Hi, I have a problem with my stitches. The problem is that the stitches are not aligned nicely, but are dancing (a little up, a little down). For example, I use the following pricking iron:
Hexagon pricking iron
Pricing iron tooth size 2mm
Distance between prickin iron tooths 3mm
I used thread of thickness 0.45mm.
The last product I had a problem with was a wallet, about 4mm thick.
I used the guitar technique when sewing (right hand down, left hand up).
I'm using that kind of sewing clamp: https://cdn11.bigcommerce.com/s-e77e4/images/stencil/1280w/products/7118/60972/Leather_Stitching_Pony_w_clamp__39370.1707874680.jpg
Below is a picture where you can see the stitch (dont look at cornes and other mistakes, the only plan was to test the stitching line and align it). I used the pricking iron to pierce the leather all the way through. On one side I sewed as the pricking iron did, on one side I used a diamond owl to enlarge the hole from the sewing side, and on one side I used a diamond owl to create a hole from the back. All the stitches have the same problem (back of of the wallet is better vs the front), so I can probably rule out the hole problem.
Maybe it's because of the thickness itself? What can I do in this case?
If it is not, any idea or recommendation for a straight stitch?
Thank you very much!
@ffzanchetta raises some good points.
I think the main issue here is the use of soft leather. If you are new to leatherwork, it takes more experience to see the same perfection in stitching as firm vegetable tanned leather (which is much easier to work with).
Are you using any kind of reinforcement behind each layer? A thin fabric backing, glued with PVA makes for more rigidity and cleaner stitching (plus a stronger product).
The truth is you are making a few minor mistakes here and there, and soft or thin leathers are unforgiving of any change in technique, no matter how minor. With experience and practice, your consistency will improve where the leather type will not matter.
Judging from the photos I can point out a few potential issues.
it looks like you are having trouble following a straight line when punching the holes. Are you using a crease line or a line made with a compass? You can even try using masking tape to make sure you get a straight line, just make sure to test if the tape doesn’t disrupt the leather finish. Also, have a good lighting source. Short pricking irons are also more prone to cause this problem.
another potential issue is the total thickness. It’s very difficult to punch through thick leather and maintains the iron perfectly straight (perfectly perpendicular to the work surface). Chances are the holes will vary slightly, being either closer or further away from the edge. Anything over 2 mm starts to get difficult to punch perfectly, in my opinion. Also, it looks like the edges are thinner than the rest, which can make the whole piece tilt when you position the iron, making alignment much more difficult. Having said that, I think your problem lies on the face side…
Finally, if the leather has a soft hand, punching completely through can also cause some compression may lead to misalignments.
As for recommendations, I’d suggest practice and also testing on some scraps (same leather and thickness) to help determine the cause of the problem. Also, test on some firm or lighter coloured leather to see how it changes. Also, you can try pre punching on both sides and then aligning the holes. That requires some precision but it completely doable.
I hope that helps!