Dynabrade 50320 User manual

Parts Page Reorder No. PD07•29
Effective August, 2007
Supersedes PD02•32
Models:
50320 — 8,000 RPM, 5/8"-11 Spindle
50321 — 11,000 RPM, 5/8"-11 Spindle
50324 — 11,000 RPM, 3/8"-24 Spindle, 4" Roloc® Pad
50325 — 11,000 RPM, 4" Roloc®Sanding Kit
Always operate, inspect and maintain this tool in accordance with the Safety Code for portable air tools
(ANSI B186.1) and any other applicable safety codes and regulations. Please refer to Dynabrade’s
Warning/Safety Operating Instructions for more complete safety information.
Air Motor and Machine Parts
41/2"- 5" Pistol Grip
Disc Sander
See inside for Important Operating, Maintenance and Safety Instructions.
Oil: O
1
= Air Lube
Adhesive: A
1
= Loctite #609
A
2
= Loctite #271
A
8
= Loctite #567
Torque: N•m x 8.85 = In. - lbs.
A
T
O
KEY
155029 Cover
255031 Felt Ring
355034 5/8"-11 Thread Adapter
455038 Adapter
501007 Bearing
601121 Shim (3/pkg.)
755026 Bearing Plate
850767 Pin (2)
901028 Cylinder
10 01010 Spacer
11 01185 Blade (4/pkg.)
12 55025 Rotor
13 01743 Bearing Plate
14 02649 Bearing
15 96255 Shim
96256 Shim (2)
96257 Shim
16 55032 Governor Cage
17 50399 Governor Weight (2)
18 50938 Governor Pin (2)
19 55054 Governor Valve
20 50470 Pin
21 50940 Spring-8,000 RPM
07169Spring-11,000 RPM
22 95611 Shim Pack (6/pkg.)
23 50471 Spring Holder
24 53163 Handle Assembly
25 55023 Housing-8,000 RPM
55022Housing-11,000 RPM
55047 Housing-Roloc
®
26 96025 Pin
27 55024 Grip
28 50936 Pin
29 55035 Trigger
30 55043 Trigger Post
31 55052 Valve Stem
32 96069 Spring
33 55039 Bushing
34 50939 O-Ring
35 02027 O-Ring (2)
36 55051 Valve Stop (2)
37 55041 Valve
38 96147 O-Ring
39 55058 Trigger Assembly
40 57075 Cone Muffler
41 57066 Muffler Body
42 56028 Muffler Cap
43 56023 Inlet Bushing
44 50264 Disc Mount
45 50267 Fiber Plate
46 50268 Flange
47 501324" Dia. Roloc
®
Pad
Hard Density
501314" Dia. Roloc
®
Pad
Medium Density (Optional)
Index Key
No. Part # Description
5
21 10
17
8
12
28 29
30
44
45
46
32
33
39
34
35
36
37
47
38
13 14
20
24
25
18
8
79 6
15 19 21 22
26
27
40
41
42
23
For Serial No. 6B5500 and Higher
Disc Assemblies
A
2
A
1
A
1
O
1
O
1
A
8
23 N•m T
17 N•m
T
17 N•m
T
28 N•m
T
10 N•m
T
43
11
31
36
4
3
Left Hand Threads
Left Hand Threads
16
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade

Important Operating, Maintenance and Safety Instructions
Carefully read all instructions before operating or servicing any Dynabrade
®
Abrasive Power Tool.
Warning: Hand, wrist and arm injury may result from repetitive work motion and overexposure to vibration.
Important: All Dynabrade rotary vane air tools must be used with a Filter-Regulator-Lubricator to maintain all warranties.
Operating Instructions:
Warning: Eye, face, respiratory, sound and body protection must be worn while operating power tools. Failure to do so may result in serious injury or death.
Follow safety procedures posted in workplace.
1. With power source disconnected from tool, securely fasten abrasive/accessory on tool.
2. Install air fitting into inlet bushing of tool. Important: Secure inlet bushing of tool with a wrench before attempting to install the air fitting to avoid
damaging valve body housing.
3. Connect power source to tool. Be careful not to depress throttle lever in the process.
4. Check tool speed with tachometer. If tool is operating at a higher speed than the RPM marked on the tool or operating improperly, the tool should be
serviced to correct the cause before use.
5. Air tools are not intended for use in explosive atmospheres and are not insulated for contact with electrical power sources. Sanding/Grinding certain
materials can create explosive dust. It is the employers responsibility to notify the user of acceptable dust levels. Sanding/Grinding can cause sparks
which can cause fires or explosions. It is the users responsibility to make sure the work area is free of flammable materials.
