Dynabrade 51420 User manual

Models:
51420 – 3-1/2" 3,200 RPM
51425 – 4" 5,000 RPM
Parts Page Reorder No. PD02•36
Effective July, 2002
Supersedes PD97•60
Air Motor and Machine Parts
.4 Hp/7°/Rear Exhaust
Disc Sander
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. See inside for Important Operating, Maintenance and Safety Instructions.
150126 Backing Pad - 51420
50132 Backing Pad - 51425
250781 Rear Exhaust Cover
350782 Adapter
454552 Bearing (2)
554472 Gear Shaft (2)
606213 5,000 RPM Gear (2)
54519 3,200 RPM Gear (2)
750786 3,200 RPM Carrier
50787 5,000 RPM Carrier
854468 Ring Gear
950778 Spacer
10 02649 Bearing
11 54529 Shim Pack (3/pkg.)
12 01478 Front End Plate
13 50767 Pin (2)
14 01479 Spacer
15 Rotor
54553 5,000 RPM
54554 3,200 RPM
16 01480 Blade (4/pkg.)
17 01476 Cylinder
18 02673 Rear Bearing Plate
19 02696 Bearing
20 02679 Shield
21 01041 Grease Fitting
22 50784 Set Screw
23 50776 Motor Housing
24 01548 Gasket
25 01461 Lock Nut
26 01558 Collar
27 95523 O-Ring
28 01470 Insert
29 02109 Housing - 51420
02110 Housing - 51425
30 12132 Pin
31 01448 Throttle Lever
01462 Safety Lock Lever
32 95558 Retaining Ring
33 01449 Valve Stem
34 95730 O-Ring
35 01024 O-Ring
36 01469 Speed Regulator
37 94519 Muffler Assembly
38 01464 Seal
39 01472 Tip Valve
40 01468 Spring
41 01564 Air Control Ring
42 95711 Retaining Ring
43 95438 O-Ring
44 94521 Muffler Base
45 94528 Felt Muffler
46 94522 Muffler Cap
47 95375 O-Ring
48 94526 Spacer
49 94523 Inlet Adapter
13
8
749
11
1214
13151713
18
24
25
26
27 28 33
32
31 30
38 39
40
4236
41
43 44 45 46 47 48 49
37
34
35
23
19
20 4
Right Hand
Threads
Left Hand Threads
Index Key
No. Part # Description
O
A
T
Adhesive: A2= Loctite #271
A8= Loctite #567
Torque: N•m x 8.85 = In. - lbs.
G
Oil: O1 = Air Lube
Grease: G1= Lubriplate 630 AA
KEY
10
For Serial No. 9J1264 and Higher
Open-End Wrench
95262 – 14mm Open-End.
Hex Wrench
96401 – 2mm Hex.
A2
A8O1
G1
G1
G1
O1
G1 A8
A8
A8
A8
17 N•m
T
45 N•m
T
28 N•m T
23 N•m T
2
6
516
21
22
29

2
(PD02•36)
Model Motor Motor Sound Maximum Air Flow Air Pressure Spindle Weight Length Height
Number hp (W) RPM Level CFM/SCFM (LPM) PSIG (Bars) Thread Pound (kg) Inch (mm) Inch (mm)
51420 .4 (298) 3,200 80 dB(A) 3/24 (680) 90 (6.2) 3/8"-24 male 2.3 (1.0) 9 (229) 5-1/4 (133)
51425 .4 (298) 5,000 78 dB(A) 3/24 (680) 90 (6.2) 3/8"-24 male 2.3 (1.0) 9 (229) 5-1/4 (133)
Additional Specifications: Air Inlet Thread 1/4" NPT • Hose I.D. Size 1/4" or 8mm
• 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.
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 sparks which can cause fires or explosions. It is the user 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. Some silencers on air tools may clog with use. Clean and replace as required.
3. 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.
4. An Air Line Filter-Regulator-Lubricator must be used with this air tool to maintain all warranties. 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.
5. Lubricate planetary gears through the grease fitting with 2 plunges for every 50 hours of use, to achieve maximum gear life (order 95542 Grease
and 95541 Gun).
