Jet J-4210 Service manual

Operating Instructions and Parts Manual
Belt and Disc Sanding Machine
Model J-4210
Part No. M-414550
Revision A2 03/2010
Copyright © 2010 Walter Meier (Manufacturing) Inc.

Warranty and Service
Walter Meier (Manufacturing), Inc., warrants every product it sells. If one of our tools needs service or repair, one of our
Authorized Service Centers located throughout the United States can give you quick service. In most cases, any of these
Walter Meier Authorized Service Centers can authorize warranty repair, assist you in obtaining parts, or perform routine
maintenance and major repair on your JET® tools. For the name of an Authorized Service Center in your area call
1-800-274-6848.
MORE INFORMATION
Walter Meier is consistently adding new products to the line. For complete, up-to-date product information, check with your
local Walter Meier distributor, or visit waltermeier.com.
WARRANTY
JET products carry a limited warranty which varies in duration based upon the product (MW stands for Metalworking, WW
stands for Woodworking).
WHATISCOVERED?
This warranty covers any defects in workmanship or materials subject to the exceptions stated below. Cutting tools,
abrasives and other consumables are excluded from warranty coverage.
WHOISCOVERED?
This warranty covers only the initial purchaser of the product.
WHATISTHEPERIODOFCOVERAGE?
The general JET warranty lasts for the time period specified in the product literature of each product.
WHAT IS NOT COVERED?
Three Year, Five Year and Lifetime Warranties do not cover products used for industrial or educational purposes. Products
with Three Year, Five Year or Lifetime Warranties that are used for industrial or education purposes revert to a One Year
Warranty. This warranty does not cover defects due directly or indirectly to misuse, abuse, negligence or accidents, normal
wear-and-tear, improper repair or alterations, or lack of maintenance.
HOWTOGETSERVICE
The product or part must be returned for examination, postage prepaid, to a location designated by us. For the name of the
location nearest you, please call 1-800-274-6848.
You must provide proof of initial purchase date and an explanation of the complaint must accompany the merchandise. If
our inspection discloses a defect, we will repair or replace the product, or refund the purchase price, at our option. We will
return the repaired product or replacement at our expense unless it is determined by us that there is no defect, or that the
defect resulted from causes not within the scope of our warranty in which case we will, at your direction, dispose of or
return the product. In the event you choose to have the product returned, you will be responsible for the shipping and
handling costs of the return.
HOWSTATELAWAPPLIES
This warranty gives you specific legal rights; you may also have other rights which vary from state to state.
LIMITATIONSONTHISWARRANTY
WALTER MEIER (MANUFACTURING), INC., LIMITS ALL IMPLIED WARRANTIES TO THE PERIOD OF THE LIMITED
WARRANTYFOR EACHPRODUCT.EXCEPTASSTATEDHEREIN,ANYIMPLIED WARRANTIESORMERCHANTABILITY
ANDFITNESSAREEXCLUDED.SOMESTATESDONOTALLOWLIMITATIONSONHOWLONGTHEIMPLIEDWARRANTY
LASTS,SOTHEABOVELIMITATIONMAYNOTAPPLYTOYOU.
WALTER MEIER SHALL IN NO EVENT BE LIABLE FOR DEATH, INJURIES TO PERSONS OR PROPERTY, OR FOR
INCIDENTAL,CONTINGENT,SPECIAL,ORCONSEQUENTIALDAMAGESARISINGFROMTHEUSEOFOURPRODUCTS.
SOMESTATESDO NOTALLOWTHE EXCLUSIONOR LIMITATION OF INCIDENTALOR CONSEQUENTIALDAMAGES,SO
THEABOVELIMITATIONOREXCLUSIONMAYNOTAPPLYTOYOU.
Walter Meier sells through distributors only. The specifications in Walter Meier catalogs are given as general information
and are not binding. Members of Walter Meier reserve the right to effect at any time, without prior notice, those alterations
to parts, fittings, and accessory equipment which they may deem necessary for any reason whatsoever. JET® branded
products are not sold in Canada by Walter Meier.

3
Table of Contents
Cover Page ..........................................................................................................................1
Warranty................................................................................................................................2
GeneralSpecifications ..........................................................................................................3
WarningsandSafety .............................................................................................................4
Introduction............................................................................................................................7
OperatingInstructions............................................................................................................9
Maintenance ....................................................................................................................... 11
Wiring Diagram...................................................................................................................14
Troubleshooting...................................................................................................................16
ReplacementParts .............................................................................................................17
Wiring Diagram...................................................................................................................21
GeneralSpecifications
TheJETModel J-4210 BeltandDisc SandingMachine
is ideal for all shops. This versatile machine can be
used to grind, sand, finish, and contour all types of
parts including metal, wood, plastic, and composite
materials. Because of these capabilities, the JET
sander eliminates theneed for multiple machines to
perform the same tasks.
JETBelt/Disc Sander, Model J-4210
Specifications
Model No. J-4210
Stock No. 414550
Belt Size 6" x 48"
Disc Size 10"
Motor
Horsepower 1 HP
Voltage 115/230Vac (pre-wired for
115 Vac)
Switch Removable Safety Key
Platen Cast Iron
Tables Cast Iron (2)
BeltSpeed 1650 SFPM
Disc Speed 2100 RPM
Dust Collection Shrouds Two(standard)
Weight 120 lbs.

