UnionSpecial 39500FS Instruction sheet

From the library of: Superior Sewing Machine & Supply LLC
FINE ST QUALITY
ST YLES
39 500FS
39 500FT
395 00FU
39S 00G D
395 00GL
395 00GT
395 00J P
395 00MM
CATALOG
No.
103FS
SECOND
EDITION
LEWIS• COLUMBIA
CLASS 39500
HI-STYLED
®
INDUSTRIAL
SEWING
MACHINES
HIGH SPEED OVERSEAMERS
WITH
INTERMITTENT DIFFERENTIAL FEED
CHICAGO

From the library of: Superior Sewing Machine & Supply LLC
Here are
Oil Specifications
for Union Special
Sewing Machines
Specification 174 spec ifies a high q ualit y pet-
roleum oil, viscosity 100 sec ond s at 100° F. Recom-
mended for all oiling applications on high speed
machine s.
Specification 175 specifies a high quality pet -
ro
leum oil, viscosity 100 seconds at 100°F ., water
whit e or wi th a maximum A.S.T.M. co lor number of
1. For use where freedom from oil staining is para-
mount.
Specification 87 specifies a high quality pet ·
roleum oil, viscosi ty 300 seconds at 100°F.
Specification 100 specifies a general purpose
high quality grease for use in ball bearings and trans-
mitter s. It is similar to commerc i al N.L.G .I. , grease No .
3. Where
No. 3 grease is not obtainable, No. 2 may be
used.
UNION SPECIAL
SPECIFICATION NO. 174 175 87
Viscosity S.S.U. at 100°F
90-125 90 - 125 300-350
Flash (Min.) 350 350
350
Pour (Max.) 20 20 20
Color A.S.T.M. (Max.) 3 1 3
Neutralization No. (Max.) 0. 10 0. 10 0.10
Viscosity Index
(D & D Min .) 85 85 85
Compounding None None None
Copper Corro si on (Max .) lA lA lA
* An line No . 175-225 175-225 175- 225
*Used wi th Buna N Rubber " O" Retainers
..
NOTE 1: The use of non- corrosive additives in oil s
meeting above classification
is desirable but not
essential. These may include :
1. Oxidation inhib i tors
2. Rust inhibitors
3. Lubr i city addit i ves
4. Anti - oxidant s
5.
Film strength additives
These additives must be completely so lubl e in the oil
and not removable by wick feeding nor shall they
separate.
NOTE 2: Oil s c onta ining th e following type addit i ve s
shall
not be used at a ny time :
1. Extreme pressure additives-corrosi ve
2. Tackiness or adhesive additives
3. Lead soap
additives
4. Detergents
®
f! NUT OUA U TY
CORPORATION

From the library of: Superior Sewing Machine & Supply LLC
October, 197 3
Catalog No. 103 FS
INSTRUCTIONS
FOR
ADJUSTING AND OPERATING
LIST OF PARTS
Class 39500
39500 FS
39500 FT
39500 FU
39500 GD
Styles
39500 GL
39500 GT
39500 JP
39500 MM
Second Edition
Copyright 1967
By
Union Special Corporation
Rights Reserved in All Countries
CORPORATION
INDUSTRIAL SEWING MACHINES
CHICAGO
Printed in U.S. A.
3

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IDENTIFICATION OF MACHINES
Each Union Special machine is identified by a Style number on a name plate on
the machine. Style numbers are classified as standard and special. Standard Style
numbers have one or more letters suffixed. but never contain the letter "Z". Ex-
ample: "Style 39500 FS". Special Style numbers contain the letter "Z". When only
minor changes are made in a standard machine. a "Z
II
is suffixed to the standard
Style number. Example: "Style 39500 FSZ".
Styles of machines similar in construction are grouped under a Class number
which differs from the Style number in that it contains no letters. Example: "Class
39500".
APPLICATION OF CA TA LOG
This catalog applies specifically to the standard Styles of machines as listed
herein. It can also be applied with discretion to some Special Styles of machines in
Class 39500. References to directions, such as right. left, front, back. etc •• are
given from the operator's position while seated at the machine. Operating direction
of handwheel is away from operator.
STYLES OF MACHINES
Hi-Style High Speed, One or Two Curved Blade Needles. Two Looper. Three or
Four Thread Overseaming Machine. Intermittent Differential Feed. Trimming
Mechanism with Spring Pressed Lower Knife. Automatic Lubricating System.
39500 FS Single needle three thread. medium to heavy duty machine. for seaming
and intermittently gathering or shirring on woven and knit materials such as
dresses. aprons. lingerie. smocks. nightgowns and similar garments. Knee
press controlled tandem intermittent differential feed. Slotted presser foot to
separate top and bottom plies. Gathering ratio up to 3 to 1 depending on stitch
length. Seam specification 504-SSa-1. Standard width of seam 1/8 inch (3.17
mm). Stitch range 8-20 per inch. Cam adjusted main and differential feeds.
Maximum recommended speed 6000 R.P.M.
