The 500A was the top of the line, followed by the 503
The 400 series was produced before the 500's, with the 401A being the top of the line.  Followed by the 403, then the 404
Free Machine Tips & Schematics
Tip on Bobbin Usage for all Slant-O-Matics
Tip 1 on new way to thread the machine
Tip 2 on new way to thread the machine
Is your machine having problems with not making
a full zig zag, or other patterns?  Perhaps the
needle bar area is gummed up - This might help
I think I need to clarify the "new threading" of the Slant-O-Matic, as I've received a few queries on it.
This method actually started back in the mid 70's, when Singer introduced the
Knit Kit (see above) for the Slant-O-Matic.
And perhaps you are already threading your machine this way.  But if you are threading the machine per the Instruction Book, then you might wish to consider the
new method as an option, along with the use of the 66 class plastic bobbins.
500A-M - Service Manual
For: Slant-O-Matic 500A & 503
Applies To: Slant-O-Matic 401A & 403 - 404
Can apply to 431G in certain aspects only
Download Only - No Hard Copy Sent
$12.00
172336 - 66 Class Plastic Bobbins - pack of 10
Fits: Slant-O-Matic series
401A - 403 - 404 - 500A - 503
In Stock
Yes Usually ships in 2-3 business days
$6.25
163477WS - Slide Plate w/matching spring

Fits all 500A - 503 - 401A - 403 - 404 models
In Stock
No Usually ships in 2-3 business days
$15.30
172200 - General Purpose ZigZag Needle Plate
(See other notes about this plate)
Fits: Slant-O-Matic 500A - 503 - 401A - 403
Does not fit the 404
In Stock
Yes Usually ships in 2-3 business days
$16.90
Bobbin Case Removal 401 - 403 - 404 - 500A - 503
Threading 401 - 403 - 404 - 500A - 503 Parts ID
Checking Hook Point for Burr's
Improved Threading - provided w/Knit Kit
Singer 403
Threading Guide from a 403 Door Panel Plate
Singer 503
Singer 401A
Singer 500A - Rocketeer
Tip 3 on new way to thread the machine
Pattern Dial Plate from a 401A, applies to 500A also
400 Motor & Wiring
172550 - Bobbin Winder Unit
For: 500A & 503 only
Bobbin Tire replacements below
In Stock
Yes Usually ships in 2-3 business days
$38.80
Repair Manuals & Parts
172509 - Spool Pin
Fits: 500A & 503 Machines Only
In Stock
Yes Usually ships in 2-3 business days
$2.75
172512 - Spool Pin Return Spring
Fits: 500A & 503 Only
In Stock
Yes Usually ships in 2-3 business days
$5.80
174124 - Rubber Base Cushion / Foot Peg
172203 old part number
Fits all Slant-O-Matic machines
In Stock
Yes Usually ships in 2-3 business days
$1.25
15287A - Standard Bobbin Tire / Friction Ring
Slant-O-Matic's, 401A / 403 / 404
Other outside mount bobbin winder 66 / 99 /128K type
In Stock
Yes Usually ships in 2-3 business days
$1.00
172075 - Presser Foot - ZigZag
Fits: 401A, 403, 500A - 503
Note: This foot does not snap
on/off the shank like T&S machines
In Stock
Yes Usually ships in 2-3 business days
$5.50
194407-002 - Rubber Base Cushion
Singer Foot Controller
(Set of 4)
In Stock
Yes Usually ships in 2-3 business days
$10.80
196221 - Light Socket Assembly
Fits 301 - 401A - 403 - 404
& 500A & 503
In Stock
No Usually ships in 2-3 business days
$24.50
172552 - Bobbin Winder Return Spring
Fits the 500A & 503 models
In Stock
Usually ships in 2-3 business days
Yes
$4.50
153758 - Bobbin Case - New
Fits all Slant-O-Matic: 500A, 503, 401A, 403, 404
In Stock
No Usually ships in 2-3 business days
$47.95
163950S - Replacement Stop Screw & Washer
Fits: All Slant-O-Matic 401, 403, 404, 500A, 503
Goes on the end of the stitch length lever
In Stock
No Usually ships in 2-3 business days
$4.00
153758U - Bobbin Case - 2nd Time Around
Same as 153787 - 44834 - 172081 - 172081-001 - 172082-007
Pulled from working machines, used but have been in service & work
Fits all Slant-O-Matic: 500A, 503, 401A, 403, 404
In Stock
No Usually ships in 2-3 business days
$24.95
Should you find any of my
FREE information helpful -
please consider making a little
donation to support those
efforts.  $1.00 - $2.00 - $5.00
Any amount helps contribute to
supporting free knowledge
401 Schematic
404 Schematic
403 Schematic
503 Schematic
500 Schematic
163123 Needle Clamp Complete
Includes: 163123, 163431, 141453-880 & 163822
- Clamp, Screw, Gib, Thread Guide & Clamp
Screw -
Condition: Used - Like New
Will replace 172223
In Stock
Yes
Usually ships in 2-3 business days
$4.95
163289 Rotating Hook
Fits all
Auto Wind Bobbin US made T&S - 700 series
While being a Touch & Sew Hook, this will work in the
Slant-O-Matic series machines
In Stock
Yes Usually ships in 2-3 business days
$35.95
Ships Flat Rate Small Box Only
Counter
Owners Manuals
Download Only, No Hard Copy Provided - Click on picture then your back button to return to this page - very good quality
401 Owners Manual - Download Only
6.3meg in size - Click on picture to enlarge,
please do not ask what is the difference
