Pfaff 138 Sewing Machine Instruction Book OEM

• Covers the Pfaff 138 in Model A for lightweight materials and Model B for medium-weight materials, with a needle-and-thread selection chart for matching the setup to the fabric.
• Maps each covered subclass to the correct needle system: 438 KK for -6/21, -6/21-915/02, -34/01, -45/01-915/02, -45/02-915/02, and -66/01; 130 B for the corresponding -915/05 versions; and 134 EK for -275/01 and -277/01.
• Shows bobbin winding on motor-driven and treadle-driven machines, bobbin-case and needle threading, tension balancing, stitch-length control, reverse sewing, needle-position selection, and zigzag-width locking.
• Explains the -913/52 stop-motor pedal function for needle-up or needle-down positioning, the -911/01 reverse/backtacking control, and hand- or knee-operated presser-foot lifting, including the top roller on -905 subclasses.
• Includes hook-area cleaning and hook-gib removal, lubrication-point diagrams, bevel-gear grease requirements, and troubleshooting for skipped stitches, thread breakage, needle breakage, and improper feeding.
• Documents attachment setup for standard and gimp buttonholes, cording, button sewing, quilting, roll padding and blindstitching, darning and embroidery, and bias binding, with the applicable Pfaff attachment part numbers.

Manual Identity and Intended Use

This Pfaff-branded Instruction Book is a 40-page PDF set, supplied as two 20-page files. The same operating information appears in German, English, French, and Spanish. It is suited to instructed operators and experienced sewing-machine owners handling setup, stitch formation, routine maintenance, and basic repair checks; the safety section reserves electrical-equipment work for qualified electricians or properly instructed personnel.

The manual is specific enough to prevent a common setup mistake: needle system selection depends on the full subclass number, not simply on the Pfaff 138 model name. The -915 subclasses receive separate twin-needle coverage. Their needle gauge runs from 2 mm to a version-dependent maximum of 3, 4.5, or 6 mm; -915/02 uses individually adjustable needle-holder jaws, while -915/05 uses a screw-type gauge adjustment.

Threading, Stitch Formation, and Machine Care

The operating section follows the complete thread path through the bobbin winder, bobbin case, needle-thread guides, tension discs, check spring, take-up lever, and needle. Illustrated stitch cross-sections show correct thread interlock as well as the results of excessive or insufficient upper and lower tension. Separate controls cover forward stitch length, matching reverse stitch length, left/center/right needle position, straight-stitch selection, zigzag width, and restoration of a preset zigzag width after a temporary change.

Maintenance coverage goes beyond a generic “oil regularly” note. The manual identifies the lubrication points and specifies Pfaff sewing-machine oil 280-1-120 144, or an acid-free equivalent meeting the stated viscosity and density requirements. It also calls for Pfaff soda-soap grease 280-1-120 243 on the bevel gears and varies lubrication frequency for normal, industrial, and lint-heavy or high-speed use. Hook-race cleaning includes removal of the hook gib when packed lint or jammed thread requires deeper access.

For repair diagnosis, the troubleshooting tables connect skipped stitches, broken thread, broken needles, and poor feeding to needle choice and installation, hook timing and clearance, thread-check-spring adjustment, feed-dog height and tooth condition, presser-foot pressure, and lint buildup. A severe thread jam can disturb hook timing, while a bent needle can be caught by the hook point; both faults can lead to further needle or hook damage if the machine is kept running.

Attachments, Diagrams, and Parts Coverage

The specialty-work section identifies the eyelet-end/gimp buttonhole foot 91-041 420-05 and edge guide 91-041 427-91. The guide must be swung away before the presser bar is raised and aligned so the needle cannot strike its guide sleeve - an important fitting detail that helps prevent needle and attachment damage. Cording coverage for -45/...-915/... machines gives the required needle bars, needle holder, cording foot, and cover plate, with separate component references for 438 KK and 130 B setups.

Other documented accessories include button-sewing foot 91-041 047-05, straight- and zigzag-quilting feet 91-026 242-93 and 91-041 296-93, roll-padding/blindstitching attachment 91-744 700-91, darning/embroidery cover plate 91-041 251-25, and bias binder 91-041 894-23 with foot 91-041 895-04. The number 91-041 420-05 is an accessory-foot part number, not a Pfaff 138 series designation.

Useful visual references include the oiling-point layouts, separate motor- and treadle-driven bobbin-winder arrangements, stitch-interlock and tension examples, the pedal-function chart, the buttonhole sewing layout, and a wearing-parts plate with gauge-part views and an exploded hook/shuttle assembly. Parts coverage is limited to that wearing-parts reference; this is not a complete parts catalog or a factory machine-overhaul manual. It does not contain wiring diagrams, motor repair procedures, or full internal disassembly and reassembly instructions.

Disconnect the machine from electrical power before threading, changing gauge parts, cleaning the hook area, or performing maintenance, and never operate a motor-driven installation without correctly fitted belt guar