39500 FT Single needle three thread, medium to heavy duty machine. for seaming
and intermittently gathering or shirring on woven and knit materials such as
dresses. aprons. lingerie. smocks. nightgowns and similar garments. Knee
press controlled _ tandem intermittent --.? ifferential feed. Independent swing-out
pressure plate att a c lmien t for shirring .! Gathering ratio up to 3 to 1 depending
on stitch length ';- Seam specificat T <5il" 504-SSa-1. Standard width of seam 3/16
inch (4. 76 mm). Stitch range 8-20 per inch. Cam adjusted main and differential
feeds. Maximum recommended speed 6000 R.P.M.
39500 FU Single needle three thread. medium to heavy duty machine. for seaming
and intermittently gathering or shirring on woven and knit materials such as
dresses, aprons. lingerie. smocks. nightgowns and similar garments. Knee
press controlled tandem intermittent differential feed. Presser foot bottom
grooved for 1/ 8 inch cord. Independent swing-out pressure plate attachment for
shirring. Gathering ratio up to 5 to 1 depending on stitch length. Seam speci-
fi cation 504-SSa-1. Standard width of se am 3/16 inch (4. 76 mm). Stitch range
8-20 per inch. Cam adjusted main and differential feeds. Maximum recommend-
ed speed 5500 R.P.M.
39500 GD Two needle four thread. medium to heavy duty machine. for seaming and
intermittently gathering or shirring on woven and knit materials such as dres -
ses. aprons. lingerie. smocks. nightgowns and similar garments. Knee press
controlled tandem intermittent differential feed. Independent swing-out pres -
su re plate attachment for s hirring. Gath er ing r atio up to 3 to 1 de pending on
stitch length. Seam specification 512-SSa-1. Standard width of seam from left
needle 17 / 64 inch (6. 75 mm). Stitch range 8-20 per inch. Cam adjusted main
and differential feeds. Maximum recommended speed 6000 R.P.M.
4

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STYLES OF MACHINES (Continued)
39500 GL Two needle four thread, medium to heavy duty machine, for seaming and
intermittently gathering or shirring on woven and knit materials such as dres -
ses. aprons, lingerie, smocks, nightgowns and similar garments. Knee press
controlled tandem intermittent differential feed. Independent swing-out pres -
sure plate attachment for shirring. Gathering ratio up to 5 to 1 depending on
stitch length. Seam specification 512-SSa-1. Standard width of seam from left
needle 17/ 64 inch (6. 75 mm). Stitch range 8-2 0 per inch. Cam adjusted main
and differential feeds. Maximum recommended speed 5500 R.P.M.
39500 GT Single needle three thread. medium to heavy duty machine, for seaming
and intermittently gathering or shirring on all types of cotton, dacron, rayon
and silk fabrics where a 3/ 32 inch (2. 38 mm) turned down hem is desired. Knee
press controlled tandem intermittent differential feed. Presser foot has a short
curler stitch tongue. Independent swing-out pressure plate attachment for
shirring. Gathering ratio up to 3 to 1 depending on stitch length. Seam speci-
fication 504-EFe-1 inverted. Standard width of seam 3/32 inch (2. 38 mm).
Stitch range 10-20 per inch. Cam adjusted main and differential feeds. Maxi-
mum recommended speed 6000 R.P.M.
39500 JP Single needle three thread. light to medium duty machine, with operator
adjusted intermittent differential feed for seaming and trimming all types and
weights of flat, warp and ribbed knit cotton, wool, rayon and silk fabrics where
long straight seams are necessary. Thumbscrew feed which allows either re-
versed or forward differential feeding. Seam specification 504-SSa-1. Standard
width of seams 3/32 and 1/8 inch (2.38 and 3.17 mm). Stitch range 8-30 per
inch. Cam adjusted main and differential feeds. Maximum recommended speed
6000 R.P.M.
39500 MM Single needle three thread, medium to heavy duty machine, for seaming
and intermittent gathering or shirring on woven and knit materials such as
dresses, aprons, lingerie, smocks. nightgowns and similar garments. Knee
press controlled tandem (in termitten t differential feed. Independent swing-out
pressure plate g tac h men t fo .~.. shi !. rin )~ Gathering ratio up t? 5 to 1 depending
on stitch length. S eam specification SU 4-SSa-1. Standard width of seam 3/16
inch (4. 76 mm). Stitch range 8-20 per inch. Cam adjusted main and differential
feeds. Maximum recommended speed 5500 R.P.M.
OILING
CAUTION! Oil was drained from machine when shipped. so reservoir must be
fiiled before beginning to operate. Oil capacity of Class 39500 is sw ounces. A
straight mineral oil of a Saybolt viscosity of 90 to 125 seconds at 100 Fahrenheit
should be used.
Machine is filled with oil at spring cap in top cover. Oillevel is checked at sight
gauge on front of machine. Red bulb on oil level indicator should show between gauge
lines when machine is stationary.
Machine is automatically lubricated. No oiling is necessary, other than keeping
main reservoir filled. Check oil daily before the morning start; add oil as required.
The oil drain plug screw is located at back of machine near bottom edge of base.
It is a magnetic screw designed to accumulate possible foreign materials which may
have entered the crank case. It should be removed and cleaned periodically.
5

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NEEDLES
Each Union Special needle has both type and size number. The type number de-
notes the kind of shank, point, length, groove, finish and other details. The siz e
number, stamped on the needle shank, denotes largest diameter of blade, measured
in thousandths of an inch, midway between shank and eye. Collectively, type and
size number represent the complete symbol which is given on the label of all nee-
dles packaged and sold by Union Special.
