UnionSpecial 39500 Series Instruction sheet

®
FINE ST QUALITY
STYLE
39500QD
CATALOG
No . .
103QD
CLASS 39500
MARK IV
HIGH SPEED OVERSEAMER
WITH
INDUSTRIAL
SEWING
MACHINES
STITCH SHORTENI G MECHANISM
UNION SPECIAL CORPORATION
C H ICAGO
From the library of: Superior Sewing Machine & Supply LLC

Catalog No. 103 QD
(Supplement to Catalog No. 103 QA)
INSTRUCTIONS
FOR
ADJUSTING AND OPERATING
LIST OF PARTS
CLASS 39500
Style
39500 QD
First Edition
Copyright @ 1973
by
Union Special Corporation
Rights Reserved in All Countrie s
UNION SPECIAL CO RPORATION
INDUSTRIAL SEWING MACHINES
CHICAGO
Printed in U.S. A.
2
October, 1975
- --- - -
From the library of: Superior Sewing Machine & Supply LLC

IDENTIFICATION OF MACHINE
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 QD". Special Style numbers contain the letter "Z". When
only minor changes are made in a standard machine, a "Z" is suffixed to the stand-
ard Style number. Example: "Style 39500 QDZ".
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 QA and should be used in con-
junction therewith. Only parts found on Style 39500 QD, but not on Style 39500 QB
are illustrated. On the page opposite the illustration will be found a listing of the
parts with their part numbers, description 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
MARK IV Hi-Styled High Speed, Single Curved Blade Needle, Two Looper, Three
Thread, Overseaming Machine, Differential Feed, Trimming Mechanism with Spring
Pressed Lower Knife, Automatic Lubricating System, Improved Air Cooling System.
39500 QD Light to medium duty machine for seaming of "T" shirts, polo shirts,
panties, slips, etc., with knee controlled stitch shortening mechanism to
minimize the ~ossibility of ravelling. Seam Specification, 504-SSa-1; standard
seam width 1f8 inch (3.17 mm); stitchrange 8-30 per inch; cam adjusted main
and differential feed. Maximum recommended speed 8000 R. P. M. depending
on stitch length and operation.
SPEED RECOMMENDATION
39500 MARK IV machines have been tested in their complete stitch range at their
maximum rated speeds. Varied field conditions, severity and cleanliness of the
sewing operation may necessitate operating at a lower speed. When operating from
50-100% machine running cycle and a longer than recommended stitch length, it
may be necessary to reduce the machine's speed by 10-15%.
The MARK IV is a precision manufactured and tested sewing machine. To obtain
maximum performance, the machine should be operated at 1000 R. P. M. below maxi-
mum recommended speed,for the first 20 days of field operation. This will minimize
readjustment of precision mechanisms.
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OILING
CAUTION! Oil was drained from machine when shipped, so reservoir must be
filled before beginning to operate. Oil capacity of Class 39500 is s~ 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. Oil level 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.
To maintain maximum recommended speed and serviceability of this equipment
when operating continuously, the oil must be changed at least every six months. In
no case should oil remain in machine for more than one year.
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 a type and size number. The type number
denotes the kind of shank, point, length, groove, 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 nee-
dles packaged and sold by Union Special.
Style 39500 QDuses a curved blade needle. The standard needle for this style is
Type 154 GAS. It has a round shank, round point, curved blade, standard length,
single groove, struck groove, s:potted, chromium plated and is available in sizes
055/022, 065/025, 070/027, 075/029, 080/032, 090/036, 040, 044, 049, 054, 060.
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: "1000 Needles, Type 154 GAS, Size 070/027
11
•
Selection of 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 machines 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 swing presser arm (U) out of position. Turn handwheel in operating
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. Returnpresser arm (U) to position; re-lockpresser foot release bushing (AG).
4
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THREAD STAND
After thread comes from cones on cone support (A, Fig. 1), they are brought up
through the back hole of thread eyelet (B), then down through the front hole of thread
eyelet. The needle and upper looper threads are then threaded through the upper hole
of tension thread guide (C) from front to back, and then through the lower hole from
back to front. The lower looper thread is threaded through the upper hole back to
front, through the middle hole from front to back, and finally through the lower hole
from back to front. All three threads then continue between the tension discs (J),
through tension post slot (K) in tension post (G) and on through front thread guide (M).
