 done 7 missed)
10 3 48* (1 done 1 missed) 36
3 16 24* (1 done 3 missed)
23 4-1/2 4* (16 done 8 missed)
29-1/2 2 96* 25
33 1 96*
or 33 5/8 288*
SPECIMEN II.--Tools 28, 36; Click-plate 288.
Bed-plate. Slide rest. Circles done. Tool.
1 1/2 12 28
4 1-1/2 12
7-1/2 2 4 (8 done 4 missed) 36
13 3-1/2 24 28
19-3/4 3-1/2 4 (16 done 8 missed) 36
19-3/4 1/2 4 (in spaces)
21-3/4 1 4 (above last)
B 17-3/4 m 1 4 (below last) 36
30 1/2 12 (20 done 4 missed) 28
29-3/8 1/2 12 {( 1 " 18 " )
{( 1 " 4 " )
28-3/4 1/2 12 Ditto.
28-1/8 1/2 12
27-1/2 1/2 12 {(15 done 4 missed)
{( 1 " 4 " )
26-7/8 1/2 12 {( 1 " 18 " )
{( 1 " 4 " )
26-1/4 1/2 As before
25-5/8 1/2 Ditto.
25 1/2 12 (20 done 4 missed)
From B to here, border, if with 96 click-plate, not good-looking;
tool a boring-bit.