UnionSpecial 39500PA Setup guide

CATALOG NO.
103PA
First Edition
STYLES
39500PA
39500PE
39500PF
39500PP
39500PT
39500PW
Finest Quality
Adjusting instructions and
illustrated parts list ([)
Class 39500-Differential feed overseamers
with thumbscrew adjusted feed travel
From the library of: Superior Sewing Machine & Supply LLC

FOREWORD
This technical manual has been prepared to guide you in the maintenance of your
new UNION SPECIAL machine. Careful attention to the instructions for operating and
adjusting these machines will enable you to maintain the superior performance and re-
liability designed and built into every UNION SPECIAL machine.
The Adjusting Instructions portion of this manual explains in detail the proper
setting for each of the components related to forming the stitch and completing the
functions
of the machine. The text of the Adjustments is divided into two sections -
Check and Procedure. The Check depicts conditions when the parts are adjusted cor-
rectly. The Procedure is given to explain the proper steps to be taken in the event
adjustments are required. Figures are
used to illustrate the adjustments using refer-
ence letters to point out specific items discussed.
Adjustments are presented in sequence
so that a logical progression is accom-
plished. Some adjustments performed out of sequence may have an adverse effect on
the function of other related parts.
Implementation of preventative maintenance procedures can bring about signifi-
cant improvements in operator productivity by avoiding costly equipment breakdowns.
Whenever it becomes necessary to make repairs or replace parts on your machine, be
sure to insist on genuine UNION SPECIAL Repair Parts. These parts are designed speci-
fically for your machine and manufactured with utmost precision to assure long last-
ing service.
To simplify identification of repair parts, the mechanisms are illustrated by
exploded views. These illustrations will usually be shown in conjunction with a KEY
VIEW which presents the mechanisms of the machine assembled. The specific parts
illustrated on this page will appear shaded in the KEY VIEW.
Catalog No. 103 PA
39500 PA
39500 PE
39500 PF
For Styles
39500 pp
39500 PT
39500 PW
First Edition
Copyright 1981
By
Union Special Corporation
Rights Reserved In All Countries
Printed In U.S.A.
May, 1981
2
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CLASS DESCRIPTION
High Speed, one and two curved needles, two loopers, three and four thread, differ-
ential feed overseaming machines. Fabric trimmer with spring pressed lower knife.
Independent
thumbscrew adjustments for main and differential feed travel. Enclosed
automatic
lubrication system. Fan cooled.
STITCH AND
SEAM TYPE .......... .
FEED SYSTEM ........ .
MAXIMUM SPEED ...... .
(Depending on
Operation)
LUBRICATION ........ .
TECHNICAL DATA
504 SSa-1, Styles 39500 PA, PE, PF, PP, PT
512 SSa-2, Style 39500 PW
Independent thumbscrew adjustments for both
Main and Differential Feeds.
6500 RPM, Styles 39500 PF, PP, PT, PW
7000 RPM, Styles 39500 PA, PE
Enclosed Automatic Splash System with Oil
Return Pump
MACHINE STYLES
39500 PA- One needle, low capacity machine for sewing light to mediumweight knit or
woven fabrics. Stitch range is 8-20 S.P.I. Typical application - For seaming long
straight seams on pajamas and women's underwear. Available Seam Widths: 3/32 inch
(2.4mm), l/8 inch (3.2mm), 5/32 inch (4mm).
39500 PE - Same as 39500 PA except fitted with narrow sewing parts. Typical applica-
tion -
Seaming women's robes and lingerie.
39500 PF - Same as 39500 PA except machine is high capacity for sewing medium to
heavyweight knit
or woven fabrics. Also equipped with a main feed dog having 16
T.P.I. Stitch range is 8-16 S.P.I.
39500 PP- Same as 39500 PF except equipped with a main feed dog having 12 T.P.I.
39500 PT - Same as 39500 PF except prepared for continuous or intermittent shirring.
Maximum shirring ratio is 3 to 1. Available Seam Width: 1/8 inch (3.2mm).
39500 PW - Same as 39500 PP except machine has two needles. Available Seam Width:
17I 64 inch ( 6. 7mm) .
