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Light Milling Machines

Light Milling Machines AIRCRAF T ENGINEERING March, 1937 A Self-Contained Machine for Finishing Large Numbers of Small Parts H E selection of a milling machine for shaft. In place of the standard cone pulleys production milling is governed mainly for transmitting the power from the lower by the class of work to be done, and the shaft to the spindle, plain pulleys are used— quantities which can be put in hand at one two of equal size on the lower shaft, of the time. same diameter as the small step of the standard When large quantities are to be dealt with, cone, and two of equal size on the spindle, of automatic machines will probably give the th e same diameter as the large step of the most economical results. If the work allocated spindle cone. Two belts, each the width of the to a machine varies considerably in size, standar d belt, connect the lower and upper machining costs for the smaller parts will be pulleys, thus doubling the belt power and high. compensating for the lower belt-speeds. Twin belts are used as they are more easily put in Long experience in milling has proved that position than a single wide belt. when large quantities of small parts have to be machined, it pays to install small machines. The main spindle is of case-hardened chrome The Herbert No. 1 Plain Milling Machine nickel steel and is mounted on ball-and roller with hand or cam feed falls within the category bearings ; double purpose ball-bearings take of light milling machines and is a high-class th e end thrust in both directions as well as part self-contained motor-drive machine suitable for of the journal load. finishing large quantities of small parts rapidly All the main bearings are specially made and accurately. The use of roller-bearings for and are of precision typo. They have their th e spindle and ball-bearings throughout the inner and outer races clamped and are supported driving mechanism, combined with the special directly in strong housings integral with the driving arrangement, enables the remarkable column. speed range of 257 to 1,940 r.p.m. to be used. The spindle has a special taper hole with When the machine is supplied for milling steel clutch drive for arbors and cutters ; shanks a modified form of drive is furnished enabling cannot stick. slower speeds t o be obtained. The machine with The overhanging arm carries the arbor automatic feed is furnished with modified feed support having a special precision ball-bearing motion to give finer feeds than standard. Thus mounting for the outer end of the arbor. correct speeds are obtainable for cutting any On the hand feed machine the knee is moved material from steel to aluminium ; the final b y rack and pinion and the adjustable hand drive by belt ensuring a perfectly smooth finish lever, and can be clamped in position. It is t o the work. counter-balanced by a chain and weight inside The drive to the spindle is by a reversible th e column. On the automatic and cam feed flanged motor bolted to th e back of the column. machines the knee is moved by a hand crank A lever-operated switch having "forward," which operates on the elevating screw through "stop " and "reverse " positions mounted on mitre gears, the weight is carried on a ball- left-hand side of the column. An idler inside right-hand side of the column gives finger-tip thrus t bearing; a clamping screw binds the the column, adjustable by hand, facilitates control. knee firmly to the column. Adjustable stops belt-changing from one step to another and The motor, running at constant high speed, maintains correct belt tension. limit the movement in both directions. drives a cone pulley shaft inside the column When the machine is supplied with the The saddle is moved by a screw and fluted through pick-off gears which are easily accessible modified form of drive for milling steel, the hand wheel on the hand feed machine, and by through a cover in front of the column. The main motor runs at half the speed used with th e same crank that is used for elevating the three-step cone pulley drives a similar pulley th e standard