4
You — the stationary power tool user — hold the key to safety.
Read and follow these simple rules for best results and full benefits from your machine. Used properly, JET
machinery is among the best in design and safety. However, any machine used improperly can be rendered
inefficient and unsafe. It is absolutely mandatory that those who use our products be properly trained in how to
use them correctly. They should read and understand the Operators and Parts Manual as well as all labels
affixed to the machine. Failure in following all of these warnings can cause serious injuries.
Machinery general safety warnings
1. Alwayswearprotectiveeyewearwhenoperating
machinery. Also use face or dust mask if cutting
operation isdusty. Everyday eyeglasses only
have impact resistant lenses, they are NOT
safety glasses. Eye wear shall be impact resis-
tant, protective safety glasses with side shields
whichcomplywith ANSI Z87.1specifications.
Use of eye wear which does not comply with
ANSI Z87.1 specifications could result in severe
injuryfrom breakageof eyeprotection.
2. Wearproper apparel.Do notwear looseclothing,
gloves, neckties, rings,bracelets, or otherjewelry
whichmay getcaught inmoving parts.Nonslip
footwearisrecommended.Wear protectivehair
covering to containlonghair.
3. Do not overreach.Keep proper footing and
balance at all times.Failureto maintainproper
working position can cause you to fall into the
machine or cause your clothing toget caught —
pulling you into the machine.
4. Keep guards in place and in proper working order.
Donot operate themachine with guardsremoved.
5. Don't use in dangerous environment. Don’t use
power tools in damp or wet locations, or expose
them to rain. Keep work area welllighted.
6. Reduce the risk of unintentional starting. Make
sure switch is in off position before plugging in.
7. Neverleavethemachinerunningwhile unat-
tended. Don't leave machine until it comes to a
complete stop.
8. Disconnecttools beforeservicing; whenchanging
accessories, such as blades, bits, cutters, and
the like. Whenever changing accessories or
general maintenanceis doneon themachine,
electrical power to the machine must be discon-
nected before work is done.
9. Maintain all machine tools with care.Keep tools
sharp and clean for best and safest performance.
Follow all maintenance instructions for lubricating
and the changing of accessories. No attempt
shallbemade tomodifyor have makeshift repairs
done to the machine. This not only voids the
warranty but also renders the machine unsafe.
10. Machinery must be anchored to the floor.
11. Secure work. Use clamps or a vise to hold work,
when practical. It’s safer than using your hand
and it frees both hands to operate tool.
12. Never brush away chips while the machine is in
operation.
13. Keep work area clean. Cluttered areas invite
accidents.
14. Removeadjusting keysand wrenchesbefore
turning machine on. Form habit of checking to
see that keys and adjusting wrenches are
removedfrom toolbefore turningit on.
15. Use the right tool. Don’t force a tool or attach-
ment to do a job it was not designed for.
16. Use recommended accessories. Consult the
owner’smanualforrecommendedaccessories.
The use of improper accessories may cause risk
ofinjury to persons.
General Machinery Cautions
- Misuse of this machine can cause serious injury.
- For safety, machine must be set up, used and
servicedproperly.
- Read, understand and follow instructions in the
operator’s and parts manual which was shipped with
your machine.
When setting up machine:
- Always avoid using machine in damp or poorly
lighted work areas.
- Always be sure machine is securely anchored to
the floor.
- Always keep machine guards inplace.
- Always put start switch in “OFF” position before
pluggingin machine.
When using machine:
-Never operatewith machineguardsmissing.
- Always wear safety glasses with side shields (See
ANSIZ87.1)
- Never wear loose clothing or jewelry.
- Never overreach — you may slip andfall into the
machine.
- Never leave machine running while you are away
from it.
- Always shut off the machine when not in use.
When servicing machine:
- Always unplug machine from electrical power while
servicing.
- Always follow instructions in operators and parts
manual when changing accessory tools or parts.
-Nevermodifythemachine withoutconsultingWalter
Meier(Manufacturing)Inc.