Class 39500 machines use a curved blade needle. The standard recommended
needle for Styles 39500 FS, FT., FU, GD, GL, JP and MM is Type 154 GAS .. while the
standard needle for Style 39500 GT is Type 154 GBS. Below are the type numbers,
description and sizes available of the recommended needles.
Type No.
154 GAS
154 GBS
Description and Sizes
Round shank, round point., curved blade, standard length, single
groove, struck groove, spotted, chromium plated and is available
in sizes 022., 025, 027, 029, 032, 036, 040, 044, 049, 054, 060.
Round shank, round point, curved blade, standard length, double
groove, struck groove, spotted, chromium plated and is available
in sizes 027, 029, 032.
To have needle orders promptly and accurately filled, an empty package, a
sample needle, or the type and size number should be forwarded. Use description
on label. A complete order would read:
11
1000 Needles, Type 154 GAS, Size 027
11
•
Selection of the proper needle size is determined by size of thread used. Thread
should pass freely through needle eye in order to produce a good stitch formation.
Success in the operation of Union Special machinee can be secured only by use
of needles packaged under our brand name, ~ ., which is backed by a re-
putation for producing highest quality needles in materials and workmanship for
more than three-quarters of a century.
CHANGING NEEDLES
Release pressure on presser foot by turning presser foot release bushing (AG,
Fig. 1 and lA) and swing presser arm (U) out of position. Turn handwheel in opera-
ting direction until needle is at its lowest point of travel. Using hexagonal socket
wrench No. 21388 AU., furnished with machine, loosen needle clamp nut about 1/4
turn. Again turn handwheel until needle "is at high position; withdraw needle.
To replace needle, leave needle holder at high position and, with the flat to the
left, insert needle in holder until it rests against stop pin. Keeping needle in this
position, turn handwheel until holder is again at its low point of travel, then tighten
nut. Return presser arm (U) to position; re-lock presser foot release bushing (AG).
THREAD STAND (504 STITCH)
After thread comes from cones on cone support (A., Fig. 1 ), it is brought up
through back hole of thread eyelet (B)., then down through the front hole of thread
eyelet. Next it is threaded through the upper holes of tension thread guide (C) from
front to back and then throu gh the lower holes from back to front. It should be noted
that the lower looper thread is threaded through the tension thread guide (C ), first
through the upper hole back to front., second throu gh the middle hole front to back and
third through the lower hole back to front. All threads then continue between the
tension discs (J)., through tension post slot (K) in tension post (G) and on through
front thread guide (M).
6

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li] Tension Nut
II Tension Spring Fe r~
II Tension Spring~ ---~~~
[!] Tension Post
IIJ spring Shield .. ..-::: :, ~
O Tension Discs :~.:: ··
l3 Tension Post Slot :
IITension Disc Felt ·..
[i Te nsion Thr e ad Guide
FIJ Front Thr e ad Guide
IIJupper Looper Thread Eyelet
Iii Auxiliary Looper Thread Eyelet
(9Lower Looper Thread Eyelet
DFrame Looper
Thread Guide
DJ Presser Arm
Fig. 1
l;) Thread Eyelet
7
Top Cover
.. ..,.,. Needle Thread Eyelet
Upper Looper
Thread Tube Assembly
m Lower Looper

From the library of: Superior Sewing Machine & Supply LLC
m Tension Nut
[!] Tension Po st
ll) spring Shield
..
O Tension Di scs ·.. __ _
(I Tension Post Slot ·.
nTe nsion Dis c Felt ·.
[i Tension Thr e ad Guid t,
f,I) Front Thr ead Guide
(II Upper Looper Thread Eyelet
Iii Auxiliary Looper Thread Eyelet
i9 Lower Looper Thr e ad Eyelet
(il Fabric Guard Br a cket
D Frame Looper
Thread Guide
m Presser Arm
Fig. lA
(;) Thr e ad Ey elet
---...
8
i
I
I
I
I
I
\
I
I
I
I
Top Cover
.. lllli.. Needl e Thread Eyelet
Upper Looper
Thread Tube Aa sembly
~ Upper Looper
m Lower Looper

From the library of: Superior Sewing Machine & Supply LLC
THREAD STAND (512 STITCH)
After thread comes from cones on cone support (A, Fig. lA ), the needle threads
are threaded through the back bar of the thread eyelet (B), under the middle bar and
through the center holes of the front bar. The looper threads come from the cones,
through holes of the middle bar from back to front and then through the two outside
holes of the front bar. Next it is threaded through the upper holes of tension thread
guide (C) front to back and then through the lower holes from back to front. The
threads continue between the tension discs (J), through tension post slot (K) in tension
post (G) and on through front thread guide (M).
NOTE: Refer to Fig. 1 for threading Styles 39500 FS, FT, FU, GT, JP and MM, or
refer to Fig. lA for threading Styles 39500 GD and GL.
THREADING
Only parts involved in threading are shown in threading diagrams (Fig. 1 and
lA). Parts are placed in their relative positions for clarity.
