I would like to know what stitch number to put my sewing machine onto to stitch stretch material. I have a Elna 40 sewing machine regards Judy

try less down pressure to the foot

Knit fabric stretches and flexes more than woven fabrics. You probably want to add a stabilizer under the fabric when you hoop it. If you use washable stabilizer, it will disintegrate when it gets wet.

Here's a copy of your owner's manual:

ELNA 500 ELECTRONIC Manual Page 16

Although it does not show a "stretch" stitch per se, there are several that can work. Machines without any stretch stitch can simply use a zig-zag.

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A special stretch stitch is not required to sew stretchy fabric. All one needs is a zig-zag that is wide enough and close together enough to allow the fabric to stretch without breaking the stitching thread. (Test it on a piece of scrap fabric you are using, give it a good tug and see if the thread breaks.)

NOTE: be sure to use a ball-point needle. A sharp needle will tend to cut the fabric threads and your stretch fabric will eventually develop holes and runs commonly found in knits.

There doesn't appear to be a manual for your machine, however, you can usually find a manual close to your machine model and the instructions will be similar enough to suffice. Perhaps you will find one with instructions for sewing stretch fabric:

ELNA Other manuals

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I have looked but can't see a manual, but looks like push button stitch selection on front of machine, often it will be same as straight stitch, but need to take stitch width from 0 to 4

This isn't possible. There needs to be slack in the thread in the direction of the stretch in order to achieve this and there is none to speak of in a straight stitch.

The best you can do is to use one of the zig-zag types, depending on what you need to sew.

For manuals, look here: http://sewingonline.co.uk/elna-manuals.html
and here: http://www.whitesewingcenter.com/manuals.php#elna
and here: Elna Sewing Machine Instruction and Service Manuals
and here: Elna Instruction Manuals

The last link may be your best bet (scroll down the list) and whitesewingcentre.com is very also good but you'll need to state the exact machine type - there are more than one Elna Jubilee models.

A transcript from the Elna SU manual reads as follows, and the manual can be viewed on line at http://sewingonline.co.uk/instructions/elnasp/

First make a few trial runs with a scrap of material exactly as the buttonhole will be stitched, with the machine adjusted as you intend to use it.
1. Use the embroidery and buttonhole foot. It can be chnged without a screwdriver by using the fixation screw.- With the stitch width knob at "0", turn the selector to zigzag "1".
2. De-center the needle to the left.
3. Set the stitch width knob at 2, with the solid mark on top.
4. Set the stitch length dial between 1/2 and 1/4.
5. a) Mark the desired length on the material.
b) Sew the first side of the buttonhole. Stop with the needle in the material and the mark (right).
c) Raise the foot and pivot the material round the needle. Lower the foot and raise the needle.
6. a) Set the stitch width knob at 4.
b) Sew a few stitches. Raise the needle.
7. a) Set the stitch width knob at 2.
b) Sew the second side and stop just short of the length of the first. Raise the needle.
8. a) Set the stitch width knob at 4.
b) Finish off the buttonhole by sewing a few stitches. Raise the needle.
9. a) Set the stitch width knob at "0".
b) Sew a few stitches to fasten the threads, holding the material back by hand.
10. Open with the buttonhole knife, which you will find in the accessory box.

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.

I'm a bit confused, this isn't a serger machine as far as I can see. So do you mean an overcasting foot where you sew a XXXXX type stitch along the edge of the fabric? The overcasting foot just helps you to line up the fabric edge and sew over it neatly.

if you go to this page http://www.sewingpartsonline.com/necchi-6022-sewing-machine-parts.aspx
there is an instruction manual for sale.

http://sewmamasew.com/blog2/2009/06/feet-feet-feet/ is also a great resouce on sewing machine feet with good photos of what they are used for.

Here is a video of overcasting foot in action http://www.sewingmachine-sales.co.uk/sewing_machine_info/video/34/adjustable-overcast-foot.html

If you are wanting to sew knit fabric then you just need to use a small zig zag stitch and a ball point needle to put elasticity into the seam. Or your model may have a stretch stitch, where the fabric is moved forwards and backwards during the stitch formation to add some elasticity.

Sewing elastic stretched onto fabric is a bit different with a SM, can be fiddly and hard to keep everything lined up nicely and stretched. Some machines have a little device which clips onto the needle plate in front of the needle that you can feed elastic through and tighten it to tension it, then just use a three step zig zag stitch to seam over this onto your fabric. But I don't know if Necchi has such a thing, your needle plate would need holes in front for it to clip into. Elna had these on their swiss machines in the 80's but haven't seen a similar device for a while.

Hope I've answered your question and not completely misunderstood your problem. Purchasing a manual is often the best way forward when a machine is unfamilar. Or www.sewing.about.com is great resource.

Oh yes, a ballpoint needle would indeed help.

Good luck and let me know if this solves the problem.