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MODEL T31688
METAL SHRINKER/
STRETCHER SET
INSTRUCTIONS
For questions or help with this product contact Tech Support at (570) 546-9663 or techsupport@grizzly.com
Introduction
The Model T31688 Metal Shrinker/Stretcher Set is
a handy tool for sheet metal fabricators who need
custom, curve-shaped metal straps, trim, and
flanges for auto body repair and general sheet
metal work.
Specifications
Max Thickness, Aluminum ...................16 Gauge
Max Thickness, Mild Steel
Max Thickness, Stainless Steel
Smallest Radius Bend
Jaw Depth......................................................... 1"
Bolt Pattern
Mounting Bolt Hole Size
...................................21/2" on Center
...................18 Gauge
.......... 20 Gauge
...................................... 3"
3
/8"-16.......................... 2
Inventory
Description Qty
A. Body & Shrinker Die Set ............................ 1
Stretcher Die Set ........................................ 1
B.
Lever ........................................................... 1
C.
Damage to your eyes and fingers could
result from using this item without proper
protective gear, such as safety glasses and
leather gloves. Be sure to use these items
for personal safety.
Assembly
The Shrinker/Stretcher Set comes from the factory almost completely assembled. To finalize
assembly, install lever in body (see Figure 2) and
secure with pre-installed M5-.8 x 8 set screw.
Tools Needed Qty
Hex Wrench 3mm .............................................. 1
Body
A
B
Screw
C
Figure 1. Inventory.
COPYRIGHT © OCTOBER, 2019 BY GRIZZLY INDUSTRIAL, INC.
NO PORTION OF THIS MANUAL MAY BE REPRODUCED IN ANY SHAPE
OR FORM WITHOUT THE WRITTEN APPROVAL OF GRIZZLY INDUSTRIAL, INC.
(FOR MODELS MFD. SINCE 10/19) #MN20683 PRINTED IN CHINA
Figure 2. Lever installed in body.
Lever
Set
V1.10.19
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Mounting
The Model T31688 is portable and can be clamped
in a vise for use. However, to take full advantage
of the shrinker/stretcher and to get 360° access to
your workpiece, you can mount the tool to a stand
intended for a bench grinder. To prevent tipping, be
sure to fasten the grinder stand to the floor.
3
. Lay out die components, as shown in Figure 4.
Stretcher
To mount shrinker/stretcher:
. Clean and lubricate as outlined in Setup.
1
Determine where you want to mount the tool.
2
. At mounting location, center punch two points
3
1
/2" apart, and drill two 3/8" diameter holes at
2
these locations.
. Secure tool to workbench or grinder stand
4
with two
3
/8"-16 bolts or cap screws of appro-
priate length to ensure that the fasteners
1
thread into casting at least
/2".
Setup
1. Raise handle, loosen (4) knob bolts, unclip
die retainer from pressure arm, and slide die
assembly away from casting (see Figure 3).
Shrinker
Figure 4. Die and jaw assembly order.
4. Clean grease, metal shavings, and debris off
tool and dies, then lightly oil.
Note: Never use a wire wheel, buffer, sand
blaster, or sandpaper on jaw teeth. Otherwise,
tooth damage may occur. It is better to let
jaws soak in mineral spirits overnight, then
use a wire brush or a fine dental pick to
remove debris.
. Use Figures 4–5 as a guide to arrange die
5
parts in correct order and reassemble.
Knob
Bolts
Figure 3. Removing die retainer.
. Grasp die retainer clip and pull upper jaw
2
from die housing.
Note: Be careful not to lose any springs.
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ShrinkerStretcher
Figure 5. Assembled dies.
6. Shrinker/stretcher are ready for operation.
Model T31688 (Mfd. Since 10/19)
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When the tool is not in use or will be placed
in storage for a period of time, we highly
recommend removing the die from the tool.
If the lever is accidently used and the
die jaws clamp down against one another
instead of a workpiece, the gripping jaw
teeth may be damaged.
Operation
The Model T31688 Shrinker/Stretcher Set is
designed to create long, compound-curved metal
pieces out of a single strip of metal without multiple splice points. Operation consists of inserting a
piece of metal in the tool and pulling down on the
lever to compress or expand the metal at various
points along the length of the metal strip, creating
the bend or shape needed.
During the bending process, as you work along
the strip of metal, the clamping pressure exerted
by the lever can be adjusted to create curves
with a nice smooth arch. The lever stop bolt (see
Figure 6) can be adjusted with a 14mm wrench to
allow the clamping lever to stop at the same location each time the lever is pulled down.
To use shrinker/stretcher:
. Verify jaw teeth are free of debris.
