Sewing Machine -- Singer 20U Industrial

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Tools at the Asylum
Industrial Sewing Machine

General Info
Model20U 23
Mfr. Specs
Training (experimental section)
Tool SpeciesSewing Machines
(Includes rubric, training information, and testing information.)
Asylum Info
LocationFiber Arts
Ownerthe Asylum
Operational Status
Latest Status
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This machine is capable of high speed and sustained operation. Read the safety warnings below so you do not damage the machine or hurt yourself.

Its speed is very helpful on large projects such as banners, drapery, and theatrical drops.

Some other advantages and differences:

  • The knee lever raises the presser foot. This is indescribably handy.
  • The motor is much more powerful than a domestic machine, so it does not stall on thick material.
  • With more power it can tolerate much more pressure on the presser foot, improving feed reliability.
  • You can wind bobbins while sewing.
  • It is fast (2,000 stitches per minute) - faster than domestics but slower than most industrials.
  • The 20U is a zig-zag machine with controls that let you easily make interesting patterns.
  • The 20U also has a reverser for backtacking.



2018 the standard clutch motor was replaced with a servo motor, allowing for better speed control.

Parts and Supplies Needed

  • Oil specifically for industrial sewing machines
  • Small flat-blade screwdriver for maintenance and attachment changes
  • Tiny flat-blade screwdriver to adjust bobbin case tension
  • Spare presser foot, zigzag type, so machine can be used when the foot gets damaged

Supply Specifications

  • Needle system is 135x65 (1955), or 134(R), 135x5, or DPx5. T
  • Bobbin is Singer p/n 55623 (for the 20U) - NOT the same as the 281 industrial. Class 95 type bobbins are not correct though they appear to work OK.
    • Dimensions of bobbin are 21.0 mm diameter and 9.0 mm thick.
  • Bobbin case is singer p/n 541678, or 410025

Safety Warnings

You MUST be qualified and approved to use this machine. It can cause severe injury. Beware of these differences from a common domestic sewing machine:

  • The needle is driven with enough force to go right through a finger.
  • The head is very heavy - use extreme care if you lift it up from the table.

To prevent damage to the machine

  • Oil regularly. It doesn't hurt to give it an oiling if you are the first one to use it in a while.
  • The needles are unique to this machine. Be sure the needle you are installing is the correct type (system), and it is oriented correctly. The wrong needle will cause damage.
  • Never run the machine or turn the balance wheel without fabric under the presser foot, or the feed dogs will damage the presser foot which will subsequently tear fabric.
  • The bobbins (and bobbin cases) are a special type for this machine only. Do not interchange with domestics or the Singer 281.
  • If the bobbin or bobbin case does not fit easily and snap in to place securely, check if it is the correct size.
  • Turn off the motor and wait for it to stop before removing the bobbin case. It can be accessed from under the table if you don't want to lift the machine up.


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