UnionSpecial 39500MK Instruction sheet

F INES T QUALITY
ST YL E
395 00M K
CATALOG
No.
103MK
®
INDUSTRIAL
SEWING
LEWIS • COLUMBIA
MACHINES
CLA SS 39500
HI-STYLED HIGH S PEED
TWO NEEDLE FOUR THREAD
THUMBSCREW ADJU S TED
DIFFERENTIAL FEED MACHINES
C HI CAGO
From the library of: Superior Sewing Machine & Supply LLC

Catalog No. 103 MK
(Supplement to Catalog No. 103 FS)
INSTRUCTIONS
FOR
ADJUSTING AND OPERATING
LIST OF PARTS
CLASS 3 9500
Style 39500 MK
First Edition
Copyright 1971
by
Union Special Machine Co.
Rights Reserved in All Countries
MACHINE COMPANY
INDUSTRIAL SEWING MACHINES
CHICAGO
Printed in U.S. A.
2
October, 1971
From the library of: Superior Sewing Machine & Supply LLC

IDENTIFICATION OF MACffiNE
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".
Example: "Style 39500 MK". Special Style numbers contain the letter "Z". When
only minor changes are made in a standard machine, a "Z" is suffixed to the standard
Style number. Example: "Style 39500 MKZ".
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 CATALOG
This catalog is a supplement to Catalog No. 103 FS and should be used in con-
junction therewith. Only those parts used on Style 39500 MK, but not on Style
39500 GD are illustrated and listed at the back of this catalog. On the page opposite
the illustration will be found a listing of the parts, with their part numbers, des cript-
ion and the number of pieces required. Numbers in the first column are reference
numbers only, and merely indicate the position of that part in the illustration.
Reference numbers should never be used in ordering parts. Always use the part
number listed in the second column.
This catalog applies specifically to the standard Style of machine 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.
STYLE OF MACHINE
Hi-Styled High Speed, Two Curved Blade Needles, Two Loopers, Four Thread
Overseaming Machines, Upper Looper Thread is Caught by Both Needles. Differen-
tial Feed, Trimming Mechanism with Spring Pressed Lower Knife, Automatic
Lubricating System.
39500 MK Medium to heavy duty machine for seaming operations on coat linings,
pockets, bathing suits, house dresses, children's wear, ladies undergarments,
and similar garments of medium to heavy weight woven and knitted materials
of cotton, wool, silk and synthetics. Thumbscrew adjustable feed which allows
either reverse or forward differential feeding. Seam specification 514-SSa-1.
Standard seam width approximately 17/64 inch from left needle. Stitch range
6-20 per inch. Cam ad jus ted main and differential feeds. Maximum recommended
speed 6000 R. P. M.
OILING
CAUTION! Oil was drained from machine when shipped, so reservoir must be
filled before beginning to operate. Oil capacity of Class 39500 is six ounces. A
straight mineral oil of a Saybolt viscosity of 90 to 125 seconds at 100° Fahrenheit
should be used.
3
From the library of: Superior Sewing Machine & Supply LLC

OILING (Continued)
Machine is filled with oil at spring cap in top cover. Oil level is checked at
sight gauge on front of machine. Red bulb on oil levelindicator 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 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.
NEEDLES
Each Union Special needle has both type and size number. The type number
denotes the kind of shank, point, length, g roove, finish and other details. The size
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 needles
packaged and sold by Union Special.
Class 39500 machine s use a curved blade needle. The standard recommended
needle for Style 39500 MK is Type 154 GAS. Below is the description and sizes avail-
able of the recommended needle.
Type No.
154 GAS
D
es cr i pt i on and Sizes
Round shank, round point, curved blade, standard len g th, si ngle gr oove,
struck groove, spotted, chromium plated and is available in s iz es 022,
025, 027, 029, 032, 036, 040, 044, 049, 054, 060.
To have needle orders promptly and accurately filled, an empty pac kage , a
sample needle, or the type and si ze numbe r should be forwarde d. U se d es c ri pt i on
on label. A complete orde r would r e ad: " 1000 Needles, Type 154 GAS, Si ze 036".
Selection of prope r needle s i ze is de termined by s i ze of thr ea d us ed. Thread
should pass freely through needle ey e in orde r to produce a goo d st i tch formation.
Success in the operation of Union S pe ci al ma ch in es can be secur ed only by u se
of needles packaged under our bran d na me, ~ , which is bac ke d by a r e -
putation for producing highest quality nee dl es in m ate ri als a nd wor km ans hip for
more than three-qu a rters of a century.
4
From the library of: Superior Sewing Machine & Supply LLC

