Jet BD-920N User manual

JET
EQUIPMENT & TOOLS
OPERATOR S MANUAL
BD-920N Belt Drive Bench Lathe
(shown with optional stand)
JET EQUIPMENT & TOOLS, INC.
A WMH Company
www.jettools.com
P.O. BOX 1349
Auburn, WA 98071-1349
e-mail [email protected]
253-351-6000
Fax [phone]
M-321373 2/02

Important Information
1-YEAR
JET offers a one-year limited
LIMITED WARRANTY
warranty on this product
REPLACEMENT PARTS
Replacement parts for this tool are available directly form JET Equipment & Tools.
To place an order, call 1-800-274-6848. Please have the following information ready:
1. Visa, MasterCard, or Discover Card number
2. Expiration date
3. Part number listed within this manual
4. Shipping address other than a Post Office box.
REPLACEMENT PART WARRANTY
JET Equipment & Tools makes every effort to assure that parts meet high quality and durability
standards and warrants to the original retail consumer/purchaser of our parts that each such
part(s) to be free from defects in materials and workmanship for a period of thirty (30) days from
the date of purchase.
PROOF OF PURCHASE
Please retain your dated sales receipt as proof of purchase to validate the warranty period.
LIMITED TOOL AND EQUIPMENT WARRANTY
JET makes every effort to assure that its products meet high quality and durability standards and warrants
to the original retail consumer/purchaser of our products that each product be free from defects in materials
and workmanship as follows: 1 YEAR LIMITED WARRANTY ON THIS JET PRODUCT. Warranty does not
apply to defects due directly or indirectly to misuse, abuse, negligence or accidents, repairs or alterations
outside our facilities or to a lack of maintenance. JET LIMITS ALL IMPLIED WARRANTIES TO THE
PERIOD SPECIFIED ABOVE FROM THE DATE THE PRODUCT WAS PURCHASED AT RETAIL.
EXCEPT AS STATED HEREIN, ANY IMPLIED WARRANTIES OR MECHANTABILITY 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. JET SHALL IN NO
EVENT BE LIABLE FOR DEATH. INJURIES TO PERSONS OR PROPERY 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. To take advantage of this warranty, the product or part must be returned for examination, postage
prepaid, to an authorized service station designated by our Auburn office. Proof of purchase date and an
explanation of the complaint must accompany the merchandise. If our inspection discloses a defect, JET
will either repair or replace the product or refund the purchase price, if we cannot readily and quickly
provide a repair or replacement, if you are willing to accept such refund, JET will return repaired product or
replacement at JET’S expense, but if it is determined there is no defect, or that the defect resulted from
causes not within the scope of JET's warranty, then the user must bear the cost of storing and returning the
product. This warranty gives you specific legal rights, and you have other rights, which vary, from state to
state.
JET Equipment & Tools • P.O. Box 1349, Auburn, WA 98071-1349 • [phone]

A WARNING
1 Read and understand the entire instruction
manual before operating machine
2. Always wear approved safety glasses/face
shields while using this machine
3. Make certain the machine is properly
grounded
4 Before operating the machine, remove tie,
rings, watches, other jewelry, and roll up
sleeves above the elbows Remove all
loose clothing and confine long hair Do
NOT wear gloves,
5 Keep the floor around the machine clean
and free of scrap material, oil and grease
6 Keep machine 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
7, Do NOT over reach Maintain a balanced
stance at all times so that you do not fall or
lean against blades or other moving parts
8 Make all machine adjustments or
maintenance with the machine unplugged
from the power source
9 Use the right tool Don't force a tool or
attachment to do a job which it was not
designed for,
10, Replace warning labels if they become
obscured or removed
11, Make certain the motor switch is in the OFF
position before connecting the machine to
the power supply
12, Give your work undivided attention. Looking
around, carrying on a conversation, and
"horse-play’ 1 are careless acts that can
result m serious injury.
13 Keep visitors a safe distance from the work
area
14 Use recommended accessories; improper
accessories may be hazardous
15 Make a habit of checking to see that keys
and adjusting wrenches are removed
before turning on the machine.
16 Never attempt any operation or adjustment if
the procedure is not understood.
17. Keep fingers away from revolving parts and
cutting tools while in operation.
18 Keep belt guard in place and in working
order
19 Never force the cutting action
20 Do not attempt to adjust or remove tools
during operation.
21. Always keep cutters sharp
22. Always use identical replacement parts
when servicing.
23 Failure to comply with all of these warnings
may cause serious injury
22. WARNING: Some dust created by power
sanding, sawing, grinding, drilling and other
construction activities contains chemicals
known to cause cancer, birth defects of other
reproductive harm
Some examples of these chemicals are
• Lead from lead based paint
• crystalline silica from bricks and cement
and other masonry products, and
• arsenic and chromium from chemically-
treated lumber.
23. Your risk from those exposures 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 those dust masks that are specifically
designed to filter out microscopic particles
1