THREADING
Only parts involved in threading are shown in threading diagram (Fig. 1). Parts
are placed in their relative positions for clarity.
It will simplify the threading of this machine to follow the recommended sequence
of threading the lower looper first, upper looper second, and the needle third.
Before beginning to thread, swing cloth plate open, turn hand wheel in operating
direction until needle (X) is at high position, release pressure on presser foot by
turning presser foot release bushing (AG) and swing presser arm (U) out of position.
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).
TO THREAD THE LOWER LOOPER
Double end of thread and lead it through the right eyelet of front thread guide
(M, Fig. 1). Then lead thread through both eyes of lower looper thread eyelet (R)
from right to left. NOTE: Thread must pass in front of looper thread pull-off (AF).
Lead thread behind fabric guard ( S) and through 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 THE UPPER LOOPER
Thread upper looper thread through left eyelet of front thread guide (M). Then
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 lo.oper thread tube assembly
(AA), lead thread under neck of top cover casting and down through thread tube
assembly (AA). Pull thread out bottom of tube; push tube down, then insert thread
through upper looper eye from front to back.
TO THREAD THE NEEDLE
Thread needle thread through middle eyelet of front thread guide (M). Then turn
handwheel in operating direction until needle (X, Fig. 1) is at its highest position.
Insert needle thread from right to left, through both eyes of needle thread eyelet
(AD), under neck of top cover casting; then down through hole in top cover needle
thread eyelet (AC). Thread needle from front.
THREAD TENSION
The amount of tension on the needle and looper threads is regulated by knurled
tension nuts (D, Fig. 1). Tension on threads should be only enough to secure proper
stitch formation.
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(;] Tension Nut
O Tension Discs ·. _'
(3 Tension Post Slo~ · · --..
nTension Disc Felt··..
[i Tension Thr e ad Guide
~ Front Thr ead Guide
IIJ Upper Looper Thr ead Eyelet
~~ Lower Looper Thr e ad Eyelet
(;~ Fabric Guard Bracket
D Frame Looper
Thread Guide
m Presser Arm
/
(;) Thr e ad Eyelet
6
Cone Support
Top Cover
_...,.,.. Needle Thread Eyelet
Upper Looper
Thr ead Tube Assembly
Upper Looper
F i g. 1
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PRESSER FOar PRESSURE
Sufficient presser foot pressure to feed work uni-
formly 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 tighten-
ing 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 adjusting screw (B).
Set cap (D) against locking nut (C).
FEED ECCENTRICS
Fig. 2
Feed eccentrics used in Style 39500 QD machines have been selected to produce
approximately 12 stitches per inch. It will be noted that the part number of main
feed eccentric is No. 39540 B-12 while that of differential feed eccentric is No .
39540 B-10. Minor numbers of the part symbol indicate approximately the number
of stitches obtainable when using that eccentric. Unless otherwise specified, rna-
chine Style 39500 QD will be shipped with above combination of eccentrics.
Generally speaking, differential (right hand) feed eccentric determines number
of stitches produced; main (left hand) feed eccentric is selected in relation to degree
and direction of stretch of material being sewn, or type of operation.
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, Addi-
tional eccentrics may be ordered separately. To order an eccentric use No.
39540 B with a minor number suffixed to indicate number of stitches desired.
Example: "39540 B-12".
Fig. 3
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 se-
quence.
CLOTH PLATE REMOVAL AND ASSEMBLY
CAUTION: When removing the cloth plate (A, Fi g. 3)
loosen the cloth plate stud locking screw (B) and lift up cloth
plate with the cloth plate stud (C) and cloth plate scr ew (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 of the 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.
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SETTING THE NEEDLE
With throat plate attached to the throat plate support (39580 C) and resting on the
throat plate support bracket (39580 AB), needle should center in the front end of
needle slot. When needle is at high position, needle
point should be set 1/2 inch (12. 70 mm) above t hroat
plate (A, Fig. 4). To align needle or set the height
Fig. 4
above the throat plate, move needle driving arm (B),
by loosening clamp screw (C). After needle has been
set properly, tighten screw (C) and remove throat
plate.
