Wood bending in ship building


Material Information

Wood bending in ship building
Physical Description:
Peck, Edward C
Forest Products Laboratory (U.S.)
U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory ( Madison, Wis )
Publication Date:

Record Information

Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 29302355
oclc - 39530053
System ID:

Full Text
April 1943

U. S. DEPT. Oi- fx
L! I33F
ATLA 11 H '1A

No. IP1430

Madison, Wisconsin
In Cooperation with the University of Wisconsin

Im Of

- ~ ~ ~ r ~ C c~liL
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Vn- ti 7rr' n r n Mis 17 ty-~ o-4h r7 .:
7 7na -fC ov 7for s- ari-h rq~n~ 11 > r ni h r -n
orco- o 5 or cmor>.' :Trnn in7 f rl P 30 r rr ta& r 1~ ih r'-.
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f-:n~hV v-y ri th i~-rA 7,'~ -hc 1r nh-. off1hr~I r
~ i~ rTOhp -r rcr' -' Urt2' ion nf~~ 7'r th 'r
n,~e CIA 700 nin c-< on- :QTs 1! ~ a 1 t rin 01 <' 1 cn
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ONO c -:v Yrn s+W of -.I-. rir; Y, 1r r m

boon usrd in s;-ir I uildinr T, er'rf,:rr.d for I r-t i nr 17o I
wood. from, a ,r-cics ordinarily. ausoi for b -ndin,-~e l~nj~ t
be strai,-ht-grained; the devint-icn in *cr r c~rc s-- -h--k'ho i. nc
exceed 1 inchE in 11; inches. Tr1.s 7.rr 1 i (77 t cb ira in cf TrrL-
whole and also to irr ,,%larit**,s in. tj 4icnity-, of ?.not.si r~
voodl muast b freeo from decay. W o o d of 11i,-h d- ns ity ip i, s -irat I rc'
i t Ssu7.Perior strength rro-pertie-s but with 'crcr.,Ir Tpchrni,-uo -,:ci of :t
density or ,ith~ a partic,. ar raPte of -~rowth is not (-,s -ntial to 'W~
bending. WooO, of high density has a hi,7 r1 et-, of uc';or
is diffic,-lt to dete~rmin(e this Ierc, ntar:e in hardwoods. An i- 'LJ'( = <
is to note 7_h_ number and size of the pores. Efc ,s s,,,rh -, i -nr*:,, 'r., '
holes, and~~,m s-arface ch- cks ar de-trimental, s-Inc,7 thel- c
failure s, b-r_ small sound ; nots n-,ar the ends, moderat- S-arfrle ~ r~
and scattrd worm holes are -permiss3ible. A riec ccntainin r
or the heart center of tI- trpo is not su~i-able for -,din -.
Seasoninr- of Stoci
There i con, erT l iffor anc of opinion re, ar .nJ V c
ture content of the stock at 111r timp of bezndin'. _? ndinF, i7,t":'I
wood ,lhose, moisture con'nt rar,-- from thr, g~r er ccndit ion e' to 12
rercpnt. '-7ee ,i "oci 7it xc-jt, ionatlly hi h moi ;t are conr.7 -c': 'L
able for severe be nds becausf- yJrstatic rrpss,:rct ma'-Ic;.c or Q
in contact 1-it~ t- form and comi errr(io +alrs rma~
stands cint the oim-i_ :n oi ;ture' contend t is r'~~ in th vic Initv of
f iber- saturat ion joint, from 211 to 7)" r-rc -nt rnoistc arp rrTr -
-i.Te oo-d for b; ndin, c,7nnot V :rt en in t-- r- confi ti-
wit'ho7)t the: levelop-ment of stain and dcay~: expertt durin,7r cc16" r
mor-t stock must undergo -orr, ,, a ,ninp btfor,- I-ndinp7. L~at niaI '
waIrm ,,eather must be -rrotc eted. from s-an and r,-i ni i or. V I~
ile 1,7iting shil Jnt Or.iiJia ci -illn ~ le
shc-alO. be r,-led or, st t nr itr r ir1 a 3hpd or inr an. Fir s pa s cn r TI
I r tcte d f r oii s-.n and p re oc. i-1E,/_3rirng coldwar -ri 7
catosare- reo-ire Uc 1-s~ r~n ,tpe o-aisr,-. lro e!
active. it is cood rrnotie to aT, r a, mois- inrc rr- J_,+tr coat r.- to t-
;-nds of f ie tireiti af- __e _hr C13,r) to rf dn c- nvro -At
of -i -sedr nd end sT,11itcin.
Pr-par~ntion of Bendinp' 3ri,17s.
Fies for any farti-al,-ir sho:I rcl riu o --n orm
.~~~~eV hro ua~~ tlh, leg Trrev th IS'o> r&r
n'ai. 7,i' --,,ough rAilo-ane~ for _riks.Io r n~ebei~-~
,,idtI shc-_ld0 be r'etrtt~ h e i ics arn cor.,- fs ber nr
multi-rl-n of des1-red ~t~ and ae af' -r ',;iz. S~fe~ ~
next to tnt form ;and r I~ mWJear.t s -s il Leic 'jj -r of -Cir