IDENTIFICATION OF MACHINES
Each UNION SPECIAL machine carries a style number, which on this class machine is
stamped in the style plate located to the right rear of the machine.
The serial number is stamped in the extension of casting at the right rear base of
machine.
3
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SAFETY RULES
A
CAUTION!
THIS SAFETY SYMBOL INDICATES YOUR PERSONAL SAFETY IS INVOLVED.
TO PREVENT PERSONAL INJURY:
-All power sources to the machine MUST be TURNED OFF before threading, oiling, ad-
justing or replacing parts.
- Wear safety glasses.
-
All shields and guards MUST be in position before operating machine.
- DO NOT tamper with safety shields, guards, etc., while machine is in operation.
LUBRICATION
Oil capacity of Class 39500 is eight ounces (227 milliliters). Use a straight
mineral oil with a Saybolt viscosity of 90 to 125 seconds at 100 degrees F. This is
equivalent to UNION SPECIAL specification No. 175.
Machine is filled with oil at spring cap in top cover. Before operating, check
oil level at sight gauge on front of machine. When proper oil level is reached, red
bulb
on oil level indicator will register between red gauge lines.
To drain oil remove magnetic plug from back of machine near bottom edge of base.
Clean magnetic plug of any metallic material that may have accumulated in crankcase.
Oil MUST be changed periodically to minimize wear.
THREADING
Be sure machine is threaded properly according to threading diagram Fig. 1, for
Styles 39500 PA, PE, PF, PP, PT, or Fig. lA, for Style 39500 PW.
THREADING DIAGRAM STYLES 39500 PA, PE, PF, PP, PT
Before threading machine; unlock presser foot release bushing, swing presser
arm and cloth plate out of position and pull uppe r looper thread tube up. Turn hand-
wheel in operating direction until needle is at highest position. Thread tweezers
No . 660-240 are furnished with machine to aid in threading.
Thread machine in sequence as shown; (1) lower looper thread, (2) upper looper
thread, (3) needle thread.
THREADING DIAGRAM STYLE 39500 PW
Before threading machine; unlock presser foot release bushing, swing presser
arm and cloth plate out of position and pull upper looper thread tube up. Turn hand-
wheel in operating direction until needles are at highest position. Thread tweezers
No. 660-240 are furnished with machine to aid in threading.
Thread machine in sequence as shown; (1) lower looper thread, (2) upper looper
thread, (3)
right needle thread and (4) left needle thread.
4
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ROUTE THREAD THRU
TENSION POST SLOT
TURN TO RELEASE
PRESSER ARM
ROUTE LOOPER THREAD
IN FRONT OF LOOPER
THREAD PULL-OFF
·· · ~.
"'-- · · "~
SWING PRESSER ARM OUT ~\,~ .. A
~··~
~ .. ~
5
Fig. 1
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TURN TO RELEASE
PRESSER ARM - ---.ll"!:j
6
Fig. 1A
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ADJUSTING INSTRUCTIONS CLASS 39500
NOTE: Instructions stating direction or location, such as right, left, front or rear
of machine, are given relative to operator's position at the machine. The
handwheel rotates clockwise, in operating direction; when viewed from the
right end of machine.
NEEDLES
EXAMINE NEEDLE AND/OR NEEDLES TO ASSURE PROPER
TYPE AND SIZE IS BEING USED. THE FOLLOWING
CHECKS RELATED TO NEEDLE(S) MUST BE MADE BE-
FORE ADJUSTING THE NEEDLE(S), LOOPERS OR NEED-
LE GUARDS. DISCARD AND REPLACE ANY DEFECTIVE
NEEDLE(S).
-Place a new needle of the same type and size
alongside the existing needle to check cur-
vature of needle blade
as shown {A, Fig. 2).
-
Apply the thumbnail test to check for blunt-
ness and/or
hooks on the tip of needle(s) as
shown (B, Fig. 2).
-
Check for any sharpness around eye and/or
grooves of needle(s).
For a quick check, pull
forth through the needle
eye as shown (C, Fig.
shred
and severe the thread.
Fig. 2
the thread
up and down, back and
2). If any sharpness exists, it will
-
Be sure needle(s) is all the way up in needle holder and positioned correctly with
the spot or
scarf to the rear as shown (D, Fig. 2).
