Pleatishness, more

Probably the simplest pleats are Pin Tucks - made with a nice bit of 19th-century technology.. here you see two pin tuck feet, with different numbers of grooves. Each needs the appropriate Twin Needle.  here I am going to get all Stern and point out that you actually do need a machine which zigzags to do this - I get a dozen enquiries a month from vintage machine-users asking if it's possible to do twin-needle work on a straight-stitch machine.. Er, No!
Anyway, digressing aside, the needles come in lots of sizes, and the feet come with lots of different sets of grooves..

So, thread your machine (all these years you were wondering what that second spool pin was for? This is it.. If the machine has three tension discs, take one thread into each side, otherwise just run the two threads side-by-side all the way through the regular thread path until you reach the needles, then thread one strand into each. It's nice to use two colours, so you can see what happens.. the bobbin is threaded in the usual way

Sew a straight line.. The fabric pops up magically between the needles and is pin-tucked automatically



Your first though may have been to wonder why the extra grooves are there - this is why - you can run the foot over the previous tuck to get closely-spaced lines

Now try some wibbles and wobbles, and crossings, and such...

And here's the back.. Tension needs work, I think..
You can also run a fine cord into the pin tuck..
More tomorrow.. Sleep well...