Jet ZH Series Troubleshooting guide

Operation and Maintenance Instructions
ZH Series Large Bore Lathes
Models GH-2680ZH; GH-26120ZH
Model GH-2680ZH shown
For ZH-Series Lathes Parts List and Electrical Diagrams, see document M-321860-1
WALTER MEIER (Manufacturing) Inc.
427 New Sanford Road
LaVergne, Tennessee 37086 Part No. M-321860
Ph.: 800-274-6848 Revision A 11/2011
www.jettools.com Copyright © 2011 Walter Meier (Manufacturing) Inc.
This .pdf document is bookmarked

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1.0 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 = Metalworking, WW =
Woodworking).
WHAT IS COVERED?
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.
WHO IS COVERED?
This warranty covers only the initial purchaser of the product.
WHAT IS THE PERIOD OF COVERAGE?
The general JET warranty lasts for the time period specified in the product literature of each product.
WHAT IS NOT COVERED?
Five Year Warranties do not cover woodworking (WW) products used for commercial, industrial or educational
purposes. Woodworking products with Five Year Warranties that are used for commercial, 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.
HOW TO GET SERVICE
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.
HOW STATE LAW APPLIES
This warranty gives you specific legal rights; you may also have other rights which vary from state to state.
LIMITATIONS ON THIS WARRANTY
WALTER MEIER (MANUFACTURING) INC., LIMITS ALL IMPLIED WARRANTIES TO THE PERIOD OF THE
LIMITED WARRANTY FOR EACH PRODUCT. EXCEPT AS STATED HEREIN, ANY IMPLIED WARRANTIES OR
MERCHANTABILITY AND FITNESS ARE EXCLUDED. SOME STATES DO NOT ALLOW LIMITATIONS ON HOW
LONG THE IMPLIED WARRANTY LASTS, SO THE ABOVE LIMITATION MAY NOT APPLY TO YOU.
WALTER MEIER SHALL IN NO EVENT BE LIABLE FOR DEATH, INJURIES TO PERSONS OR PROPERTY, OR
FOR INCIDENTAL, CONTINGENT, SPECIAL, OR CONSEQUENTIAL DAMAGES ARISING FROM THE USE OF
OUR PRODUCTS. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU.
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.

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2.0 Table of Contents
1.0 Warranty and Service .......................................................................................................................2
2.0 Table of Contents .............................................................................................................................3
3.0 Safety warnings................................................................................................................................4
4.0 Specifications...................................................................................................................................6
5.0 Dimensions and mounting hole centers.............................................................................................8
6.0 General description and nomenclature..............................................................................................9
7.0 Unpacking......................................................................................................................................11
Contents of the Shipping Container....................................................................................................11
8.0 Installation......................................................................................................................................12
8.1 Leveling the lathe........................................................................................................................12
8.2 Completing installation................................................................................................................12
8.3 Chuck Preparation.......................................................................................................................13
8.4 Break-In Period...........................................................................................................................13
9.0 Maintenance/Lubrication ..................................................................................................................14
9.1 Coolant Preparation ....................................................................................................................16
10.0 Electrical Connections...................................................................................................................16
10.1 Conversion to 460 Volt Operation ...............................................................................................17
11.0 Basic Controls ..............................................................................................................................18
12.0 Operation......................................................................................................................................21
12.1 Tool Setup.................................................................................................................................21
12.2 Spindle Speed...........................................................................................................................22
12.3 Feed and Thread Selection .......................................................................................................22
12.4 Thread Cutting ..........................................................................................................................22
13.0 Adjustments..................................................................................................................................23
13.1 Chuck Jaw Reversal..................................................................................................................23
13.2 Gib Adjustments........................................................................................................................23
13.3 Tailstock Adjustments................................................................................................................24
13.4 Gap Section..............................................................................................................................24
13.5 Belt Adjustment and Replacement ...............................................................................................24
13.6 Brake Strap...............................................................................................................................25
13.7 Friction Clutch Adjustment.........................................................................................................25
13.8 Aligning Tailstock to Headstock.................................................................................................26
13.9 Spindle Bearings.......................................................................................................................26
13.10 Speed Control.........................................................................................................................26
13.11 Lead Screw.............................................................................................................................26
13.12 Apron Feed Clutch ..................................................................................................................27
13.13 Tool Post.................................................................................................................................27
13.14 Cross Slide Nut Adjustment.....................................................................................................27
13.15 Shear Pin Replacement...........................................................................................................28
13.16 Steady Rest Adjustment..........................................................................................................28
13.17 Follow Rest Adjustment...........................................................................................................28
14.0 Troubleshooting the ZH Series Lathes ..........................................................................................29
15.0 Lubrication Schedule and General Maintenance............................................................................30
16.0 Reference Tables .........................................................................................................................31
16.1 Inch Lead And Feed..................................................................................................................31
16.2 Special Inch Lead And Feed......................................................................................................31
16.3 Speed Selection Lever Positions ...............................................................................................32
17.0 Electrical – 230 volt to 460 volt Conversion...................................................................................32
18.0 Change Gear Diagram.................................................................................................................. 33

