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Singer 491D, Service Manual

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Singer 491D Service Manual Download Page 5

                              DESCRIPTION

     Class 491D Machines are high speed, rotary hook, fully automatic lubricated 
long arm flat bed lockstitch machines with drop feed and hand operated reverse 
feeding mechanism. Recommended for general stitching operations on a range of 
light to heavyweight fabrics.

                            

- 1 -

                            GENERAL FEATURES

Balanced horizontal axis rotating hook. 

Pendant link feed with feed leveling hinge pins. 

Dial type stitch regulator on feed reverse lever, 

Thread take-up lever guard. Equipped with improved head end lubrication. 

Knee lifter mechanism is integral with the machine base and oil reservoir. 

Arm top cover with oil flow indicator.

The arm is provided with a seat for mounting a light fixture.

                             SPECIFICATIONS

Needle bar stroke                                      30.5 mm - 491D200AA

                                                       36.5 mm - 491D300AA

Clearance under presser foot                            7.2 mm - 491D200AA

                                                        7.9 mm - 491D300AA 

  (Maximum lift of presser foot when raised with knee lifter - 12.7 mm) 

Maximum stitch length                                  6 S.P.I. 

Maximum speed                                          5,500 S.P.M. - 491D200AA

                                                       5,000 S.P.M. - 491D300AA 

Oil                                                    SINGER* Type "C" Oil 

Bed size                                               475 mm x 178 mm

Summary of Contents for 491D

Page 1: ...SERVICE MANUAL FOR SINGER 491D SEWING MACHINE PARTS CHART FOR 491D200GA 491D300GA SEWING MACHINE ...

Page 2: ...Restored from web copy Available from Internet Archive archive org ...

Page 3: ...Form U251 1273 THE SINGER COMPANY Service Manual Machine 491D ...

Page 4: ...se Lever 6 To Time the Feed 6 To Set Feed Dog at Correct Height 7 REMOVAL AND REPLACEMENT OF PRINCIPAL ASSEMBLIES To Remove the Sewing Hook 8 To Replace Oil Filter 143042 9 To Replace the Sewing Hook 9 To Remove and Replace the Hook Shaft 10 The Oil Pump 11 To Remove and Replace the Upright Arm Shaft 12 13 To Remove and Replace the Needle Bar 13 To Remove and replace the Presser Bar 14 Needle Thre...

Page 5: ...tor on feed reverse lever Thread take up lever guard Equipped with improved head end lubrication Knee lifter mechanism is integral with the machine base and oil reservoir Arm top cover with oil flow indicator The arm is provided with a seat for mounting a light fixture SPECIFICATIONS Needle bar stroke 30 5 mm 491D200AA 36 5 mm 491D300AA Clearance under presser foot 7 2 mm 491D200AA 7 9 mm 491D300AA ...

Page 6: ...hat UPPER TIMING MARK is level with lower end of bushing Then securely tighten screw C Replace throat plate and slide plate When replacing the face plate make certain that the screw holes in the face plate gasket are aligned with the respective screw holes in the face plate avoiding injury to the gasket and consequent oil leakage TO SET CHECK SPRING HEIGHT PREPARATION Thread the machine and place ...

Page 7: ...the machine securely tighten set screw E Fig 4 Make certain thumb nut is on stud F fig 4 CHECK Tension on check spring D Fig 4 should be sufficient to ensure action at top speed but still light enough to permit it self to be drawn all the way down as take up lever approaches height of stroke before any thread is drawn through the tension discs SETTING Using a large screwdriver in slot of stud F turn...

Page 8: ...g 5 2 When presser foot is at its highest point and needle bar is at its lowest top of presser foot should clear lower end of needle bar as shown in Fig 6 SETTING Loosen clamping screw J Fig 5 Raise or lower guide bracket G as required Securely tighten screw J CAUTION Whenever guide bracket has been moved on presser bar inspect the check spring for correct setting as instructed on pages 2 and 3 G ...

Page 9: ...rance is provided between hub of hook and oil retaining collar SETTING Loosen two set screws L Fig 7 in hub of hook Then retighten one of the set screws very lightly so that the sewing hook can still be turned on the shaft Hold shaft immovable and turn hook as required to bring point of hook to center of needle as shown in Fig 7 and at the same time adjust clearance between needle and hook point a...

Page 10: ...regulating dial stopper C4 on the underside of the feed reverse lever as shown in Fig 10 CAUTION MAKE SURE the feed dog clears the front and rear edges of the throat plate slots when maximum stitch length is changed to 5 1 mm TO TIME THE FEED Before the machine leaves the factory the fear and feed lifting eccentric is set for average sewing conditions having the timing screw screw M which appears ...

Page 11: ... eccentric B4 Fig 13 Insert screwdriver into access hole in end of bed and turn hinge pin B4 as required to level the feed dog Securely tighten clamp ing screw A4 Check feed dog height It is found necessary to adjust the feed dog height due to the material being sewn and or exchanging the feed dog and throat plate it should be adjusted in the manner explained above NOTE Feed dog should not contact...

