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
LocationMultipurpose Room 2
Ownerthe Asylum
Operational Status
Latest Status
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The Singer 20U "Artisan" is one of the nicest industrial sewing machines you can hope to meet. It belongs to ???.



This is most decidedly not your grandmother's sewing machine. It is an industrial sewing machine, capable of high speed and sustained operation. Read the safety warnings below so you do not damage the machine or hurt yourself.

What is it good for? You can be much more productive with an industrial sewing machine. It can sew very fast, and is designed to run all day. The foot and knee controls let you work more efficiently. Its powerful motor will not stall or get bogged down. It happily sews through thick upholstery fabric and webbing and handles heavy (#69) thread. 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 pretty 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.


Motor works fine, machine appears to be in essentially good condition and well cared for.

Parts and Supplies Needed

  • Need a dedicated oil bottle full of "Lily White" oil specifically for industrial sewing machines. Chain it down.
  • Get these supplies to make it useful:
    1. Assortment of needles including heavier sizes, e.g. (singer) 12, 14, 16, 18, 22.
    2. Extra bobbin case or two (numbers below)
  • Need a small flat-blade screwdriver to keep in the parts drawer, for maintenance and attachment changes.
  • Need a tiny flat-blade screwdriver to keep in the parts drawer, to adjust bobbin case tension
  • Spare presser foot, zigzag type, so machine can be used when the foot gets damaged.

NOTE: The bobbin case and bobbins that came with the 20U appear to be Class 95 types, which are not correct though they appear to work OK. It would be a good idea to get the precisely correct bobbin cases and bobbins for the 20U, and move the Class 95 ones over to the Singer 281 for which they are (coincidentally!) correct.

Supply Specifications

  • Needle system is 135x65 (1955), or 134(R), 135x5, or DPx5. There are some spare needles in parts drawer.
    • (NOTE: this is the same as the 281, but don't let them get too friendly, and beware of people thinking any parts are interchangeable because they'll swap bobbins next.)
  • Bobbin is Singer p/n 55623 (for the 20U) - NOT the same as the 281 industrial.
    • 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 motor is 1/3 hp and runs constantly. You activate the machine with a clutch controlled by the treadle.
    • The motor coasts for a long time after you turn it off and it will drive the machine unexpectedly if you engage the clutch. Wait for the motor to stop before sticking your fingers in the bobbin area.
  • The needle is driven with enough force to go right through a finger. There is no need to test this for yourself.
  • The head is very heavy - use extreme care if you lift it up from the table.

To prevent damage to the machine

  • Be sure it is oiled 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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