JET EGH-1740 Operating Instructions and Parts Manual
Operating Instructions and Parts Manual
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1700 Series Lathe
Models: EGH-1740 | EGH-1760
®
JET
427 New Sanford Road
LaVergne, Tennessee 37086
www.jettools.com
Ph.: 855-336-4032
Part No. M-EGH-1740
REV C2 07/2020
Copyright © 2015 JET
1.0 WARRANTY AND SERVICE
JET® warrants every product it sells against manufacturers’ defects. If one of our tools needs service or repair, please
contact Technical Service by calling 1-855-336-4032, 8AM to 5PM CST, Monday through Friday.
WARRANTY PERIOD
The general warranty lasts for the time period specified in the literature included with your product or on the official JET
branded website, jettools.com.
WHO IS COVERED?
This warranty covers only the initial purchaser of the product from the date of delivery.
WHAT IS COVERED?
This warranty covers any defects in workmanship or materials subject to the limitations stated below. This warranty does not
cover failures due directly or indirectly to misuse, abuse, negligence or accidents, normal wear-and-tear, improper repair,
alterations or lack of maintenance.
HOW TO GET TECHNICAL SUPPORT
Please contact Technical Service by calling 1-855-336-4032. Please note that you will be asked to provide proof of initial
purchase when calling. If a product requires further inspection, the Technical Service representative will explain and assist
with any additional action needed. JET has Authorized Service Centers located throughout the United States. For the name
of an Authorized Service Center in your area call 1-855-336-4032 or use the Service Center Locator on the JET website.
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1700 Series Lathe
MORE INFORMATION
JET® is constantly adding new products. For complete, up-to-date product information, check with your local distributor or
visit the JET website, jettools.com.
HOW STATE LAW APPLIES
This warranty gives you specific legal rights, subject to applicable state law.
LIMITATIONS ON THIS WARRANTY
JET LIMITS ALL IMPLIED WARRANTIES TO THE PERIOD OF THE LIMITED WARRANTY FOR EACH PRODUCT.
EXCEPT AS STATED HEREIN, ANY IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE EXCLUDED. SOME STATES DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED WARRANTY
LASTS, SO THE ABOVE LIMITATION MAY NOT APPLY TO YOU.
JET 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.
JET sells through distributors only. The specifications listed in JET printed materials and on official JET website are given as
general information and are not binding. JET reserves 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 JPW Industries, Inc.
NOTE: JET is a division of JPW Industries, Inc. References in this document to JET also apply to JPW Industries, Inc., or
any of its successors in interest to the JET brand.
EGH1740 | EGH1760
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2.0 TABLE OF CONTENTS
1.0 WARRANTY AND SERVICE ........................................................................................................................................2
2.0 TABLE OF CONTENTS ................................................................................................................................................4
3.0 SAFETY PRECAUTIONS ............................................................................................................................................5
4.0 INTRODUCTION ..........................................................................................................................................................6
5.0 SPECIFICATIONS ........................................................................................................................................................7
6.0 GENERAL INSTRUCTION ...........................................................................................................................................8
6.1 GENERAL LAYOUT OF LATHE ...............................................................................................................................8
6.2 FOUNDATION PLAN................................................................................................................................................9
6.3 MOVING THE MACHINE WITH A FORKLIFT ......................................................................................................10
7.0 INSTALLATION ...........................................................................................................................................................11
7.1 LEVELING THE LATHE ......................................................................................................................................... 11
7.2 CHUCK PREPARATION ........................................................................................................................................12
7.3 CHUCK AND CHUCK MOUNTING (FOR D1-6 SPINDLE) .................................................................................13
7.4 LUBRICATION CHECKS .......................................................................................................................................13
7.5 COMPLETING INSTALLATION .............................................................................................................................14
7.6 BREAK-IN PERIOD ................................................................................................................................................14
8.0 ELECTRICAL CONNECTIONS .................................................................................................................................14
9.0 OPERATION ...............................................................................................................................................................14
9.1 LATHE CONTROLS ...............................................................................................................................................14
9.2 ELECTRICAL CONTROL PANEL .........................................................................................................................15
9.3 HEADSTOCK SELECTORS ..................................................................................................................................15
9.4 THREADS AND FEEDS .........................................................................................................................................15
9.5 APRON CONTROLS ..............................................................................................................................................16
9.6 THREADING DIAL INDICATOR ............................................................................................................................17
9.7 CROSS SLIDE AND TOP SLIDE ..........................................................................................................................17
9.8 TAILSTOCK ............................................................................................................................................................18
9.9 END GEAR TRAIN .................................................................................................................................................18
9.10 DRIVING BELTS ...................................................................................................................................................18
10.0 RECOMMENDED CUTTING SPEED OF LATHE ..................................................................................................20
11.0 REPLACEMENT PARTS ..........................................................................................................................................20
12.0 WIRING DIAGRAM ....................................................................................................................................................68
WARNING: This product can expose you to chemicals including lead and cadmium which are known to the State of California to
cause cancer and birth defects or other reproductive harm. For more information go to http://www.p65warnings.ca.gov.
