Pfaff Industrial 337 Guide

ADJUSTMENT MANUAL
296-12-18 644/002
Justieranleitung engl. 06.09
This Adjustment Manual is valid for machines
from the following serial numbers onwards:
# 7 207 686
337

The reprinting, copying or translation of PFAFF Service Manuals, whether in whole or in part,
is only permitted with our previous authorization and with written reference to the source.
PFAFF Industriesysteme
und Maschinen AG
Hans-Geiger-Str. 12 - IG Nord
D-67661 Kaiserslautern

Adjustment
11 - 1
11 Adjustment
11.01 Notes on adjustment
All adjustments in this instruction manual refer to a completely assembled machine and
must only be carried out by appropriately trained technical personnelappropriately trained technical personnel
appropriately trained technical personnelappropriately trained technical personnel
appropriately trained technical personnel. Machine covers
that have to be removed and replaced for checks and adjustment work are not mentioned in
the text.
The screws and nuts indicated in brackets () are for the fixation of machine parts that have to
be unscrewed before adjustment and tightened again afterwards.
11.02 Tools, gauges and other equipment for adjusting
●Screwdrivers with blade widths from 2 to 10 mm
●Spanners (wrenches) in sizes from 7 to 14 mm
●Allen keys from 2 to 6 mm
●Metal rule (part No. 08-880218-00)
●Needle-rise gauge (part No. 61-111600-01)
●Screw clamp (part No. 61-111600-35/001)
●Gauge, 7-mm, for lifting presser stroke (part No. 61-11163 0-14)
●Needles, system 134-35
●Sewing thread and material for stitching off
11.03 Abbreviations
t.d.c. = top dead centre
b.d.c. = bottom dead centre

Adjustment
11 - 2
●Re-position feed dog 1(screws 2) according to Requirement.
Fig. 11 - 01
11.04 Adjusting the basic machine
11.04.01 Position of the bottom feed dog crosswise to sewing direction
Requirement
The bottom feed dog 1must clear the feed slot by the same amount at the left and right.
2
1
xx

Adjustment
11 - 3
11.04.02 Adjusting the bottom feed dog in sewing direction
Requirement
With the longest stitch length set, bottom feed dog 5must clear the feed slot by the
same amount at the front and rear end of its stroke.
Fig. 11 - 02
●Set the longest stitch length.
●Position clamp sleeve 1(screws 2and 3) on the flat of shaft 4as far to the left as
possible, making sure that screw 2is still on the flat.
●Position feed dog 5(screws 6) according to Requirement.
2
1
3
4
6
5
x
x

Adjustment
11 - 4
11.04.03 Needle position in needle hole
Requirement
1. In sewing direction the needle centre must be at a distance of approx. 0.7 mm from
the front inside edge of the needle hole.
2. Crosswise to sewing direction the needle must be centred in the needle hole.
Fig. 11 - 03
●Turn the balance wheel to lower the needle into the needle plate.
●Position needle-bar frame 1(nut 2with locknut) according to Requirement 1.
●Position needle-bar frame 1(screws 3and 4) according to Requirement 2.
4
1
2
3
0.7 mm

Adjustment
11 - 5
11.04.04 Needle height (preliminary adjustment)
Requirement
With the needle bar at b.d.c. the clearance between needle bar and needle plate must be
15 mm.
Fig. 11 - 04
●Position the height of needle bar 1(screws 2) according to Requirement, but do not turn it.
2
1
15 mm

Adjustment
11 - 6
11.04.05 Top-feed pendulum
Requirement
At stitch length ”0” and the largest gather setting, presser bar 4must be at the centre
between needle bar guide and presser bar.
Fig. 11 - 05
●Push linkage rod 1(screw 2) fully up in its slot 3.
●Set stitch length at ”0” and press the pedal to set the largest gather setting.
●Position presser bar 4(screw 5) according to Requirement.
2
1
35
4

Adjustment
11 - 7
11.04.06 Feeding stroke of top and bottom feeds
Requirement
When the lower edge of the descending needle bar is 33 mm above the top edge of the
needle plate, the top and bottom feeds should not move when the stitch length
adjustment lever is activated.
●Set the longest stitch length.
●Loosen screws 1far enough, so that the eccentric 2can be turned on the shaft with
difficulty.
●Bring the needle bar into the appropriate position.
●Turn eccentric 2according to the requirement..
..
.
●Tighten screws 1.
Fig. 11 - 06
1
2
33 mm

Adjustment
11 - 8
11.04.07 Top feed stroke
Requirement
When lever 1is in the middle of its slot, vibrating presser 3 and lifting presser 4must be
at the same height above the needle plate.
Fig. 11 - 07
●Set stitch length at ”0”
●Set lever 1(screw 2) at the middle of its slot.
●Lower lifting presser 3.
●Turn balance wheel in sewing direction until vibrating presser 4is at its highest point.
●Turn crank 5(screw 6) according to Requirement
5
6
2
1
34
x