1
. Determine job requirements:
2
— Using the shrinker die, a curve in the
metal is created by compressing the inside
radius of a curve (see Figure 7).
— Using the stretcher die, a curve in the
metal is created by expanding the outside
radius of the curve (see Figure 8).
Note: Shrinking/stretching will create small
teeth marks from the jaws and cannot be
avoided. Limit depth of teeth marks by making
more, lighter pulls with the lever.
Compression
Area
Lever
Stop Bolt
Figure 6. Location of lever stop bolt.
Note: If metal splits during shrinking/stretching
procedure, it is typically because too much bend
is trying to be achieved with just a few heavy pulls
of the lever. To avoid splitting, make pulls lighter
and increase number of pulls on lever. If metal still
splits, radius of desired bend may be too small for
the metal, or the metal is of the incorrect type.
Figure 7. Shrinking a workpiece into a bend.
Stretching
Area
Figure 8. Stretching a workpiece into a bend.
Model T31688 (Mfd. Since 10/19)
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T31688 Parts Breakdown & List
Please Note: We do our best to stock replacement parts whenever possible, but we cannot guarantee that all parts shown here
are available for purchase. Call (800) 523-4777 or visit our online parts store at www.grizzly.com to check for availability.
7
22
21
20
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Specifications
Max Thickness:
Aluminum: 16 Ga.
Mild Steel: 18 Ga.
Stainless Steel: 20 Ga.
Jaw Depth: 1"
Weight: 26 lbs.
Mfd. for Grizzly in China
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Damage to your eyes and fingers
could result from using this item
without proper protective gear,
such as safety glasses and
leather gloves. Be sure to use
these items for personal safety.
T31648 METAL
SHRINKER/STRETCHER SET
WARNING!
To reduce risk of serious injury:
1. Read manual before using tool.
2. Wear eye protection during use.
3. Wear gloves during use.
4. Do not modify tool in any way.
5. Do not exceed rated capacity.
6. Mount tool to stable workbench.
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T31688
37
35
34
14
15
16
17
18
8
13
9
12
11
10
1
2
3
36
4
6
32
5
33
25
26
15
27
31
23
24
28
29
30
REF P ART # DES CRIP TION REF P ART # DES CRIP TION
1 PT31688001 BODY 20 PT31688020 LOWE R J AW (LEFT, SHRI NK ER)
2 PT31688002 FULCRUM ARM PI N 21 PT31688021 RETAI NER CLI P (SHRINKE R)
3 PT31688003 EXT RETA I NI NG RI NG 10MM 22 PT31688022 DI E RETAI NER (S HRI NKER)
4 PT31688004 EXT RETA I NI NG RI NG 12MM 23 PT31688023 FLAT WA SHER 4MM
5 PT31688005 KNOB BOLT M5-.8 X 8, D12, ROUND KD 24 PT31688024 PHLP HD SCR M4-. 7 X 12
6 PT31688006 PRESSURE ARM PI N 25 PT31688025 UPPER V-BLOCK (STRETCHER)
7 PT31688007 CLEVIS PIN 5 X 30 26 PT31688026 UPPE R J AW (RI G HT, STRETCHER)
8 PT31688008 PRESSURE ARM 27 PT31688027 PHLP HD SCR M4-. 7 X 30
9 PT31688009 EXTENSI ON SPRING 28 PT31688028 L OWER J AW (RI GHT, S TRETCHER)
10 PT31688010 HEX BOLT M8-1.25 X 35 29 PT31688029 LOWE R J AW (LEFT, STRETCHER)
11 PT31688011 SET SCREW M5-.8 X 8 30 PT31688030 LOWER V-BLOCK (STRETCHER)
12 PT31688012 FULCRUM ARM 31 PT31688031 DI E RETAI NER (S TRETCHER)
13 PT31688013 LEVER 32 PT31688032 RETAI NER CLI P (STRETCHER)
14 PT31688014 UPPER V-BLOCK (SHRINKER) 33 PT31688033 UPPE R J AW (LEFT, STRETCHER)
15 PT31688015 COMPRESSION SPRING 34 PT31688034 MACHINE ID LABEL
16 PT31688016 UPPE R J AW (RI G HT, SHRINKE R) 35 PT31688035 EYE/HAND WARNING LABEL
17 PT31688017 LOWE R J AW (RI G HT, SHRINKE R) 36 PT31688036 TOUCH-UP PAI NT, G RI ZZLY GREE N
18 PT31688018 LOWER V-BLOCK (SHRINKER) 37 PT31688037 QR CODE LABEL
19 PT31688019 UPPE R J AW (LEFT, SHRI NK ER)
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Model T31688 (Mfd. Since 10/19)
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