WARNING: Some dust, fumes and gases created by power sanding, sawing, grinding, drilling, welding and other construction ac-
tivities contain chemicals known to the State of California to cause cancer and 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 dust masks that are specifically designed to filter out microscopic particles. For more information go to http://www.p65warnings.ca.gov/ and http://www.p65warnings.ca.gov/wood.
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1700 Series Lathe
3.0 SAFETY PRECAUTIONS
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, JET®, 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. Do not use power tools in damp/wet locations or other dangerous environments. Do not expose them to rain. Keep
work area well lighted. 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.
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. Do not operate the lathe in flammable or explosive environments. Do not use in a damp environment or expose to
rain.
EGH1740 | EGH1760
5
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. Disconnect tools before servicing; when changing
accessories, such as blades, bits, cutters, and the like.
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. Secure Work. For safety and use of both hands, use clamps or a vise to hold work when practical.
33. Workpieces longer than 3 times the chucking diameter must be supported by the tailstock or a steady rest.
34. Avoid small chuck diameters with large turning diameters.
35. Avoid short chucking lengths and small chucking contact.
36. Turn off the machine and disconnect from power before cleaning. Use a brush to remove shavings or debris — do not
use your hands.
37. Do not stand on the machine. Serious injury could occur if the machine tips over.
38. Never leave the machine running unattended. Turn the power off and do not leave the machine until moving parts
come to a complete stop.
39. Remove loose items and unnecessary work pieces from the area before starting the machine.
40. Direction of feed — feed work into a blade or cutter against the direction of rotation of the blade or cutter only.
41. Installation work and electrical wiring must be done by qualified electrician in accordance with all applicable codes
and standards.
42. Tighten all locks before operating.
43. Rotate workpiece by hand before applying power.
44. Rough out workpiece before installing on faceplate.
45. Do not mount split workpiece or one containing knot.
46. Use lowest speed when starting new workpiece.
Familiarize yourself with the following safety notices used in this manual:
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.
4.0 INTRODUCTION
This manual is provided by JET® covering the safe operation and maintenance procedures for a JET Model EGH-1740
and EGH-1760. This manual contains instructions on installation, safety precautions, general operating procedures,
maintenance instructions and parts breakdown. Your machine has been designed and constructed to provide years of
trouble-free operation if used in accordance with the instructions as set forth in this document.
If there are questions or comments, please contact your local supplier or JET. JET can also be reached at our web site:
www.jettools.com. Retain this manual for future reference. If the machine transfers ownership, the manual should accompany it.
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1700 Series Lathe
5.0 SPECIFICATIONS
MODEL EGH-1740 EGH-1760
STOCK NUMBER 892100 892150
CAPACITY
Swing over Bed 17 in.
Swing over Cross Slide 11 in.
Distance between Centers 40 in.
BED
Width of Bed 12 in.
Swing Through Gap 24-1/4 in.
Length of Gap 7-2/3 in.
HEADSTOCK
Spindle Mount D1-6
Spindle Bore 3-1/8 in.
Number of spindle speeds 12
Range of spindle speeds 36-1800 R.P.M
Spindle Taper MT-5
CROSS SLIDE
Cross Slide Travel 9-1/4 in.
Top Slide Travel 6-2/7 in.
TAIL STOCK
Tailstock Spindle Travel 5 in.
Tailstock Diameter 2-1/3 in.