Machines are sewn off and shipped from the factory with needle(s) listed in
chart per machine style:
Machine Sty le
39500 PA, PE, PF, PP, PT
39500 PW
Type and Size
154 GAS-075/029
154 GAS-090/036
The following chart lists additional needle types and sizes available for Class
39500 machines.
NEEDLE TYPE
154 GAS
154 GBS
DESCRIPTION
Round shank, round point, curved
blade, standard length, single
groove, struck groove, spotted,
chromium plated.
Same as 154 GAS except it has a
double groove.
7
SIZES AVAILABLE
055/022, 065/025, 070/027,
075/029, 080/032, 090/036,
100/040, 110/044, 125/049,
140/054, 150/060
070/027, 075/029,
080/032
From the library of: Superior Sewing Machine & Supply LLC

NEEDLE TYPE
154 GES
154 GHS
154 GJS
154 GLS
DESCRIPTION
Same as 154 GAS except it has a
shorter blunt point.
Same as 154 GAS except it has a
ba 11 point.
Same as 154 GAS except it has a
tapered b
1ade.
Same as 154 GAS except it has a
ball eye.
SIZES AVAILABLE
055/022, 065/025, 070/027,
075/029, 080/032, 090/036,
100/040, 11 0/044, 125/049,
140/054, 150/060
065/025, 070/027, 075/029,
080/032, 090/036
055/022, 065/025, 070/027,
075/029, 080/032, 090/036,
100/040
070/027, 075/029, 080/032,
090/036, 100/040
To have needle orders promptly and accurately filled, an empty package, a sample
needle or type and size number should be forwarded. Use description on label. A
complete order
would read
11
1000 needles, Type 154 GAS, Size 075/029
11
•
Fig. 3
Fig. 4
NEEDLE REPLACEMENT
Rotate presser foot release bushing
counterclockwise
and swing presser foot to the
left. Turn handwheel in operating direction
until needle(s)
is at lowest position. Loosen
clamp nut using socket wrench No. 21388 AU
(A, Fig. 3), then remove needle(s).
Turn handwheel until needle holder (B)
is at highest position. Insert new needle(s)
all the way up in needle holder with spot or
scarf to the rear. Tighten clamp nut, swing
presser foot to the right and lock foot into
sewing position with presser foot release
bushing.
NEEDLE ALIGNMENT
Check:
Needle(s) must enter the center of needle
slot(s) (left to right) in throat plate, as
shown in Fig. 4. If adjustment is necessary,
remove fabric guard and looper thread pull-
off.
8
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Procedure:
Loosen needle driving arm clamp screw
(A, Fig. 5) and center needle(s) in needle
slot(s) of throat plate by adjusting needle
driving
arm (B) left to right as required.
Temporarily tighten
clamp sc.rew (A), then
proceed to needle height adjustment.
NEEDLE HEIGHT
Check:
Rotate handwheel in operating direction until
needle(s) is at highest position. The needle
height
measurement from point of needle(s) to
top of
throat plate must be 1/2 inch (12.7mm)
as shown in Fig. 5.
Procedure:
Fig. 5
Loosen clamp screw (A) and adjust needle driving arm (B) front to back as required to
obtain needle height
shown in Fig. 5, then tighten clamp screw (A) and replace looper
thread
pull-off.
PRIOR TO MAKING THE FOLLOWING ADJUSTMENT; REMOVE CLOTH PLATE, CHIP GUARD, UPPER KNIFE,
MAIN, DIFFERENTIAL AND CHAINING FEEDS. ON MACHINE STYLE 39500 PT REMOVE THE SHIRRING
BLADE ASSEMBLY.
CLOTH PLATE
Remove cloth plate {A, Fig. 6) by loosen-
ing screw
{B) and lifting upward with stud (C)
and screw (D) still assembled to plate.
Before replacing cloth plate, hold stud
(C) and tighten screw (D) only enough to re-
move end play, yet allowing cloth plate to
swing open when assembled. Assemble cloth
plate to machine by inserting stud (C) with
flat and
11
V
11
notch to the rear into hole of
machine bed. Tighten screw (B) to press
11
V
11
notch of stud (C) against screw (D).
