t
so hard that you split the bolt head. Three or four good center-punch
dents upon the wire over the slot will help to expand it.

131. The Framework is made of wood, the dimensions being shown in Fig.
70. A 5/16 hole should be made for S B, the thread of which will stick
through about 1/4 in. so that the winder-nut, W N, can be turned onto
it. W N should be on but 2 or 3 threads of S B. This will leave part of
it for the thread of the bolt magnet, and when this and S B meet in
center of W N they will bind against each other and hold the bolt tight.
The winder can be nailed or screwed at S to the edge of a table or held
in a vise.

APPARATUS 94.

[Illustration: Fig. 71.]

_132. Winder._ Fig. 71. This shows a winder that can be used for several
purposes by arranging different attachments. It will be first described
as shown in Fig. 71, where it is being used to wind a bolt magnet. The
principal dimensions are shown in the figure. It is made of 3/4 in. wood
about 3 in. wide, the two outer parts X and Z being nailed to the center
one, Y, which is to be held in a vise, or fastened to the edge of a
table. A 5/16 in. hole should be made through the upper part X and Z at
one side of the center, so that a long 5/16 bolt can be put through and
used as described in App. 93, if desired. A smaller hole, 1/4 in.,
should be made on the other side of the center for a 1/4 in. dowel. The
dowel, D, is shown, and this size is a little smaller than the hole in
ordinary spools, shown at A and B. One-quarter in. dowels can be made to
fit fairly tight into the holes by wrapping paper around them.
Five-sixteenth bolts can be screwed into the spool holes, shown by the
bolt magnet in Fig. 71. To firmly hold a spool from twisting around upon
the dowel-axle, a set-screw, S S, is needed. These are small screws, say
5/8 in. long, No. 5. A small hole should be made into the spool before
forcing in the screw. (App. 25.)

The spools A and B are fastened in this way, by set-screws, to D. The
handle, H, is made as in App. 93, in this case a short stove bolt, S B,
being used and screwed into B. Fig. 69 shows a very simple form of
handle for all such purposes, which may be used instead of the one here
shown. The details of winding on the wire are given under App. 88.

APPARATUS 95.

_133. Attachment for Winder._ Fig. 72. By using this addition to App. 93
or 94, almost any ordinary kind of windings can be made. The wooden
block, A, may be about