5
17. Keep hands in sight andclear of allmoving parts
and cutting surfaces.
18. All visitors should be kept at a safe distance from
the work area. Make workshop completely safe
by using padlocks, master switches, or by
removing starter keys.
19. Know the tool you are using — its application,
limitations, and potential hazards.
20. Keepchildrenaway. Allvisitors should bekept
safedistance from workarea.
21. Make workshops kidproof with padlocks, master
switches, or by removing starter keys.
22. Don't force tool. It will do the job better and safer
at the rate for which it was designed.
23. Never stand on tool. Serious injury could occur if
the tool is tipped or if the cutting tool is uninten-
tionallycontacted.
24. Checkdamagedparts. Before furtheruse of the
tool, a guard or other part that is damaged should
be carefully checked to determine that it will
operateproperlyandperform itsintendedfunction
-check for alignmentof movingparts, bindingof
moving parts, breakage ofparts, mounting, and
any other conditions that may affect its operation.
A guard or other part that is damaged shouldbe
properlyrepairedor replaced.
25. Directionoffeed -Feed work intoa bladeor
cutter against the direction of rotation of the blade
or cutter only.
26. Neverleavetoolrunningunattended.Turnpower
off. Don’t leave tool untilit comes to a complete
stop.
Grounding Instructions
1. All grounded, cord-connected tools:
Inthe eventof amalfunction orbreakdown, grounding
providesa path ofleast resistanceforelectric current
to reduce the risk of electric shock. This tool is
equippedwithan electric cord havinganequipment-
grounding conductorand agrounding plug.The plug
must be plugged into a matching outlet that is
properly installed and groundedin accordancewith all
local codes and ordinances.
Do not modify the plug provided - if it will not fit the
outlet, have the proper outlet installed by a qualified
electrician.
Improperconnectionof the equipment-grounding
conductor can result in a risk of electric shock. The
conductorwith insulation havingan outersurfacethat
is green with or without yellow stripes is the equip-
ment-groundingconductor.Ifrepair orreplacementof
the electric cord or plug is necessary, do not connect
theequipment-groundingconductortoa liveterminal.
Checkwith aqualified electricianor servicepersonnel
ifthe groundinginstructionsare notcompletely
understood, or if in doubt as to whether the tool is
properlygrounded.
Useonly 3-wireextension cords that have 3-prong
grounding plugs and 3-pole receptacles that accept
the tool’s plug.
Repair or replace damaged or worn cordimmediately.
FigureA
2. Grounded, cord-connected tools intended for
use on a supply circuit with a nominal rating less
than 150 V:
This tool is intended for use on a circuit that has an
outlet that looks like the one illustrated in Sketch A in
Figure A. The tool has a grounding plug that looks like
the plug illustrated in Sketch A in Figure A.A tempo-
rary adapter, which looks like the adapter illustrated in
Sketches B and C, may be used to connect this plug
to a 2-pole receptacle as shown in Sketch B if a
properlygroundedoutletisnot available.
General Electrical Cautions
This machine should be grounded in accordance with
the National Electrical Code and local codes and
ordinances. This work should be done by a qualified
electrician. The machine should be grounded to
protect theuser from electrical shock.
Wire sizes
Caution: forcircuits whicharefar awayfrom the
electrical service box, the wire size must be in-
creased in orderto deliver ample voltage tothe motor.
Tominimize power losses and to prevent motor
overheating and burnout, the use of wire sizes for
branch circuits or electrical extension cords accord-
ingtothefollowingtable is recommended:
Volts Total length of cord in feet
Ampere Rating 120V 25 ft 50 ft 100 ft 150 ft
240V 50 ft 100 ft 200 ft 300 ft
More Not more
than than AWG
0 6 18 16 16 14
6 10 18 16 14 12
10 12 16 16 14 12
12 16 4 12 Not recommended

6
Abrasivesandingcanbe hazardousto operatorsand
bystanders. Sanding sparks, chips and dust particles
thrown off by the sanding disc can cause serious
injury by contact or inhalation. To avoid injuries you
must comply with the following safety requirements:
1. Always wear protective eyewear when operating
machinery. Eye wear shall be impact resistant,
protectivesafety glasseswith sideshieldswhich
comply with ANSI Z87.1. Use of eye wear which
does not comply with ANSI Z87.1 specifications could
result in severe injury from breakage of eye protec-
tion. See Figure B, below.
2. Wear leather safety gloves, arm guards, leather
aprons and safety shoes.
3. A dust collection system is recommended,
Operator shall also wear a dust mask at all times.
See Figure C, below.
4. Additional precautions may be necessary for
sanding materials which are flammable or have other
hazardous properties. You should always consult the
manufacturer of such materials for instructions on
sanding and handling.
5. Do not force or jamb the workpiece into the
sanding disc.
6. Before sanding, always allow the motor to come
up to operating speed, then check the sanding disc
Safety Requirements for Abrasive Sanding Machines
forwobble, runout,or anyunbalanced condition. If
the disc is not operating accurately and smoothly,
immediatelystop themotorand makerepairsbefore
attemptinganysandingoperations.
7. Abrasive discs must be stored in a controlled
environmentarea. Relativehumidity should be35%
to 50% and the temperature should be between 60
and 80 degrees Farenheit. Failure to do so could
causeprematuredisc failure.
8. Examine the face of the sanding disc carefully.
Excessive sanding which wearsdown to thebacking
material can tearing of the disc. Never use a disc
which shows backing, nicks or cuts on the surface or
edgeor damagedue to creasingor poorhandling.
9. When installing a new disc, be certain the disc is
accurately centered on the drive wheel. Failure to do
so could cause a serious unbalanced condition.
10.Always present the workpiece to the wheel while
resting the workpiece firmly on the table. Failure to
do so could result in damage to the workpiece or
throwingof theworkpieceoff thewheel.
11.Safety shoes whichcomplywith ANSIZ41.1shall
be worn. See Figure D.
12.Personal hearing protection such as ear plugs or
ear muffs shall be used to protect against theeffect of
noise exposure. See Figure E.
Figure B Figure C Figure D Figure E
The temporary adapter should be used only until a
properly grounded outlet can be installed by a quali-
fiedelectrician.Thegreen-coloredrigidear, lug,and
the like, extending from the adapter must be con-
nected to a permanent ground such as a properly
grounded outlet box.
3. Grounded, cord-connected tools intended for
use on a supply circuit having a nominal rating
between 150 - 250 V, inclusive:
This tool is intended for use on a circuit that has an
outlet that looks like the one illustrated in Sketch D in
Figure A. The tool has a grounding plug that looks like
the plug illustrated in Sketch D in Figure A. Make
sure the tool is connected to an outlet having the
same configuration as the plug. No adapter is avail-
able or should be used with this tool. If the tool must
bereconnectedfor useon a differenttypeof electric
circuit, the reconnectionshould be made by qualified
servicepersonnel; andafter reconnection,thetool
should comply with all local codes and ordinances.
4. Permanently connected tools - This tool should
beconnected to agrounded metalpermanent wiring
system; or to a system having an equipment-ground-
ingconductor.
5. Polarized Plugs - To reduce the risk of electric
shock, this equipment has a polarized plug (one blade
is wider than the other). This plug will fit in a polarized
outlet only one way. If the plug does not fit fully in the
outlet, reverse the plug. If it still does not fit, contact a
qualifiedelectrician toinstall the properoutlet. Donot
change the plug in any way.

