MIL-L-23251E
When specified (see 6.2), a temperature sensor shall be provided to monitor the
temperature o f the headstock lubricant and to shut the machine off at a preset
t e m p e r a t u r e limit below the flashpoint of the oil vapor.
3 . 4 . 4 Headstock spindle. The lathe shall have a headstock spindle to provide
a c c u r a t e mounting and rotation of a chuck,
faceplate, or collet. The spindle
type and
s h a l l be supported by roller or ball type bearings that have a size,
precision c l a s s s u i t a b l e f o r t h e a p p l i c a t i o n . Means for adjusting thrust
b e a r i n g s shall be provided. The spindle nose shall conform to the requirements
o f ANSI B5.9 and unless otherwise specified (see 6.2) shall be the type and
s i z e s p e c i f i e d i n t a b l e I . The end of the hollow spindle shall have a standard
t a p e r as specified in table I and shall conform to the requirements of ANSI
B5.10. The spindle nose shall be accurately machined to provide locating
s u r f a c e s for lathe centers, faceplates and chucks. The inner and outer surfaces
of the spindle nose on which work holding devices are mounted shall have a
surface hardness not less than Rockwell C-40.
3 . 4 . 5 S p i n d l e d r i v e . T h e spindle shall be driven through either an all gear
o r combination gear and belt drive by an electric motor as specified in table I.
The combination drive shall provide non-slip positive belt drive in the high
s p e e d range; t h e intermediate and low speeds shall be gear drive. The spindle
s h a l l operate in both directions of rotation.
3 . 4 . 6 Spindle speed change mechanism.
The spindle speed mechanism shall be
either the manual speed change typen or the variable speed type. When only one
type spindle speed change mechanism i s acceptable the mechanism shall be as
s p e c i f i e d ( s e e 6 . 2 ) . T h e shifting mechanism shall be designed so that speed
c h a n g e cannot occur u n i n t e n t i o n a l l y . E x c e p t f o r t h e v a r i a b l e s p e e d d r i v e ,
speeds s h a l l be in geometric progression, plus or minus 10 percent through the
r a n g e of speeds specified in table I. The manual speed change mechanism shall
a l l o w spindle speed changes by positioning gear shift levers or dials located on
t h e f r o n t s i d e o f t h e h e a d s t o c k . S p e e d s shall be selected by positioning the
l e v e r s as indicated on a conveniently located speed chart or by positioning a
d i r e c t r e a d i n g d i a l . The variable speed change mechanism shall permit spindle
speed adjustments to compensate for varying machine conditions. Optimum speeds
s h a l l b e o b t a i n e d b y g e a r r a n g e s e l e c t i o n and by variable speed adjustment
within the range. It shall be possible to adjust speed within a gear range
w h i l e r u n n i n g . T h e actual spindle speed in revolutions per minute (rpm) shall
be shown by a speed indicating device located convenient to the operator.
3 . 4 . 7 F e e d thread gearbox. U n l e s s otherwise specified (see 6.2), the lathe
s h a l l be equipped with a selective type, combination inch and metric gearbox to
p r o v i d e a full range of inch and metric feeds and threads as specified in table
1. The thread selections shall include the U.S. Standard Fine and Coarse Thread
Series and Pipe Threads. The cross slide feed screw and the compound slide feed
screw shall each be equipped with dials graduated to read measurements in both
t h e inch system and the metric system. Power feeds and thread leads shall be
p r o v i d e d by the totally enclosed quick change gearbox. Longitudinal and cross
f e e d s shall be provided by a feed rod from the gearbox to a feed mechanism
within the apron. Feeds shall be In either direction regardless of the
d i r e c t i o n o f s p i n d l e r o t a t i o n . Threading shall be done using a leadscrew from
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business