I!]Tension Nut
--
..... _ .. _ ... :: .,"'
OTension Discs ::..
l3ll Tension Post Slot.. ',,_
nTension Disc Felt·· ..
[i Tension Thr ead
liJ Front Thr ead Guide
fm Upper Looper Thread Eyelet
~~Auxiliary Looper Thread Eyelet
I3Lower Looper Thread Eyelet
mFabric Guard Bracket
DFrame Looper
Thread Guide
m Presser Arm
Fig. 1
~--
5
Top Cover
.....-::~ji\1~"'11:.\!1 Needle Thread Eyelet
. ... ............
Upper Looper
Thread Tube As sembly
~Upper Looper
From the library of: Superior Sewing Machine & Supply LLC

CHANGING NEEDLES
Release pressure on presser foot by turning presser foot release bushing (AG,
Fig. 1) and swing presser arm (U) out of position. Turn handwheel in operating
direction until needles are at their 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 needles are at high position. Withdraw needles.
To replace needles, leave needle holder at high position and with the flats to
the left, insert needles in holder until they rest against stop pin. Keeping needles
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 bush-
ing (AG).
THREAD STAND
After thread comes from cones on cone support (A, Fig. 1), 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 tensionpost slot (K) in tens-
ion post (G) and on through front thread guide (M).
THREADING
Only parts involved in threading are shown in the threading diagram (Fig. 1).
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 needles third.
Before beginning to thread, swing cloth plate open, turn handwheel in operating
direction until needles (X) are 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 threads, as they come from the tension thread guide (C) are between
tension discs (J) and in diagonal slots (K) in tension posts (G). The tension posts
should be positioned so the tension post slot will be at the approximate an:gle for the
different threads as indicated in Fig. 1.
TO THREAD LOWER LOOPER
Double end of thread and lead it through both eyes of lower looper thread eye-
let (R, Fig. 1) from right to left. NOTE: Thread must pass in front of looper thread
pull-off (AF). Lead thread behind fabric guard (S) and through eyelet 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
6
From the library of: Superior Sewing Machine & Supply LLC

TO THREAD UPPER LOOPER (Continued)
tube assembly (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 looper thread is under lower looper thread when
passing from tube assembly to upper looper eye.
TO THREAD NEEDLES
Turn handwheel in operating direction until needles (X) are at their highest
position. Insert both needle threads from right to left, through BOTH eyes of needle
thread eyelet (AD), under neck of top cover casting and down through holes in top
cover needle thread eyelet (AC). The right needle thread should be threaded in the
right hole and the left needle thread through the left hole of the top cover needle
thread eyelet. Thread needles from the front.
THREAD TENSION
The amount of tension on needle and looper threads is regulated by tension nuts
(D, Fig. 1). Tension on threads should be only enough to secure proper stitch for-
mation.
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 aright hand thread so tightening increases pres-
sure, loosening decreases pressure. When pressure adjust-
ing screw (B) has been properly set, tighten lock nut (A).
With presser foot resting on throat plate, position locking
nut (C) sothat its undersurface is approximately 1/32 inch
to 1/16 inch from the top surface of adjusting screw (B).
Set cap (D) against locking nut (C).
FEED ECCENTRICS
Fig. 2
Feed eccentrics used in machine Style 39500 MK have been selected to produce
approximately 12 stitches per inch. It will be noted that thepart number of the main
feed eccentric is No. 39540 B-12, while the part number of the differential feed
eccentric is No. 39540 B-4 . Minor numbers of the part symbol indicate approximate-
ly the number of stitches obtainable when using that eccentric. Unless otherwise
specified, machines will be shipped with the above combination of eccentrics.
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.
Following stitch number feed eccentrics are available under No. 39540 B-4, -5,
-6, -7,
-8, -9, -10, -11, -12, -13, -14, -15, -16, -18, -20, -22, -24, -26, -28,
-30, -32, -34, -36, -40, -50, -60, -70, -100. Only two eccentrics are supplied
with each machine. Additional eccentrics may be ordered separately. To order,
use No. 39540 B with a minor number suffixed to indicate number of stitches desir ed.
Example: "39540 B-12 ".
7
From the library of: Superior Sewing Machine & Supply LLC