Maintenance Instructions:
1. Check tool speed regularly with a tachometer. If tool is operating at a higher speed than the RPM marked on the tool, the tool should be serviced to
correct the cause before use.
2. Check the governor of this tool on a regular basis, the governor is preset at the factory to maintain the maximum rated speed for the tool,
if any inconsistency is found in the operating speed the tool must not be used and must be further tested by a Dynabrade factory technician.
3. Some silencers on air tools may clog with use. Clean and replace as required.
4. All Dynabrade rotary vane air motors should be lubricated. Dynabrade recommends one drop of air lube per minute for each 10 SCFM (example: if
the tool specifications state 40 SCFM, set the drip rate of your filter-lubricator at 4 drops per minute).
Dynabrade Air Lube (P/N 95842: 1 pt. 473 ml.) is recommended.
5. It is strongly recommended that all Dynabrade rotary vane air tools be used with a Filter-Regulator-Lubricator to minimize the possibility of misuse due
to unclean air, wet air or insufficient lubrication. Dynabrade recommends the following: 11405 Air Line Filter-Regulator-Lubricator — Provides accurate
air pressure regulation, two-stage filtration of water contaminants and micro-mist lubrication of pneumatic components.
Operates 40 SCFM @ 100 PSIG has 3/8" NPT female ports.
6. Use only genuine Dynabrade replacement parts. To reorder replacement parts, specify the Model #, Serial #, and RPM of your machine.
7. A Motor Tune-Up Kit (P/N 96047) is available which includes assorted parts to help maintain motor in peak operating condition.
8. Mineral spirits are recommended when cleaning the tool and parts. Do not clean tool or parts with any solvents or oils containing acids, esters,
keytones, chlorinated hydrocarbons or nitro carbons.
2
(PD07•29)
OneYear Warranty
Following the reasonable assumption that any inherent defect which might prevail in a product will become apparent to the user within one year from the date
of purchase, all equipment of our manufacture is warranted against defects in workmanship and materials under normal use and service. We shall repair or
replace at our factory, any equipment or part thereof which shall, within one year after delivery to the original purchaser, indicate upon our examination to have
been defective. Our obligation is contingent upon proper use of Dynabrade tools in accordance with factory recommendations, instructions and safety
practices. It shall not apply to equipment which has been subject to misuse, negligence, accident or tampering in any way so as to affect its normal
performance. Normally wearable parts such as bearings, sanding pads, rotor blades, etc., are not covered under this warranty.
• Important: User of tool is responsible for following accepted safety codes such as those published by the American National Standards Institute (ANSI).
• Operate machine for one minute before application to workpiece to determine if machine is working properly and safely before work begins.
• Always disconnect power supply before changing abrasive/accessory or making machine adjustments.
• Inspect abrasives/accessories for damage or defects prior to installation on tools.
• Please refer to Dynabrade’s Warning/Safety Operating Instructions Tag (Reorder No. 95903) for more complete safety information.
• Warning: Hand, wrist and arm injury may result from repetitive work, motion and overexposure to vibration.
Notice
All Dynabrade motors use the highest quality parts and metals available and are machined to exacting tolerances. The failure of quality pneumatic motors can most
often be traced to an unclean air supply or the lack of lubrication. Air pressure easily forces dirt or water contained in the air supply into motor bearings causing
early failure. It often scores the cylinder walls and the rotor blades resulting in limited efficiency and power. Our warranty obligation is contingent upon proper use
of our tools and cannot apply to equipment which has been subjected to misuse such as unclean air, wet air or a lack of lubrication during the use of this tool.
Safety Instructions:
Products offered by Dynabrade should not be converted or otherwise altered
from original design without expressed written consent from Dynabrade, Inc.