Table of Contents
Warnings.1
Table of Contents.2
Specifications.3
Contents of the Shipping Container.3
Set-Up and Preparation for Operation.3
General Description.4-6
Controls.7
Operation.8-13
Adjustments.14-16
Electrical Connections.16
Lubrication Schedule.17
Parts Lists and Breakdowns.18-41
Wiring Diagram.42
CAUTION
The three jaw chuck and the face plate have a set screw on their flanges that secures them to the
threaded spindle. Before removing the three jaw chuck or the faceplate, remove the set screw
completely from the flange. Failure to remove the set screw may cause damage to the threads on
the spindle. When installing either the three jaw chuck or the faceplate, tighten the set screw
firmly to prevent the chuck or the faceplate from coming off the spindle during operation.
The specifications in this manual are given as general information and are not binding. JET
Equipment and Tools reserves the right to effect, at any time and without prior notice, changes or
alterations to parts, fittings, and accessory equipment deemed necessary for any reason whatsoever.
2

Specifications:
Stock No.
Capacities:
Swing Over Bed.
Swing Over Cross Slide.
Distance Between Centers.
Headstock:
Hole Through Spindle.
Spindle Nose.
Taper in Spindle Nose.
Spindle Bearing Type.
Number of Spindle Speeds
Range of Spindle Speeds.
Gear Box:
Number of Longitudinal Feeds
Range of Longitudinal Feeds..
Number of Inch Threads.
Range of Inch Threads.
Number of Metric Threads.
Range of Metric Threads.
Leadscrew.
BD-920N Compound and Carriage:
.321373 Toolpost Type.Single and 4-Way
Maximum Tool Size.1/2" x 1/2"
.9" Maximum Compound Slide Travel.1-7/8"
.5-5/16" Maximum Cross Slide Travel.5"
.20" Maximum Carriage Travel.16"
Tailstock:
.25/32" Tailstock Spindle Travel.1-9/16"
1-1/2" x 8 T.P I. Diameter of Tailstock Spindle.1-1/16"
.MT-3 Taper in Tailstock Spindle.MT-2
Tapered Roller Miscellaneous:
.6 Steady Rest Capacity.1/4"'-1-1/8"
.130-2000 RPM Follow Rest Capacity.1/4"-1-7/8"
Length of Bed.32"
.27 Width of Bed.4-1/2"
.005"- 011" Height of Bed.6-5/8"
.27 Overall Dimensions.. 37-1/2"Lx19-3/4"Wx15-3/4"H
.8-56 T P.l Main Motor.3/4 HP, 1 Ph., 115V
.11 Net Weight (approx.).235 lbs.
.05-3 0 mm Shipping Weight (approx.).250 lbs
9/16"x16 T.P.I
Contents of the Shipping Container Toolbox Contents
1 Lathe
1 7" Four-Jaw Independent Chuck
1 4" Three-Jaw Universal Chuck
1 Faceplate
1 Four Way Tool Post
1 Operator's Manual
1 Warranty Card
1 Steady Rest
1 Follow Rest
1 Single Tool Holder
3 Chuck Jaws
2 Chuck Keys
1 #1 Cross Point Screwdriver
1 #1 Flat Blade Screwdriver
1 5 pcs Hex Wrench Set
1 8/10mm Open End Wrench
1 MT-2 Center
1 MT-3 Center
1 28T Gear
1 30T Gear
1 36T Gear
1 42T Gear
1 45T Gear
1 80T Gear
Set Up and Preparation for Operation
To avoid twisting the bed, make sure the location to which the lathe is bolted is absolutely flat and
level. Place a machinist’s level on the bedways and check for level side to side and front to rear
If stand mounted, the stand must be fastened to the floor.
Remove rust protected from all surfaces with kerosene, diesel oil, or a mild solvent. Do not use
gasoline, paint thinner, or lacquer thinner These will damage painted surfaces. After cleaning,
wipe with a clean, dry cloth and cover all machined surfaces with a light film or machine oil.
3