drive. With this modified form knee on the automatic and cam feed machines. on the spindle. Access to the cones for moving of drive three pairs of pick-off gears are included The table of the hand feed machine is moved the belt is obtained through two doors in the for connecting the motor to the lower pulley by rack, pinion, and adjustable hand lever. Adjustable stops limit the travel of the table in both directions. The table of the automatic TABLE I and cam feed machines can be moved by a hand wheel. Saddle and table have taper gibs and GE NERAL DIMENSIONS Hand Feed Automatic Feed Ca m Feed can be clamped in position. 10" 7" Longitudinal feed .. .. .. .. .. .. .. 2" max. The automatic feed is driven by a small 3½" 3½" 3¼" Transverse adjustment .. .. .. .. .. .. ⅝" 2½" Transverse adjustment with arm brace in position .. .. flanged motor bolted to the underside of the 7 " 7" Vertical adjustment .. .. .. .. .. .. 7" saddle apron. By means of reduction gearing Maximum distance from centre of spindle to table 8 " 8" 8" .. .. 16" x 4¾" 15" x 6¾" and pick-off gears in the apron, three standard Working surface of table .. .. .. .. .. .. 18" x 5¼" Maximum stroke of table (Cam feed machine only) 2" .. .. — — rates of feeds from 3⅞ in. to 9⅞ in. per minute ½" Width of Tee-slot .. .. .. .. .. .. .. ½" ½" 2" Diameter of overhanging arm 2" can be obtained. Five rates of feed, from ½ in. .. .. .. .. .. 2" 4" Centre of spindle to underside of arm 4" 4" .. .. .. .. t o 3 in. per minute, are available when machine 3½" 3¼" 3½" 4⅞" 4⅞" 4⅞" is supplied for steel work. The control gear for Diameter of steps of cone pulleys .. .. .. .. .. 6¼" 6¼" 6½" th e feed motor is interlocked with that of main 1¾" 1¾" 1¾" Width of belt .. .. .. .. .. .. .. Horse power of main motor ¾ h.p. ¾ h.p. ¾ h.p. motor so. tha t spindle and feed motion start .. .. .. .. .. 1420 1420 1420 Speed of main motor, r.p.m. .. .. .. .. .. and stop simultaneously. The feed is dis­ Number of pick-off pears for main drive, in standard set 4 4 .. 6 6 Number of spindle speeds, with standard pick-off gears 6 engaged by a dropping worm carried in the .. 257, 400, 610, 257, 460, 610, 257 , 460, 610, Spindle speeds, r.p.m. .. .. .. .. .. .. anti-friction worm box, which ensures tha t the 820, 1080, 1940 820, 1080, 1940 820 , 1080, 1940 .. 4 4 release is positive. The table has an adjustable Number of pick-off gears for feed drive, in standard set .. .. Number of feeds with standard pick-off gears 3 .. .. .. — — stop by which the feed is disengaged auto­ Range of feeds in inches per minute .. .. .. .. — 3⅞" to 9⅞" — 12—15 matically and a lever is provided for engaging Strokes per minute (Cam feed machine) .. .. .. — — and releasing the feed by hand. Gears in the 3 ' 8" x 3 ' 8" 3 ' 8" x 3 ' 8" 3 ' 8" x 3 ' 8" Floor space occupied .. .. .. .. .. .. 1,000 lbs. Approximate net weight .. 1,100 lbs. 1,100 lbs. worm box run in an oil bath. .. .. .. .. .. 1,400 lbs. Approximate gross weight .. 1,500 lbs. 1,500 lbs. .. .. .. .. .. Th e cam feed takes the place of the regular Approximate shipping dimensions 50 cu. ft. 60 cu . ft. 60 cu . ft. .. .. .. .. automati c feed. The table is reciprocated by a The following dimensions apply only to machines filled with hand or automatic feed modified for cutting steel: cam drum driven by a separate motor. Different Speed of main motor .. .. .. .. .. .. .. .. .. .. .. .. .. .. 720 Number of pick-off gears for main drive in set .. .. .. .. .. .. .. .. .. .. .. 6 cams can be fitted to the drum to suit th e work. Number of spindle speeds with above pick-off gears .. .. .. .. .. .. .. .. .. .. 4 The maximum stroke of table is 2 in. The Spindle speeds, r.p.m. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 100, 164,310,530 Number of pick-off gears for feed drive in set (machine with auto-feed) .. .. .. .. .. .. .. 6 number of strokes per minute on the standard Number of feeds (machine with auto-feed) .. .. .. .. .. .. .. .. .. .. .. 5 Feeds in inches per minute (machine with auto-feed) machine is 12 t o 15. .. .. .. .. .. .. .. .. .. .. ½", ¾", 1¾", 1⅞", 3" http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

