For the first few years that Singer produced the model 66 sewing machine, the machines had back clamping presser feet instead of the low shank side clamping feet used on their other machines. The back clamp feet are expensive and hard to find, and you are limited as to what feet and attachments are available, so it’s nice to convert a back clamp Singer 66 to side clamp if you plan to use it regularly. These sewing machines are so old they were made before zippers were used in clothing, so you probably won’t be able to find a back clamping zipper foot. After converting to side clamp, you can use those new-fangled inventions like zipper feet, walking feet, and buttonholers with your machine. You can also use a low shank snap on foot adapter with the machine so you can use modern snap on feet.
You’ll need a side clamping presser bar from a Singer 66 parts machine. You can find these on ebay sometimes, but I found it was cheaper to just get a whole parts machine for myself. I got mine on the shopgoodwill auction site. Just make sure you get one with a side clamping presser foot.
The conversion process is pretty simple, but you might run into problems due to old hardened oil and rust. If you have any problems with stuck parts, apply some penetrating oil (such as kerosene or Liquid Wrench) and let it sit for a bit, then heat the area up with a hair dryer, which does wonders to soften up hardened oil. I don’t like to get WD-40 near my sewing machines, but if you choose to use it, make sure to clean it off thoroughly before putting the machine back together. If left on the machine, it will eventually dry to a film that will glue the parts together.
On my rusty parts machine, in order to remove the foot pressure knob, I had to wrap the knob with a strip of leather, then grip it with locking pliers. I use the locking pliers as a last resort, though, because no matter how much I try to protect the knob from damage, I usually end up scraping it up. My presser bar was a bit rusty on the ends, but after soaking it in Evapo-Rust and polishing it with metal polish it looked pretty good.
The procedure for removing the presser bar from a donor side clamping machine is basically the same as for the back clamping version, so I’ll just show the steps for the back clamping machine.
This probably goes without saying, but clean all parts and rub them down with sewing machine oil before putting them back in the machine.
- Remove the needle, just so it isn’t in the way and you don’t stab yourself. Remove the presser foot and the screw that holds it in place. On a back clamping machine, also unscrew and remove the presser foot holder that the presser foot attaches to.
- If you have a thread cutter, remove that too. To remove it, wrap it in a rag so you don’t hurt your hand, then twist it back and forth as you pull down on it.
- Lower the presser foot lever. Clean the exposed portion of the presser bar. I use rubbing alcohol on a cotton swab to remove hardened oil (be careful not to drip any alcohol on the black finish – alcohol dissolves the shellac used on it). Rub some sewing machine oil on the bar after cleaning it.
- Loosen or remove the upper screw holding the side plate in place, remove the thumbscrew, and remove the side plate.
- Unscrew and remove the foot pressure knob.
- Remove the spring through the top of the machine. There should be a washer sitting on top of the spring, so be careful not to lose it.
- Loosen or remove the set screw that holds the presser bar in place. Remove the presser bar through the top of the machine.
- Insert the side clamping presser bar down into the machine. Turn it so the flat edge on the lower end of the bar is facing the left side of the sewing machine.
- Put a general purpose presser foot on the bar. Turn the flywheel (hand wheel) until the feed dogs are in the lowered position. Adjust the position of the foot so it is straight and down against the machine bed.
- Adjust the position of horizontal bar that the set screw goes in so there is about a 2 mm gap between the lower edge of the bar and upper edge of the presser foot lifting lever (this is just based on how my machine was originally adjusted – I don’t know what the official gap should be). Insert the set screw and tighten it. Raise the presser foot lifting lever, turn the flywheel a full revolution, and make sure the needle bar doesn’t hit the presser foot. If the needle bar hits the presser foot, lower the presser foot and adjust the horizontal bar up a little further.
- Lower the presser foot lever. Insert the spring down through the top of the machine. Place the washer on top of the spring.
- Screw the foot pressure knob back in.
- Put the side plate back on.
- Remove the presser foot and the screw that holds it in place. Slide the thread cutter onto the presser bar. I used a small flat head screw driver to pry it open a little as I got it started. Put the presser foot back on.
- Test out your machine and adjust the presser foot pressure. The pressure should be just enough to feed your fabric evenly and give you stitches that are all the same length.