9
Fig. 6
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Fig. 7
left needle on Style 39500 PW.
Procedure:
LOWER LOOPER
Check:
PRIOR TO CHECKING LOOPER ADJUSTMENT; REMOVE
FRONT AND REAR NEEDLE GUARDS.
LOOPER GAUGE - With looper at extreme left
position, 1/8 inch (3.2mm) is the distance
between looper point and centerline of needle;
1/16 inch
(1.6mm) to left needle on Style
39500 PW, as shown in Fig. 7.
LOOPER CLEARANCE TO NEEDLE(S) - Turn handwheel
in operating direction so that looper travels
from the extreme left into scarf of needle or
Point of looper should touch but
NOT deflect needle(s).
PRIOR TO ADJUSTING LOOPER, POSITION UPPER LOOPER UP AND AWAY FROM LOWER LOOPER.
Gauge No. 21225-l/8 or 21225-1/16 should be used to properly set looper gauge.
Position lower looper
(A) to extreme right and loosen clamp nut (B). Then position
looper to extreme
left and set looper gauge by adjusting looper in or out of the loop-
er shaft to obtain l/8 inch (3.2mm) or 1/16 inch (1.6mm) for Style 39500 PW. Rotate
handwheel to position looper into scarf of needle or left needle on Style 39500 PW and
set looper point to touch but NOT deflect needle(s), then position looper to extreme
right and tighten clamp nut (C).
REAR NEEDLE GUARD
Remove spring from inside of lower knife
holder
{A, Fig. 8), then assemble knife holder
into
throat plate support block.
Replace rear needle guard (B) using screw
(C) with front edge of guard centered in slot
of knife holder as shown. Temporarily tighten
screw
(C) to hold guard in position, yet allow-
ing guard to
be adjusted.
Rotate
handwheel in operating direction
so lower looper (D) travels from the extreme
Fig. 8
left into scarf of needle(s). Set guarding
surface of guard (B) to touch but
NOT deflect
needle(s) while also setting guard as low as possible to prevent it from interfering
with needle thread as loop is being formed to rear of needle(s), then tighten screw
(C) securely.
Guard must NOT interfere with lower knife holder movement or contact lower
looper
at any point of travel.
10
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FRONT NEEDLE GUARD
Replace front needle guard (E, Fig. 8) using screw (F). Temporarily tighten
screw
(F) to hold guard in position, yet allowing guard to be adjusted.
Rotate
handwheel in operating direction until needle(s) is at lowest position,
then
set guarding surface of guard (E) to needle(s) with minimum clearance -approxi-
mately .004 inch (.
lOmm) and tighten screw (F) securely. Check adjustment to ensure
needle(s}
is NOT being pinched between front and rear needle guards.
UPPER LOOPER
PROPER ADJUSTMENT OF THE UPPER LOOPER IS
ESSENTIAL FOR SUCCESSFUL MACHifiE OPERATION.
THE PATH TRAVELED BY THE UPPER LOOPER EFFECTS
THE MAXIMUM SEAM THICKNESS SEWN.
Rotate handwheel in operating direction
and closely observe the path of upper looper
as
it travels from the extreme right and ap-
proches the lower looper
as shown in Fig. 9.
The point of upper looper MUST pass the notch
in
head of lower looper with minimum clear-
ance and pass under lower looper thread.
Again rotate the handwheel until the
upper looper
is positioned to extreme left
as shown in Fig. 10. At this time, point of
upper looper MUST be in position so the de-
scending needle or
right needle will pass to
the
right of the upper looper thread, which
extends from the eye of the looper to the
previously
formed stitch. The upper looper
must NOT contact the lower looper or needle(s)
at any point of travel.
Fig. 9
Fig.
10
Figures 11, 12, 13 and the following chart relate approximate dimensions for ad-
justing the upper looper at extreme right and left positions of travel.