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:
CLOTH PLATE REMOVAL AND ASSEMBLY
CAUTION: When removing the cloth plate (A, Fig. 3)
loosen the cloth plate stud locking screw (B) and lift up
cloth plate with the cloth plate stud (C) and cloth plate screw
(D), assembled.
In assembly, the cloth plate screw and the cloth plate
stud are tightened to the point of removing all play and yet
turn in cloth plate. The cloth plate is then assembled to the
machine with the flat and "V" slot ofthe cloth plate stud (C)
towards the rear. Stud locking screw (B) is tightened secure-
ly which collapses the body of the stud to the screw (D) so
that only the cloth plate will turn when opening or closing.
SETTING THE NEEDLE
With throat plate assembled in position, needles should
center in the front end of needle slots. When needles are at
high position, needle points should be set 31/64 inch above
Fig.
3
throat plate (Fig. 4). To align or set the height above the
throat plate, move needle driving arm (A, Fig. 4) by loosen-
i ng clamp screw (B). Remove throat plate. after needle has been set properly and
clamp screw (B) has been tightened.
Fig. 4
If needle thread cam pull-
off (A, Fig. 5) overlaps looper
thread pull-off (B). separate by
moving looper thread pull-off
to the back. When re-tightening
looper pull-off screw, be sure
to take up end play in needle
driving arm.
At th is point. insert lower
looper (A, Fig. 6) into bar (B).
With the lower looper at the
left end of its stroke, set looper
point 1/ 16 inch from center of
left needle (Fig. 6), using loop- Fi g. 5
er gauge No. 21225-1/16. Do
not have lower looper de flectin g n ee dl e. Tigh ten nut (C).
Now assemble differential (front) feed dog.
8
I / •
From the library of: Superior Sewing Machine & Supply LLC

SETTING THE REAR NEEDLE GUARD
Set rear needle guard (A, Fig. 7) as high as pos-
sible, without interfering with either lower looper or
movement of lower knife holder, but still in position
to deflect needles forward . 002-. 004 inch. 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 Fig. 6
looper moves to the right, its point should be set into
the scarf of the left needle (A. Fig. 8) until the needles spring forward from rear
guard surface another . 002-. 004 inch.
Fig. 7
SETTING THE FRONT NEEDLE GUARD
Assemble front needle guard (C.
Fig. 7). When lower looper is springing
needles off rear needle guard, set front
needle guard as close as possible to
needles without touching. Screw (D) is
used to adjust and set front needle guard.
After this setting, make sure there is
no interference between needle guards
and differential feed dog.
SETTING THE UPPER LOOPER
Fig. 8
Insert upper looper (A, Fig. 9) 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 upper looper in its holder so that the shank extends
1 /8 inch 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 s li g htly back of vertical (F i g. 9).
Fig. 9
By adjusting looper hold er in or out of
upper looper shaft and by turning the looper
around it s s hank. s e t upper looper
point to cross lower looper to the left of
the lower looper eye w it h . 002 to . 004
clearance (Fi g. 10).
Next, turn the handwheel until upp er
looper is at the left end of it s tr a vel. Ch e ck
dimensions of upper looper po i nt with
respect to the left needle and throat pl ate
(Fig. 11). If resettin g is nece ssary, do it
by moving the upper looper holder (A, Fig.
11). Figure 11 represents the correct di -
mensional setting.
9
F ig. 10
From the library of: Superior Sewing Machine & Supply LLC

SETTING THE UPPER LOOPER (Continued)
Dimension 39/64 inch is increased by turning upper looper
holder counterclockwise looking from left end of machine. Di-
mension 3/16 inch is increased bypulling upper looper holder to
t he left, out of the upper looper shaft. After these changes are
made, it may be necessary to t urn the upper looper around its
shank slightly to maintain the condition shown in Fig. 10.
Check setting to a void interference between upper looper and
needle on needle downstroke. If needle rubs t he back of upper
looper, 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. 10 and 11.
SETTING THE FEED DOGS
Assemble the main and differential feed dogs (A, B, F ig. 12).
Fig· 11 Main and differential feed dogs should be leveled with respect to
the throat plate by rotating feed tilting adjusting pin (C). This
pin raises or lowers the back end of the feed bar.
The feed dogs should be set
level at the time the teeth first
appear above the throat plate. Screw
(D) locks feed tilting adjusting pin in
place. With the feed dogs at their
highest point of travel, the top of the
teeth on the main and differential feed
dogs (A, B) should be the depth of a
full tooth above the throat plate. The
chaining feed dog is made as an inte-
gral part of the main feed dog.
SETTING THE LOWER KNIFE
Fig. 12
Fig. 13
Replace lower knife holder assembly. Lower k nife
(A, Fig. 13) should be set with cutting edge flus h with
throat plate surface. Adjustments are made with hexa-
gonal head screw which holds lower knife. Lower knife is
spring pressed against upper knife, so no lateral adjust-
ment is necessary when width of trim is changed.
Lower knife may be secured in any position by tight-
ening screw (B) and locking nut (C) against support bracket.
Because screw (B) also serves as latch pin for th e cloth
plate latch spring, it should always be locked w it h nut (C)
even when screw is not tightened against low er kn i fe
holder.
SETTING THE UPPER KNIFE
Replace upper knife assembly. Cl a mp u ppe r kni fe (D,
Fig. 13) in position, setting nut (E) to hold cl a mp (F ) in
its most clockwise position ag ainst upper knife . Upper
knife chain guard (J) should be positioned s o t hat th e
guarding section is approximately 1/64 i nch be hind the
cutting edge and in contact with the top surfac e of t he upper
knife.
10
From the library of: Superior Sewing Machine & Supply LLC