Model Motor Motor Air Inlet Sound Air Flow Rate Air Pressure Spindle Weight Length Height
Number HP (W) RPM Thread Level CFM/SCFM (LPM) PSIG (Bars) Thread Pound (kg) Inch (mm) Inch (mm)
50320 .58 (433) 8,000 1/4 NPT 72 dB(A) 4/30 (850) 90 (6.2) 5/8"-11 male 2.2 (1.0) 6-5/8 (168) 5-5/8 (143)
50321 .75 (559) 11,000 1/4 NPT 72 dB(A) 4/32 (906) 90 (6.2) 5/8"-11 male 2.2 (1.0) 6-5/8 (168) 5-5/8 (143)
50324 .75 (559) 11,000 1/4 NPT 72 dB(A) 4/32 (906) 90 (6.2) 3/8"-24 female 2.2 (1.0) 6-5/8 (168) 5-5/8 (143)
50325 .75 (559) 11,000 1/4 NPT 72 dB(A) 4/32 (906) 90 (6.2) 3/8"-24 female 2.2 (1.0) 6-5/8 (168) 5-5/8 (143)
Additional Specifications: Hose I.D. Size 3/8" (10mm)
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade

Disassembly/Assembly Instructions
Important: Manufacturer’s warranty is void if tool is disassembled before warranty expires.
Warning: The governor in this tool is preset at the factory to maintain the maximum rated speed for the tool, any repairs to this assembly should be
done at the Dynabrade factory. A Motor Tune-Up Kit is available (P/N 96047) to help maintain motor in peak operating condition.
Warning: This pistol Grip Tool is equipped with a governor that requires
FACTORY PRECISION ADJUSTMENT if the governor needs servicing,
the complete tool must be returned to the factory for proper adjustment of the governor.
To Disassemble:
1. Remove disc mount assembly or Roloc®Pad and 53163 Side Handle.
2. Place machine housing in soft jaw vise. Important: Be careful not to over tighten vise to prevent damage.
3. Turn 55029 Cover clockwise (left hand threads) and remove.
4. Pull motor assembly from housing.
5. Remove 56028 Muffler Cap. Use a 12mm hex key to unscrew 57066 Muffler Body and 57075 Cone Muffler from housing.
6. Unscrew 56023 Inlet Bushing and remove.
Motor Disassembly:
1. Secure motor in a vise using flats on 55034 or 55038 Adapter.
2. Remove the governor assembly by turning it clockwise. (Left Hand Thread)
Important:
SAVE ALL SHIMS that are found between the governor and the rotor. The exact total thickness of these shims is necessary to maintain the
correct spacing and function of the governor. These shims must be installed between the governor and rotor when the air motor is assembled.
3. Press rotor from 02649 Bearing and 01743 Bearing Plate.
4. Press 02649 Bearing from 01743 Bearing Plate.
5Remove 01028 Cylinder and 01185 Blades (4) from rotor.
6. Secure 55025 Rotor in soft jaw vise.
7Unscrew 55034 or 55038 Adapter and remove from rotor.
8. Remove 01007 Front Bearing, 55026 Bearing Plate and 01010 Spacer from rotor.
9. Remove 01007 Bearing and any shims from 55026 Bearing Plate.
Valve Disassembly:
1. Drive 96025 Pin through housing and remove valve assembly from housing.
2. Remove 96025 Pin from housing.
3. Remove trigger/valve assembly from housing.
4. Remove first 55051 Valve Stop (Press valve stem from valve stop, be careful not to damage 55041 Valve. A small bearing puller is recommended).
5. Remove 55041 Valve and separate.
6. Press 55042 Valve Stem through the second 55051 Valve Stop.
Motor Assembly:
Important: Be certain all parts are cleaned, properly greased and in good repair before assembling.
1. Install 01007 Front Bearing into 55026 Bearing Plate. (Note: Shimming may be required in upcoming steps).
2. Install 01010 Spacer on rotor.
3. Install bearing assembly onto rotor and spacer.
4. Secure 55025 Rotor in padded vise.
5. Screw 55034 or 55038 Adapter onto 55025 Rotor, torque to 17 N•m/150 in. - lbs.
6. Use a .001" thick feeler gauge to set clearance between the 55026 Bearing Plate and 55025 Rotor.
Note: If shimming is required, use the 01121 Shim Pack accordingly to shim between the 01007 Bearing and 55026 Bearing Plate to obtain a .001"
clearance between the bearing plate and rotor.
7. Install 01185 Blades (4) onto 55025 Rotor. (Note: Blades should be lubricated with Dynabrade Air Lube P/N 95842 or equivalent before installation).
8. Install 01028 Cylinder over 55025 Rotor and onto 55026 Bearing Plate. Be sure to line up 50767 Pin in 55026 Bearing Plate with hole in 01028 Cylinder
Note: Air inlet holes in cylinder should face away from 55026 Bearing Plate.
9. Press 02649 Bearing into 01743 Bearing Plate.
10. Press bearing and bearing plate onto rotor. Be sure 50767 Pin in 01743 Bearing Plate lines up with hole in 01028 Cylinder.