SHANK EXTENDED HEIGHT ABOVE POINT OF LOOPER TO
MACHINE
ABOVE HOLDER THROAT PLATE CENTERLINE OF NEEDLE
STYLE
DIM. non FIG. 11 DIM. nEn FIG. 13
DIM. nFn FIG. 13
39500 PA, PE l/32 inch (.
8mm}
31/64 inch (12.3nm)
5/32 inch (4nm)
39500 PF, PP,
3/32 inch
(2.4mm) 35/64 inch (13.9mm)
9/64 inch (3.6mm)
PT, PW,
(right needle on
Style PW)
11
t ...
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Fig. 11
Fig. 12
Fig. 13
To adjust upper looper, follow instruc-
tions listed in sequence as follows:
1. Position upper looper
at the left end of
travel, loosen clamp screw {A, Fig. 11)
and set looper shank to dimension "0"
Fig. 11 above holder (B), then temporari-
ly tighten
screw (A).
2. With upper looper positioned at the right
end of travel, loosen screw (C) and rotate
holder (B) as required to set shank of
looper
slightly back of vertical, as shown
in Fig. 12, then temporarily tighten screw
(
C, Fig. 11 ).
3. Rotate
handwheel in operating direction
bringing the upper looper into the lower
looper,
See Fig. 9. Loosen screw
(A, Fig. 11) and set the point of upper
looper to
enter the notched area behind
head of lower looper with minimum clear-
ance.
4.
Again rotate handwheel in operating dir-
ection until the upper looper is at the
extreme
left end of travel. Loosen screw
(C, Fig. 11} and rotate upper looper hold-
er as required to set point of upper loop-
er to dimension "E" Fig. 13 from top of
throat plate.
5. With upper looper still positioned at the
left end of travel, it may be necessary to
adjust the looper holder in
or out of its
shaft to set point of looper to dimension
"F" Fig. 13 to the left of needle and/or
right needle centerline. Rotate handwheel
to position upper looper to the right end
of travel, then tighten screw {C, Fig. 11}
and screw (A) securely.
6.
If the needle(s} is being deflected by the
upper looper, clearance to the needle(s)
can be increased by reducing the length of
looper shank above holder, See Step 1. It
will then be necessary to slightly reduce
the angle
back of vertical, See Step 2.
Also reset upper looper to lower looper,
See Step 3. Reversing this procedure will
position the upper looper
closer to the
needle(s).
12
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MAIN AND DIFFERENTIAL FEEDS
ASSEMBLE MAIN, DIFFERENTIAL, CHAINING FEEDS
AND THROAT PLATE TO MACHINE.
Check:
Rotate handwheel in operating direction until
teeth of rising feeds are above the top sur-
face
of throat plate. The feeds should be
level with the throat plate at this time. With
feeds at highest position of travel, their
teeth should extend approximately 3/64 inch
(1.2mm) above throat plate as shown in Fig. 14.
Procedure: Fig.
14
Loosen lock screw (A, Fig. 14) and rotate tilt adjusting pin (B) as required to level
feeds, then tighten lock screw
(A).
Loosen feed attaching screws (C) and adjust feeds up or down to obtain proper height
above throat plate as shown in Fig. 14, then tighten screws (C).
On all Styles except 39500 PW; with feeds at highest position, loosen screw (D) and
set height of chaining feed even with the stitch tongue of throat plate, then tighten
screw
(D).
LOWER KNIFE
INSERT SPRING BACK INTO LOWER KNIFE HOLDER
AND ASSEMBLE HOLDER TO THROAT PLATE SUPPORT.
Check:
Cutting edge of knife (A, Fig. 15) must be even
and parallel with top surface of throat plate.
Examine sewn sample for specified seam width
and appearance.
Procedure:
Loosen screw (B) and adjust knife (A) up or
down until its cutting edge is flush with top
of throat plate, then tighten screw (B).
Fig.
15
If cutting edge of knife is tilted, loosen screw (C) and rotate holder (D) front to
rear as required, then tighten screw (C). Holder MUST move freely, left to right,
and NOT bind, with needle guard centered in slot of knife holder.
Adjust knife
(A}, left to right, by loosening locknut (E), screw (F) and set knife
to specified seam width by measuring from center of needle to cutting edge of knife.
