Altering knitwear - tips please

[Djangor]

Bought a jumper a couple of years ago because I loved the fabric - alpaca & silk and despite the very swing shape which is hugely unflattering to my curvy figure. Have worn it as an extra layer but after a clear out I was going to send it to a charity shop. Instead decided to unpick the side seams & having just pinned it together in a straight shape it already looks good even with lumps & bumps from where I've folded the fabric. Presumably I don't cut wool sections at all, just fold in but would it be best to add interfacing to the folded in edges to stop possible fraying? Front has a cable pattern which will usefully hide extra seams. Any tips please.

Meant bias binding, not interfacing - sorry.

I've done plenty of steeking in my own knitting (not cut into machine knitted fabric), and what usually works for that is a couple of parallel rows of machine stitching, followed by... the scissors. Then fold under and stitch over by hand, preferably with wool or something grippy. If seaming, you might be able to get away with something similar?

If the knitted stitches are large, you could do a crochet type steek, either side of the seam, before you cut (Look for crochet steek tutorials on YouTube before attempting). Although if I understand right, rather than steeking down the centre front, you're re-doing the side seam shaping - something like this might work? (Also it might not, so use your judgement!)

I'm wearing a hand knitted cardi today that I steeked and I covered the cut side with Petersham ribbon which I sewed on. That's often used to reinforce inside steeks and stop the edges drooping/stretching. Might be too bulky at a seam but then if it's aran or chunky knit, you might get away with it?

Thanks Joffrey. Thats hugely helpful. I confess the last knitting that I did was when I made a scarf for the dog aged about 10 and I'd never heard of steeking before your post. Have now done further research on it & feel much more confident on cutting my sweater - I'll go for the machine stitching reinforcement before cutting as I have yet to learn any crochet.

Oh fingers crossed. Try and set your machine to small stitches, and I do at least 2 rows, either side, before I cut. I think wool lends itself more to this kind of thing than alpaca/silk, and you risk ending up with a bulky seam even if it works... but so long as you're willing to risk it! You could practice on something expendable first.

If it's a chunkier knit, you should be able to get away with it. Good luck!