70ft~h~rjaW rcn ir T
i nrk Tol Va~~od ) -a 7r pimf~cn; j'> ~jd
Loc nt iz mlo of Tv-,nrin7 -m fro~~~j or r icf yrpsp
r ~ T tprn ion
T 1:o r nir. nr"I- h. V 7. ac*~r rno-tA :h
07 -f rA r7 kithou r~ YK 7" ~ r s o
0. n St 1ar ;i -ri -A 1o frrii 17 :zor fir v nF or
2 ~ ~ ~ ~ ~ ~ ~ ~ l- --ich is t o i 1,i~o 'u1r c~s ~r o''' ~i~'~
7? fOr ,c ro! n nn! onac As .r1t iir p: o' ~ s> ~~
mrnr lon r Y! cnc -a 'ns ":n C r- r :?1-' cc'~ 2t
xr-s- -re orl -of Vnc Y in tcv~'1 r ';~~C. i~s >r~i
on, 0) AnD': !Lc ; r-r Y1-7~''' P orc t
1Ko. -cn-v- ;!V.- 7hm. n t co'r-~ royt Vi M-1c
f w ho A nl _rr0 ;7r- qqd h-nlin l-~r-r ns-s 74-~ry -0 ;ro-;7
S'-r nV reaup rr' p : -r t np ro r p :7of
-Y I~ Annre 1-7- i -nt' 1C c f -nk V~ i or wz
n.fr, 0 : of von rou lv rrr -r. Trn2=r- cn nr 1 1- r -l rn
- ~ 1 11 n'< o i cPr r z .y 1j' is wr t3sary~' i nr-- a :c~f
-17 "I7 -11 n~o- 7 rtu rn on!' to m;1r~ ar- 1~
no, Y PC ~ pi Nprt bir A I d 1 0
3) Az 7h "-nd q-sr, >
r rrn- N( as i l 1 C V

has seasoned enough to hold its share. Scrtirn s t, nsicn f~ir ,on
outer side of the curve, takc~ -rlac- durin this lryirg rrocc 37 0; T. r "
this a mninor strap is soml. tim -s rrplied to the 1-'~~or r, -in;. 1C-
bending, a chain is attached to thp~ Pnds of this strar, ,,,hich :it 1
holding the share of the riece and in retaining sufficient rA p n -'-I:
prevent tension failure during seasoning.
Sometimes bent parts check severely during coolir.7. S, A.,h c h, 1n 5
is likely to be severe in stocks that is bent while grc en er T;.artiall1
seasoned. Heat stored in the bending blank during the softpnin, -roc-
causes very rapid evaporation. Then thle ripe is cooled in the :,ir ,fter
bending shrinkage occurs in surface layers before the interior of t-ne
-piece hns lost sufficient moisture~ to cause it to shrink. Ccoiin-- un, ~r
~rEter at normal temperatures TrPvents this raid evaporation ani --i-tits
the subs,7(uent drying to take place More slowV'ly.

"'imeo "o : 1430


--) 7 I-A


4--49 F

t9L OC K I


Figure 5.--Wood bending process using reversedlever principle: a, piece; b, two sections
of I-beam as reversed levers; c, form; d, strap, welded near its ends to b;
e, end abutments welded to strap; f, steel plates bearing against ends of
piece; g, end screws threaded through e to apply pressure to steel bearing
plates f; h, steel cable to pull the piece into position around the form;
i, one ofthe clamping mechanisms made with a shank to fit into holes in the
ZM39136F bending table so that the piece will maintain close contact with the form.
Note: End screws I must be centered carefully on the ends of the piece
otherwise buckling, as shown on the right end, is likely to occur.

P S T Y 0 ;: F L OR I E) A
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