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 96174) is available which includes assorted parts to help maintain motor in peek operating condition. Please refer to
Dynabrade’s Preventative Maintenance Schedule for a guide to expectant life of component parts.
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.
9. DO NOT clean or maintain air tools with chemicals that have a low flash point (example: WD-40®).
One Year 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, contact wheels, rotor blades, etc., are not covered under this warranty.
Safety Instructions:
Products offered by Dynabrade should not be converted or otherwise altered
from original design without expressed written consent from Dynabrade, Inc.

3
Disassembly/Assembly Instructions - .4 Hp/7˚/Rear Exhaust
Important: Manufacturer’s warranty is void if tool is disassembled before warranty expires.
Notice: Dynabrade strongly recommends the use of their 52296 Repair Collar (sold separately) during assembly/disassembly activities. All of the
special repair tools referred to in these instructions can be ordered from Dynabrade. Please refer to this parts page for proper part identification.
Planetary Gear Case Disassembly:
1. Disconnect tool from power source.
2. Remove the disc pad.
3. Use the 52296 Repair Collar to secure the tool in a vise so that the 50782 Adapter is pointing up.
4. Use the 50971 Lock Ring Wrench to remove the 50781 Rear Exhaust Cover by turning it counterclockwise.
5. Use the 96401 2mm Hex Key to remove the 50784 Set Screw.
6. Pull the 50782 Adapter Along with the planetary gear assembly out of the 50776 Motor Housing.
7. Fasten the 96346 2" Bearing Separator between the 54468 Ring Gear and the rear 54552 Bearing.
8. Place the planetary gear assembly and the separator on the table of the 96232 Arbor Press so that the 50782 Adapter is pointing down.
9. Carefully place the 96213 Bearing Removal Tool against the 50786 or 50787 Planetary Carrier removing it from the rear 94552 Bearing.
10. Remove the ring gear, shafts and gears from the planetary carrier.
11. Secure the planetary carrier in a vice with aluminum or bronze jaws so that the 50782 Adapter is pointing up. Use an adjustable wrench to remove the adapter from
the planetary carrier.
Planetary Gear Case Disassembly Complete.
Motor Disassembly:
1. Pull the motor assembly from the housing.
2. Remove the 50778 Spacer from the motor.
3. Fasten the 96346 2" Bearing Separator around the rear portion of the 01476 Cylinder closest to the rear bearing plate.
4. Place the separator and the motor assembly on the table of the 96232 Arbor Press so that the pinion gear of the rotor is pointing down. Use a 3/16" dia. flat end drive punch
as a press tool. Place it against the rear bearing journal of the rotor and push the rotor from the 02696 Bearing.
5. Remove the 02679 Shield from the 02696 Bearing.
6. Use the 96210 Bearing Removal Tool to remove the 02696 Bearing from the 02676 Rear Bearing Plate.
7. Remove the 01480 Blades from the rotor.
8. Press the 02649 Bearing from the rotor, removing the 01478 Front Bearing Plate and the 54529 Shims.
9. Remove the 01479 Spacer from the rotor.
Motor Disassembly Complete.
Valve Disassembly:
1. Place the 52296 Repair Collar around the valve housing and secure it in a vise so that the air inlet is pointing up.
2. Use two wrenches when removing the air fitting. Place one wrench on the 94523 Inlet Adapter to hold it stationary and use another wrench to remove the air fitting.
3. Remove the inlet adapter from the valve housing. Note: Refer to the exploded view of the muffler assembly to identify the parts and their order of disassembly.
4. Use a needle nose pliers to remove the 01468 Spring and the 01472 Tip Valve. The 01464 Seal can be removed from the valve housing with a small screwdriver.
5. Use retaining ring pliers to remove the 95558 Retaining Ring and push the 01469 Speed Regulator Assembly along with the 01449 Valve Stem out of the valve housing.
6. Use a 2.5mm drive punch to remove the 12132 Pin and the throttle lever.
Valve Disassembly Complete.
Valve Assembly:
Important: Clean and inspect all parts before assembling.