Page 12: ... near the bottom as shown in Figs 15 and 16 The sewing hook can then be re moved from the hook shaft INSTRUCTIONS FOR REMOVAL AND REPLACEMENT OF PRINCIPAL ASSEMBLIES CAUTION TO MECHANICS Machines of Class 491D are made with extreme precision in machining and assembly and the Superfinish process provides microscopically smooth bearing surfaces Therefore special care should be taken not to permit any...

Page 13: ... S making certain that the finger Y see above enters the notch W at the top of the bobbin case holder Then securely fasten the position finger by means of the screw R Replace the needle Time the sewing hook as instructed on page 5 Re place the bobbin case throat plate and slide plate TO REPLACE OIL FILTER 143042 While the sewing hook is off the shaft it is advisable to replace the oil filter 143042 F...

Page 14: ... gear While holding the two gears Z and T in mesh as instructed in Fig 17 withdraw the old hook shaft and INSERT THE NEW SHAFT 4 Replace the sewing hook as instructed on page 9 5 Make certain that set screw 1 seats over flat on the hook shaft Remove all end shake from hook shaft pushing gear T Fig 17 toward the hook on the shaft Securely tighten first set screw 1 then securely tighten the second scr...

Page 15: ...of the upright arm shaft TO REPLACE 1 Place oil pump body on underside of machine bed so that position pins G2 slip into proper holes in machine casting as shown above 2 Replace and securely tighten the three screws F2 Make certain that machine turns freely as screws are tightened 3 Carefully replace impeller E2 turning it over toward the LEFT to screw it on arm shaft see CAUTION above 4 Make cert...

Page 16: ...e re assembled in their original relative positions without difficulty if necessary 5 Loosen set screws K2 in bevel gear at upper end of upright arm shaft To loosen set screw K2 remove screw L2 in the rear of the arm and insert screwdriver through the hole 6 Make certain bevel gear at lower end of upright arm shaft is fastened securely Then while holding upper bevel gears J2 in mesh draw upright ar...

Page 17: ...TE If it becomes necessary to remove upper needle bar bushing N2 first remove screw M2 and take up lever oil guard P2 Then loosen set screw Q2 and drive bushing N2 down and out of head of machine Use a 10 mm driving pin Before replacing needle bar replace upper needle bar bushing N2 by driving it down into hole provided for it in head of the machine Make certain top of bushing N2 is level with top ...

Page 18: ...ar bushing Make sure that the O ring is placed between lifting lever link H and guide bracket G 2 Replace presser foot 3 Replace presser bar pressure regulating thumb screw R2 with presser bar guide 4 Set the presser bar at the correct height as instructed on page 4 5 Tighten screw J TO REMOVE AND REPLACE THE PRESSER BAR To remove the needle thread take up 1 Remove face plate and arm hole plug S2 ...

Page 19: ...needle bar crank as shown in Fig 21 2 Place the needle thread take up link 22 and take up A3 in the head of the machine so that the stud E3 Fig 21 in the center of the linkage slips into the hole provided for it in the needle bar crank as shown in Fig 21 3 Slip the upper end of the take up A3 through the slot provided for it in the head of the machine 4 Insert stud Y2 through needle thread take up...

Page 20: ...D NEEDLE BAR CONNECTING STUD WICK See Fig 23 Arm side shield wick may be removed after removing the face plate and the screw F3 Lift arm side shield G3 up and out of machine When replacing arm side shield wick make sure that lower end of wick drops into oil pool bereath needle bar crank and that the two upper wick loops are located as close as possible to the needle bearings at B3 Fig 24 without t...

Page 21: ...25 This will insure free passage of oil Use tweezers through the screw hole at J3 to loop the wick and bring it into positive contact with the arm shaft approximately at point M3 shown in Fig 25 NOTE DO NOT FORCE the wick leaders down too tightly against the edge L3 of oil tube as shown in Fig 26 as this will decrease the flow of oil from the arm shaft to the needle bar link and take up bearings CA...

Page 22: ...late as instructed on page 2 REMOVAL See Figs 28 to 30 1 Remove the face plate 2 Remove the arm side shield and wick and the thread take up oil guard as instructed on pages 16 and 17 3 Remove the needle bar upper needle bar bushing presser foot and presser bar as instructed on pages 13 and 14 4 Remove entire thread take up lever assembly as instructed on pages 14 and 15 5 Loosen the four screws in...

Page 23: ...inserting the temporary shaft or a drift pin make certain that every care is taken to avoid injury to the oil seal and ring in the arm shaft bushing back and consequent oil leakage 13 Finally grasp the needle bar crank end of the arm shaft firmly at the face plate end and pull the arm shaft straight out of the machine 9 Loosen the two set screws S3 Fig 28 and remove the machine pulley 10 Turn the n...