It will simplify the threading of these machines to follow the recommended se -
quence of threading lower looper first, upper looper second, and needle or needles
third.
The threading in Fig. 1 and Fig. lA are the same, the only difference will be
the threading of two needle threads in Fig. lA as compared to one needle thread in
Fig. 1. The additional needle in Fig. lA moves the lower looper thread tension post
to the right.
Before beginning to thread, swing cloth plate open, turn handwheel in operating
direction until needle (X) is in high position, release pressure on presser foot by
turning presser foot release bushing (AG), and swing presser arm (U) out of posi-
tion.
Be sure the threads, as they come from the tension thread guide (C), are be-
tween the tension discs (J) and in tension post slot (K) in tension post (G). The tens-
ion posts should be positioned so the tension post slot will be at the approximate angle
for the different threads as indicated in Fig. 1 and lA.
TO THREAD LOWER LOOPER
Double end of thread and lead it through both eyes of lower looper thread eye -
let (R, Fig. 1 or lA) from right to left. NOTE: Thread must pass in front of looper
thread pull-off ·(AF). Lead thread behind fabric guard (S) and through hole of frame
looper thread guide (T). Turn handwheel in operating direction until heel of lower
looper (V) is all the way to the left; then thread through both eyes from left to right.
Left eye of lower looper can be threaded easily if tweezers are in left hand.
TO THREAD UPPER LOOPER
Turn handwheel until point of upper looper (W) is all the way left. Lead thread
through auxiliary looper thread eyelet (P)from back to front, then through both eyes
of upper looper thread eyelet (N) from left to right. NOTE: Thread must pass in front
of looper thread pull-off (AF). After pulling up upper looper thread tube assembly
(AA). lead thread under neck of top cover casting and down through thread tube as -
sembly (AA). Pull thread out bottom of tube; push tube down, then insert thread
through upper looper eye from front to back.
CAUTION! Be sure upper looperthread is under lowerlooperthreadwhenpass-
ing from tube assembly to upper looper eye.
9

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TO THREAD THE NEEDLE
Turn handwheel in operating direction until needle or needles (X. Fig. 1 or lA)
is at its highest position. Insert needle thread or threads from right to left. through
both eyes of needle thread eyelet (AD). under neck of top cover casting; and then down
through hole or holes in top cover needle thread eyelet (AC). Thread needle from
front.
THREAD TENSION
The amount of tension on needle and looper threads is regulated by tension nuts
(D. Fig. 1 or lA). Tension on threads should be only enough to secure proper stitch
formation.
PRESSER FOOT PRESSURE
Sufficient presser foot pressure to feed work uniformly
should be maintained. Should it be necessary to increase or
decrease amount of pressure on presser foot. loosen lock
nut (A. Fig. 2) and turn adjusting screw (B). Adjusting screw
has a right hand thread so tightening increases pressure.
loosening decreases pressure. When pressure adjusting
screw (B) has been properly set. tighten lock nut (A). With
presser foot resting on throat plate. position locking nut
(C) so that its under surface is approximately 1/ 32 inch
to 1/16 inch (. 79 to 1. 59 mm) from the top surface of ad-
justing screw (B). Set cap (D) against locking nut (C).
FEED ECCENTRICS
Fig. 2
Feed eccentrics used in Style 39500 FS machines have been selected to produce
approximately 14 stitches per inch. It will be noted that the part number of main
feed eccentric is No. 39540 B-14 while ' that of the differential feed eccentric is No.
39540 B-4. Minor numbers of the part symbol indicate approximately the number
of stitches obtainable when using that eccentric. Unless otherwise specified. machine
will be shipped with above combination of eccentrics. Refer to exploded views for
eccentrics used on the other styles of machines covered in this catalog.
Generally speaking. the main (right hand) feed eccentric determines the number
of stitches produced; the differential (left hand) feed eccentric is selected so as to
give the proper differential or gathering action.
Following stitch number feed eccentrics are available under No. 39540 B-4.
5., 6. 1. 8., 9. 10. 11. 12. 13. 14., 15., 16., 18., 20., 22. 24. 26., 28., 30., 32., 34. 36.
40. Only two eccentrics are supplied with each ma-
chine. Additional eccentrics may be ordered separ-
ately. To order an eccentric. use No. 39540 B with
Fig. 3
a minor number suffixed to indicate number of
stitches desired. Example: "39540 B-14".
ASSEMBLING AND ADJUSTING SEWING PARTS
Before assembling and adjusting sewing parts.
remove cloth plate., fabric guard., chip guard., upper
knife assembly. lower knife holder assembly. then
follow this suggested sequence.
10

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SETTING THE NEEDLE
With throat plate assembled in position, needle
should center in the front end of needle elot. When
needle is at high position, needle point should be set
1/2 inch (12. 70 mm) above throat plate (A, Fig. 3)
for Styles 39500 FS, FT, FU, GT, JP and MM; 15/32
inch (11. 91 mm) for Styles 39500 GD and GL. To
align needle or set the height above the throat plate,
move needle driving arm (B, Fig. 3) by loosening
clamp screw (C). After needle has been set proper-
ly, tighten clamp screw and remove throat plate.
Fig. 4
If needle thread cam pull-off (A, Fig. 4) over-
laps looper thread pull-off (B), separate by moving
looper thread pull-off back. When retightening
looper pull-off screw, be sure to take up end play
in needle driving arm.