7
Introduction
Thismanual includesoperatingand maintenance
instructions for theJET Model J-4210 Beltand Disc
Sander. This manual also includes parts listings and
illustrations of replaceable parts.
Belt and Disc Sander
Features
Figures 1 and 2 depict themain features of the JET
Model J-4210 Belt and Disc Sander. (Specifications
for the sanding machine are provided on page 3.)
Figure 1: Belt and Disc Sander Features
(Right Side View)
Figure 2: Belt and Disc Sander Features
(Left Side View)
The sander has both a sanding belt and a sanding
disc for use on a variety of work pieces and materi-
als.
The platen housing for the belt sander can be posi-
tionedverticallyor horizontally. When in thevertical
position, the drum at the upper end of the platen
housing can be used for contouring. A tracking
adjustment mechanism for the sanding belt is pro-
vided at the upper end of the platen housing.
The platen housing has a lever that is used to apply
tension to the sanding belt. The sanding belt is easily
replaced by releasing the tension lever, removing a
sanding shroudand dust collection duct at thebottom
of the platen housing, and slipping the belt from the
belt sander drums. Installation is the reverse of the
removalsteps.
Tracking Adjustment
Belt Tensioning Lever
Belt Work Table
Clamping Knob
Sanding Disk
Miter Gauge
Disc Work Table
Clamping Knob
Disc
Debris
Duct
Sanding Belt
Belt Guard
Platen Housing
Debris Duct
On/Off
Switch
Power Cord
Stand
Machine
Base
Belt Sander
Work Table

8
The disc sander consists of an aluminum disc onto
which is installed an adhesive-backed sanding and
other abrasive discs. The disc is contained within a
ducted shroud.
The sanding disc can be replaced by removing the
table and a cover over the lower portion of the disc.
If desired, the aluminumdisc can be removed from
its drive shaft to ease replacement of the sanding
disc.
The drive motor for the beltand disc sander is
attached to the underside of the machine base. An
ON/OFF switch is mounted on themachine base on
the side opposite the disc sander. Electrical wiring
for the motor enters the machine basebelow the ON/
OFF switch and is routed to the switch and motor
inside the machine base.
The belt and disc sander is driven by V-belts con-
nected to the drive motor. A pulley on the motor shaft
drives a V-belt that drives a dual-groove pulley onan
idler shaft. A second V-belt is installed in the second
groove of the dual-groove pulley andconnects to a
pulley on belt sander drive shaft.
The aluminum sanding disc is driven off the end of
the idler shaft. A shaft connected to the second V-
beltpulley drivesthe beltsander drivedrum.
The belt and disc sander is mounted on a stand that
can be secured to the floor to stabilize the machine.
The stand has a door for access to the fasteners for
the machine base.
Installation and Setup
Mounting
It is recommended that the belt and disc sander be
secured to the floor for safe operation. The machine
stand has mounting holes in a flange on the inside of
stand enclosure. The stand can be secured to the
floor using these mounting holes.
ElectricalConnection
Refer to the Wiring Data section for wiring informa-
tion. Electrical power should be connected by a
qualified electrician. Observe local electrical codes
when connecting and grounding the machine.

9
Operation
This section defines the controls and other features
with which the operator should be familiar. Refer to
Figures 3 and 4 for some typical sander operations.
Figure 3. Contouring with Belt Sander
Figure4. Sanding using DiscSander
Controls
The ON/OFF switch is located on the side of the
machine base (refer to Figure 5).
Miter Gauge
A miter gauge is provided with the machine and can
be used on either the belt sander of disc sander work
tables. The angle of the miter gauge can be adjusted
up to 45 degrees to accommodate angular work
piece surfaces.
Figure 5. ON/OFF Switch
Adjustments
AdjustingBeltTracking
The tracking of the sanding belt may require adjust-
ment after changing the belt. The belt housing has a
tracking adjustment mechanism (Figure 6) that is
used to adjust tracking.
1. Start the machine.
2. Check tracking of the sanding belt. The belt
should track at the center of the drums.
3. Adjustbelt trackingby turningthe adjustment
knob. Turn the knob as needed to correct the
tracking of the belt.
Figure6. Adjusting Belt Tracking
Belt Tracking
Adjustment Knob
Belt should track
at center of drums;
no side-to-side
movement.
Belt Tensioning
Lever