Hold knife in this position and tighten screw (F). Adjust UPPER KNIFE; then sew-off
on a piece of selected material to further check adjustment, by measuring the dis-
tance from needle penetration to edge of material. Readjust if necessary, to obtain
specified
seam width or appearance.
13
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UPPER KNIFE
REMOVE NEEDLE(S) AND RE-ASSEMBLE UPPER KNIFE HOLDER INTO SLOT OF UPPER KNIFE DRIVING
ARM. ALSO RE-ASSEMBLE UPPER KNIFE IN HOLDER AND HOLD KNIFE FIRMLY IN POSITION.
Check:
At lowest position the front tip of upper knife cutting edge must extend l/£4 -l/32
inch (.4 -
.8mm) below cutting edge of lower knife. ·
Procedure:
With upper knife (G, Fig. 15) at lowest position of travel and while holding upper
knife firmly against
lower knife, adjust knife holder (H) left to right, to position
front
tip of upper knife cutting edge l/64 -l/32 inch (.4 - .8mm) below cutting edge
of lower knife, then tighten screw (J).
Assemble knife clamp (K) and chain guard (L) in position using nut (M). Set chain
guard (L) against top surface of upper knife and slightly back of its cutting edge,
then tighten nut
{M).
Loosen screw {F) to enable spring pressed lower knife to move freely left to right.
If desired, the lower knife can be locked in position by tightening screw (F) against
knife holder.
NOTE: Locking nut {E) must be tightened to hold screw (F) in position; screw (F)
also serves as a latch pin for cloth plate.
Fig. 16
PRESSER FOOT ALIGNMENT
LOCK THE PRESSER FOOT IN SEWING POSITION AND
ROTATE HANDWHEEL UNTIL NEEDLE(S) IS AT LOWEST
POSITION.
Check:
Right edge of presser foot must align with
left edge of needle slot in throat plate
as shown Ref. Point A, Fig. 16.
Presser foot must lie flat on throat plate.
The adjustable stitch tongue on pr.esser foot
must center over stitch tongue of throat plate
as shown in Fig. 16.
14
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Procedure:
With presser foot locked in sewing position by
release bushing (A, Fig. 17), loosen collar
screws (B) and clamp screw (C), then adjust
lifter lever shaft (D) left to right until the
right edge of presser foot aligns with the
left edge of needle slot in throat plate as
shown Ref. point A, Fig. 16. Tighten collar
screws (8, Fig. 17) and while holding lifter
lever arm (E) so its stop screw (F) is against
intermediate lever (G), tighten
clamp screw
(C).
Completely unlock release bushing
(A, Fig. 17). Plunger should clear presser arm
without binding.
Loosen screw (8, Fig. 16) and adjust stitch
Fig. 17
tongue (C) left to right, to center over stitch tongue of throat plate as shown in
Fig. 16, then tighten screw (B).
PRESSER FOOT LIFT
Check:
Lift presser foot to highest position and rotate handwheel in operating direction.
Upper looper must not contact presser foot at any point of travel.
Procedure:
Loosen locknut (H, Fig. 17) and adjust stop screw (J) so presser foot will not inter-
fere with upper looper, then tighten locknut (H).
Loosen locknut (K) and set stop screw (F) on upper end of lifter lever arm so there
is approximately 1/16 inch (1.6mm) free motion in lifter lever before presser foot
starts to rise, then tighten locknut (K).
PRESSER FOOT PRESSURE
Check:
Sufficient pressure must be maintained to feed work uniformly. Excessive spring
pressure will cause feeds
and presser foot to wear prematurely when chaining.
Procedure:
Rotate
handwheel in operating direction until both main and differential feeds are
positioned
below throat plate. Loosen locknut (L, Fig. 17) and turn adjusting screw
(M) clockwise for more pressure or counterclockwise for less pressure, then tighten
locknut (L).
NOTE: Adjusting screw (M) will effect the function of pressure release bushing (A).
Plunger must clear presser arm when pressure release bushing is unlocked.
When release bushing is locked in position, presser foot must be held firmly
against
throat plate. If these conditions do not exist the following adjust-
ment must be made.