SETTING THE UPPER KNIFE (Continued)
At the bottom of its stroke, front cutting edge of upper knife should extend not
less than 1/64 inch below cutting edge of lower knife.
After upper knife has been set for the proper width of trim, screw (G) must be
tightened to lock the upper knife holding block (H) in place. This will simplify reset-
ting 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) act-
uates differential (front) feed dog; while
the inner (right) eccentric (B) actuates
the main (rear) feed dog.
In assembling feed eccentrics, be
sure hubs are facing each other. Be
careful not todamage shaft or key. Use
nut (C) and washer (D) and tighten se-
curely.
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). Re-
move nut (H) from stud (J). Link (K)
and eccentric (A) will now slip off.
Fig. 14
A
Fig. 15
Using hooked eccentric extractor (E), supplied with
machine, reach behind eccentric (B) as shown and with-
draw eccentric. It may be necessary to move handwheel
back and forth slightly during extraction.
SETTING THE DIFFERENTIAL RATIO
Differential feed action is obtainable thru the use
of a micrometer adjusting screw (A, Fig. 15).
The position of the differential control lever (B,
Fig. 15) is governed by an upper stop (C) and a lower
stop (D). The amount of lever movement between these
two stops determines the feed action.
Rotating the adjusting thumbscrew in a clockwise
direction increases the differential action by moving the
the upper stop (C) down, a counterclockwise turn acts
in a reverse manner. Now set the lower stop screw (D)
so as to obtain the required differential feed. The two
stops may be reversed to meet a specific sewing re-
quirement.
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
differential feed dog does not strike the throat plate.
11
From the library of: Superior Sewing Machine & Supply LLC

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 holes in throat plate.
Fig. 16
It is also important that the bottom of the
presser foot be flat on the throat plate. If
necessary, presser foot can be realigned with
throat plate slots by shifting the foot lifter
lever shaft (H, Fig . 16). To move the shaft,
loosen collar screws (B, Fig. 16) anCI . clamp
screw (G) and then shift the foot lifter lever
shaft to the left or right as required. Re-
tighten collar screws and clamp screw.
The foot lifter lever arm (A, Fig. 16) and
the collar (B) secure the shaft. Be sure the
presser arm does not bind and rise when
presser foot release bushing is unlocked.
Adjust lifter lever stop screw (C) so that
presser foot can be raised no hi~her than
upper looper will permit: then lock the nut (D). There should be from 1j16 to 1/8
inch 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 make assembly of chip guard easy, turn
handwheel until upper knife assembly reaches its highest position.
SETTING THE PRESSER FOOT HOLD DOWN PLATE
This machine is 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 cor-
rectly 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 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. Ti g hten the two
screws and remove the shim.
Fi g. 17
NOTE: Always be sure the feed dogs are below s urface of throat pl ate wh en making
this setting.
STARTING TO OPERATE
Be sure machine is threaded accordin g to threading dia g ram ( Fig . 1). W it h
thread tensions light, set looper th r ead ey ele ts (N & R) about h or iz ont al an d in th e
middle of their front to back locations. Op e rat e machin e slow ly , wi thout pr esse r
foot in place, to make sure that chain form s a nd mov es off th e ton gue f reel y. Sw ing
presser foot into position, insert material, and sew slowly.
12
From the library of: Superior Sewing Machine & Supply LLC