General Description
Lathe Bed
The lathe bed is made of high grade iron. By combining
high cheeks with strong cross ribs, a bed of low vibration
and rigidity is produced (Fig. 1) The two precision-
ground V-slideways, re-enforced by heat hardening and
grinding, are and accurate guide for the carriage and
tailstock. The main motor is mounted to the rear of the
bed. (Fig. 2)
Headstock
The headstock is cast from high grade, low vibration cast
iron It is bolted to the bed with four screws and uses
four adjusting screws for alignment. In the head, the
large main spindle is mounted on two precision taper
roller bearings. The hollow spindle is a Morse taper No
3 with a 25/32" bore. (Fig 3)
A quick change of the belt can be accomplished by
easing the tension on the idler (Fig 4)
To protect the machine against accidental damage, a
clutch is fitted to the reduction pulley at the 130 R.P.M
speed.

Carriage
The carriage is made from high quality cast iron. The
sliding parts are smooth ground. (Fig. 5) They fit the V
on the bed without play. The lower sliding parts can be
easily and simply adjusted. The cross slide is mounted
on the carriage and moves on a dove tailed slide. Play in
the cross slide may be adjusted with the gibs.
Move the cross slide with it's conveniently positioned
handwheel. There is a graduated collar on the
handwheel. One graduated mark equals 0.0254
millimeters or 0.001 inches. (Fig. 6)
The top slide, mounted on the cross slide, can be rotated
360°. The top slide and the cross slide travel in dove
tailed slides and have gibs, adjustable nuts, and
graduated collars.
A four way tool post is fitted on the top slide. The four
way tool post can be converted to a single tool holder
with parts enclosed in the tool box. (Fig. 6)
For accurate facing operations, the carriage can be
locked by tightening the hex socket cap screw.
(A, Fig. 7) '
Apron
The apron is mounted on the bed. A half nut is fitted to
the apron. The half nut gibs can be adjusted from the
outside.
The half nut is engaged by the half nut lever. A rack,
mounted on the bed, and a pinion operated by
handwheel on the carriage allow for quick travel of the
apron. (Fig. 8)
5
Fig. 8

Tailstock
The tailstock slides on a V way and can be clamped at
any location. (Fig 9) The tailstock has a heavy duty
spindle with a Morse taper No. 2 socket and a graduated
scale. The spindle can be clamped at any location with a
clamping lever. The spindle is moved with a handwheel
at the end of the tailstock.
Leadscrew
The leadscrew is mounted on the front of the machine
bed. It is connected to the gear box at the left for
automatic feed and is supported by bearing on both
ends. The nut and set screw on the right end are
designed to take up play on the leadscrew. (Fig. 10)
Gear Box
The gear box is made from high quality cast iron and is
mounted on the left side of the machine bed
(Fig. 11) The motor drives through nine changeable
speeds. Always raise idler to the disengaged position
when changing speeds. (A, Fig. 12)
Drive and Electrical Equipment
The main drive is provided by a single phase, A.C. motor
mounted on the rear of the lathe bed. (B, Fig. 12) The
forward-reverse switch (C, Fig. 12) is mounted on the top
of the electric box. The motor condenser is also
contained in this box.
6
Fig. 9
Fig. 10
Fig. 12