Page 24: ...he hub of the machine pulley 5 Replace and tighten the arm shaft screw R3 Test the arm shaft for freedom in rotation 6 Move feed and feed lifting eccentric X3 toward machine pulley and securely tighten feed timing screw M 7 Place the first finger of one hand on one side of the arm shaft and the first finger of the other hand on the other side of the arm shaft so that both fingers contact the bevel gear...

Page 25: ...16 ll Replace presser bar and presser foot as instructed on page 14 12 Replace the upper needle bar bushing and the needle bar as instructed on page 13 13 Replace thread take up oil guard P2 Fig 23 page 16 14 Replace arm side shield and wick as instructed on page 16 15 Replace arm top cover and tighten its four screws 16 Replace face plate and tighten its three screws as instructed on page 2 ...

Page 26: ...Copyright 1973 THE SINGER COMPANY All Rights Reserved Throughout the World ...

Page 27: ...491D200GA D300GA ...

Page 28: ...BLANK ...

Page 29: ...Form U250 Rev 1177 Rev 2 for 491 D200GA 491 D300GA A Trademark of THE SINGER COMPANY Copyright 1973 THE SINGER COMPANY All Rights Reserved Throughout the World MACHINE PARTS CHART ...

Page 30: ...BLANK ...

Page 31: ...w 504129 850 Needle Bar Bushing upper Set Screw 504129 850 Presser Bar Bushing lower Set Screw 504134 850 Feed Regulating Dial Set Screw NUMERICAL LIST OF PARTS FOR MACHINE 491D200GA PART NO DESCRIPTION 504134 850 Feed Reverse Lever Hinge Stud Collar Set Screw 504134 850 Rotating Hook Shaft Oil Retaining Collar Set Screw 2 504145 809 Oil Removing Tube Retaining Clamp Screw 505001 Arm Dowel Pin 2 5...

Page 32: ...crew Hole Plug Screw 545038 819 Arm Shaft horizontal Flanged Bushing front Oil Tube Cap Screw 545040 809 Face Plate Screw short PART NO DESCRIPTION 545043 819 Feed Lifting Rock Shaft Crank front Clamping Screw 545046 819 Feed Reverse Lever Clamping Screw 545047 850 Feed Reverse Lever Hinge Stud Cap Screw 545049 805 Oil Pump centrifugal Impeller Locking Screw 545050 805 Oil Pump centrifugal Screen ...

Page 33: ...Spring Screw Spec No 1019 549396 Rotating Hook Oil Flow Regulating Thumb Screw CAT 1901 Needle 135 x 7 14 PARTS FOR 491D300GA MACHINE WHICH DIFFER FROM 491D200GA MACHINE 125314 Tension Spring in place of 540682 142061 452 Throat Plate large needle hole for 149057 in place of 52033 452 149057 Feed Dog 21 teeth 22 teeth per inch in place of 149031 PART NO DESCRIPTION 540525 Needle Bar Bushing lower ...

Page 34: ...BLANK ...

Page 35: ...5403 549363 545876 540610 52454 504094 540619 545040 546925 149111 545901 549128 544066 505151 540673 505152 504129 505649 504063 545881 55623 505643 504084 540770 540769 505351 505355 505353 545991 505354 504087 505356 504032 545994 545990 545950 545954 549187 545951 549186 545841 CAT 1901 540663 540703 504007 504112 540702 545909 540528 545983 540524 540771 546933 149031 504051 545955 549182 545...

Page 36: ...BLANK ...

Page 37: ...04095 504002 549230 540722 540406 540720 545059 540561 545755 545037 540606 545761 52239 545036 154781 548970 146610 545872 545871 505008 545873 154983 545054 540669 545053 545868 505007 545806 545852 545949 545862 540608 154781 540544 504103 545808 545789 545987 540537 545836 545791 540538 545788 504103 545885 545890 504134 545886 545839 540716 540681 545775 540541 545949 540671 99691 540683 5458...

Page 38: ...BLANK ...

Page 39: ...45846 549183 540644 540657 540656 540652 540654 540626 540645 540625 540557 540556 545264 545072 504029 540641 545295 545047 545244 540653 540657 540649 549183 540636 549288 545181 540650 540655 545181 545863 504002 540706 540667 545765 545757 545059 540648 540642 549384 540639 540635 548091 504119 549230 540718 540695 540665 545773 540708 540612 504099 540707 505101 545799 545767 545766 540553 50...

Page 40: ...BLANK ...

Page 41: ... 545918 545915 545913 546736 545917 505402 545923 12481 142060 452 12482 452 545935 504112 540698 CAT 1901 142061 452 149057 545912 540546 540696 125314 2102 2 32758 99691 540672 540683 540684 546928 540525 540685 504118 540661 540662 540688 540662 540676 543367 543369 543417 ACCESSORIES AND AT TACHMENTS PARTS FOR 491D300GA MACHINE WHICH DIFFER FROM 491D200GA MACHINE MACHINE BASE AND OIL RESERVOIR...

Page 42: ...BLANK ...

Page 43: ...BLANK ...

Page 44: ...Copyright 1973 THE SINGER COMPANY All Rights Reserved Throughout the World ...

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