At this point, insert lower looper (A, Fig. 5)
into bar (B). With lower looper at left end of its
stroke, set looper point 1/8 inch (3.17 mm) from
center of needle (Fig. 5), using looper gauge No.
21225-1/8, on Styles 39500 FS, FT, FU, GT, JP and
MM. On Styles 39500 GD and GL, with lower looper
at left end of its stroke, set looper point 1 /16 inch
(1. 59 mm) from center of left needle, using looper
gauge No. 21225-1/16. Do not have lower looper
deflecting needle. Tighten nut (C ). Now assemble
differential (front) feed dog.
SETTING THE REAR NEEDLE GUARD
Fig. 5
Set rear needle guard (A, Fig. 6) as high as possible, with-
out interfering with either lower looper or movement of lower
knife holder, but still in position to deflect needle or needles for-
ward • 002-. 004 inch (. 051-.102 mm). Screw (B) is used to set
rear needle guard. Make sure there is no interference between
rear needle guard and lower looper.
SETTING THE LOWER LOOPER
Now finish lower looper adjustment. As
lower looper moves to the right, its point
Fig. 6 should be set into the needle scarf (A, Fig.
7) until the needle springs forward from rear
needle guard surface another. 002-. 004 inch (. 051-.102 mm).
Tighten nut (C, Fig. 5) securely.
SETTING THE FRONT NEEDLE GUARD
Assemble front needle guard (C, Fig. 6). When lower looper
is springing needle off rear needle guard, set front needle guard
as close as possible to needle without touching. Screw (D) is used
to adjust and set front needle guard. After this setting make sure
Fig. 7
the r e is no int e r fer enc e between needle guards and differential feed dog.
11

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SETTING THE UPPER LOOPER
Insert upper looper (A. Fig. 8) in its holder. Screw (B).
holds upper looper in its holder. and permits it to be pushed
in or out or turned around its shank. Insert upper looper holder
into upper looper shaft. if it is not already in place. Screw
(C ). on clamp holds the upper looper holder in the shaft.
Locate uprer looper in its holder so that the shank extends
1/16 to 3 32 inch (1. 59 to 2. 38 mm) beyond holder (Fig. 8)
on Styles 39500 FS. FT. FU. GD. GL. GT and MM.
NOTE: On Style 39500 JP the shank should extend 1/32 to
1/16 inch(. 79 to 1. 59 mm) beyond holder.
When the upper looper is at the right end of its stroke.
upper looper holder should be set to position upper looper
shank approximately vertical on Styles 39500 FS. FT. FU. GT
and MM (Fig. 8).
•
Fig. 8
NOTE: On Styles 39500 GD. GL and JP the upper looper holder
Fig. 9
should be set to position upper looper shank slightly back of
vertical when the upper looper is at right end of its stroke. Be
sure on all styles. there is a clearance between heel of looper
and casting. By adjusting looper holder in or out of upper
looper shaft and by turning the looper around its shank. set
upper looper point to cross lower looper to the left of the
lower looper eye with • 002 to • 004 inch (. 051 to • 102 mm)
clearance (Fig. 9).
As the upper looper moves toward the top of its stroke.
the heel of the upper looper should pass behind the lower looper
head with 1/64 to 1/32 inch (.40 to. 79 mm) clearance.
Next. turn handwheel until looper is at the left end of its
travel; check dimensions of upper looper point with respectto needle and throat plate
(Fig. 1O). If resetting is necessary. do it by moving the upper looper holder (A.
Fig. 10). Figure 10 represents the dimensional setting for
Styles - 39500 FS. FT. FU. GT and MM.
NOTE: For Style 39500 JP. the settings are 5/32 and 31/64
inch (3. 97 and 12. 30 mm). For Styles 39500 GD and GL. the
settings are 1/8 inch (3.17 mm) to the left of right needle
Fig. 11
and 17 /32 inch (13.49 mm). For ex-
ample dimension 1/2 inch (12. 70 mm)
is increased by turning upper looper
holder counterclockwise looking from
left end of machine; dimension 9/ 64
inch (3. 57 mm) is increased by pulling
upper looper :q.older to the left. out of
upper looper shaft. After these changes
are made. it may be necessaryto turn
upper looper around its shank slightly
to maintain the condition shown in F ig. 9.
Fig. 10
When the correct setting is obtained. it can be checked
quickly as follows: As upper looper is moving to the right.
when upper looper eye centers on the needle. the eye s of the
upper looper and needle should align exactly (Fig. 11 ).
12

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SETTING THE UPPER LOOPER (Continued)
Check setting to avoid inter-
ference between upper looper and
needle on needle downstroke. If
needle rubs the back of upper loo-
per, pull looper out of its holder
slightly and rotate looper a short
distance counterclockwise, looking
from left end of machine. Reset to
maintain dimensions of Figs. 9, 10,
11.
SETTING THE FEED DOGS
Now assemble differential feed
Fig. 12 dog (A, Fig. 12) if not already on
machine. Assemble main feed dog
(B) and set both feeds so the top surfaces of the teeth all lie in the same plane.