1. Place the 52296 Repair Collar around the valve housing and secure it in a vise so that the air inlet is pointing up.
2. Install the 01469 Speed Regulator Assembly (includes o-rings) into the motor housing and secure it in place with the 95558 Retaining Ring.
3. Insert the 01449 Valve Stem so that the end with the hole fits into the 01469 Speed Regulator Assembly.
4. Install the 01469 Seal into the air inlet so that it is lying flat.
5. Use a needle nose pliers to gasp the white nylon portion of the 01472 Tip Valve and insert the metal pin of the tip valve into the hole in the 01449 Valve Stem.
6. Install the 01468 Spring so that the smaller end of the spring fits against the center of the tip valve.
7. Note: Refer to the exploded view of the muffler assembly to identify the parts and their order of assembly. Apply a small amount of the #567 Loctite (or equivalent) to the
threads of the inlet adapter and install it into the air inlet of the valve housing. (Torque to 23 N•m/200 in.- lbs.)
8Install the throttle lever and secure it in place with the 12132 Pin.
9. Use two wrenches when installing the air fitting. Place one wrench on the 94523 Inlet Adapter to hold it stationary and use another wrench to install the air fitting.
Valve Assembly Complete.
Motor Assembly:
1. Install the 01479 Spacer onto the rotor.
2. Select .003" thickness in shims from the 54529 Shim Pack and place these into the 01478 Front Bearing Plate.
3. Install the 02649 Bearing into the front bearing plate.
4. Use the 96240 Bearing Press Tool (position the raised inside diameter against the inside diameter of the bearing) and the 96232 Arbor Press to install these parts onto the
pinion end of the rotor.
5. Check the rotor/plate clearance with a .001" (0.03mm) feeler gage. The clearance should be .001"-.0015" (0.03-0.04mm). If the rotor/plate clearance needs adjustment,
repeat steps 4-5 and shim as required.
6. Apply the 95842 Dynabrade Air Lube (10W/NR or equivalent) to the 01480 Blades (4) and install these into the slots in the rotor.
7. Install the 01476 Cylinder over the rotor so that the air inlet opening of the cylinder will align with the air inlet opening of the 02676 Rear Bearing Plate.
8. Use the 96216 Bearing Press Tool (position the raised outside diameter against the outside diameter of the bearing) and 96232 Arbor Press to install the 02696 Bearing into
the rear bearing plate.
9. Use the 96216 Bearing Press Tool (position the raised inside diameter against the inside diameter of the bearing) and 96232 Arbor Press to install these parts onto the rear
bearing journal of the rotor. Important: Press the rear bearing/plate assembly down onto the rotor only until the 02676 Rear bearing Plate comes in contact with the 01478
Cylinder. This fit will establish a preload on the motor bearings producing a “snug fit” between the bearings and the cylinder. If the fit is too tight it will cause the bearings to
wear prematurely, too loose and the desired preload will not be achieved. If an adjustment is required disassemble and repeat steps 7-8.
10. Apply a small amount of the 95542 Grease to the seal of the 02696 Bearing and install the 02679 Shield against the bearings.
(continued on next page)

Disassembly/Assembly Instructions (continued)
11. Orient the motor assembly so that the node of the 02676 Rear Bearing Plate will align with the notch inside the motor housing.
12. Install the motor assembly into the 50776 Motor Housing.
Motor Assembly Complete.
Planetary gear Case Assembly:
1. Use the 96239 Bearing Press Tool (position the raised inside diameter against the inside diameter of the bearing) and the 96232 Arbor Press to install the front 54552 Bearing
onto the female threaded end of the 50786 or 50787 Planetary Carrier.
2. Apply a small amount of Loctite #271 (or equivalent) to the male threads of the 50782 Adapter and install the adapter onto the planetary carrier. (Torque to 17 N•m.150 in.- lbs.)
3. Apply the 95542 Grease to the shafts, bearings and gears of the planetary carrier. Install these parts into the carrier.
4. Orient the 54468 Ring Gear on the planetary carrier so that the set screw and grease fitting notches will align properly with the openings in the 50776 Motor Housing
once it's installed.