15
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Lock presser foot in position with pressure release bushing (A); loosen capnut (N)
and adjust nut (P) up or down so its under surface is l/16 inch (1.6mm) above screw
(M) as shown in Fig. 17. Hold nut (M) in position and tighten capnut (N).
Fig. 18
SHIRRING BLADE FOR STYLE 39500 PT
Replace shirring blade assembly. With
shirring blade in position, lock presser foot
in
sewing position and turn handwheel in oper-
ating direction
until feed dogs are at their
highest position. Loosen screws (A, Fig. 18)
and adjust shirring blade mounting bracket (B)
so the shirring blade (C) is level and lies
flat on the feed dog teeth. Position mounting
bracket
(B) forward or rearward to obtain 1/32
inch
(.8mm) clearance between top front edge
of shirring blade (C) and the underside of
presser
foot, then tighten screws (A).
With feed dogs still at their highest
position, loosen screws (D) and set shirring blade (C) so its front edge is parallel
to the differential feed dog teeth. Hold blade in position and tighten screws (D)
maintaining the 1/32 inch (.8mm) clearance between top front edge of shirring blade
and underside of presser foot.
Fig.
19
To center shirring blade (C) over differ-
ential feed dog, loosen screws in collar
(A, Fig. 19), actuating collar (B), operating
lever
(C) and loosen tension screw (D). Move
shaft (E) to the left or right as required to
center
shirring blade over differential feed
dog. While holding blade in position, thrust
both collars (A and B) against shaft bracket
(F) to eliminate any end play in the shirring
blade shaft, then tighten screws in collars
(A and B). With the shirring blade properly
adjusted
and in position, set operating lever
(C) in the slot of the shaft bracket and tight-
en its screw.
Tension
on the shirring blade can be ob-
tained
by turning shaft collar (G) with spanner
wrench No. 21388 Y, furnished with machine. When the proper amount of tension is ob-
tained, hold shirring blade in position and tighten screw (D).
SETTING . STITCH LENGTH
The actual stitch length produced is usually measured as the number of stitches
sewn per inch of seam. This is determined by the distance feeds travel with their
teeth protruding above the throat plate.
Class 39500 machines are fitted with a feed system having two separate feed dogs
-MAIN (rear) and DIFFERENTIAL (front).
16
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The resulting stitch length is determined
to a great extent by travel of the main feed.
The differential feed travel can be adjusted
independent
of the main feed and is used to
gather
or stretch the fabric prior to being
stitched.
On the graduated scale of indicator plate
(A, Fig. 20) the forward marking
11
L
11
indicates
longest
stitch length and the rear marking
11
S
11
indicates shortest stitch length.
To adjust stitch length turn both main
and differential thumbscrews (B and C) clock-
wise to increase feed travel
or counterclock-
wise to decrease feed
travel.
Fig. 20
After desired stitch length is obtained check the clearance between the main and
differential feeds, also check clearance between the throat plate and both feeds. If
an adjustment is necessary, set the feeds to have the same travel, then turn the
handwheel in operating direction until the differential feed is positioned all the
way to the rear. Loosen nut (D) and rotate eccentric ferrule (E) until maximum clear-
ance is obtained. Hold ferrule in position and torque nut to 19-20 in. lbs. (22-23
em/kg).
If clearance cannot be obtained, See FEED DRIVE SEGMENT ADJUSTMENT.
If desired, thumbscrews can be locked in position by tightening nut (F) for the
differential feed or.by tightening pressure plug screw for the main feed, located in
the
bed directly above the main feed stitch regulating screw. This will prevent
accidental changing of
stitch length during machine operation.
NEEDLE THREAD CONTROL
Check:
The needle thread is controlled by the needle
thread
eyelet (A, Fig. 21) and the needle
thread
cam pull-off (B). The needle thread
eyelet is set so the securing screw is center-
ed in the screw slot front to back. Raise or
lower the eyelet to have the needle thread
barely touch the needle thread
cam pull-off
when the needle carrier is in its lowest posi-
tion. Moving the eyelet up and back increases
the needle thread in the
stitch, moving the
eyelet down and forward acts in the reverse.
Procedure:
Fig.
21
To adjust needle thread control, loosen screw (C) and position thread eyelet (A) as
described in check.