This can be checked by sighting across the teeth with
.a straight edge. Now assemble throat plate. Feed dogs
should now be leveled with throat plate surface by ro-
tating feed tilting adjusting pin (C ). This pin raises or
lowers the back end of both feed bars at the same time.
The feed dogs should be set level at the time teeth
first appear above the throat plate. Screw (E) locks
feed tilting adjusting pin in place. Now set feed dogs
so that teeth rise about 3/64 inch (1.19mm) above
throat plate. The differential feed may be set slightly
higher if desired.
NOTE: On Style 39500 JP, set the chaining feed dog
level with the top of throat plate when feed is at the top
of its travel.
SETTING THE LOWER KNIFE
Replace lower knife holder assembly. Lower knife Fi.g· 13
(A, Fig. 13) should be set with cutting edge flush with
throat plate surface. Adjustments are made with hexagonal head screw which holds
lower knife. Lower knife is spring pressed against upper knife, so no lateral ad-
justment is necessary when width of trim is changed.
Lower knife may be secured in any position by tightening screw (B) and locking
nut (C) against support bracket. Because screw (B) also serves as latch pin for the
cloth plate latch spring, it should always be locked with nut (C) even when screw is
not tightened against lower knife holder.
SETTING THE UPPER KNIFE
Replace upper knife assembly. Clamp upp er knife (D, F ig. 13) in posit i on,
setting nut (E ) to hold clamp (F ) in it s most clockwi se po s ition again st upper kn i fe.
Upper knife chain guard (G) should be positioned so that the guarding section is
approximatelyl/64 inch (.40 mm) behind the cutting edge and in contact with the top
surface of the upper knife.
13

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SETTING THE UPPER KNIFE (Continued)
At the bottom of its stroke, front
cutting edge of upper knife should ex -
tend not less than 1/ 64 inch (. 40 mm)
below cutting edge of lower knife.
After upper knife has been set for
proper width of trim, screw (H) must
be tightened to lock the upper knife
holding block (J) in place. This will
simplify resetting when upper knife is
replaced.
SETTING THE STITCH LENGTH
Length of stitch is determined by
the combination of feed eccentrics
used. Outer (left) eccentric (A, Fig.
14) actuates differential (front) feed
dog; while the inner (right) eccentric
(B) actuates the main (rear) feed dog.
In assembling feed eccentrics,
Fig. 14
be sure hubs are facing each other. Be careful not to damage shaft or key. Use nut
(C) and washer (0) and tighten securely.
To change feed eccentric, remove thrust finger (L) from its seat on the main
frame (M). Remove nut (C) and washer (D) from end of shaft (G). Remove nut (H)
from stud (J). Link (K) and eccentric (A) will now slip off.
Fig. 15
Using hooked eccentric extractor (E ),
supplied with machine, reach behind eccentric
(B) as shown and withdraw eccentric. It may
be necessaryto move handwheel back and forth
slightly during extraction. When reassembling
allow • 003 inch (. 076 mm) clearance between
the thrust finger and the differential feed drive .
connecting rod in a 3 60° turn.
SETTING THE DIFFERENTIAL RA TIO
Differential feed action is obtainable thru
the use of one micrometer adjusting screw on
Style 39500 JP and two micrometer adjusting
screws on Styles 39500 FS, FT, FU, GD, GL, GT
and MM.
The position of the differential control lever (A, Fig. 15 and 15A) is governed
by an upper and a lower stop. The amount of lever movement between these two
stops determines the feed action.
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SETTING THE DIFFERENTIAL RA TIO (Continued)
On Style 39500 JP, rotating the one adjusting thumbscrew (located near the tension
post assembly) in a clockwise direction increases the differential action by moving
the upper stop (B) down, a counterclockwise turn acts in a reverse manner. Now set
the lower stop screw (C) so as to obtain the required intermittent differential feed.
On Style 39500 JP, th e two stops may be reversed to meet a specific sewing requir e -
ment.
NOTE: After lower stop screw has been set, push differential control lever down,
hold in this position and turn handwheel in operating direction to be sure the differ -
ential feed dog does not strike the throat plate.
Fig. 15A
On Styles 39500 FS, FT, FU, GD, GL, GT
and MM the differential feed action is also
controlled by the movement of the differential
control lever between an upper and a lower
stop, but on these machines both stops are
moved by an adjusting thumbscrew rod (Fig.
15A).
To set the amount of differential or plain
feed, turn the plain feed control adjusting rod,
it is the larger knurled head screw located on
the bed in back of the tension post assembly.
Turning this rod clockwise decreases the
amount of differential and turning it counter-
clockwise increases the amount of differential.
The amount of intermittent differential
feed is set by turning the differential feed
control adjusting rod, it is the smaller knurled head screw located just above the
plain feed control adjusting rod. Turning this screw clockwise lowers the stop and
thus increases the amount of differential, when the differential feed control lever ,
is actuated. Turning this screw counterclockwise acts the reverse.
SETTING THE PRESSER FOOT
Assemble the presser foot to presser arm.
With needle in high position, swing presser arm
into sewing position and set the presser foot to
align needle holes (front and back) and flat on
throat plate.