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3.0 Safety warnings
1. Read and understand the entire owner’s manual before attempting assembly or operation.
2. Read and understand the warnings posted on the machine and in this manual. Failure to comply with all of these
warnings may cause serious injury.
3. Replace the warning labels if they become obscured or removed.
4. This lathe is designed and intended for use by properly trained and experienced personnel only. If you are not
familiar with the proper and safe operation of a lathe, do not use until proper training and knowledge have been
obtained.
5. Do not use this lathe for other than its intended use. If used for other purposes, Walter Meier (Manufacturing)
Inc., disclaims any real or implied warranty and holds itself harmless from any injury that may result from that
use.
6. Always wear approved safety glasses/face shields while using this lathe. Everyday eyeglasses only have impact
resistant lenses; they are not safety glasses.
7. Before operating this lathe, remove tie, rings, watches and other jewelry, and roll sleeves up past the elbows.
Remove all loose clothing and confine long hair. Non-slip footwear or anti-skid floor strips are recommended. Do
not wear gloves.
8. Wear ear protectors (plugs or muffs) during extended periods of operation.
9. Some dust created by power sanding, sawing, grinding, drilling and other construction activities contain
chemicals known to the state of California to cause cancer, birth defects or other reproductive harm. Some
examples of these chemicals are:
•Lead from lead based paint.
•Crystalline silica from bricks, cement and other masonry products.
•Arsenic and chromium from chemically treated lumber.
Your risk of exposure varies, depending on how often you do this type of work. To reduce your exposure to these
chemicals, work in a well-ventilated area and work with approved safety equipment, such as face or dust masks
that are specifically designed to filter out microscopic particles.
10. Do not operate this machine while tired or under the influence of drugs, alcohol or any medication.
11. Make certain the switch is in the OFF position before connecting the machine to the power supply.
12. Make certain the machine is properly grounded.
13. Make all machine adjustments or maintenance with the machine unplugged from the power source.
14. Remove adjusting keys and wrenches. Form a habit of checking to see that keys and adjusting wrenches are
removed from the machine before turning it on.
15. Keep safety guards in place at all times when the machine is in use. If removed for maintenance purposes, use
extreme caution and replace the guards immediately after maintenance is complete.
16. Check damaged parts. Before further use of the machine, a guard or other part that is damaged should be
carefully checked to determine that it will operate properly and perform its intended function. Check for alignment
of moving parts, binding of moving parts, breakage of parts, mounting and any other conditions that may affect
its operation. A guard or other part that is damaged should be properly repaired or replaced.
17. Provide for adequate space surrounding work area and non-glare, overhead lighting.
18. Keep the floor around the machine clean and free of scrap material, oil and grease.
19. Keep visitors a safe distance from the work area. Keep children away.
20. Make your workshop child proof with padlocks, master switches or by removing starter keys.