5. Use the 96239 Bearing Press Tool (position the raised inside diameter against the inside diameter of the bearing) and the 96232 Arbor Press to install the rear bearing down
onto the carrier only until the 54552 Bearing comes in contact with the 54468 Ring Gear. This fit will establish a preload on the bearings producing a "snug fit" between the
bearings and the ring gear. If the fit is too tight it will cause the bearings to wear prematurely, if the fit is too loose the desired preload will not be achieved. If an adjustment is
required disassemble and repeat this step.
6. Install the 50778 Spacer with the flat side of the spacer against the 02649 Bearing of the motor assembly.
7. Slide the planetary gear assembly into the 50776 Motor Housing so that the set screw and grease fitting notches align with the corresponding openings in the motor housing.
8. Apply a small amount of the #567 Loctite (or equivalent) to the 50784 Set Screw and install it into the motor housing.
9. Apply a small amount of the #567 Loctite (or equivalent) to the threads of the motor housing and install the 50781 Rear Exhaust Cover. (Torque to 28 N•m.250 in.- lbs.)
10. Lubricate the planetary gear assembly with the 95542 Grease through the grease fitting. Use the 95541 Grease Gun and apply 2-3 plunges of grease for every 50 hours of use.
11. Install the disc pad.
Planetary Gear Case Assembly Complete.
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.
Throttle Lever Positioning Procedure:
1. Place the 52296 Repair Collar around the valve housing and secure it in a vise so that the 50776 Housing is pointing up.
2. Slip the 01558 Collar down onto the valve housing to expose the 01461 Lock Nut.
3. With a firm hold on the 50776 Housing, use a 34mm or an adjustable wrench to turn the 01461 Lock Nut counterclockwise to loosen the 50776 Housing from
the valve housing.
4. Orient the throttle lever to the operators desired grip and positioning. Note: Allow for additional rotation of the 50776 Housing as the 01461 Lock Nut is tightened.
5. With a firm hold on the 50776 Housing to reduce its rotation, use a 34mm or an adjustable wrench to tighten the 01461 Lock Nut. (Torque to 45 N•m/400 in.- lbs.)
Important: Carefully preform this procedure so as not to entirely separate the 50776 Housing from the valve housing. Loosen the 01461 Lock Nut only enough to make desired
throttle lever adjustment.
Loctite®is a registered trademark of Loctite Corp.
96174 Motor Tune-Up Kit
• Includes assorted parts to help maintain
and repair motor.
50971 Lock Ring Wrench
• Lock Ring Tool has a 3/8 in. square socket
for use with 3/8 in. drive; breaker bar,
ratchet head, or torque wrenches.
96346 Bearing Separator
• Use the separator to remove gears
and bearings.
96210 & 96213 Bearing Removal Tool
• This tool is designed to pass through the I.D.
of the bearing plate and push against the I.D.
of the bearing.
96216, 96239 & 96240 Bearing Press Tool
• These tools are designed to safety press a
bearing into a bearing plate and onto a shaft.
96232 #2 Arbor Press
• This arbor press is ideal
for the disassembly and
assembly of air motors.
52296 Repair Collar
• Specially designed collar for use in vise to
prevent damage to valve body housing
during disassembly/assembly.
Dynaswivel
®
• Swivels 360° AT TWO PIVOT POINTS allowing the air hose to
drop directly to the floor while providing superb tool handling.
94300 – 1/4" NPT.
95542 Grease 10 oz.
• Multi-purpose grease for all types of bearings, cams, gears.
• High film strength; excellent resistance to water, steam, etc.
• Workable range 0˚ F to 300˚ F.
95541 Push-type Grease Gun
• One-hand operation.
Dynabrade Air Lube
• Formulated for pneumatic equipment.
• Absorbs up to 10% of its weight in water.
• Prevents rust and formation of sludge.
• Keeps pneumatic tools operating longer
with greater power and less down time.
95842: 1 pt. (473 ml)
95843: 1 gal. (3.8 L)
Optional Accessories
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., 2002 PRINTED IN USA
Visit Our Web Site: www.dynabrade.com Email: Customer[email protected]