The front edge of needle hole in presser
foot must be aligned with front edge of needle
hole in throat plate. It is also important that the
bottom of the presser foot be flat on the throat
plate. If necessary, presser foot can be re-
aligned with throa,t plate slots by shifting the foot Fig. 16
lifter lever shaft (H, Fig. 16). Tomove the shaft,
loosen collar screws (B, Fi g. 16) and clamp
screw (G) and then shift the foot lifter lever shaft to the left or right as required.
Retighten collar screws and clamp screw.
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SETTING THE PRESSER FOOT (Continued)
The foot lifter lever arm (A. Fig. 16) and the collar (B) secure the shaft. Be
sure the presser arm does not bind or rise when presser foot release bushing is un-
locked.
Adjust lifter lever stop screw (C) so that presser foot can be raised no higher
than upper looper will permit; then lock the nut (D). There should be from 1/ 16 to
1/ 8 inch (1. 59 to 3. 17 mm) free motion of foot lifter lever before the presser foot
begins to rise. This adjustment should be made with screw (E) and locked with nut
(F). Re-assemble the chip guard. fabric guard and cloth plate. To assemble chip
guard. turn handwheel until upper knife assembly reaches its highest position.
SETTING THE PRESSER FOOT HOLD DOWN PLATE
Styles 39500 FT. FU. GD. GL. GT and MM are equipped with a presser foot hold
down plate (A. Fig. 17 ). The purpose of this plate is to hold down the rear of the
presser foot and when set correctly it will help produce
a more flat pucker free seam. An approximate setting
is shown in Fig. 17. Set the machine with the feed dogs
below the throat plate and insert a. 005 inch (. 127 mm)
shim (B) under the front portion of presser foot (C).
Loosen screws (D) which hold the hold down plate in
position and move the plate down until it rests firmly
against the presser foot. Tighten the two screws and
remove the shim.
NOTE: Always be sure the feed dogs are below sur-
face of throat plate when making this setting.
Fig. 17
SETTING THE PRESSURE PLATE ASSEMBLY (FOR STYLES
39500 FT. FU. GD. GL. GT and MM)
1. Swing the pressure plate assembly
in and out of its operating posi-
tion and check to assure that it
hinges freely on its pivot. If not.
loosen lock nut (A. Fig. 18) and
adjust shoulder screw (B) for
smooth operation.
2. Loosen set screw (C. Fig. 18) and
turn the shaft collar (D) counter-
clockwise (viewed from the left
side of machine) using the spanner
wrench provided. so there is some
tension on the tension spring lo-
cated in the shaft bracket (E) and
the pressure plate (A., Fig. 19) is
forced down slightly.
Fig. 18 3. Adjust tension spring. located in
the mounting bracket (B., Fig. 19)
with inner screw., after removing outer screw (C ). Spring should be tight enough
to allow assembly to snap into place and still allow the mechanism to swing out
easily. Lock inner screw with outer screw (C).
4. With the feed dogs down., look horizontally between the pressure plate and the
throat plate from the front of the machine to assure that the pressure plate lies
flat on the throat plate. If not., loosen the two screws (D., Fig. 19) which hold the
pressure plate (A) and adjust flat to the throat plate.
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From the library of: Superior Sewing Machine & Supply LLC
SETTING THE PRESSURE PLATE ASSEMBLY (FOR STYLES
39500 FT. FU. GD. GL. GT and MM) (Continued)
5. Raise or lower the mounting bracket (B. Fig. 19) by loosening screws (E) so
that. from the side. the pressure plate is parallel and fl.at on the throat plate.
Retighten screws (E ).
6. Adjust screw (F. Fig. 19) so that the front edge of the pressure plate is square
to the feed dog teeth. Lock with screw (G).
Fig. 19
,.,.. ,,
.,.
.~\) ..
I
.005-.010
(.127 to .254mm)
7. Center pressure plate over the feed dogs by loosening the screws in the actuat-
ing collar (F. Fig. 18) and the operating lever (G). and then adjust shaft (H)
laterally as required.
8. When retightening operating lever screw make sure that the feed dogs and the
pressure plate are down. then tighten operating lever screw leaving approxi-
mately • 005 to • 010 inch (.127 to • 254 mm) clearance (See Fig. 19) between
operating lever and shaft bracket (E. Fig. 18).
9. With feed dogs up, check from the left side to see if the clearance between the
pressure plate and the presser foot is wide enough to allow the largest seam
pass. If not. adjustment can be made by loosening screws (E, Fig. 19) and
moving the mounting bracket (B) straight toward the operator. Retighten screws
(E). Recheck Step 4.
10. The actuating collar (F, Fig. 18) should now be set so that. throughout one
revolution of the machine. the minimum distance between the lifter rod and the
presser foot is 1/ 32 inch (. 79 mm). The lifter rod should be set to clear the tip
of the presser foot if it is important that the shirring mechanism can be swung
away without moving the presser foot away first.
11. Loosen set screw (C. Fig. 18) for final adjustment of pressure plate tension
spring. Turn shaft collar (D) with spanner wrench until desired tension is ac-
quired to obtain a uniform shirr. Retighten set screw (C).