Light Milling Machines

Aircraft Engineering and Aerospace Technology , Volume 9 (3): 1 – Mar 1, 1937
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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb030160
Publisher site
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Abstract

AIRCRAF T ENGINEERING March, 1937 A Self-Contained Machine for Finishing Large Numbers of Small Parts H E selection of a milling machine for shaft. In place of the standard cone pulleys production milling is governed mainly for transmitting the power from the lower by the class of work to be done, and the shaft to the spindle, plain pulleys are used— quantities which can be put in hand at one two of equal size on the lower shaft, of the time. same diameter as the small step of the standard When large quantities are to be dealt with, cone, and two of equal size on the spindle, of automatic machines will probably give the th e same diameter as the large step of the most economical results. If the work allocated spindle cone. Two belts, each the width of the to a machine varies considerably in size, standar d belt, connect the lower and upper machining costs for the smaller parts will be pulleys, thus doubling the belt power and high. compensating for the lower belt-speeds. Twin belts are used as they are more easily put in Long experience in milling has proved that position than a single wide belt. when large quantities of small parts have to be machined, it pays to install small machines. The main spindle is of case-hardened chrome The Herbert No. 1 Plain Milling Machine nickel steel and is mounted on ball-and roller with hand or cam feed falls within the category bearings ; double purpose ball-bearings take of light milling machines and is a high-class th e end thrust in both directions as well as part self-contained motor-drive machine suitable for of the journal load. finishing large quantities of small parts rapidly All the main bearings are specially made and accurately. The use of roller-bearings for and are of precision typo. They have their th e spindle and ball-bearings throughout the inner and outer races clamped and are supported driving mechanism, combined with the special directly in strong housings integral with the driving arrangement, enables the remarkable column. speed range of 257 to 1,940 r.p.m. to be used. The spindle has a special taper hole with When the machine is supplied for milling steel clutch drive for arbors and cutters ; shanks a modified form of drive is furnished enabling cannot stick. slower speeds t o be obtained. The machine with The overhanging arm carries the arbor automatic feed is furnished with modified feed support having a special precision ball-bearing motion to give finer feeds than standard. Thus mounting for the outer end of the arbor. correct speeds are obtainable for cutting any On the hand feed machine the knee is moved material from steel to aluminium ; the final b y rack and pinion and the adjustable hand drive by belt ensuring a perfectly smooth finish lever, and can be clamped in position. It is t o the work. counter-balanced by a chain and weight inside The drive to the spindle is by a reversible th e column. On the automatic and cam feed flanged motor bolted to th e back of the column. machines the knee is moved by a hand crank A lever-operated switch having "forward," which operates on the elevating screw through "stop " and "reverse " positions mounted on mitre gears, the weight is carried on a ball- left-hand side of the column. An idler inside right-hand side of the column gives finger-tip thrus t bearing; a clamping screw binds the the column, adjustable by hand, facilitates control. knee firmly to the column. Adjustable stops belt-changing from one step to another and The motor, running at constant high speed, maintains correct belt tension. limit the movement in both directions. drives a cone pulley shaft inside the column When the machine is supplied with the The saddle is moved by a screw and fluted through pick-off gears which are easily accessible modified form of drive for milling steel, the hand wheel on the hand feed machine, and by through a cover in front of the column. The main motor runs at half the speed used with th e same crank that is used for elevating the three-step