10
Adjusting Platen Housing
Position
The sanding belt can be operated with theplaten
housing horizontal, vertical, or at any angle in
between. Change position of the platen housing as
follows:
WARNING: DISCONNECT ELECTRICAL POWER
TOTHEMACHINEBEFOREPERFORMINGANY
MAINTENANCE.
1. Disconnect electrical power.
2. Remove four screws (52) and pulley cover (12).
3. Using an open end wrench, loosen two hex
screws (13) (refer to Figure 7).
4. Move the platen housing to the desired position.
When the platen housing is to be placed in the
horizontal position, lower the platen housing onto
stop screw (28) on the machine base.
5. If the stop requires adjustment, loosen jam nut
(29), adjust stop screw (28) to desired position,
and tighten nut (29).
6. Tighten two hex screws (13).
7. Install pulley cover (12) and secure with four
screws (52).
8. Start the machine to check operation.
Figure7. Platen Housing Clamping Screws
DiscTable
1. To change the disc table angle, loosen the knob
on the left side of the table (refer to Figure 8).
2. Move the table to the desired angle.
3. Tighten the knob to secure the table.
Figure 8. Adjusting Sander TableAngle
BeltTable
1. To change the belt table angle, loosen the knob
on the right side of the platen housing (refer to
Figure 8).
2. Move the table to the desired angle.
3. Tighten the knob to secure the table.
Adjusting the Sander Tables
The belt and disc sander tables can be adjusted
from 0 to 45 degrees to accommodate the work
piece.
Clamping
Screws
Platen
Housing
Table Clamping Knob
Disc Table Angle Scale
Belt Table
Clamping Knob
Belt Table Angle Scale
(left underside of table)

11
Maintenance
This section provides procedures required to main-
tain the belt/disc sander. The numbers in parenthe-
ses throughout the manual correspond with reference
numbers for parts shownin the exploded views in the
Replacement Parts section.
Lubrication
The bearings used in the sanding machine are
sealed, pre-lubricated bearing. The bearings do not
require periodic lubrication.
Cleaning
Periodically use a vacuum cleaner to remove sanding
debris from the machine. In hard to reach areas,
brush the debris loose while vacuuming.
Replacingthe SandingBelt
WARNING: DISCONNECT ELECTRICAL POWER
TOTHEMACHINEBEFOREPERFORMINGANY
MAINTENANCE.
1. Disconnect electrical power.
2. Position sanding belt platen (4) in the vertical
position. Remove eight screws (97) and guard
(96).
3. Remove screw (76) andguard (75).
4. Movetensioning lever (50) downwardto slacken
sanding belt (79).
Refer to Figure 9. Slip sanding belt off drums (5) and
(39).
Figure 9. Replacing Sanding Belt
1. Install replacement sanding belt on drums.
Position edges of sanding belt evenly on the
drums.
2. Lift tensioning lever to tighten sanding belt on
drums.
3. Install guard (75) and secure with screw (76).
4. Install guard (96) and secure with eight screws
(97).
5. Connect electrical power and operate machine to
check operation.
6. If belt does not track properly, adjust tracking
(refer toAdjusting Belt Tracking).
ReplacingtheSanding Disc
WARNING: DISCONNECT ELECTRICAL POWER
TOTHEMACHINEBEFOREPERFORMINGANY
MAINTENANCE.
1. Disconnect electrical power.
2. Loosen screw (65). Remove disc table (60).
3. Remove four screws (56) and plate (55) from
disc shroud (53).
4. Insert a long T-handle Allen wrench through the
side opening in shroud (53) and into set screw
(57). Loosen disc set screw (57) and remove
disc (58).
WARNING: USECARE WHENUSING KNIFETO
SEPARATE SANDING DISC (59) FROM DISC (58).
INJURYFROMTHE KNIFEMAYOCCURIF THE
KNIFESLIPSOR IF SANDINGDISC SHOULD
SUDDENLY COME FREE.
5. Using a knife, slowly work the tip ofthe knife
blade under sanding disc (59). Slowly work the
tip around the circumference of disc (58).
Continue to work around the circumference until
sanding disc can be separated by hand from
disc (58).
6. Remove paper backing from replacement sand-
ing disc (59). Place sanding disc (59) on disc
(58). Make sure the sanding disc is place evenly
at the outside diameter of disc (58).
7. Press on the sanding disc to remove any en-
trapped air and to make sure the sanding disc is
adhering to disc (58).
8. Install disc (58) onto shaft (16). Position the disc
onthe shaftto provideclearance between plate
(55) and sanding disc. Tighten set screw (57).
NOTE: There is a close fit between the edge of disc
(58) and disc shroud. To ease installation and posi-
tioning of the disc, use an L-shaped tool (such as an
Allen wrench) under outer edge of the disc to support
and position the disc while tightening set screw.

