Machine Sewing Stitch Question

[dikman]

I've got my machine to a useable stage, and have been trying a few stitches on denim and scrap leather. I'm using some thread that came with it (cone of M40, which = T80) and the needles are labelled 134 PCL 100 (I'm guessing that 100 is the size). This is the setup that the previous owner used to make shoes with. When stitching, the first two or three stitches appear loose, and pulling either the top or bottom thread can pull up the other one.

So, 1) is this normal?

2) if so, how do you stop it unravelling?

3) if it's not normal, why is it happening?

I've experimented with the tensions but it doesn't make any difference. It seems to me that it's because the needle is making a bigger hole than the thread, so there's no friction against the thread, but not having machine-sewn leather before it's all guesswork on my part.

Edited August 12, 2015 by dikman

[Wishful]

If I understand you correctly, you should hold on to your top and bottom threads as you start sewing and or start sewing with your needle down. Look on youtube for Arthur porter who will provide info on leather sewing. Also, one of the sponsors here has a nice chart on suggested needle and thread combination. http://www.tolindsewmach.com/thread-chart.html

[mlapaglia]

Are you back stitching your first stitch to lock the thread in place? If not it will loosen up like you are saying.

[dikman]

Aha! No, I'm not. (I've sewn a fair bit of cloth/calico with an ordinary machine, with no issues, but haven't tried really thick stuff before). So, with leather I should run the first couple of start stitches backwards, and then revert to the forward direction?

I should add that I'll still be handstitching my belts/holsters, mainly because I can use thicker thread than the machine can handle - I'll use the machine threadless to run the stitch holes first, which will give me nice even stitch lines and make it easier to push the awl through. I would still like to know that I can use it to sew leather, however.

[mlapaglia]

Aha! No, I'm not. (I've sewn a fair bit of cloth/calico with an ordinary machine, with no issues, but haven't tried really thick stuff before). So, with leather I should run the first couple of start stitches backwards, and then revert to the forward direction?

I should add that I'll still be handstitching my belts/holsters, mainly because I can use thicker thread than the machine can handle - I'll use the machine threadless to run the stitch holes first, which will give me nice even stitch lines and make it easier to push the awl through. I would still like to know that I can use it to sew leather, however.

Yes, Also make sure you are holding tension on the upper and bobbin thread for the first few stitches. I start and end with 2 back stitches. I do the same with Saddle stitch also.