It is one of the first buttonhole makers from an older electrical Singer machine. I had one with the first machine (used) that I purchased in 1964.

That is definitely a buttonhole attachment. I am telling my age, but I had one mannnnny years ago. They work great when you learn the basics. It makes both straight and 'keyhole' buttonholes (that's the reason for the cams). Check out the site previously mentioned and you will really enjoy it.

Definitely a buttonhole maker. It is amazing how many designs they can develop for one piece of equipment. I have several for different machines and they all look different. Thank goodness my Viking does not require an attachment.

Regarding irons, I love my Rowenta, it almost makes ironing fun.

That's my guess too.

THAT IS A BUTTON HOLE MAKER... MY MOTHER'S SINGER HAS ONE JUST LIKE IT .... IT ATTACHED RIGHT TO THE PRESSURE FOOT..AND THE CAMS ARE THE DIFFERENT SIZE BUTTON HOLES

Its a buttonhole attachment. The attachment opens from the underside and the cams (metal things) fit in. The cams determing the shape of the button hole. If they don't immediately fit properly, turn the knob to move the "thingy" inside so that it sits at the proper location on the cam, close the bottom. From behind the machine, attach the forked looking thing over the screw that holds the needle in place. In other words, the green part should be in the back with the metal part closer to you.

Now put a double thickness of fabric under the metal part of the attachment. If the machine is zigzag, set your zigzag width to a medium width and set you stitch length to medium also. You may not need to do this, the attachment may regulate this for you, I don't remember.

Anyway, this is the basics of this older approach to buttonholes. I hope this helps a little.

Definitely a buttonhole maker! I still have one in green that my mom bought that I use to use with my featherweight.

Hi, My name is Zeta and this is my first attempt to answer someone. I have a buttonholer some over 50 years and it still works fine on my singer that I bought in 1957.
The attachment fits on the sewing machine in place of the pressure foot. There is also an attachment that is screwed down over the
feet of the machine. The button sizer is put into the attachment
that controls the size of button hole you want.

Zeta again, I live in Rockdale, Texas which is about 50 miles from
our capitol city of Austin, Texas.
My husband Glynn and I have 4 grown children, 7 grandsons and
l 5year old great grandson.I do lots of quilting now days or making new tops.