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) so that needle 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)
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 dis-
tance behind needle thread cam pull-off (AE). Frame looper thread guide (T) should
be set with its eyelet approximately 1/8 inch to the right of lower looper (V) heel
eyelet at the ti me lower looper is at extreme left end of its travel.
While sewing on material, check drawin g off of looper thread as follows: A
portion of lower looper thread should be drawn through the tension before lower
looper 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) balance all
four tensions to give a normal appearin g 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 thread throu gh the tension. When normal amount of looper thread is
drawn, upper looper thread will have almost all slack take n up as loop er thread
pull-off reaches its most rearward position.
POSITIONING THE PURL
To move the pur l more under the ed ge , both looper thread eyelets (N a nd R,
Fig. 1) should be raised keeping the same amount of pull-off. Usually, it is be tter
to have slightly more pull-off on upper thread than on lower thread.
If it becomes necessary to move looper th read pull-off (AF), be sur e to t ake up
all end play in needle drive shaft before ti g htenin g. If upper looper is loc ated s o
that it is higher over throat plate than recomm e nd ed in (Fig. 11), the purl will tend
to form near top edge. If upper looper is too low, the purl will form ne a rer bottom
edge.
THREAD TENSIONS
The ne e dl e thr e ad tension requ i red is a func ti on of needle thread and materi al
being s ewn. In g en er a l, lower looper thread tens i on should be set as high as pos s i-
ble without causin g ne edle thread to be pulled down. Upper looper thread tension
should be increas ed as long as the elasticity of the chain increases, or until th e
purl is pulled t oo far over the top. Keep tension s as light as possible and use ey e-
lets and take-ups to g et the proper stitch.
13
From the library of: Superior Sewing Machine & Supply LLC

14
From the library of: Superior Sewing Machine & Supply LLC

The parts illustrated on the preceding page and described below represent the parts
that are used on Style 39500 MK, but not used on Style 39500 GD.
Those parts shown in phantom views and bearing no reference numbers are common
to Styles 39500 GD and MK.
Use Catalog No. 103 FS (Style 39500 GD) for all parts not illustrated or described
in this catalog.
Reference numbers that are inside a bracket on the picture plate and have indented
descriptions indicate they are component parts of a complete part or assembly.
Ref.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Part
No.
39592 AR-5
39508 c
39536 AB
161
88
39536 AD
161 A
22764
43139 A
39536 AC
39536 AJ
8372 A
22728 A
29477 HJ
39568 p
39568 J
22743
39526 AT
39580 AE
39580 E
39505 AT
39520 w
39597 w
39530
22768 B
39540 B-12
Description
Am.t.
Req.
Upper and Lower Looper Thread Tension Spring ----- 2
Upper Looper, marked "CJ" ----------------------- 1
Differential Feed Control Adjusting Rod------------- 1
Adjusting Rod Stop Collar, upper------------------- 1
Screw --------------------------------------- 1
Spring Washer------------------------------------ 1
Adjusting Rod Stop Collar, lower------------------- 1
Screw --------------------------------------- 1
Nut, for stop screw------------------------------- 1
Differential Feed Control Adjustable Stop------------ 1
Differential Feed Control Mounting Bracket---------- 1
Washer, for stop screw --------------------------- 1
Differential Feed Stop Screw----------------------- 1
Upper Looper Thread Tube Assembly--------------- 1
Thread Tube --------------------------------- 1
Thread Tube Tension Spring ------------------- 1
Screw, for thread tube tension spring----------- 1
Differential Feed Dog, marked "FF", 12 t. p. i. ------ 1
Throat Plate and Lower Knife Support Bracket------- 1
Shim, for support bracket ------------------------- 1
Main Feed Dog, marked "FE", 12 t. p. i. ------------ 1
Presser Foot------------------------------------- 1
Stitch Tongue, marked "EF" ------------------- 1
Hinge Spring --------------------------------- 1
Screw --------------------------------------- 1
Main Feed Driving Eccentric ... ---------------------- 1
15
From the library of: Superior Sewing Machine & Supply LLC

'
"'
Q
...
~·lf
.,.o
WORLD'S FINEST QUALITY
*
INDUSTRIAL SEWING MACHINES
UNION SPECIAL maintains sales and service
facilities throughout the world. These offices
will
aid you in the selection of the right sewing
equipment for your particular operation. Union
Special representatives
and service men are fac-
tory trained and are able to serve your needs
promptly
and efficiently. Whatever your loca-
tion, there is a Union Special Representative to
serve you. Check with
him today.
ATLANTA, GA. MONTREAL, CANADA
BOSTON, MASS. TORONTO, CANADA
CHICAGO,
ILL. BRUSSELS, BELGIUM
DALLAS, TEXAS
LEICESTER, ENGLAND
LOS ANGELES, CAL. LONDON, ENGLAND
NEW YORK, N. Y. PARIS, FRANCE
PHILADELPHIA,
PA. srunGART, GERMANY
Repres e ntative s and distribu t ors In all i mportant
i ndustr i al citi es throughout the world.
MACHINE
COMPANY
400 N. FRANKLIN ST., CHICAGO, ILL. 60610
From the library of: Superior Sewing Machine & Supply LLC