Taper in Tailstock Spindle MT-4
THREADS AND FEEDS
Longitudinal feeds (IPR) 0.0015-0.04”
Cross feeds (IPR) 0.00075-0.02”
Inch threads Number/Range (45) 2-72”
Metric threads Number/Range (39) 0.2-14mm
D.P. threads Number/Range (21) 8-44
M.P. threads Number/Range (18) 0.3-3.5
ELECTRICS
Motor
Coolant Pump Motor 1/8 HP
Overall Dimensions 94.5 x 44 x 69 in. 114 x 44 x 69 in.
Machine Net Weight 3,748 lbs. 4,079 lbs.
Gross Weight 4,409 lbs. 4,740 lbs.
We reserve the right to modify and improve our products.
7-1/2HP, 230/460V, 3-PH
Prewired 230V CSA/CUS Certified
EGH1740 | EGH1760
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6.0 GENERAL INSTRUCTION
6.1 GENERAL LAYOUT OF LATHE
15
14
1 2
9
3
13
4
5
6
12
7 8
9
11 10
Fig. 1
1. Headstock
2. Spindle
3. Bed
4. 4-Way tool post
5. Top slide
6. Saddle and Cross slide
7. Splash guard
9. One piece solid stand
10. Leadscrew
11. Feed shaft
12. Apron
13. Footbrake
14. Gearbox
15. End cover (Gear train)
8. Tailstock
8
1700 Series Lathe
6.2 FOUNDATION PLAN
Fig. 2 Fig. 3
Model TA TB
EGH-1740, EGH-1760 42.15” 48.25”
EGH1740 | EGH1760
Fig. 4
(One piece solid stand combined with the chip tray in the middle)
Model A B C D
EGH-1740 112.2” 87.0” 59.25” 60.43”
EGH-1760 131.88” 106.69” 78.93” 80.11”
9
6.3 MOVING THE MACHINE WITH A FORKLIFT
Preparation:
1. Ensure the power is disconnected from machine.
2. Move the saddle and tailstock to the far right side of
machine in order to achieve balance.
Hexagon socket head bolt
3. Ensure that tailstock and saddle are firmly locked
into place before attempting to move machine.
• Make sure that the minimum forklift capacity is
more than 3 tons.
• Forklift work should be done by two people, an
operator and watchman.
10
Forklift
Fig. 5
• Insert forks under the bed as close to the
headstock as possible.
• Make sure to keep the machine’s center of
gravity spread evenly across the forks.
1700 Series Lathe
Read and understand the entire contents of this
manual before attempting set-up or operation.
Failure to comply may cause serious injury.
Confirm that all suspension equipment is properly
rated and in good condition for lifting lathe. Do not
allow anyone beneath or near load while lifting.
7.0 INSTALLATION
1. Finish removing all crate material from around lathe.
2. Unbolt lathe from shipping pallet.
3. Choose a location for the lathe that is dry and
has sufficient illumination (consult OSHA or ANSI
standards for recommended lighting levels in
workshop environments).
4. Allow enough room to service the lathe on all four
sides, and to load and off-load work pieces. In
addition, if bar work is to be performed, allow enough
space for stock to extend out the headstock end. If
used in production operations, leave enough space
for stacking unfinished and finished parts.
5. The foundation must be solid to support the weight of
the machine and prevent vibration, preferably a solid
concrete floor.
6. The lathe’s center of weight is near the headstock.
Before lifting, move the tailstock and the carriage to
the right end of the bed and lock them.
7. With properly rated lifting equipment, slowly raise
lathe off shipping pallet. (see Figure 6). Do not lift
lathe by the spindle.
8. The lathe can be placed upon the cast iron leveling
pads under each foot hole, and adjusted using the
adjusting bolts with hex nuts. Or, it may be secured
to the floor using bolts placed head-down in the concrete, and using shims where needed to level the
machine. Refer to Figure 1 for mounting hole dimensions.
7.1 LEVELING THE LATHE
It is imperative that the lathe be on a level plane; that is,
where headstock and tailstock center points remain aligned
throughout the tailstock travel, with the bed ways absent of
twist and thus parallel to the operational center line.