Controls
1. Forward/Reverse Switch
2. V-Belt Tension Lever
3. Longitudinal Travel Handwheel
4. Half-Nut Lever
5. Cross Slide Handwheel
6. Top Slide Handwheel
7. Longitudinal Lock Screw
8. Tool Post
9 Tailstock Spindle Handwheel
10. Tailstock Spindle Clamping Lever
11. Tailstock Locking Screw
12. Tailstock Off-Set Adjustment
13. End Gear Cover Lock Screw
14. Automatic Feed Lever
15. Gear Box Quick Change Lever
7

Operation
Tool Set-Up
The cutting angle is correct when the cutting edge is in
line with the center axis of the work piece. The correct
height of the tool can be achieved by comparing the tool
point with the point of the center mounted in the tailstock.
The correct tool height can be obtained by using shims
under the tool. (Fig. 13)
When turning, the tool has a tendency to bend under
pressure. For best results, tool overhang should be kept
to a minimum of 3/8" or less.
Manual Turning
Apron travel, cross travel, and top slide handwheels can
be operated for longitudinal or cross feeding. (Fig. 14)
Fig. 14
Longitudinal Turning with Auto-Feed
Three automatic feeds are available. (Fast = 0.011 "/rev.,
medium = 0.007"/rev., slow = 0.005"/rev.) These can be
set by altering the gear wheel combinations (See table -
Fig. 15)
By moving lever (A, Fig. 16) upward, the automatic feed
is engaged.
% ■
-fK 4 0
a-J ^ 8 0
120-J 40
b-. r 1 27
Lever
9
1 9 1
a
28 28
45 45
b
60 60
60
60
Feed
.005 .007
.007
.011
Fig.15
8

Taper Turning Using Tailstock Off-Set
Work to a side angle of 5° can be turned by off-setting
the tailstock. The angle depends on the length of the
workpiece. (Fig. 17)
To off-set the tailstock, loosen locking screw (1, Fig. 17).
Loosen the front adjusting screw (2) and take up the
same amount by tightening the rear adjusting screw (3)
until the desired taper has been reached. Tighten the
front screw to lock the tailstock in position. The
workpiece must be held between to centers and driven
by a face plate and driver dog
After taper turning, the tailstock should be returned to it's
original position. The zero position of the tailstock is
checked by turning a test piece with constant adjustment
until the piece is absolutely true.
Taper Turning by Setting the Top Slide
By angling the top slide, tapers may be turned (Fig 18)
To rotate the top slide:
Loosen two screws (1, Fig. 18), top slide can then be
rotated. A graduated scale permits accurate adjustment
of the top slide. This method can only be used for short
tapers.
Turning Between Centers
For turning between centers, it is necessary to remove
the chuck from the spindle. Fit the MT-3 center into the
spindle nose and the MT-2 center into the tailstock.
Mount the workpiece fitted with the driver dog between
the centers. The driver is driven by a catch plate or face
plate. (Fig. 19)
Note: Always use a small amount of grease on the
tailstock center to prevent center tip from overheating
9

Thread Cutting
As indicated on the threading charts below, several
different threads can be cut using the proper combination
of gears and settings. When cutting inch threads, the
half nut and threading dial (figures 20 and 21) are used
to thread in a conventional manner The thread dial
charts specifies at which point a thread can be entered
using the threading dial
Metric Thread Cutting
The only difference in metric thread cutting is the half nut
must be engaged during the entire threading process
The thread dial cannot be utilized
Set the machine up for the desired thread pitch
(according to the metric threading chart below). Start the
machine and engage the half nut When the tool
reaches the part, it will cut the initial threading pass.
When the tool reaches the end of the cut, stop the
machine by turning the motor off and at the same time
back the tool out of the part so that it clears the thread
Do not disengage the half nut lever. Reverse the motor
direction to allow the cutting tool to traverse back to the
starting point Repeat these steps until you have
obtained the desired results.
Example of Gear Set-Up to Cut 10 T.P.I. (Fig 22)
According to the chart. The gear pattern should be set
up 40-80-40, (a)60-127-(b)30 Depending on the gear
pattern your currently using these instructions may vary
1 Loosen hex socket cap screw (1) with a 5mm wrench
2. Unscrew hex socket cap screw (2) Remove washer's
(3) and gear (4) Also, remove the bushing that is
located behind the gear
3. Loosen square nut (7) to allow movement in the center
gear position.
4 Loosen square nut (5) and unscrew shaft.
5. Loosen set screw on the bushing, and slide the bushing
off of the shaft.
6 Remove the gears. Place the 60-tooth gear (6) facing
out on the shaft. Follow with the 40-tooth gear.
7. Replace the bushing and tighten the set screw
8 Re-install the shaft Tighten square nut (5). Make sure
that 40-tooth gear lines up with plastic gear (8).
9 Place 30-tooth gear in position (4) Place the bushing
on the shaft and tighten with washer's (3) and socket
head cap screw (2).
10. 127-tooth gear should mesh with upper and lower
Fig. 22
gears. Tighten square nut (7).
11. You should allow for a Je backlash in the gears.
They should not be so close and so tight that they do
not spin smoothly
Slip Clutch
To avoid overloading the drive, a safety slip clutch is
fitted in the 130 rpm position. Overloading the drive
(rattling noise) means the depth of cut is too deep and
should be reduced.
10

