| 8 | 7-15/16 | 9- 9/32 | 11-23/64 | 4 | 5- 3/16 |
| 8- 3/8 | 8- 5/16 | 9-23/32 | 11- 7/8 | 4- 3/16 | 5- 7/16 |
| 8- 3/4 | 8-11/16 | 10- 5/32 | 12- 3/8 | 4- 3/8 | 5-11/16 |
| 9- 1/8 | 9- 1/16 | 10-19/32 | 12-15/16 4- 9/16 | 5-15/16 |
|_________|_________|__________|__________|_________|_________|


The dimensions given for diameter at root of threads are also those
for diameter of hole in nuts and diameter of lap drills. All bolts and
studs 3/4 in. diameter and above, screwed into boilers, have 12
threads per inch, sharp thread, a taper of 1/16 in. per 1 inch; tap
drill should be 9/64 in. less than normal diameter of bolts.

The table is based upon the following general formulæ for certain
dimensions:

Short diam. rough nut or head = 11/2 diam. of bolt + 1/8.
" finished nut or head = 11/2 diam. of bolt + 1/16.
Thickness rough nut = diameter of bolt.
Thickness finished nut = diameter of bolt - 1/16.
Thickness rough head = 1/2 short diameter.
Thickness finished head = diameter of bolt - 1/16.

* * * * *




AN ENGLISH RAILWAY FERRY BOAT.