A lathe which is not properly leveled will be inaccurate, producing tapered cuts. Also, the center point of the tailstock
will vary as it is positioned along the bed, thus requiring
constant readjustment.
9. Use a machinist’s precision level on the bed ways
both front to back and side to side, as shown in Figure 7. Take the reading in one direction every ten
inches. Make sure the ways are clean and free of any
debris before placing a level upon them.
10. Deviation over bed length (see Figure 7):
(a) Maximum 0.02/1000mm
(b) Maximum 0.04/1000mm
EGH1740 | EGH1760
Fig. 6
Fig. 7
11
11. Tighten foot screw nuts evenly to avoid distortion.
12. Leveling should be inspected occasionally, and
especially if the accuracy of the lathe begins to
diminish.
7.2 CHUCK PREPARATION
Read and understand all directions for chuck
preparation. Failure to comply may cause serious
injury and/or damage to the lathe.
Chucks are heavy; use an assistant to help remove.
The three-jaw scroll chuck is shipped pre-installed on the
lathe. It can be used for clamping cylindrical, triangular and
hexagonal stock, and has reversible jaws.
The four-jaw chuck has independently adjustable jaws,
and permits the holding of square and asymmetrical
pieces. It also enables accurate concentric set-up of
cylindrical pieces.
diameter of chuck, for easier installing and removal. Figure
8 shows an example.
To remove a chuck from the spindle:
1. Support the chuck while turning six camlocks 1/4turn counterclockwise, using the chuck wrench from
the tool box. See Figure 9.
2. Carefully remove the chuck from the spindle and
place on a firm work surface. If the spindle seems
stuck, use a mallet at various points on the back
side to help free it from the spindle.
3. Inspect the camlock studs. Make sure they have not
become cracked or broken during transit. Clean all
parts thoroughly with solvent. Also clean the spindle
and camlocks.
4. Cover all chuck jaws and the scroll inside the chuck
with #2 lithium tube grease. Cover the spindle, camlocks, and chuck body with a light film of 20W oil.
5. Lift the chuck up to the spindle nose and press onto
the spindle. Tighten in place by turning the camlocks
1/4 turn clockwise. The index mark (A, Figure 9) on
the camlock should be between the two indicator
arrows (B) when tight, as shown in Figure 9.
• If the index mark (A) is not between the two
arrows, i.e. the cam turns beyond the indicator
arrows, then remove the chuck and turn the
camlock stud IN one full turn.
• If a camlock will not engage, remove the chuck
and turn the camlock stud OUT one full turn.
6. Make sure chuck is secure on the spindle with the
camlocks correctly engaged.
Fig. 8
Before removing a chuck, place a flat piece of thick
plywood across the bedways under the chuck to prevent
damage to the bedways should the chuck fall from your
hands. Alternatively, many users make a wood chuck
cradle that sits atop the ways and accepts the specific
12
Fig. 9
1700 Series Lathe
7.3 CHUCK AND CHUCK MOUNTING (FOR D1-6 SPINDLE)
Use only high-speed chucks with these machines.
Reference mark on spindle nose and chuck
A
C
Cam release datum
Turn stud out one turn
When fitting chucks or faceplate, ensure that spindle and
chuck tapers are thoroughly cleaned and that all cams lock
in the correct positions the first.
It may be necessary to re-set the camlock studs (A) when
mounting a new chuck. To do this, remove the hexagon
socket locking screws (B) and set each stud so that the
scribed ring (C) is flush with the rear face of the chuck with the slot - lining up with the locking screw hold.
Now mount the chuck or faceplate on the spindle nose and
tighten the six cams in turn.
When fully tightened, the cam lock line on each cam
should be between the two V marks on the spindle nose.
If any of the cams do not tighten fully within these limit
marks, remove the chuck or faceplate and readjust the
stud as indicated in the illustration.
Fit and tighten the locking screw (B) at each stud before
remounting the chuck for work. A reference mark should
be made on each correctly fitted chuck or faceplate to
coincide with the reference scribed on the spindle nose.
This will assist subsequent remounting.
Note: Do not interchange chucks or faceplates
between lathes without checking for correct cam
lock.
Take careful note of speed limitations when using
faceplates; 12 inch faceplates should not be run
at speeds higher than 1000 rev/min. and 14 inch
faceplates should not be run at speeds higher
than 770 rev/min.