Adjustment
11 - 9
11.04.08 Top feed lifting motion
Requirement
When the lower edge of the descending needle bar is 33 mm above the top edge of the
needle plate, the top feed should not move, when the slotted lever 3is moving up and down.
●Loosen screws 1far enough, so that the eccentric 2can be turned on the shaft with
difficulty.
●Bring the needle bar into the appropriate position.
●Turn eccentric 2according to the requirement.
●Tighten screws 1.
Fig. 11 - 08
2
1
1
33 mm
3

Adjustment
11 - 10
●Set the longest stitch.
●Loosen screws 1and 2(screw 2is on the rear side of the machine).
●Set the needle bar at b.d.c. and place the 1.8 mm thick feeler gauge with its cutout close
under the lower needle bar bearing.
●Place the screw clamp up against the feeler gauge and tighten it.
●Remove the feeler gauge and turn the balance wheel until the screw clamp is resting
against the needle bar bearing.
●Adjust the hook according to Requirements..
..
.
●If necessary adjust the needle height, see Chapter 11.04.04 Needle height (preliminary
adjustment).
●Move hook shaft bearing 3against the hook and tighten screw 2.
●Move bevel gear 4against bearing 5and tighten screws 1.
On machines with thread trimmer –900/51, adjustment of the axial play of the
hook shaft and hook-shaft bearing 33
33
3 does not apply.
11.04.09 Hook clearance, needle rise and needle height
Requirement
With the longest stitch length set and in needle-rise position (= 1.8 mm past b.d.c. of the
needle bar)
1. The hook point must be at”needle centre” and the clearance between hook and
needle 0.05 to 0.1 mm, and
2. the top of the needle eye must be 0.8 mm below the hook point.
Fig. 11 - 09
12
3
0.05 - 0.1 mm
0.8 mm
1
5
4

Adjustment
11 - 11
11.04.10 Needle-thread tension release
Requirement
With the lifting presser raised, there must be a clearance of at least 0.5 mm between
tension discs 4.
Fig. 11 - 10
●Raise the lifting presser.
●Position pressure plate 1behind mounting bracket 2according to Requirement.
When the tension is engaged, release pin 3 must not be under load.
2
4
1
3
0.5 mm

Adjustment
11 - 12
11.04.11 Thread check spring
Requirement
The movement of thread check spring 5must be finished when the needle point enters
the material (==
==
= spring stroke of about 7 mm).
Fig. 11 - 11
●Adjust stop 1(screw 2) according to Requirement.
●To adjust the pressure of the spring, turn screw 3(screw 4).
For technical reasons the length of the thread check spring stroke may vary
upwards or downwards a little.
2
1
3
5
7 mm
4

Adjustment
11 - 13
11.04.12 Bobbin winder
Requirement
1. With the bobbin winder engaged, friction wheel 5must be driven reliably.
2. With the bobbin winder disengaged, friction wheel 5must not run against drive wheel 1.
3. The bobbin winder must switch itself off when the filled thread is about 1 mm from
the rim of the bobbin.
●Position drive wheel 1(screws 2) according to Requirements 1 and 2.
●Position pin 3(screw 4) according to Requirement 3.
Fig. 11 - 12
2
15
1 mm
4
3

Adjustment
11 - 14
11.04.13 Pressure of the lifting presser
Requirement
The material must be properly fed, even at the highest sewing speed.
●Turn screw 1according to the Requirement.
Fig. 11 - 13
1

Adjustment
11 - 15
11.05 Adjusting the thread trimmer –900/56
11.05.01 Control cam (preliminary adjustment)
Requirement
With the needle bar at b.d.c., groove 4of control cam 2must be vertically below control
pin 5.
Fig. 11 - 14
●Loosen screws 1through the hole in the machine housing.
●Set the take-up lever at b.d.c.
●Turn control cam 2according to Requirement..
..
.
●Move control cam 2 down against bearing 3and tighten the accessible screw 1.
●Make the second screw 1accessible and tighten it also.
2
3
4
5
1
2

Adjustment
11 - 16
11.05.02 Control lever height
Requirement
With the needle bar at b.d.c. there must be a clearance of 1.0 mm between control lever 3
and control cam 4.
●Set the needle bar at b.d.c.
●Position bracket 1(screws 2) of control lever 3in the elongated hole according to
Requirement.
Fig. 11 - 15
2
1
3
4
1 mm

Adjustment
11 - 17
11.05.03 Control pin
Requirement
With the needle bar at b.d.c. control pin 5 must drop easily into the track of control cam 7
when engaging solenoid 6is operated.
●Set the needle bar at b.d.c.
●Operate the solenoid core by hand.
●Turn screw 2 (nut 3) inwards until it is resting lightly against control lever 4.
●Turn screw 22
22
2 back again by about half a turn until the movement of control pin 5
corresponds with the Requirement..
..
.
Fig. 11 - 16
61
5
7
4
2
3

Adjustment
11 - 18
11.05.04 Engaging solenoid
Requirement
With the needle bar at b.d.c. and solenoid core 1fully operated there must be a clearance
of approx. 0.5 mm between locking pawl 7and fixing collar 6.
Fig. 11 - 17
●Set the needle bar at b.d.c.
●Push solenoid core 1fully in.
●Position solenoid housing 2(screw 3) according to Requirement
If solenoid housing 2strikes against lever 4, position lever 4(screw 5) a little
farther to the left.
5
4
321
7
6
0.5 mm