Cant hem unable to workout what length to start with to end up with the correct length required looking at the manual it says to take the hem and fold it over etc. but its very confusing

Select the blind hem stitch. Be sure to have the correct presser foot. Then set the stitch width so the "zag" will catch the fabric fold and set the stitch length so there are probably about 10-12 stitches per inch.

The best way to hem around a garment where the seam is going to receive stretching during wearing is with a stretch twin (double) needle.

Pretty easy, just turn up an even hem of 15mm right around the hem line (I am assuming that the bottom edge is even, if not, trim it up first), and press this hem allowance up, pin if you have a jersey that won't stay flat but many cotton knits are fine and the pressing will be enough.

Then thread up your sewing machine for twin needle sewing, refer to your manual if you have never done this before. You will thread two spools of same colour thread up on top of the machine and bring both threads through all threading points down to your needle, then one through each needle eye. Some machines will have a tension device where you can run each thread on either side of a tension disc, most will have twin spools on top of the machine to hold both spools.

You need a stretch twin needle, Schmetz do these in two sizes,
Stretch Twin
Size: 2.5/75, 4.0/75
Twin needles look like this.
I prefer the 2.5mm gap between the needles. Dont try with a regular twin, it must be stretch needle with ball point points. On some computerised machines, you need a twin needle with a blue bridge, on mechanical machines it will have a red bridge (something to do with horizonal hooks I think). But read your manual or look in your accessory box, your machine may have come with a twin needle and if so, make a note of the needle bridgecolour, then buy that one next time.

Now, set the machine for a straight stitch and place the garment right side up, with the folded hem allowance underneath on the sewing machine and align the folded edge on your 10mm marking. Start at a side seam, and stitch SLOWLY around the whole hem line until you get back to the starting point. Stop, cut your threads and press again. Voila done. I never bother to zigzag a knit fabric, just stitch it. Knits don't fray.

Just trim the fabric to the desired hem length plus one inch, then overlock around this raw edge with thread close colour match to the fabric.

You then have the choice of either stitching around with a stretch stitch on your sewing machine, or hand sewing.

Being lycra shouldn't change how you hem them unless the trouser leg is extremely close fitting and the hem seam is going to be under tension.

My first choice would be using a twin needle in straight stitch from top side but this finish can pop/break if the hem is under tension. But perfect for most knit hems.

If you hand sew then you can turn up hem allowance and put a length of fusible hemming web inside the hem allowance and press it to hold. Then do a back stitch hand sew around to hold hem in place.

If you sew with the regular sewing machine, then use either the stretch stitch or a very small zig zag, and a ball point or stretch needle.

On ready to wear you would see a coverstitch hem but your overlocker doens't have this stitch.

Adjustment of stitch length:
To select stitch length, turn the upper on the left side dial.
The larger the number, the longer the stitch. The stitch length cold be adjusted from 1 to 5 mm. Position "R" is for rolled and narrow hemmings.

Check to make sure that your plug is okay, then check that you have it set for a stitch, length and threaded right. Look at your manual

For the rolled hem: the needle is in the O2 or right position, the length is 1.5 in the rolled section- you will see this, if you look on the side of the bottom knob- you can decrease this to 1, but you have to stay within the rolled section, the width is 3.5. the stitch selector is on D, the upper looper selector is UP, the blade is engaged and the subsidiary looper is to the right. You can use a decorative thread in the upper looper- Madeira Decor, Superior Threads made for bobbin work, or YLI Pearl Crown Rayon- or use a wooly nylon for excellent coverage and not need to decrease stitch length. I usually don't need to change the length with these threads.

You can use a twin needle if you want the look of top stitching (like t-shirt).

For the blind hem, you need to baste the hem and then the fold so they do not shift as the machine stitches the hem.

I like to test each of these techniques by making a sample with the same fabric and adjusting length when using the twin needle or width and length when doing the blind hem.

Twin needle does limit the stitching to a straight stitch or a very, very narrow zig-zag - this has to be hand walked to be sure neither swing hits the presser foot or needle plate before stitching.

Hi:

You can easily trim a hem down a bit before actually hemming it up. Many patterns allow for a lot longer hem than you will ever use, but that also allows for people both for adult and childrens patterns that may need the extra length. Often if you know the length you will need before you cut the pattern you can make the adjustments before you cut the pattern. As to putting a button hole in a hem, I have done so, especially on an adults outfit where the hem will never likely need to be let down. Sometimes on a childs pattern, putting the button hole in a hem means you can not let the hem down, and as I learned with my youngest two kids, who went through growth spirts twice a year and could easily grow 3 inches in less than 3 weeks during this time, I did not want to limit my options so I never put a button home or any trim through a hem line that might limit my ability to lengthen a newly made outfit.

Hope that was helpful to you.

Patchz

The easiest way to get your threads adjusted and learn which thread does what is to thread the machine with 4 different colors. Set your tension dials at 4,3,2,1 from left to right. This is the starting point. Sew on a test strip and look at the threads. You can then adjust the correct tension dial according to the thread color. This is a great way to get the machine set back to correct tensions as well as a learning tool to figure out what each thread looks like so you can adjust later when using all one color.

Stitch length should be set between 1 to 2.