cone pulley drives a similar pulley th e standard drive. With this modified form knee on the automatic and cam feed machines. on the spindle. Access to the cones for moving of drive three pairs of pick-off gears are included The table of the hand feed machine is moved the belt is obtained through two doors in the for connecting the motor to the lower pulley by rack, pinion, and adjustable hand lever. Adjustable stops limit the travel of the table in both directions. The table of the automatic TABLE I and cam feed machines can be moved by a hand wheel. Saddle and table have taper gibs and GE NERAL DIMENSIONS Hand Feed Automatic Feed Ca m Feed can be clamped in position. 10" 7" Longitudinal feed .. .. .. .. .. .. .. 2" max. The automatic feed is driven by a small 3½" 3½" 3¼" Transverse adjustment .. .. .. .. .. .. ⅝" 2½" Transverse adjustment with arm brace in position .. .. flanged motor bolted to the underside of the 7 " 7" Vertical adjustment .. .. .. .. .. .. 7" saddle apron. By means of reduction gearing Maximum distance from centre of spindle to table 8 " 8" 8" .. .. 16" x 4¾" 15" x 6¾" and pick-off gears in the apron, three standard Working surface of table .. .. .. .. .. .. 18" x 5¼" Maximum stroke of table (Cam feed machine only) 2" .. .. — — rates of feeds from 3⅞ in. to 9⅞ in. per minute ½" Width of Tee-slot .. .. .. .. .. .. .. ½" ½" 2" Diameter of overhanging arm 2" can be obtained. Five rates of feed, from ½ in. .. .. .. .. .. 2" 4" Centre of spindle to underside of arm 4" 4" .. .. .. .. t o 3 in. per minute, are available when machine 3½" 3¼" 3½" 4⅞" 4⅞" 4⅞" is supplied for steel work. The control gear for Diameter of steps of cone pulleys .. .. .. .. .. 6¼" 6¼" 6½" th e feed motor is interlocked with that of main 1¾" 1¾" 1¾" Width of belt .. .. .. .. .. .. .. Horse power of main motor ¾ h.p. ¾ h.p. ¾ h.p. motor so. tha t spindle and feed motion start .. .. .. .. .. 1420 1420 1420 Speed of main motor, r.p.m. .. .. .. .. .. and stop simultaneously. The feed is dis­ Number of pick-off pears for main drive, in standard set 4 4 .. 6 6 Number of spindle speeds, with standard pick-off gears 6 engaged by a dropping worm carried in the .. 257, 400, 610, 257, 460, 610, 257 , 460, 610, Spindle speeds, r.p.m. .. .. .. .. .. .. anti-friction worm box, which ensures tha t the 820, 1080, 1940 820, 1080, 1940 820 , 1080, 1940 .. 4 4 release is positive. The table has an adjustable Number of pick-off gears for feed drive, in standard set .. .. Number of feeds with standard pick-off gears 3 .. .. .. — — stop by which the feed is disengaged auto­ Range of feeds in inches per minute .. .. .. .. — 3⅞" to 9⅞" — 12—15 matically and a lever is provided for engaging Strokes per minute (Cam feed machine) .. .. .. — — and releasing the feed by hand. Gears in the 3 ' 8" x 3 ' 8" 3 ' 8" x 3 ' 8" 3 ' 8" x 3 ' 8" Floor space occupied .. .. .. .. .. .. 1,000 lbs. Approximate net weight .. 1,100 lbs. 1,100 lbs. worm box run in an oil bath. .. .. .. .. .. 1,400 lbs. Approximate gross weight .. 1,500 lbs. 1,500 lbs. .. .. .. .. .. Th e cam feed takes the place of the regular Approximate shipping dimensions 50 cu. ft. 60 cu . ft. 60 cu . ft. .. .. .. .. automati c feed. The table is reciprocated by a The following dimensions apply only to machines filled with hand or automatic feed modified for cutting steel: cam drum driven by a separate motor. Different Speed of main motor .. .. .. .. .. .. .. .. .. .. .. .. .. .. 720 Number of pick-off gears for main drive in set .. .. .. .. .. .. .. .. .. .. .. 6 cams can be fitted to the drum to suit th e work. Number of spindle speeds with above pick-off gears .. .. .. .. .. .. .. .. .. .. 4 The maximum stroke of table is 2 in. The Spindle speeds, r.p.m. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 100, 164,310,530 Number of pick-off gears for feed drive in set (machine with auto-feed) .. .. .. .. .. .. .. 6 number of strokes per minute on the standard Number of feeds (machine with auto-feed) .. .. .. .. .. .. .. .. .. .. .. 5 Feeds in inches per minute (machine with auto-feed) machine is 12 t o 15. .. .. .. .. .. .. .. .. .. .. ½", ¾", 1¾", 1⅞", 3"

Journal

Aircraft Engineering and Aerospace Technology – Emerald Publishing

Published: Mar 1, 1937

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