Views & Specifications of the Jet
BD-920N 9x20 Lathe
Last updated on
Saturday, September 03, 2011 08:28:34 AM
Eastern US Time Zone
Original Design, Jet BD-920N, Specifications, Gears, Gear Ratios, Lathe Machine Mounts
9x20 Lathe DRO X & Z1 axes Scales. 9x20 Lathe Tachometer & SFM BD-920N manual.
Original Design
Original 8"x17" (195mm x 450mm) Emco-Maier Compact 8
(Austria),
father of the current breed of 9x20 lathes.
Jet BD-920N
DRO-equipped Jet
9x20 belt drive metal lathe Model BD-920N & S-920N stand (manual).
The lathe is at the upper limits of weight & size that I could move safely down a
hill & into my lower level walkout.
| Swing Over Bed | 9" |
| Swing Over Cross Slide | 5-5/16" |
| Distance Between Centers | 20" |
| Hole Through Spindle | 25/32" (0.78125") |
| Spindle Mount | 1½ x 8 TPI |
| Spindle Taper With Sleeve | MT-3 |
| Number of Spindle Speeds | 6 |
| Range of Spindle Speeds | 130 - 2,000 RPM |
| Number of Longitudinal Feeds | 27 |
| Range of Longitudinal Feeds | 0.005 - 0.011"/rev |
| Number of Inch Threads | 27 |
| Range of Inch Threads | 8 - 56 TPI |
| Number of Metric Threads | 11 |
| Range of Metric Threads | 0.05 - 3 mm |
| Max Tool Size | ½" x ½" |
| Max Compound Slide Travel | 1⅞" |
| Max Cross Slide Travel | 5" |
| Max Carriage Travel | 16" |
| Tailstock Spindle Travel | 1-9/16" |
| Taper in Tailstock Spindle | MT-2 |
| Steady Rest Capacity | ¼" x 1⅞" |
| Follow Rest Capacity | ¼" x 1⅛" |
| Width of Bed | 4½" |
| Overall Dimensions with Stand | 37½" L x 20" W x 45" H |
| Main Motor | ¾ HP, 1 Ph 115V only |
| Weight | 235 lbs. |
| Stock Number | 321373 |
Gear
Ratios
Gear ratios for feed rates. See
Jet feed gears.
Other 9x20 lathes have additional gear
sizes that are interchangeable with the Jet
BD-920N.
Gear ratio charts differ among the machines (e.g.,
Jet vs. Enco).
I bought additional gear sizes (e.g., 120t), 127t) to have more ratios.
The OEM lathe stands are low in height to accommodate the
installation of machine mounts which can easily
add 1½ to 2 inches to the lathe's overall
height. Each mount has a steel cup with a rubber vibration absorber &
an adjustment
screw. The six holes in the stand are threaded (⅜-16 for a Jet) but I drilled them out
to 9.5 mm for
a tight fit to the Enco machine mount
M10-1.5 adjustment screws. There are four mounts under the spindle & motor
since
that is where most of the weight is located; six mounts total. They allow easy leveling of
the machine.
Check the front-to-back leveling on both the left & right sides of the
bed to insure that it is not twisted.
Addition of the machine mounts increased lathe height,
afforded adjustment, reduced noise, reduced vibration &
eliminated any
possible walking. Teflon furniture moving pads
(double-sided foam tape) are used under the feet.
Similar pads are used on the
mill/drill & the
band saw.
Machine feet manual.