12
9. Install plate (55) and secure with four screws (56).
Checkfor clearancebetween plate(55) and the
sanding disc.
10. Install table (60) onto rod (74). Position table so
it is level and tighten screw (65) against rod (74).
11. Connect electrical power and operate machine to
check operation.
ReplacingtheV-Belts
WARNING: DISCONNECT ELECTRICAL POWER
TOTHEMACHINEBEFOREPERFORMINGANY
MAINTENANCE.
1. Disconnect electrical power.
2. Removesandingbelttable.
3. Removesandingdisctable.
4. Remove sanding disc and shroud.
5. Remove pulley cover. Loosen set screw in pulley.
6. With second person holding belt housing,
alternatelyloosenandremove twoscrews.
7. RemoveV-beltfrom pulley(11). Remove pulley
from shaft while separating assembled belt
housing from the machine base.
8. Remove key from sanding belt drum shaft.
9. Loosen set screw in pulley (20).
10. Removepulley. Whileremoving pulley,slip V-
beltsfrom pulley.
11. Remove four screws from base. With assistance
of the second person, lift base from stand.
NOTE: Place base on bench. As an alternative, the
stand may be used to support the base while remov-
ing drive motor screws.
12. Place base on bench with underside of the base
facing up.
13. Remove two hex head screws,two nuts, and two
washers from the motor base on the shaft side of
motor.
14. Loosen (but do not remove) two hex bolts, two
nuts, and two washers on the side of motor base
opposite the motor shaft.
15. Tip motor enough to provide clearance between
end of shaft and wall of base. Remove motor
drive belt.
16. With base still on the bench, slip V-belt (15) over
end of idler shaft.
NOTE: Install V-belt for sanding belt first, followed by
themotorV-belt.
17. Install replacement V-belt over end of motor shaft.
18. Install two hex bolts, two nuts, and two washers in
the motor base on the shaft side of motor.
Tighten all four hex nuts and hex head screws.
19. Install key in idler shaft with keyway facing up.
Install pulley (20) on idler shaft.
20. Installmotor V-belt(18) in outermostgroove of
pulley (20) and on pulley (18) on motor shaft.
21. Position motor belt (18) on idler shaft so it is
parallel with the innerwall of thebase. Tighten
set screw in pulley (20).
22. Place assembled base on stand. Secure with
four screws, washers, nuts.
NOTE: Because of the weight of the belt housing, a
second person should hold the belt housing in
position while installing pulley (10).
23. Hold belt housing in position in bracket (3). Start
two screws (13) in threaded holes in platen.
Install key (8) in shaft.
NOTE: Because of the length of screws (13), the
screws will have to be installedalternately. Asthe
screws are installed, there will be enough clearance
to slide the belt drum drive pulley a little at a time onto
shaft (8).
24. Alternately install two screws (13). As the screws
are tightened, slide pulley (10) onto the idler shaft
as allowed by the protrusion of screw heads.
Make sure V-belt remains on pulleys (11 and 20).
25. When screws (13) are fully installed, align pulley
(20) with pulley (11). Tighten set screw (10).
26. Install shroud (53) on base and secure with four
screws and washers.
27. Install pulley cover (12) and secure with two
screws.
28. Install disc (58) onto shaft (16) and over key.
Position the disc on the shaft to provide clear-
ance between plate (55) and the sanding disc.
Using long T-handle Allen wrench, tighten set
screw (57).
NOTE: There is a close fit between the edge of disc
(58) and the disc shroud. To ease installation and
positioning of the disc, use an L-shaped tool (such as
an Allen wrench) under the outer edge of the disc to
support and position the disc while tightening the set
screw.
29. Install plate (55) and secure with four screws
(56). Check for clearance between plate (55)
and the sanding disc.
30. Install table (60) onto rod (74). Position table so
it is level and tighten screw (65) against rod (74).
31. Installassembledtable(88).
32. Connect electrical power and operate machine to
check operation.

13
Replacement of Motor
WARNING: DISCONNECT ELECTRICAL POWER
TOTHEMACHINEBEFOREPERFORMINGANY
MAINTENANCE.
1. Disconnect electrical power.
2. Remove four screws from base. With assistance
of the second person, lift base from stand.
NOTE: Place base on bench. As an alternative, the
stand may be used to support the base while remov-
ing drive motor screws.
3. Place base on bench with underside of the base
facing up.
4. Remove four hex head screws, nuts, andwash-
ers from the motor base.
5. Remove motor V-belt from motor pulley.
6. Removemotor frombase.
7. Loosen set screw in pulley (18). Remove pulley.
8. Align set screw in pulley with flat on motor shaft
and install pulley. Do not tighten set screw.
9. Install replacement V-belt over end of motor shaft
and install motor in base . Secure with four
screws, washers and nuts.
10. Install and tighten four hex bolts, nuts, and
washers in the motor base.
11. Position pulley (18) on motor shaft so the V-belt
is parallel with the inner wall of the base. Tighten
set screw in pulley (20) against flat on motor
shaft.
12. Place assembled base on stand. Secure with
four screws, washers, nuts.
13. Connect electrical power and operate machine to
check operation.

