OK bob
My machine is a Jap copy of the famous Singer 111W series .. the 111 is the classic auto trimmers machine .. from the 1940's era . CONSEW or Seiko copied it and many of the Jap parts will interchange with SINGER.
The 111 machines are ubiquitous .. made in USA and Germany , the German version is 111G and USA is 111W ... they come in many variants ... most of them are walking foot ... this means the foot drags the work throught he machine .. eg for canvas .
Needles and most spares are very easy to buy . Mine will sew through 6 layers of 16 oz canvas .. thats about 3/8" thick !
The other classic machine widely used around here is the SINGER K6 or 132 K6 . This is a heavier machine than the 111 series and many pros use them .
I made the pullies to slow the machine down..not for torque. In factories , these machines are made for speed......speed = money . But it takes ages to adjust to the fast speed .. for a beginner its a nightmare .
The other 111 copy is the JUKI LU 563 .. considered to be the best copy .... it has a larger bobbin , which means less changing of the bobbin . The other makes like mine have a smaller bobbin ....but there are so many variations .
If the machine is overloaded or jams there is a clutch that comes in.....but I have bent a few needles trying to sew thick nylon strapping .. they are virtually indestructable .....
check this link
http://www.industrialsewmachine.com/...ngers/111w.htm
MIKE