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21. Give your work undivided attention. Looking around, carrying on a conversation and “horse-play” are careless
acts that can result in serious injury.
22. Maintain a balanced stance at all times so that you do not fall or lean against moving parts. Do not overreach or
use excessive force to perform any machine operation. Never force the cutting action.
23. Maintain a balanced stance at all times so that you do not fall or lean against moving parts. Do not overreach or
use excessive force to perform any machine operation. Never force the cutting action.
24. Use the right tool at the correct speed and feed rate. Do not force a tool or attachment to do a job for which it
was not designed. The right tool will do the job better and more safely.
25. Use recommended accessories; improper accessories may be hazardous.
26. Maintain tools with care. Keep cutting tools sharp and clean for the best and safest performance. Follow
instructions for lubricating and changing accessories.
27. Do not attempt to adjust or remove tools during operation.
28. Never stop a rotating chuck or workpiece with your hands.
29. Choose a low spindle speed when working unbalanced workpieces, and for threading and tapping operations.
30. Do not exceed the maximum speed of the workholding device.
31. Do not exceed the clamping capacity of the chuck.
32. Workpieces longer than 3 times the chucking diameter must be supported by the tailstock or a steady rest.
33. Avoid small chuck diameters with large turning diameters.
34. Avoid short chucking lengths and small chucking contact.
35. Turn off the machine and disconnect from power before cleaning. Use a brush to remove shavings or debris —
do not use your hands.
36. Do not stand on the machine. Serious injury could occur if the machine tips over.
37. Never leave the machine running unattended. Turn the power off and do not leave the machine until moving
parts come to a complete stop.
38. Remove loose items and unnecessary work pieces from the area before starting the machine.
39. Do not operate the lathe in flammable or explosive environments. Do not use in a damp environment or expose
to rain.
Familiarize yourself with the following safety notices used in thismanual:
This means that if precautions are not heeded, it may result in minor injury and/or possible
machine damage.
This means that if precautions are not heeded, it may result in serious injury or possibly even
death.

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4.0 Specifications
Model Number............................................................................GH-2680ZH.......................................GH-26120ZH
Stock Number....................................................................................321860................................................321890
General Capacities:
Maximum Swing over Bed.....................................................26” (660 mm).......................................26” (660 mm)
Maximum Swing over Cross Slide....................................16-1/2” (420 mm).................................16-1/2” (420 mm)
Maximum Swing Through Gap...............................................34” (870 mm).......................................34” (870 mm)
Length of Gap.................................................................8-1/32” (204 mm).................................8-1/32” (204 mm)
Distance between Centers...................................................80” (2030 mm)...................................120” (3050 mm)
Width of Bed..........................................................................16” (405mm)........................................16” (405mm)
Motors and Electrical:
Main Motor.........................................................................TEFC Induction................................... TEFC Induction
Horsepower....................................................................10 HP (7.5kW).....................................10 HP (7.5kW)
Phase...........................................................................................3 PH....................................................3 PH
Voltage..........................................................230/460V (prewired 230V)................... 230/460V (prewired 230V)
Full Load Amps....................................................................25.4/12.7A...........................................25.4/12.7A
Cycle............................................................................................60 Hz..................................................60 Hz
Feed Motor..................................................................................Induction.............................................Induction
Horsepower................................................................................1/2 HP.................................................1/2 HP
Phase...........................................................................................3 PH....................................................3 PH
Voltage..........................................................230/460V (prewired 230V)...................230/460V (prewired 230V)
Full Load Amps....................................................................2.85/1.65A...........................................2.85/1.65A
Cycle............................................................................................60 Hz..................................................60 Hz
Coolant Pump Motor.....................................................................Induction............................................. Induction
Horsepower................................................................................1/8 HP.................................................1/8 HP
Phase...........................................................................................3 PH....................................................3 PH
Voltage..........................................................230/460V (prewired 230V)...................230/460V (prewired 230V)
Full Load Amps....................................................................0.54/0.27A...........................................0.54/0.27A
Cycle............................................................................................60 Hz..................................................60 Hz
Power Transmission.................................................................. v-belt (x 4)...........................................v-belt (x 4)
Controls circuit...........................................................................110V A.C.............................................110V A.C.
Lamp circuit .................................................................................24V A.C. ............................................ 24V A.C.
Indicators circuit.........................................................................110V A.C.............................................110V A.C.
Headstock and Spindle:
Spindle Bore.....................................................................4-1/8” (105 mm)...................................
4-1/8” (105 mm)
Spindle Mount......................................................................D1-8 Camlock..................................... D1-8 Camlock
Spindle Taper with Sleeve.....................................113mm Dia. 1:20/ MT-5...................... 113mm Dia. 1:20 / MT-5
Number of Spindle Speeds.....................................................................12....................................................... 12
Range of Spindle Speeds..................................................36 to 1600 RPM.................................. 36 to 1600 RPM
Distance Floor to Spindle Center (approx.).......................................46-1/2”................................................ 46-1/2”
3-Jaw Scroll Chuck:
Load Capacity............................................................... 661 lb(300 kg).................................... 661 lb (300 kg)
Inside Diameter............................................................4-1/8” (105 mm)...................................4-1/8” (105 mm)
4-Jaw Independent Chuck:
Load Capacity...........................................................1476 lb (669.5 kg)................................1476 lb (669.5 kg)
Inside Diameter............................................................4-7/8” (124 mm)...................................4-7/8” (124 mm)
Carriage:
Maximum Tool Size................................1-1/4” x 1-1/4” (31.75 x 31.75 mm).......1-1/4” x 1-1/4” (31.75 x 31.75mm)
Maximum Compound Rest Travel......................................5-1/2” (140 mm)...................................5-1/2” (140 mm)
Maximum Compound Rest Swivel..............................................+/- 90 deg............................................+/- 90 deg.
Maximum Cross Slide Travel......................................... 14-9/16” (370 mm)...............................14-9/16” (370 mm)
Maximum Carriage Travel...............................................68-7/8” (1750mm)...........................108-9/32” (2750 mm)