14
WiringData
Figure 10: Pictoral diagram for single
phasemotor, 115 voltsw/plug.
Singlephaseelectricalhook-up
When connecting your machine to single phase
power you may be connecting to either 115 or 230
volts, depending upon the motor typeprovided. Local
codes may, or may not, permit the use of a plug type
of connection for your machine. Where a plug
connection is permitted, the following installation
practices mustbe followed:
1. The plug used must be a grounding type of plug.
On a 115 volt single phaseconnection, the plug
mustbe athree-prongplugwith twoflat, parallel
blades for the power wires and a single rounded
or U-shaped prong for the ground connection.
On 230 volt single phase connections, the lug
must be a three prong plug with two flat blades in
tandem to carry the current, and a third round or
U-shaped prong for the ground connection.
2. The service branch to which the plug is connected
must be a branch with a separate ground wire so
the grounding prong of the plug can be con-
nected to ground effectively.
Note: Local electrical codes in many jurisdictions do
not allow the use of plug type connections for single
phase power when the machine is used in a commer-
cial or industrial establishment.
In these cases you must connect your machine to
the service branch using a hard-wired junction box
connection.
All JET sanders are shipped with thepower cable
terminating without a plugon theassumptionthe
machine will be hard-wired to its service branch.
Circuitprotection
Where the service branch is protected with a fuse or
circuit breaker which is too high a value to offer
protection to the motor supplied, a fuse or circuit
breaker box should beused at the point wherethe
machine connection is made and the time delay fuse
or circuit breaker should be a value just slightly
higher than the maximum load current draw as
specified on the motor plate on the motor.
Figure 11: Pictoral diagram for
3-phasemotor.
Correctingmotorrotationinsingle
phase motors
JETprovides singlephasemotors inboth 115volt and
230volt configuration. Severalmotor manufactures
may be used by JET for motors of this type.
These motors may, or may not, rotate in the correct
direction -- counter-clockwise -- when connected to
your single phase power source. If, after connec-
tion, the motor runs in the correct counter-clockwise
direction, the power connection is successful.
CAUTION: IFTHEMOTORRUNS CLOCKWISE
WHENCONNECTEDTOYOURSINGLEPHASE
POWERSOURCE,YOUMUSTDISCONNECTTHE
POWERSOURCE,OPEN THEJUNCTIONBOX
ANDFINDTHE CORRECT WIRINGCONNECTIONS
FORTHEMOTOR,ORLOCATETHEWIRING
CONNECTIONSREQUIREDONTHEMOTORPLATE
ONTHEOUTSIDEOFTHEMOTOR.
Differentmanufacturers provide differentwiring
configurations for correcting the rotation of the motor
armature. Therefore, no wiring diagrams for these
motors are provided in this manual. Always consult
the motor plate and/or the wiring diagram inside the
junction box if rotation direction is not correct.

15
ConnectingPower for3-phaseMotors
1. Be certain the power to the branch you are
connecting is off, and locked out, so power
cannot be reestablished, accidentally.
2. Connect the ground wires. Thse wires will be
either green, or green with a white trace.
3. Connect the remaining three cable wires to the
three power wires in the service branch.
4. Reestablish power to the branch.
5. Turn the machine on. The motor should be
turning counter-clockwise, the beltsander should
be moving downward, and the disc sander should
Figure 12: Schematic diagram for
single phase motor with 3-wire
cable. Note:this schematic
providedforuse witholder
sanders,only. Allmachinesare
now shipped with a 4-wire cable
whethersinglephase or3-phase.
Figure 13: Schematic diagram for
singlephase motorwith 4-wire
cable.
be turning clockwise. If this is the case, the
machine can be considered wired correctly. If
the motor is not turning in the correct direction,
take the following corrective action:
6. Disconnect power in the branch again and be
certain it cannot be accidentally turned on while
you correct the wiring.
7. Reverse ANY TWO of the power wires to the
machine.
8. Reestablish power in the service branch to the
machine.
9. Turn on the machine again. The motor should
now be turning in the correct direction.
Figure 14: Schematic diagram for
3-phasemotor.

16
Troubleshooting
Fault Probable Cause Remedy
Machine does not start. 1. Blown fuse or tripped 1. Determine reason for blown fuse/tripped
circuit breaker. breaker (such as a short circuit or motor
overload). Correct reason for fault. Replace
fuse/reset breaker.
2. Motor failure. 2. Replace motor.
3. Not connected to power 3.Connect to power source.
source.
4.Motor not wired for correct 4. Correct motor wiring.
voltage.
5. Motor not connected to 5. Connect to proper voltage source.
correct voltage source.
Sanding belt does not 1. Sanding belt stretched 1. Replace sanding belt.
trackcorrectly. unevenly.
2. V-belt worn. 2.Replace V-belt.
3. Pulley worn. 3.Replace pulley.
Abrasive disc separates 1.Improperly bonded. 1. Clean residual adhesive from disc.
from disc. Reapply adhesive-backed disc to clean disc.
Sanding belt slips or stalls 1. Abrasive belt tension 1. Tightensanding belt.
when pressure is applied. inadequate.
2.Excessive pressurebeing 2. Reduce pressure on sanding belt
applied toplaten housing. (and platen housing).
3. Motor belt loose. 3. Tightenmotor belt.
Disc stalls when pressure 1.MotorV-belt loose. 1.Tightenmotor V-belt.
is applied.
Frequentreplacementof 1. Too much pressure being 1. Reduce pressure on work piece.
sandingbelt. applied to work piece.
2. Full width of belt not being 2. Stroke across sanding belt using full width
used. of belt surface.

17
ReplacementParts
This section provides exploded view illustrations thatshow the replacement parts for the JET Model J-4210 Belt/
Disc Sander. Also providedareparts listings thatprovide part numberand description. The item numbers
shown on the illustration relate the item number in the facing parts listing.
Order replacement parts from:
WALTER MEIER (Manufacturing) Inc.
427NewSanfordRoad
LaVergne,Tennessee37086
Ph.:800-274-6848
www.waltermeier.com
To order parts or reach our service department, call 1-800-274-6848 Monday through Friday (see our website for
businesshours, www.waltermeier.com).Having theModel Number andSerial Numberof yourmachine available
when you call will allow us to serve you quickly and accurately.

