BackgroundThe story
The 403A was sold as the “Slant-O-Matic Special”. Its manual calls it the world’s first semi-automatic sewing machine with a slant needle and gear drive. It shares the 401A’s body and cam mechanism but has no built-in patterns, so every zigzag stitch, even plain zigzag, comes from a drop-in disc. Nine Fashion Discs came with it, including the Zigzag disc.
The 404 was launched in 1958 to replace the popular 301 and 301A (singersewinginfo). It sews straight stitch only, from a diecast aluminium body with an internal motor. Buyers didn’t take to it. Quilters disliked the horizontal bobbin and the missing carrying handle, and singersewinginfo says its straight stitch was not as precise as the 301A’s. US production stopped after about two years and roughly 400,000 machines.
Sources disagree on where the 404 was made: singersewinginfo says entirely at Elizabethport, New Jersey, while oldsewingear lists the 404A as Anderson-built. A German 404G followed, which ISMACS dates to 1961–65.
ReferenceSpecification
Specification plate
- 403A years and factory
- 1958–60, Anderson, South Carolina (pungolivinghome and oldsewingear).
- 403A stitches
- Zigzag, but with no built-in patterns — it needs replaceable top-hat cams.
- 404 years
- Launched 1958, ending about 1960; serials AM837800 to AN312994, May 1958 to May 1960 (singersewinginfo). The ISMACS model list gives 1958–63.
- 404 factory
- Sources differ: singersewinginfo says it was made entirely at Elizabethport, about 400,000 in all; oldsewingear lists the 404A as Anderson-built. A German 404G was made at Karlsruhe. Sources vary
- 404 stitches
- Straight stitch only, with reverse. No carrying handle.
- Both
- Slant shank, rotary hook, Class 66 drop-in bobbin, 15x1 needle, internal gear-drive motor.
Serial numbers: 404 serials run from AM837800 to AN312994, May 1958 to May 1960 (singersewinginfo).
IdentificationHow to recognise a 403A & 404
Lift the top cover of a 403A and you won’t find a built-in stitch chart or selector like the 401A’s. Pungolivinghome notes the cover is made to hold 20 or more pattern discs.
Look under the cover for the disc spindle. Without a disc fitted, the 403A sews straight stitch only.
The 403A keeps the 401A’s left, centre and right needle positions and twin tension discs for twin-needle work.
The 404’s controls are simple: a stitch-length and reverse lever and a bobbin winder (ISMACS). There is no zigzag width lever.
The 404 has a quick-release throat plate over a horizontal drop-in bobbin (singersewinginfo).
Singersewinginfo describes a lever on the bed at the base of the pillar that lowers the feed dogs. The ISMACS model list instead describes a rising needle plate for darning and free motion.
In detailWhich one do I have?
If your slant-needle Singer has a zigzag lever but no built-in stitch selector, it is probably a 403A; if it sews straight stitch only and has no handle on top, it is probably a 404. The 403A shares the 401A’s frozen-cam-stack risk.
VersionsVersions and sub-models
| Version | What sets it apart |
|---|---|
| 403A | Anderson-built, cam-only zigzag sold as the Slant-O-Matic Special. |
| 403 | Listed by ISMACS as a tan-and-cream slant-needle zigzag with top-hat cams and an enclosed motor. |
| 404 / 404A | US straight-stitch slant-needle, launched 1958 to replace the 301A. |
| 404G | German-built at Karlsruhe (ISMACS). |
Parts and accessoriesBobbins, attachments and the parts it takes
The 403 Special manual lists nine discs: Zigzag, Arrowhead, Banner, Crescent, Icicle, Blind Stitch, Multi-Stitch, Ball Stitch and Ribbon Stitch. Discs made for the 401, 500 and 600 series also fit.
Both machines take the Class 66 drop-in bobbin in a horizontal rotary hook.
Use 15x1 needles. The 403 clamp holds one or two needles, flat side to the back and long groove towards you.
The manual lists a special-purpose foot, button foot, zipper foot, ruffler, seam guide, foot hemmer, multi-slotted binder and a darning and embroidery attachment.
ISMACS shows a separate attachment box made for the 404.
Both take slant-shank feet only. Ordinary low-shank feet won’t fit.
MaintenanceLooking after it
The 403 manual says to put a drop of Singer oil on each marked point, including under the arm top cover and in the hook raceway.
Apply a small amount of lubricant to the gear teeth, as the manual shows.
The manuals for this family say the motor needs no lubrication.
Archaicarcane finds the 403A easier to maintain and less prone to gumming than the 401A, but its followers and pillars can still stick. Free them with a solvent-bearing oil, never WD-40.
General advice from the sources listed below. If in doubt, follow your machine’s Singer manual.
Before you buyWhat to check on a used 403A & 404
In-person checks
QuestionsFrequently asked questions
Can a Singer 403A zigzag without cams?
No. Every zigzag stitch on a 403A, including plain zigzag, needs a disc. Without one it sews straight stitch only.
Do 401A and 500A cams fit the 403A?
Yes. Top-hat discs made for the 401, 500 and 600 series fit the 403A (oldsewingear; Freshwater Fibers).
Why was the Singer 404 discontinued so quickly?
Singersewinginfo says buyers disliked its horizontal bobbin and lack of a handle, and its straight stitch was not as precise as the 301A’s. US production ended after about two years.
Is the Singer 404 the same as a 301?
No. The 404 replaced the 301A but uses a drop-in Class 66 bobbin and an internal motor in a new diecast body.
Where was the Singer 404 made?
Singersewinginfo says Elizabethport, New Jersey; oldsewingear lists Anderson, South Carolina. The 404G was made at Karlsruhe, Germany.
ReferencesSources
Where sources disagree we show each figure rather than choosing one. Spotted an error? Tell us.
- pungolivinghome.com/home-2/our-collection-2/the-singers/model-403a-slant-o-matic
- www.singersewinginfo.co.uk/404a
- ismacs.net/singer_sewing_machine_company/singer-404-straight-stitch-sewing-machine.html
- www.manualslib.com/manual/683144/Singer-Slant-O-Matic-403-Special.html
- ismacs.net/singer_sewing_machine_company/singer-model-400-series-descriptions.html
- ismacs.net/singer_sewing_machine_company/model-list/classes-400-499.html
- ismacs.net/singer_sewing_machine_company/p403.html
- www.oldsewingear.com/401--403--404.html
- www.oldsewingear.com/blog/do-i-need-special-discs-for-my-401
- www.freshwaterfibers.com/2016/08/my-singer-403a-slant-o-matic.html
- archaicarcane.com/stuck-in-the-middle-frozen-slant-o-matics
Last reviewed October 2026