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GH-2680ZH GH-26120ZH
Gearbox:
Number of Longitudinal Feeds................................................................65....................................................... 65
Range of Longitudinal Feeds..0.0023 – 0.0937 in./rev. (0.063-2.52 mm/rev)........0.0023 – 0.0937 (0.063-2.52 mm)
Number of Cross Feeds..........................................................................63....................................................... 63
Range of Cross Feeds ............0.0010 – 0.0404 in/rev. (0.027-1.07 mm/rev)..........0.0010 – 0.404 (0.027-1.07 mm)
Number of Inch Threads.........................................................................48....................................................... 48
Range of Inch Threads...............................................................30-2 T.P.I.............................................30-2 T.P.I
Number of Metric Threads......................................................................22....................................................... 22
Range of Metric Threads ..............................................................1-14 mm..............................................1-14 mm
Number of Diametral Threads.................................................................24.......................................................24
Range of Diametral Threads........................................................56-4 D.P..............................................56-4 D.P.
Number of Modular Threads...................................................................18....................................................... 18
Range of Modular Threads..........................................................0.5-7 mm.............................................0.5-7 mm
Leadscrew Pitch..................................................................1/2” (12.7 mm).....................................1/2” (12.7 mm)
Tailstock:
Tailstock Spindle Travel ..........................................................6” (150 mm).........................................6” (150 mm)
Tailstock Taper.................................................................................. MT-5 ..................................................MT-5
Maximum Tailstock Cross Displacement..........................+/- 0.40” (10 mm).................................+/- 0.40” (10 mm)
Other:
Small Steady Rest Capacity......................................3/4” – 5” (20-125 mm)..........................3/4” – 5” (20-125 mm)
Large Steady Rest Capacity................................... 4” – 9.5” (100-240 mm)........................4” – 9.5” (100-240 mm)
Follow Rest Capacity................................................3/4” – 4” (20-100 mm)..........................3/4” – 4” (20-100 mm)
Coolant tank capacity...............................................................4 gal. (15L)..........................................4 gal. (15L)
Noise emission (idling at max. speed)
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...........................................82.4 dB............................................... 82.4 dB
Overall Dimensions.............................137-13/16”L x 53-5/32”W x 55-1/2”H........177-5/32”L x 47-1/4”W x 55-1/2”H
(3500 x 1350 x 1410 mm) (4500 x 1200 x 1410 mm)
Approximate Net Weight...............................................8532 lbs. (3870 kg)..............................9369 lbs. (4250 kg)
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Values are emission levels, not necessarily to be seen as safe operating levels. Since workplace conditions vary,
this information is only intended to allow the user to make a better estimation of the hazards involved.
The specifications in this manual were current at time of publication, but because of our policy of continuous
improvement, Walter Meier (Manufacturing) Inc., reserves the right to change specifications at any time and without
prior notice, without incurring obligations.