Lathe Accessories
Three Jaw Universal Lathe Chuck
Using this universal chuck, round, triangular, square,
hexagonal, octagonal, and twelve-cornered stock may be
clamped. (Fig. 23)
Note: new lathes have very tight fitting jaws. This is
necessary to ensure accurate clamping and long service
life. With repeated opening and closing, the jaws adjust
automatically and their operation becomes progressively
smoother.
Four Jaw Independent Lathe Chuck
This special chuck has four independently adjustable
chuck jaws. These permit the holding of asymmetrical
pieces and enable the accurate set-up of cylindrical
pieces. (Fig. 24)
Drill Chuck (Optional)
Use the drill chuck to hold centering drills and twist drills
in the tailstock. (Fig. 25)
Morse Taper Arbor (Optional)
An arbor is necessary for mounting the drill chuck in the
tailstock. It has a No. 2 Morse taper. (Fig. 25)
Live Center (Optional)
The live center is mounted in ball bearings. Its use is
highly recommended for turning at speeds in excess of
600 RPM. (Fig. 26)
11
Fig. 26

Steady Rest
The steady rest serves as a support for shafts on the
free tailstock end. For many operations, the tailstock
cannot be used as it obstructs the turning tool or drilling
tool, and therefore, must be removed from the machine.
The steady rest, which functions as an end support,
ensures chatter-free operation. The steady rest is
mounted on the bedways and is secured from below with
a locking plate. The sliding fingers require continuous
lubrication at the contact points to prevent premature
wear. (Fig. 27)
Setting the Steady Rest
1. Loosen three hex nuts (1, Fig. 28)
2. Loosen knurled screw (3, Fig. 28) and open the
sliding fingers (2, Fig. 28) until the steady rest can be
moved with its fingers around the workpiece, secure
the steady rest in position.
3. Tighten knurled screws so that fingers are snug but
not tight against the workpiece Tighten three nuts
(1, Fig. 28). Lubricate the sliding points with
machine oil.
4. When, after prolonged operation, the jaws show
wear, the tips of the fingers may be filed or remilled
Follow Rest
The follow rest is mounted on the saddle and follows the
movement of the turning tool. Only two sliding fingers
are required. The place of the third finger is taken by the
turning tool. The follow rest is used for turning
operations on long, slender workpieces. It prevents
flexing of the workpiece under pressure from the turning
tool. (Fig 29)
Set the fingers snug to the workpiece but not overly tight
Lubricate the fingers during operation to prevent
premature wear.
= s
Fig. 29
12

Four Way Tool Post
The four way tool post is mounted on the top slide and
allows four tools to be clamped. Loosen the center
clamp handle to rotate any of the four tools into position.
(Fig. 30)
Use a minimum of two clamping screws when installing a
cutting tool.
Change Gears
There are six gears with different number of teeth (28,30,
36, 42, 45, and 80). They can be combined for different
speeds and feeds as required. See chart on headstock.
(Fig. 31)
Note: The 80 tooth plastic gear is fitted to the machine
as a safety gear. Replace with a new one if damaged.
Fig. 31

