I had a query from an Etsy-customer this week. She asked me.
"I was thinking about splitting my 4 ply wool to make 2 ply have you done this before unsure of easiest way"
I responded: "Yes I have, several times.
"The two-tone
trousers for Mad Hatter were a 4-ply tweed split. Unravel a couple of
metres and hold the remainder from undoing by spearing ball with a
needle. Pick two and two strands and hold up high to allow ball to spin
and unravel the 4-plies.
"It appears to me that spinners first join two
ends and then join the pairs to make 4ply. If you are lucky you pick the
right pairs to un-spin, so if they tangle and hesitate you should
select the alternate pairs and try again. It's not easy; you have to
unspin a couple of yards and then wind up each pair again. I roll them
up over each hand in tandem as I go. You can lean out of an upstairs window
or over the bannisters to get a longer length. Then you have to re-spin
the 2-plies. I have a spinning wheel which helps no end.
"Alternatively,
use a couple (or three) of strands of embroidery threads held together -
they are around 9m long - pull them out from the centre not the end or
they too tangle.
"Hope that helps!"