18 Ref. Part
No. Number Description Qty.
1 J-5513476 Panel, Access 1
2 5513477 Knob 2
3 J-5515307 Stand,Complete 1
Assembled View and Parts Listing of Stand –
Model J-4210 Belt and Disc Sander
3
2
1

19
Exploded View – JET Model J-4210 Belt & Disc Sander

20
Parts Listing – JET Model J-4210 Belt & Disc Sander
Ref. Part
No. Number Description Qty
2 J-5513011 Base 1
3 J-5513012 Bracket 1
4 J-5513013 Platen 1
5 5513014 Drum, Drive 1
6 5513015 Shaft, Drum Drive 1
7 5513016 Bearing (6203ZZ) 2
8 5513017 Key 1
8A 5513028 Key 1
9 5513018 Ring, Retaining (S-17) 2
10 5513019 Screw, Set (1/4 X 3/8) 1
11 J-5513020 Pulley 1
12 J-5513021 Cover, Pulley 1
13 5513022 Screw (5/16 X 1-1/2) 4
14 5513023 Washer, Plain (5/16) 4
15 5513024 V-Belt (A-18) 1
16 5513025 Shaft, Drive Pulley 1
17 J-5513026 Bracket 1
18 J-5513027 Pulley, Motor 1
20 J-5513029 Pulley, Idler 1
21 5513030 V-Belt (A-25) 1
22 5513031 Screw (5/16 X 3/4) 4
23 5513032 Washer, Flat (5/16) 8
24 5513033 Nut, Hex (5/16) 4
25 5512767 Motor, 1-HP 1
26 5513035 Screw, Hex (3/8 X 1) 3
27 5513036 Washer, Flat (3/8) 3
28 5513037 Screw (3/8 X 1-1/2) 1
29 5513038 Nut, Jam 1
30 J-5513039 Bracket, Mounting 1
31 5513040 Screw (5/16 X 1) 1
32 5513041 Washer (1/4) 6
33 5513042 Screw, Hex (1/4 X 3/4) 2
34 5513043 Spring (1/4) 1
35 5513044 Shaft 1
36 5513045 Shaft, Driven Drum 1
37 5513046 Ring, Retaining (S-15) 2
38 5513047 Bearing (6202ZZ) 2
39 5513048 Drum, Driven 1
40 5513049 Nut (1/4) 1
41 5513050 Spring 1
42 5513051 Washer, Flat 1
43 5513052 Rod, Threaded, Belt
TrackingAdjustment 1
44 5513054 Support, Driven Drum 1
45 5513055 Screw (5/16 X 1/2) 1
46 5513056 Bracket 1
47 5513057 Bar 1
48 5513058 Screw (3/16 X 1/2) 6
49 5513059 Washer (3/16) 2
50 5513060 Lever, Belt Tension 1
51 5513061 Screw (5/16 X 1-1/4) 1
52 5513062 Screw (3/16 X 3/8) 2
53 J-5513063 Guard, Disk 1
54 5513064 Washer, Lock (3/16) 4
55 5513065 Plate, Cover 1
56 5513066 Screw (3/16 X ¼) 5
Ref. Part
No. Number Description Qty
57 5513067 Screw, Set (6 X 10 MM) 1
58 5512765 Disk,Aluminum 1
59 5513071 Garnet Disk 10": 1
80 Grit (Standard)
Also available:
5513073 100 Grit 1
5513075 120 Grit 1
60 J-5513077 Table,Side 1
61 J-5513078 Support,Table 1
62 5513079 Bracket, Table Support 1
63 5513080 Pin, Spring 1
64 5513081 Screw (1/4 X 3/8) 4
65 5513082 Screw, Hex (5/16 X 1) 1
66 5513083 Pin, Spring 1
67 5513084 Bracket, Table Support 1
68 5513085 Washer, Flat 2
69 5513086 Pointer 1
70 5513087 Knob 1
71 5513088 Washer 1
72 5513089 Rivet 3
73 5513090 Scale 1
73A 5513091 Pointer 1
74 5513092 Rod,Table Support 1
75 5513093 Guard,Belt 1
76 5513094 Screw (3/16 X 5/8) 1
77 5513095 Cover, Sanding Belt* 1
77A 5513096 Screw, Cap* 8
78 5512766 Switch 1
79 5051841 Belt, Abrasive(6 x 48) 1
80 Grit (Standard)
Also available:
5512764 100 Grit 1
5513103 150 Grit 1
82 5513107 Washer 1
83 5513108 Knob (1/4 X 1-1/2) 1
84 J-5512763 Bracket, Table 1
85 5513110 Screw (5/16 X 1-1/2) 3
86 5513111 Pin (4 X 15) 1
88 J-5513113 Table, Sanding Belt 1
89 5513114 Wrench* 1
90 5513115 Screw, Socket Head 2
91 5513116 Washer, Flat 2
92 5513117 Nut,Hex 2
93 5513118 Screw, Hex Head 2
94 5513119 Washer, Flat 2
95 5513120 Nut, Hex 2
96 J-5513479 Cover,Belt 1
97 5513480 Screw, Socket Head 8
98 J-5514639 Guard, Belt 1
99 5514640 Screw 4
100 5517426 Gauge, Miter 1
5515308 Head,Complete 1
* Part not shown.