B
Detail of camlock stud
ass’y
Cam lock line between arrows
Turn stud in one turn
Fig. 10
7.4 LUBRICATION CHECKS
Headstock/Gearbox/Carriage, Apron/Tailstock
Before operating the machine, make the following
important checks:
• The headstock is filled to the correct level with 11.5
liters of R-32 oil, or equivalent. Check oil weekly and
change the oil every 6 months.
• The gearbox is filled to the level marked on the oil
sight window with 1.8 liters of R-68 oil, or equivalent.
Check oil weekly and change the oil every year.
• The carriage apron is filled to the level marked on
the oil sight window with 1.8 liters of R-68 oil or
equivalent. Check oil weekly and change the oil
every year.
• In addition, using an oil can, apply oil to the points
shown on lubrication diagram which require daily
oiling. Use light machine oil or way lubricant.
• Before each working shift, operate the one shot
lubrication pump to ensure adequate lubrication of
carriage slideways.
A manually operated one shot lubrication pump (A) is
incorporated into the apron. It enables the operator to
ensure that the slideways are kept adequately lubricated.
The pump should be operated before and occasionally
during the work period.
EGH1740 | EGH1760
13
Fill oil to level
A
8.0 ELECTRICAL CONNECTIONS
Electrical connections must be made by a qualified electrician in compliance with all relevant
codes. This machine must be properly grounded
while in use to help protect the operator from electrical shock and possible fatal injury.
Push during working
Fig. 11
Oil can be added or drained via hex drain plug located in
the bottom plate of the apron.
In addition to the one shot lubrication, oiler points are
provided for the saddle cross-slide and cross-slide nut.
Use a standard oil can with light machine oil or way
lubricant.
On the tailstock and tail end of leadscrew, lubrication
points are provided for daily attention from a standard oil
can.
It is recommended that all slideways, the leadscrew and
feed shaft are cleaned daily and then lightly lubricated.
7.5 COMPLETING INSTALLATION
13. Exposed metal surfaces have been coated with a
rust protectant. Remove this using a soft rag and
mild commercial solvent or kerosene. Do not use
paint thinner, gasoline, or lacquer thinner, as these
will damage painted surfaces. Cover all cleaned surfaces with a light film of SAE-20W machine oil, such
as Mobil DTE Oil Heavy Medium.
14. Open the end gear cover. Clean all components
of the end gear assembly and coat all gears with
a heavy, non-slinging grease. Close the end gear
cover. (Note: A limit switch prevents the lathe from
operating when the end gear cover is open.)
Confirm that power available at the lathe’s location is the
same rating as the lathe.
IMPORTANT: The lathe must be wired properly
and phased correctly. The spindle should rotate
counterclockwise (as viewed from the tailstock
end) while the feed rod rotates clockwise (as
viewed from the tailstock end). If the phasing
needs correction, disconnect lathe from power
source and switch any two of the three power
leads (not the green ground wire).
Make sure the lathe is properly grounded.
Main Switch
Fig. 12
9.0 OPERATION
9.1 LATHE CONTROLS
7.6 BREAK-IN PERIOD
Do not run the lathe above 560 RPM for the first six hours
of operation, to allow gears and bearings to adapt and run
smoothly.
14
A. Headstock selector
B. Electrical control
C. Gearbox (threads and feeds)
D. Apron control units, for surfacing, sliding and
1700 Series Lathe
threading controls.
E. Spindle rotation, forward, stop and reverse.
A
A
C
B
D
E
Fig. 13
9.2 ELECTRICAL CONTROL PANEL
With the exception of the lathe isolator, all electrical
controls are fitted onto the front face of the headstock.
1. WORK LAMP: On/Off switch.
2. POWER INDICATOR LIGHT: When the power is on,
the indicator light glows.
3. COOLANT PUMP: On/Off switch.
4. JOG BUTTON: Push it to move spindle slightly, this
will make spindle speed selection easier.
5. EMERGENCY STOP SWITCH: Press in order to kill
all electric power to lathe.
9.3 HEADSTOCK SELECTORS
Spindle speed selector
1. The upper two selectors on the headstock are
for spindle speed selection. There are 16 spindle
speeds, as shown on speed chart, divided into four
groups. Each speed is the result of combining the
above two selectors.