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5.0 Dimensions and mounting hole centers
Figure 1
Lathe Size 80 inch
(GH-2680ZH) 120 inch (GH-26120ZH)
A 2560mm (100.8 in.) 3565mm (140.4 in.)
B 3495mm (137.60 in. ) 4500mm (177.2 in.)
C 1721.5mm (67.8 in)
Table 1

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6.0 General description and nomenclature
Figure 2 – General Description (GH-2680ZH shown)
The ZH series lathe operates on a centralized
gear system. The motor power is transferred
through four v-belts to a shaft, which in turn
transmits the energy through a multi-disc friction
clutch and various gear pairs, to the spindle. The
clutch also controls the spindle’s direction of
rotation. Through clutch disengagement, the
operator can stop the spindle without turning off
the motor, which will prolong the life of the
motor.
Bed and Stand
The lathe bed (A) is made of cast iron with low
vibration and high rigidity. Two precision-ground
v-slideways (B), reinforced by supersonic fre-
quency hardening, offer precision guidance for
the carriage. The main drive motor is mounted in
the stand (C) below the gearbox.
(The GH-26120ZH model has three stands: left,
center, and right).
Headstock
The headstock (D) is cast from high grade, low
vibration cast iron. In the head, the spindle is
supported at three points; by a cylindrical roller
bearing at the front and a tapered roller bearing
and ball bearing. See section 11.0 for detailed
explanation of controls. The electrical box is
mounted to the rear of the headstock.
Feed Gearbox
The gearbox (E) is made from high quality cast
iron and is mounted to the left side of the
machine bed. This lathe adopts a three-axle
sliding common gear mechanism, together with
thread selection change mechanism, and
doubling mechanism, which enable it to cut a
comprehensive range of metric, modular and
diametral pitch threads, thus eliminating the
need for gear changes except where special
threading is required.
Carriage
The carriage assembly is composed of the
Apron, the Saddle, the Cross Slide, the
Compound Rest, and the four-way Tool Post.
Apron (F). Quick travel of the Apron for
positioning is accomplished by means of a
bed-mounted rack and pinion, operated
manually by the handwheel on the front of the
apron, or automatically by the feed direction
handle (P), which has a rapid traverse (Q).
Saddle (G). The saddle is made from high
quality cast iron and rides along the v-ways.

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Cross Slide (H). The cross-slide is mounted
on the saddle and used for cross feed
operations. It moves on a dovetailed slide
which can be adjusted for play by means of
the gibs.
Compound Rest. The compound rest (I),
which is T-slotted and mounted on the cross
slide, can be rotated 360°, allowing tapers to
be turned. The compound rest travels on
dovetailed ways, with adjustable gibs.
Four-Way Tool Post. The tool post (J) is a
turret design, mounted to the compound rest.
It holds up to four tools simultaneously, and
includes an indexing function.
Tailstock
The tailstock (K) slides on a v-way and can be
locked at any location by a clamping lever. The
tailstock has a heavy duty quill with a No. 5
Morse Taper and etched graduation scale. The
tailstock can be offset for taper cutting, and
bearings can be adjusted for drag along the
ways.
Leadscrew and Feed Rod
The leadscrew (L) and feed rod (M) are mounted
on the front of the machine bed. They are
connected to the gearbox at the left and are
supported by bearings on both ends.
The leadscrew is used only for threading
functions. This maintains its accuracy and
prolonged service life.
Spindle Direction Control Axle (N)
Spindle rotation can be reversed by simply
moving the control lever (O) mounted at the right
of the carriage. (Allow spindle to come to a stop
before reversing.)
Travel Stops
Six stops (R) can be moved to any position
along the travel setting rod, and are secured in
place using socket head screws. The convex
surface of the stop contacts a limit switch on the
underside of the apron. The travel setting rod
can be rotated on an eccentric into six positions
to modulate the contact between stops and limit
switch.
A carriage stop (S) is also provided for manual
carriage operation.
Steady Rest
The ZH series lathes are provided with small
and large steady rests (T). A steady rest serves
as a support for shafts on the free tailstock end.
The steady rest is mounted on the bedway and
secured from below with a bolt, nut and locking
plate.
Follow Rest
The traveling follow rest (U) is mounted to the
saddle, and thus follows the movement of the
turning tool. Only two fingers are required as the
place of the third is taken by the turning tool.
The follow rest is used for turning operations on
long, slender work pieces. It prevents the work
piece from flexing under the pressure of the
cutting tool.
Work Lamp
Adjustable halogen lamp (V) with independent
on/off switch.
Coolant Nozzle (W)
Fully adjustable gooseneck; flow is regulated
through a valve lever at its base.
Foot Brake (X)
Activates a braking strap at the motor for
emergency stopping of all lathe functions.
Chuck Guard (Y)