between the 401 & 401A, click on the picture
$5.00
401A Owners Manual - Download Only
29meg in size - Click on picture to enlarge, please
do not ask what is the difference between the
401 & 401A, click on the picture
$5.00
403 Owners Manual - Download Only
13meg in size - Click on picture to enlarge
$5.00
404 Owners Manual - Download Only
5meg in size - Click on picture to enlarge
$5.00
500A Owners Manual - Download Only
14meg in size - Click on picture to enlarge
$5.00
503 Owners Manual - Download Only
15meg in size - Click on picture to enlarge
$5.00
431G Owners Manual - Download Only
12meg in size - Click on picture to enlarge
$5.00
More Manuals to be added for each specific model
& for other makes and models as available
Downloads are fairly large in size, but have been
down sampled over originals - Very Good Quality
Limited selection of 2nd hand parts - one time deal - may never be repeated once sold out - no warranty - no return items
174529 - SS Plate
Fits: 401A - 401 - 403 - 500A - 503 series
Slant-O-Matics - Used - Good Condition
Usually ships in 2-3 business days
In Stock
No
$8.00
172015 - OEM Style Slide Plate
Fits: 401A - 401 - 403 - 404 - 500A -  503
In Stock
Yes Usually ships in 2-3 business days
$6.00
172086 - Position Bracket Complete - Slant-O-Matic
2nd Hand Position bracket
Ftis: 401 - 403 - 404 - 500 - 503 either A or J series
Picture shows early & late release type
In Stock
Usually ships in 2-3 business days
Yes
$3.20
618642-008 - Used Motor with pinion gear
PA 17-8 - Used Motor, tested, in good working condition
Fits: All 600 series 626-628-636 638-646-648...etc
Does not fit 620 - 630 - 640 solid state machines
Also Fits: 401A, 403, 404
In Stock
No
Usually ships in 2-3 business days
Ships Medium Flat Rate Box or
Padded Flat Rate Envelope Only
$45.00
625364-005 - Used Motor with pinion gear
PA 10-8 Used Motor, serviced and testing, good working order
Fits: 500A - 503 only
New Top Bearing, Armature & Brushes Seated
Runs good and strong
Listen to it run
In Stock
Yes
Usually ships in 2-3 business days
Ships Medium Flat Rate Box or
Padded Flat Rate Envelope Only
$55.00
172007 - Stylist Spool Pin w/red felt washer
Fits: 404 - 403 - 401A - 431G Does not fit 503 - 500A
Most All Slant-O-Matic Models &
Stylist Models
Yes Usually ships in 2-3 business days
In Stock
$1.10
Looking for Top Lids, side Cover Doors for the Slant-O-Matic - Or other hard to find parts
Try the Yahoo Sewing Groups: wefixit or singerslantsewing - Perhaps someone has a donor part available
172555 - B/W Latch Return Spring
Fits the 500A & 503 models
May also use 163641
In Stock
Yes Usually ships in 2-3 business days
$3.90
172513 - Spool Pin Felt - Vendor discontinued
Fits: 500A & 503 Only
Adhesive back - sold individually - 1 each
Once sold out, that is the end of them - 5/2017
In Stock
Yes
Usually ships in 2-3 business days
$3.40
Obsolete, discontinued, no longer available
Top Motor Bearing (196630TF) for 301 - 401
- 403 - 404 - 500 - 503 & 600 T&S's
Obsolete Part
In Stock
Yes Usually ships in 2-3 business days
$3.95
Tip Installing the Position Bracket
170032 - Face Plate Hinge Pin
Fits: Slant-O-Matic, 600 & 700 Series T&S
In Stock
Yes Usually ships in 2-3 business days
$2.50
172563 - Light Cover complete
Fits: 500A - 503
Condition: Little rough, chipped paint,
signs of wear
In Stock
No Usually ships in 2-3 business days
$12.00
172540 - Pattern Indicator Plate
Fits: 500A
In Stock
No Usually ships in 2-3 business days
$8.50
172539 - Stitch Plate Cover
Fits: 500A - 503
Used in good condition
Model Number on the plate is for the 500A
In Stock
Usually ships in 2-3 business days
No
$8.50
172521 - Pattern Dials
Fits: 500A
In Stock
No Usually ships in 2-3 business days
$18.50
172190 - Original Stitch Length Lever
Fits: 500A - 503 - 401A - 403 - 404
Used but in good condition
May include slide block and mounting
hardware
In Stock
No Usually ships in 2-3 business days
$12.50
172020U
Pattern Cam Retention Spring
Fits all 700, 600 Series T&S
Fits all: Slant-O-Matics 401A, 403, 500A, 503
In Stock
Yes
Usually ships in 2-3 business days
$2.50
401A Supplement Service Manaul
38 Pages of 401 repair, removal, timing, all major
addjustment's required to keep your 401 running
really great.  I do not have other pages referenced,
so please do not ask about them.  This is a pretty
complete repair guide for the 401 -
Download Only
$10.00
Note: quality of guide view & print - fair +
15287-717 Bobbin Tire / Friction Ring
Fits: 500A/503 & T&S models with top wind
bobbin - Just a touch smaller than 15287A
Good fit for Slant-O-Matic 500A / 503
Order is for 1 Tire - not 2 as pictured
In Stock
Yes Usually ships in 2-3 business days
$1.10
988274-104 - Foot Control & Cord
Fits: 500A - 503
Fits other models, reference
page 3 of the foot
controller page
In Stock
Yes Usually ships in 2-3 business days
$49.90
TNT Repair Time