2. For instance, if 1000 r.p.m. of spindle speed is to be
chosen, then move left selector to D, and two-speed
motor switch to low range.
H-N-L selector for gearbox
1. Following each feed rate or thread pitch on gearbox
thread and feed chart, there is a prefix of either H or
L.
2. Move H-N-L selector to H or L accordingly for
feeding or threading. If this lever is positioned at
N, the headstock rotation will not be transmitted to
gearbox.
Apron orientation selector
1. This selector may affect the rotation orientation
of the lead screw, feed rod and henceforth the
movement direction of apron.
2. Right-hand arrow (toward tailstock) is used for
cutting right-hand threads. Left-hand arrow (toward
end-guard) is used for cutting left-hand threads.
1
EGH1740 | EGH1760
3
2
Fig. 15
3
2
1
9.4 THREADS AND FEEDS Gearbox, thread and feed selectors
5
4
All the thread pitches and feeds directly available from the
Fig. 14
gearbox are shown on the data plate fitted on the front
of headstock and the positioning control levers are (G1),
(G2), (G3), and (G4).
15
End gear trains diagram
The end gear train should be arranged as in the
diagram shown on the dataplate (G5) to meet threading
requirements.
Feeds:
Sliding feeds per spindle revolution range from 0.0015 to
0.04 inch (0.04mm to 1.0mm).
Surfacing feeds per spindle revolution range from 0.00075
to 0.02 inch (0.02 to 0.5mm).
Threads & Feeds
Whitworth threads:
Kinds / Range
Metric threads: 39 Kinds / 0.2–14mm
45 Kinds / 2–72 T.P.I.
G5
Fig. 17
9.5 APRON CONTROLS
In addition to handwheel traverse the carriage can be
power-operated through controls on the front of the apron.
Diametral pitch (D.P.)
worm gear
Module pitch (M.P.)
worm gear
Longitudinal feeds
Cross feeds
21 Kinds / 8–44 D.P.
18 Kinds / 0.3–3.5 M.P.
0.04–1.0mm
(0.0015" – 0.04")
0.02–0.5mm
(0.00075" – 0.02")
Gearbox Selectors
(G1) A,B,C three section selector
(G2) R,S,T three section selector
(G3) 1–8 eight section selector
(G4) W–Z five section selector
(G5) End gear train diagram
G1
G2
G3
Lever (A) is moved down for power operation and up for
manual.
The push-pull knob (B) selects power surfacing (cross
feed) when pulled out, sliding feeds are selected when the
knob is pushed right in. The adjacent push pull knob (C)
controls forward or backward feed direction.
Lever (D) is pressed downward to engage the leadscrew
nut for screwcutting. To avoid undue wear, release the nut
except when thread cutting, an interlock within the apron
prevents inadvertent engagement of levers A and D at the
same time.
Note: Do not use headstock lever for reversing
feeds except during left-hand screwcutting; Use
instead, the apron handle (C).
Feed-trip adjustment: A trip mechanism is incorporated
in the apron, enabling saddle and/or cross-slide to be
fed up to fixed stops. Trip loads can be set high or low by
adjustment of the knurled handwheel (F) on the side of the
apron. The apron handwheel may be disengaged from its
gear train during power operation or when thread cutting
by pulling the handwheel outwards to on other spring-ball
detent.
G4
16
Fig. 16
Note: This does not apply when the longitudinal
dial accessory is fitted.
1700 Series Lathe
Threading dial indicator
C
F
D
A
Handnut
Fig. 18
9.6 THREADING DIAL INDICATOR
For threads cutting:
• Tighten the handnut to retain indicator in when
engaging the indicator with the leadscrew. When not
required, release hand-nut and swing indicator out of
engagement.
• To cut threads with an even number per inch, the
leadscrew nut can be closed as any line on the dial
passes the datum mark.
• To cut threads with an odd number per inch, close
the leadscrew nut at any NUMBERED line.
• Fractional threads of 1/2 or 1/4 T.P.I. may be cut by
closing the nut at the SAME NUMBERED LINE on
each pass of the tool.