Bearings and Slide Adjustment
Adjustment of the Main spindle Bearings
The main spindle bearings are adjusted at the factory If
end play becomes evident after considerable use, the
bearings may be adjusted.
Loosen set screw (1, Fig. 32) in the slotted nut (2, Fig
32) on the back of the spindle. Tighten slotted nut until
all end play is taken up. The spindle should still revolve
freely. Caution: excessive tightening or preloading will
damaged the bearings. Tighten set screw (1, Fig. 32)
Adjustment of Cross and Top Slide
Each slide is fitted with a gib strip and can be adjusted
with screws (1, Fig. 33) fitted with lock nuts (2, Fig. 33)
Loosen the lock nuts and tighten the set screws until
slide moves freely without play. Tighten lock nuts to
retain adjustment.
Adjustment of Compound Feed Screw End Float
To adjust the slides on the saddle:
Loosen screw (1, Fig. 34) and lock nut (2, Fig 34)
Adjust the nut until all play has been taken up Lock the
nut (2) with the screw (1).
Cross Slide Screw
Remove the compound slide (Fig. 35) and adjust screw
(1, Fig. 35) until the backlash between the spindle and
the nut is eliminated.
For operator convenience, the compound may be
located in two positions on the cross slide.
14
Fig. 35

Compound Slide Spindle Backlash Adjustment
Remove two screws holding the spindle bracket in
position and unscrew the spindle. Adjust the screw ring
(1, Fig. 36) until all backlash has been eliminated.
Adjustment of Half-Nut Guide
Loosen two nuts (1, Fig 37) on the right side of the
apron and adjust the control screws (2, Fig 37) until both
half nuts move freely without play. Tighten both nuts.
Replacing the Shear Pin in the Leadscrew
If the shear pin breaks, it must be replaced. (Fig. 38)
To knock out the broken pin, the hex head screw must
be loosened and the pinion removed. Take off the
sleeve and remove the broken pin from the sleeve and
the leadscrew. Replace the sleeve, line up the holes, fit
the new pin, and assemble
15
ro

Replacing the V-Belt
Loosen the screw on the top of the headstock and open
the cover. (Fig. 39)
Remove tension on the V-belt by pulling handle toward
front of the machine. (Fig. 39) Remove belt from the
pulleys and replace with new belt Move lever toward
motor to tension belt. (Fig. 40) Close cover and secure
with screw.
Caution: to avoid breaking the belt, move the tension
lever towards the front of the machine before starting.
(Fig. 41)
Electrical Connections
The BD-920N Bench Lathe is rated at 3/4 HP, 1 Ph., 60
HZ, 115V only Confirm the power at the location is the
same as the rating of the lathe before plugging the lathe
in. Do not attempt to run this lathe on any other type of
power.
The lathe must be properly grounded The lathe is
designed to be used with an outlet as in Fig. 42. If this
type of outlet is not readily available, an adapter (as in
Fig. 43) may be used temporarily until a qualified
electrician can install a grounded outlet Make sure the
grounding tab on the adapter is secured to the cover
plate screw.
Fig. 40
Fig. 42 16
Fig. 43

Lubrication Schedule
Note: lubricate all locations daily.
Grease refers to #2 tube grease.
Oil refers to 20W machine oil.
1 . 1-2 squirts oil into oil ball on gear hub.
2. Grease teeth of feed and change gears
1-2 squirts oil into oil ball on gear hub.
3 Lightly coat gear teeth with oil.
1-2 squirts oil into oil ball on gear hub
4 Wipe bedways clean and coat lightly with oil.
5. Grease rack over complete length
6. Clean and oil leadscrew over complete length.
7. 1-2 squirts oil into oil ball on leadscrew bracket
8. Lightly coat screw and guides of top slide with oil.
9 1-2 squirts oil into oil ball on top of tailstock body.
10. 1-2 squirts oil into oil ball on top of carriage.
11. 1-2 squirts oil into four oil reservoirs on gear box.
12 1-2 squirts oil into hub for feed lever.
13 1-2 squirts oil into two oil balls on apron front
17

Headstock Assembly