I have had many requests for instructions and information on how to convert a machine to a hand crank. This will be brief until I can get up all the instructions and pictures.
For converting, you will need a Singer or a clone with a standard wheel shaft and a motor mount on the outside of the column.
http://www.treadleon.net/sewingmachineshop/motorboss/motorboss.html
The Singer 99s, 185Js, and the 128s are the ideal Singer for portability to events. The kids and adults think the machines are cute but they are 3/4 size, fully functioning sewing machines. They are easy to use and unlike most crank toy machines, they all sew very well. The 185Js are fun for 4-H events because they are green!
The Singer 128s are a long bobbin and shuttle machine. They have a learning curve that goes with winding the bobbin and loading the shuttle. But once mastered, they are superior to the round bobbin models because they don't tangle the threads when cranked backwards and some think they crank easier than 99s and 185Js. Also, the bobbin winder works easily with the larger sized spoked wheel.
The late model Singer 99s and the green 185Js are easily converted to hand cranks with little or no tinkering with the bobbin winder. Early model 99s require an unusual adjustment and a skinny bobbin winder tire but I don't find I need to cut a chunk of metal from the adjustment slot as described in these instructions for converting machines to hand cranks:
http://www.treadleon.net/sewingmachineshop/converting/converting.html
The reproduction spoked wheels and cranks can be purchased for about 24 dollars for a set or 12 dollars separately if you don't need a spoked wheel. The solid wheels on the machines can be notched if you have someone to do the job (see the link above). Some suppliers lap the wheels to make sure they will fit properly but if not follow these instructions (most wheels require lapping so they don't stick on the shaft):
http://www.treadleon.net/sewingmachineshop/lappingwheel/lappingwheels.html
If you find a machine without a base you will need it. The 99s don't have all 4 legs to support them up off the table. Again you will find instructions at the Treadle On site:
http://www.treadleon.net/woodshop/buildingbases/buildingbases.html
The last little change I made was to add a short shank to all the machines that would accept standard clip-on feet. I like to use the straight stitch foot with two equal width toes and a thick fridge magnet for a seam guide. The original Singer feet have a skinny right toe. I like to butt the fridge magnet right up against the presser foot and the larger toe gives a generous 1/4 to 3/8 inch seam allowance plus the magnet does not rub against the feed dogs with the wider toe.
I will later add a link to the download the instructions for the bean bags. The bags were constructed without the need for backstitching. Catherine has field tested them for 12 years. They are sturdy and easily made by children.
You can now find the tutorial for the Sew Green 4-H activity here (the tutorial includes the instructions for the beanbags):