MAY, 1898.

AND RAILROAD JOURNAL.

149

formed in this way and that drawn through a ring, which is
commonly known as “drawn” work. This formu1a, has been
repeatedly tested in the practical designing of dies for a wide
range of work and found perfectly satisfactory.

In cases of doubt connected with the forming or flanging
of difficult sheets, a small set of dies, made_to a scale size, of
hard wood, and used to flange a piece of sheet lead, ofalso a.
proportionate scale thickness to the full size sheet, has been
found very satisfactory, and owing to the fact that annealed
sheet lead, in its action, is analogous to a sheet of boiler steel
of full size heated to 1,700 to 1,900 deg. F., the action of the

and rather slow heat. The method of delivery of the heat to h

the bed of the furnace, in which the sheet is placed, should be
such that no one portion of a sheet can become overheated
by reason of flame contact. In color the heat should be not
exceeding a. bright cherry, and in temperature it may range
from 1,700 to 1,900 deg. F., according to the character of the
fianging.

Before flanging the first sheet, the dies should be heated up,
so that their proper expansion, which is provided for in the
formula referred to above, may take place, and the sheets,
when cool will be of the proper size. A common method of

.»_ . _:._u7.__}

Values of letters used in formulas :
W = Size of flanged sheet or any portion of it
when cold._
R = Radius to outside of flange when cold.
D = Depth of flange when cold.
T = Thickness of sheet when cold.
W: Size of female die when cold.
B = Size of male die when cold.
0 = Clearance between male and female dies
when straight and when cold. '
U = Clearance when curved and edge upset.
U’: Same when stretched.
hS ? .0078" per inch allowance for contraction of
s cc .
All dimensions in inches or decimals of an inch.
For general proportions of male and female dies:
11: 2.1 D; F = 2.1 D; P = 1.2Dand d = 1.5 D.

 

ll.‘

L_F—/“‘..__ jwjfi V -—fl§.. .

Thenlfor Fignll:
W = WS + w and

?X .1298

B=W— '—'R**~‘ +2.4’I‘=
‘J -_ 1-,;-><.0649
U: ——————R—- +1.2 T.

,1;-X .0649
U’ = 1.2 T -— ——R——
For Fig. 2: W = WS + w and
B = W ——(1.2T X 2).
O = 1.2T.

Note. —For ordinary practice and for radaii n_ot less than 3" or more than 15" and when ‘‘I)’‘ does not
exceed 4”-—“U” can = 1.27'.l‘. The female die decides size of sheet and all allowance for clearance m ust be

made on male die.

Formulas for Dies for Flanging Sheet Steel.

lead in these dies can be taken as a guide indicating the action
of the full size sheet in regularly designed dies for a similar
shap-e. The stretching or upsetting action of the piece of lead
used as an illustration in these small dies can be very readily
noted if the sheets when flat, and before being formed are
laid off in small squares of some convenient size. The distor-
tion o-f these squar-es after the flanging of the model sheet will
graphically indicate the distortion of the metal, and will be
analogous to what will occur in the full size sheet in regularly
designed dies.

The flanging press should be located in front of the furnac-e,
with a suflicient space between it and the furnace to allow of a
generous sized iron straightening floor. Convenient lifting
facilities should be provided for handling the dies, and also, in
the case of heavy sheets, an overhead rail or some satisfactory
form of quick moving crane for handling the sheets from the
furnace to the press, it being important to place the sheet in
the di-es as quickly as possible after it leaves the furnace, for
the best results.

The furnace should be provided with a level, flat floor, pref-
erably of fire brick, and may be heated by either coal, burned
in a separate re-generative chamber, produce-r gas or oil. The
construction should be such as to provide an evenly distributed

doing this is to heat the first sheet and place it on the dies
without flanging until the dies become sufficiently hot. Be-
tween the operations of flanging the dies should be thoroughly
wiped on their friction surfaces with some heavy oil, with a
hand mop.

The operating levers and the operator for operating the
press should be as close to the press as possible, so that the
various stages of the operation of the die in performing the
work may be closely observed. A center mark placed on the
sheets, and corresponding center marks on the dies, will great-
ly facilitate the centering of the hot sheet on the dies and
save time. The larger sheets, after being flanged, will be found
more or less out of true on their flat surfaces and will re-
quire straightening. The iron straightening floor referred to
is provided for this purpose, and this Work can be done with
the remaining heat in the sheet after flanging.

All flanged sheets should be thoroughly and carefully an-
nealed after they are finished and becfo-re being placed in the
boiler. Flanging by power being practically one operation,
will undoubtedly introduce into the sheet less local strains than
would be the case with hand flanging, and such as it may pro-
duce are effectively i removed by the careful annealing sug-
gested.