This stitch doesn't look quite right on the backside. What am I missing?

[SheltathaLore]

Just about got the hang of my new machine, but I've got one last thing to figure out.  I've tweaked the tensions and read a lot on the forum (I never would have known about the hook in the take-up spring otherwise!), but I can't get the backside of the stitch to look quite right. 

In these pictures, I'm using a size 18 triangle point needle and size 92 bonded nylon thread on a combined weight of 4-5 oz kidskin.

Any suggestions?

 

Front:

Back:

 

 

Threading:

[Uwe]

The stitch line looks good to me, actually. 

The seam appearance on the backside looks different than the front side, but that's mainly due to the way the needle penetrates the material on top and pushes it out on the backside as the needle exits.

Fabric is a different story because the fabric's threads just get pushed aside by the rounded needle point and seam appearance is more similar front to back. Leather needles cut the material and leave a different seam appearance front and back. 

You can experiment with variations on the leather needle tip to alter the seam appearance in subtle ways, but you will probably be disappointed if you expect the seam to look identical front and back on leather with that machine. Of course the leather itself (type, thickness, tanning method, surface treatments, etc.) also plays a role.

There are a few (monstrous and expensive) machines like needle & awl machines that come closer to a perfectly symmetric saddle stitch look on leather because the material gets penetrated from both sides,  first with the awl from one side, then with the needle from the other. This double entry makes the seam appearance more uniform front to back. 

Edited December 22, 2017 by Uwe

[SheltathaLore]

Okay, if that's what it's supposed to look like, then I'm happy.  I just wanted to make sure that I didn't have anything mis-adjusted.  Thanks for the tip!

[Uwe]

1 hour ago, SheltathaLore said:

4-5 oz kidskin.

That does sound a little disturbing, though. 

[R8R]

I saw a thread here awhile back where someone posted pics of different needle point types and typical stitch results from each (needle side and bobbin side). Can't find the dang thread now.

 

[Yetibelle]

Here are the needle point charts I made up.

 

[dikman]

Yetibelle, do you have those available as printable charts? Would be very handy 'cos these days I can't remember stuff like that!

[Wizcrafts]

@Dikman;

You can save the needle chart images to your computer then print them out from your photo app.

[Tejas]

Attached is a pdf copied from Keystone six years ago. Might still be there.

Groz-Beckert_Needles_for_leather.pdf

[Yetibelle]

I made up a needle and thread PDF that covers some basics. 

needle and thread.pdf