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NEEDLE THREAD CONTROL
While sewing on material, check needle thread control as follows: Usually all
needle thread is drawn on needle down stroke. At top of needle stroke, thread
should be just tight enough to feed chain off stitch tongue. Stitch tends to pull down
slightly if excessive thread is pulled on the up stroke. With needle at bottom of
stroke, position needle thread eyelet (AD, Fig. 1 or lA) so that needle thread cam
pull-off (AE) just contacts needle thread.
LOWER LOOPER THREAD CONTROL
With material under presser foot, set lower looper thread eyelet (R, Fig. 1 or
lA) back far enough so thread is a little slack when looper thread pull-off (AF)
reaches its most rearward position. Looper thread pull-off (AF) is set about 1/8
inch (3. 17 mm) distance behind needle thread cam pull-off (AE). Frame looper thread
guide (T) should be set with its eyelet apprxoimately 1/8 inch (3.17 mm) right of
lower looper (V) heel eyelet at the time lower looper is at extreme left end of its
travel.
While sewing on material, check drawing off of looper thread as follows: A
portion of lower looper thread should be drawn through the tension before lower loo-
per thread comes off upper looper. To increase amount of thread drawn through the
tension while lower looper thread is on upper looper, move lower looper thread
eyelet (R) down, keeping the same amount of pull-off action.
UPPER LOOPER THREAD CONTROL
Before proceeding to adjust upper looper thread eyelet (N, Fig. 1 or lA) bal-
ance all three or four tensions to give a normal appearing stitch. Moderate change
in these tensions will not markedly affect the purl.
During needle down stroke, forward stroke of looper thread pull-off (AF) will
draw upper looper thread through the tension. When normal amount of looper thread
is drawn, upper looper thread will have almost all slack taken up as looper thread
pull-off reaches it most rearward position.
POSITIONING THE PURL
To move the purl more under the edge, both looper thread eyelets (N and R,
Fig. 1 or lA) should be raised keeping the same amount of pull-off. Usually it is
better to have slightly more pull-off on upper thread than on lower thread.
If it becomes necessary to move looper thread pull-off (AF), be sure to take up
all end play in needle drive shaft before tightening. If upper looper is located so
that it is higher over throat plate than recommended in (Fig. 10), the purl will tend
to form near top edge. If upper looper is too low, the purl will form nearer bottom
edge.
THREAD TENSIONS
The needle thread tension required is a function of needle thread and material
being sewn. In general, lower looper thread tension should be set as high as possi-
ble without causing needle thread to be pulled down. Upper looper thread tension
should be increased as long as the elasticity of the chain increases,or until the purl
is pulled too far over the top.
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From the library of: Superior Sewing Machine & Supply LLC
Fig. 20
TO REMOVE CRANKSHAFT
Crankshaft can be withdrawn easier if these steps are followed:
1. Drain oil by removing plug screw located on back of machine near bottom edge
of base.,
2. Remove top and bottom covers of machine.
3. Remove feed eccentric nut (A., Fig. 20) and washer (B)., and., with the aid of the
eccentric extractor., slip off the eccentrics (C).
4. Remove key (D).,
5. Remove three counterweights (E). Identify these counterweights so that they
will be re-assembled in the proper places.
6. Remove screw (F) which holds crankshaft split bearing. This screw is reached
through bottom of bed casting.
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From the library of: Superior Sewing Machine & Supply LLC
TO REMOVE CRANKSHAFT ( Continued)
7. Remove caps of bearings on
crankshaft at points G., H, and J.
When re-assembling bearing caps
make sure they are in their ori-
ginal position. Trade marks are
stamped on both halves of the caps
and both trade marks should be
on the same side of the bearings.
Also., screws should be re-assem-
bled in the same holes from which
they were removed.
8. Loosen clamp nut (A, Fig. 21)
which holds upper knife driving
arm (B). Access to clamp nut is
through top cover. Draw driving
arm to the left until upper knife
driving lever (C) and connecting
rod (D) drop, allowing removal of
bearing cap (E). This is at bear-
ing point (K, Fig. 20) on crank
shaft. Observe same precautions
when re-assembling cap as de-
scribed in 7 above.
Fig. 21
9. Remove screw (L, Fig. 20) which holds inner right crankshaft bearing. This
screw is reached through bottom of bed casting.
10. Loosen two screws (M) in fan collar; remove both halves of cooling fan.
11. Remove screw (N); take off pulley cap (P).
12. Loosen two screws (R); remove pulley (S).
13. Remove three screws (T); take off bearing retaining plate (U); also, spacer
collars (V) and (W) may be removed at this time.
14. Crankshaft may now be removed.
15. If necessary to replace ball bearing (X), it should be pressed off shaft on an ar-
bor press. In replacing bearing it must be pressed on carefully until it seats
against ground thrust washer (Y).
16. Carefully observing reverse of the foregoing operations should simplify re-
assembly of crankshaft. Checking exploded view drawings for location of various
parts and constant testing for bi nds during re-assembly will also prove helpful.
1 7. Before re-assembling, thoroughly clean and dry top and bottom covers and
gaskets. Before re-assembling bottom cover make sure that spring pressed oil
wick which lubricates left crankshaft bearing is inserted in hole in casting and
that it contacts shaft. The wick stands vertically on its spring against bottom
cover. Coat oil drain plug with a sealing compound before re-assembling to
prevent oil leakage. No. 1 Crane Lead Seal is recommended.
20