If needle thread cam pull-off (A, Fig. 5) over-
laps looper thread pull-off (B), separate by moving
looper thread pull-offback. When retightening looper
pull-off screw, be sure to take up end play in needle
driving arm.
Insert lower looper (A, Fig. 6) 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. 6), using looper gauge No. 21225-
1/8. Do not have lower looper deflecting needle.
Tighten nut (C).
Now assemble differential (front) feed dog.
SETTING THE REAR NEEDLE GUARD
Set rear needle guard (A, Fig. 7) as high as
possible, without interfering with either lower
looper or movement of lower knife holder, but Fig. 5
still in position to deflect needle forward . 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 should be set
into the needle scarf (A, Fig. 8) until the needle
springs forward from rear needle guard surface
another. 002-.004 inch(. 051-.102 mm).
SETTING THE FRONT NEEDLE GUARD
Fig. 6 Assemble front needle guard (C, Fig. 7). When
lower looper is springing needle off rear needle
guard, set front needle g uard as close as possible to needle 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.
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SETTING THE UPPER LOOPER
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 hold-
er into upper looper shaft, if it is
not already in place. Screw (C) in
clamp, holds the upper looper hold-
er in the shaft. Locate upper looper
in its holder so that the shank extends
1/32 to 1/16 inch (. 79 to 1. 59 mm)
beyond holder (Fig. 9).
When the upper looper is at the
right end of its stroke, upper looper Fig. 8
holder should be set to position upper
looper shank slightly back of vertical (Fig. 9).
Be sure there is a clearance between heel of looper
and casting. By adjusting looper holder in or out of upper
Fig. 7 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 (. 051 to. 102 mm) clearance (Fig. 10).
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
respect to needle and throat plate (Fig.
11). If resetting is necessary, do it by
moving the upper looper holder (A, Fig.
11). Figure 11 represents the correct
Fig. 9 dimensional setting. Fig. 10
For example, dimension 31/64 inch {12. 30 mm) is increased by turning upper
looper holder counterclockwise looking from left end of
machine; dimension 5/32 inch (3. 97 mm) is increased by
pulling upper looper holder left, out of upper looper shaft.
After these changes are made it may be necessary to turn
upper looper around its shank slightly to maintain the condi-
tion shown in 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, bottom of the
needle eye should be about level with top surface of upper
looper {Fig. 12).
Check setting to avoid interference between upper looper
and needle on needle downstroke. If needle rubs the back Fig. 11
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, 11, 12.
9
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SETTING THE FEED DOGS
Now
assemble differential (front) feed dog (A, Fig. 13),
if not already in place, main (back) feed dog (B) and chaining
feed dog (C). Set the differential and main feed dogs (A and B,
Fig. 13) so the top surfaces of teeth lay in the same plane.
This can be checked by sighting across teeth with a straight
edge. Now assemble throat plate. Feed dogs should now be
leveled with throat plate surface by rotating feed tilting adjust-
ing pin (D). This pin raises or lowers the back end of both
feed bars at the same time.
The main and differential feed dogs should be set level
at the time teeth first appear above the throat plate. Screw
(E, Fig. 13) locks feed tilting adjusting pin in place. Now
Fig. 12 set main and differential feed dogs so that teeth are approxi-
mately 3/64 inch (1. 19 mm) above throat plate at high point
of travel. Set chaining feed dog (C) so its teeth are level with top of throat plate
when feed is at top of its travel.
Fig. 13
SETTING THE LOWER KNIFE
Replace lower knife holder assembly. Lower knife (A, Fig. 14) should be set
with cutting edge flush with throat plate surface. Adjustments are made with hexa-
Fig. 14
back from the cutting edge.
gonal head screw which holds lower knife. Lower
knife is spring pressed against upper knife, so no
lateral adjustment 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 sup-
port 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 tighten-
ed against lower knife holder.
SETTING THE UPPER KNIFE
Replace upper knife assembly. Clamp upper knife
(D, Fig. 14) in position, setting nut (E) to hold clamp
(F) in its most clockwise position against upper knife.
At bottom of its stroke, front cutting edge of upper
knife should extend not less than 1/64 inch (. 40 mm)
below cutting edge of lower knife. The chain g uard (G)
should be set down against the upper knife and slightly
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