Hold eyelet in position and tighten screw (C).
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LOOPER THREAD PULL-OFF
Check:
Clearance between looper thread pull-off (D, Fig. 21) and needle thread cam pull-off
(B) should be only enough to ensure proper take-up of looper thread as shown in
Fig.
21.
Procedure:
Loosen screws (E) and rotate looper thread pull-off lever (F) front to back on
needle driving shaft until proper clearance is obtained. Before tightening screws
(E) be sure to take up all end play in needle drive shaft.
LOOPER THREAD CONTROL
Check:
When a normal amount of looper thread is drawn, upper and lower looper threads will
be a little slack when needle(s) is at highest position.
Position guide so the looper thread is held in a straight line to the lower looper,
with the lower looper
at its extreme left end of travel.
The auxiliary upper looper thread guide should be centered in its adjusting slot and
set slightly above a horizontal position.
Fig.
22
lower looper thread eyelet (D)
tion and tighten screw (C).
Procedure:
Loosen screw (A, Fig. 22). Center lower loop-
er thread eyelet (B) in its adjusting slot and
set eyelet in a horizontal position. Hold eye-
let (B) in position and tighten screw (A).
Loosen screw (C). Center upper looper thread
eyelet (D) in its adjusting slot and set eye-
let so it rests on the top surface of lower
looper thread
eyelet and back of lower looper
thread
eyelet eye.
Center
auxiliary upper looper thread guide (E)
in its adjusting slot and set guide so it is
slightly above a horizontal position. Hold
and auxiliary upper looper thread guide (E) in posi-
To set frame lower looper thread guide (F) loosen screw (G) and move lower looper to
its extreme left end of travel and position the guide so the looper thread is held
in a
straight line to the lower looper. Tighten screw {G).
NOTE: Moving eyelets (B and D) to the rear increases the amount of looper thread in
the system
and moving them forward reduces the amount of thread in the system.
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POSITIONING THE PURL
If the needle thread loop is NOT being
set properly as shown in Fig. 23, excessive
seam grinning would result. Thread control
adjustments
which should be checked to correct
this condition include:
-
Lower looper thread tension too tight.
- Needle thread eyelet too high.
-
Lower looper thread eyelet too far forward.
-
Needle thread tension too loose.
If the purl is NOT being formed on the
edge of the fabric as shown in Fig. 24, an
unbalance between the looper threads is indi-
cated, and improper coverage of the seamed
edge would occur. If the purl is being pulled
under the edge,
check the following thread
control adjustments:
-
Lower looper thread too tight.
- Lower looper thread eyelet too far forward.
-
Upper looper thread eyelet too far to the
rear.
- Upper looper thread tension too loose.
If the purl is being pulled over the
edge as shown in Fig. 25, check the following
thread control adjustments:
-
Upper looper thread tension too tight.
- Upper looper thread eyelet too far forward.
-
Lower looper thread eyelet too far to the
rear.
- Lower looper thread tension too loose.
THREAD TENSIONS
Fig. 23
BOTTOM VIEW
Fig. 24
TOP VIEW
Fig. 25
Thread tension is regulated by the tension assemblies. Turning tension nuts
clockwise increases tension applied to thread, counterclockwise reduces tension.
Normally, tension
on the threads should be only enough to produce a balanced stitch.
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Fig. 26
ADJUSTING INSTRUCTIONS FOR FEED DRIVE MECHANISM
1. Assemble parts as illustrated to feed control shaft (A, Fig. 26) and feed rock
shaft (B); including feed bars.
2. Thrust feed bars (C and D) against differential thrust guide on bed. Thrust left
side of main feed bar (C) with left feed bar thrust guide (E). Align and thrust
rear of feed bars with tilt adjusting pin and washer (F) and guide pin (G).
3. Thrust the feed control shaft (A) assuring that washer (H) is against retaining
ring
(J) and flush against the recess in the bed casting. Collar (K) should be
thrusted against the bed casting and tightened securely.
4. Main feed control link (L) and main feed drive lever (M) must be in alignment
with
main feed rocker lever (N) to avoid binding and secured in position by
collars (P and Q).
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From the library of: Superior Sewing Machine & Supply LLC