stitching length

[bladegrinder]

So today I was stitching up a knife sheath on my new cowboy 4500. first I took a scrap of two pieces of 7 ounce and set the stitch to exactly 6 stitches per inch, everything looked good.

so I started on the sheath, which was three layers of 7 ounce. after I stitched it up it was obvious something changed, I was now at exactly 5 stitches per inch. so I went back to the two layers and it went back to 6 per inch.

I've run a lot of practice pieces thru this and a couple sheaths and never had this happen. anyone have an idea why this happened today?

[bladegrinder]

OK, I think I found my answer...with a compound feed system the needle moves back and forth in a pendulum motion, on thinner material it moves a fixed distance. on thicker material the needle foot is moved up higher, changing the distance of travel...and shortening the stitch length. learned a couple things today, that and.....

don't stitch the belt loop so close to the edge that when I'm stitching the edge the belt loop rides up under the foot and sends the stitch clear off the sheath !   Oh well, still learning...

[Tequila]

Never new about the pendulum thing. I guess you have to practice on the same thickness as the project.

[shoepatcher]

Did you raise the walk of the foot when sewing thicker items?

glenn

[Garyak]

On 7/29/2022 at 9:03 PM, bladegrinder said:

OK, I think I found my answer...with a compound feed system the needle moves back and forth in a pendulum motion, on thinner material it moves a fixed distance. on thicker material the needle foot is moved up higher, changing the distance of travel...and shortening the stitch length. learned a couple things today, that and.....

don't stitch the belt loop so close to the edge that when I'm stitching the edge the belt loop rides up under the foot and sends the stitch clear off the sheath !   Oh well, still learning...

It’s sewing threw thicker material while still pulling the same length of thread as it was while sewing the thinner material. Unless you add stitch length you’re gonna lose a fraction of an inch every stitch. In an inch Theres the lost stitch. 

[bladegrinder]

Garyak...gotcha.

Shoepatcher, I'm not sure I understand what your asking. I didn't raise the foot, it rode and fed the two layers the same as the three. from what I've found looking for answer, on a compound feed machine

different thickness of the piece being stitched will be influenced buy the height that the piece under the foot. I dug thru my box of practice pieces and had one that stepped from one layer to two, to three

and although I didn't notice it then, the stitches on that piece did change. it's not to noticeable on a few inches but on a longer run it is.

 

The sheath came out good, what concerned me is doing a measurement for a specific length and messing up from having the stitching come up short or having to go past a point where I wanted to stop.