Important: The fit must be snug between bearing plates and cylinder. If to tight, rotor will not turn freely. Rotor must then be lightly tapped at short end
so it will turn freely while still maintaining a snug fit. A loose fit will not achieve the proper pre-load of the motor bearings.
11. Place motor in vise using flats on 55034 or 55038 Adapter.
12. Important:
INSTALL ALL SHIMS that were saved from between the governor and the rotor. The exact total thickness of these shims is necessary to
maintain the correct spacing and function of the governor.
DO NOT ASSEMBLE the air motor if the correct spacing has been compromised in any way. If
the shims have been lost or if damage has occurred to the governor or to the mating area of the governor in the housing, the tool must ne returned to the
factory for proper spacing and replacement of the lost or damaged component(s). Apply a small amount of the Loctite®#567 (or equivalent) to the threads
of the governor cage and install the governor assembly onto the rotor. Tighten by turning counterclockwise. (Left Hand Threads)
(Torque to 10N•m/90 in.-lbs.)
Valve Assembly:
1. Slide 55039 Bushing (with o-rings) onto valve stem/trigger assembly.
2. Press 55051 Valve Stop onto 55052 Valve Stem large end out.
3. Install 55041 Valve onto valve stem.
4. Install 96147 O-Ring onto the 55051 Valve Stop.
5. Press 55051 Valve Stop onto valve stem with o-ringed end facing valve. Press valve stop until flush with valve stem end.
6. Reinsert into housing and replace 96025 Pin. 3
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade

Disassembly/Assembly Instructions (continued)
To Assemble:
1. Place machine housing in soft jaw vise. Be sure not to over tighten to prevent damage.
2. Install motor assembly into housing.
3. Screw 55029 Cover onto housing turning counterclockwise. Torque to 28 N•m/250 in. - lbs.
4. Replace 57066 Muffler Body.
5. Replace 56028 Muffler Cap onto muffler body.
6. Apply a small amount of #271 Loctite
®
(or equivalent) to the threads of 56023 Inlet Bushing. Install inlet bushing into housing torque 23 N•m/200 in. - lbs.
7. Lubricate motor by applying 2 or 3 drops of Dynabrade Air Lube P/N 95842 (or equivalent) into air inlet.
8. Complete assembling by remounting Disc assembly or Roloc
®
Pad and 53163 Side Handle.
Tool Assembly Complete. Please allow 30 minutes for adhesives to cure before operating tool.
Important: Motor should now be tested for proper operation at 90 PSIG. If motor does not operate properly or operates at a higher RPM than marked on the
tool, the tool should be serviced to correct the cause before use. Before operating, place 2-3 drops of Dynabrade Air Lube (P/N 95842) directly into air inlet
with throttle lever depressed. Operate tool for 30 seconds to determine if tool is operating properly and to allow lubricating oils to properly penetrate motor
Loctite
®
is a registered trademark of Loctite Corp.
Accessories
Abrasives
Dynaswivel
®
Swivels 360° at two locations which
allows an air hose to drop straight to the
floor, no matter how the tool is held.
• 94300 1/4" NPT
96047 Motor Tune-Up Kit
• Includes assorted parts to
help maintain and repair motor.
Grit Medium Coarse SE
Part No. 90868 90867 90863
Grit 36 60 80
Part No. 92047 92049 92050
4" Diameter Scotch-Brite Roloc Discs
4" Dia. Regalite Polycut 785C Roloc Discs
Grit 50 80 100 120
Part No. 92052 92053 92054 92055
4-1/2" Ceramic Coated Aluminum Oxide Discs
Flange Mounted / 5/8" Center Hole
Unit = 100 Discs
Spiralcool is a registered trademark of Spiralcool Co.
Regalite, Scotch-Brite and Roloc are registered trademarks of 3M Co.
4" Disc Unit = 100 Discs
DYNABRADE®
DYNABRADE, INC., 8989 Sheridan Drive • Clarence, NY 14031-1490 • Phone: [phone] • Fax: [phone] • International Fax: [phone]
DYNABRADE EUROPE S.àr.l., Zone Artisanale • L-5485 Wormeldange—Haut, Luxembourg • Telephone: [phone] • Fax: [phone]
©DYNABRADE, INC., 2007 PRINTED IN USA PD07.29_08/07
Visit Our Web Site: www.dynabrade.com Email: Customer[email protected]
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade
Buy parts on line at https://Dynashop.co.uk/ for all things Dynabrade