• This dial can not be used with an IMPERIAL
leadscrew to cut metric threads, D.P., M.P. which are
shown on gear box data plate. For the threads being
shown, the leadscrew nut must be kept closed. Use
apron control lever after each thread cutting when
the tool is withdrawn to original start of thread cutting
operation.
Gear 24T for Imperial leadscrew
(Gear 28T/22T for Metric leadscrew)
Fig. 20
Multi-start threads can be cut on a lathe in three ways:
1. By repositioning the compound (top) slide one pitch
forward for each start. Note that the slide is normally
set at 90º to the axis of the machine cross-slide. The
accuracy of this method depends upon the skill of
the operator.
2. By using an accurately divided driver plate and
turning the work-piece one division forward for each
start.
3. By advancing the driver gear a calculated number
of turns to advance the spindle by one pitch of the
thread to be cut. The accuracy of this method is
that of the machine.
• With all series lathes, two ratios exist between
the spindle and driver gear shift, i.e. the LOW
range where the ratio is 1:2 and the HIGH range
where the ratio is 2:1
• In order to use this method, the number of
teeth on the driver gear must be divisible by
the number of starts being cut. The driver gear
is then advanced by half this number of teeth
when in LOW range. And conversely, by twice
the number of teeth when in HIGH range.
• On the standard end gear train for this machine
the driver gear has 24 teeth; so that two, three
or four start threads, can readily be cut. For
other odd numbers of start a choice must be
made of methods 1 or 2.
End Gear Train
EGH1740 | EGH1760
Fig. 19
9.7 CROSS SLIDE AND TOP SLIDE
• A solid topslide is fitted as standard equipment to
the cross-slide mounted on a swivel base which is
marked 0-90-0-90º for accurate indexing.
• Handwheel dials are graduated in inch or metric
divisions to suit the operation.
17
C
D
A
Fig. 21
9.8 TAILSTOCK
• The tailstock can be freed for movement along the
bed by unlocking the clamp lever (A).
• Additional clamping may be obtained by tightening
the large nut (B) located in a recess below the
handwheel.
• Release this clamping nut before attempting to move
the tailstock or completion of the job that required
the extra clamping.
• The tailstock barrel can be locked by lever (C).
• The tailstock also can be offset for turning shallow
tapers or for realignment.
• Release the clamping lever (A) and adjust screw (S)
at each side of the base to move tailstock laterally
across the base.
• An indication of the offset is given by the datum
mark (D) at the tailstock end face, as picture shows.
• Tighten clamp lever after adjusting offset.
C
A
Fig. 23
9.9 END GEAR TRAIN
1. Drive from headstock to gear box is transmitted
through a gear train enclosed by the headstock
end guard. Intermediate gears are carried on an
adjustable swing-frame (M).
2. Gears must be thoroughly cleaned before fitting and
backlash must be maintained at 0.005” (0.127mm)
for correct meshing.
3. Lubricate gears regularly with thick oil or grease.
M
Hexagon
nut
(by 22mm
spanner)
Hexagon socket head bolt
(by 6mm allen wrench)
18
Fig. 24
9.10 DRIVING BELTS
1. To modify belt tension, remove the cover plate on
back of the headstock and adjust the screws (X) on
the hinged motor platform.
2. Ensure that the motor is correctly aligned with the
S
Fig. 22
lathe axis.
3. Apply light finger pressure at a point midway
1700 Series Lathe
between motor and head-stock pulleys, the resulted
depression will be about 3/4” (19mm) when under
tension.
X:Hexagon nuts
(by 24mm spanner)
Fig. 25
3/4” (19mm)
Fig. 26
EGH1740 | EGH1760
19
10.0 RECOMMENDED CUTTING SPEED OF LATHE
11.0 REPLACEMENT PARTS — EGH–1740 AND EGH–1760
Replacement parts are listed on the following pages.
To order parts or reach our service department, call
1-855-336-4032, Monday through Friday (see our
website for business hours, www.jettools.com). Having
the Model Number and Serial Number of your machine
available when you call will allow us to serve you quickly
and accurately.
®
JET
427 New Sanford Road
LaVergne, Tennessee 37086
www.jettools.com
Phone: 855-336-4032
20
1700 Series Lathe
HEADSTOCK ASSEMBLY
EGH1740 | EGH1760
21
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