Thread tension or..?

[DasMike]

Hello, 

I'm Mike and I'm 100% sure I'm the rookiest member on the forum. Before I type anything else, since this is my first post, I just wanted to say how grateful I am to all of you for sharing your time and knowledge. This forum has been a great resource. 

I'm looking for some guidance on getting good stitches on a 1341 clone. I'm experimenting with #92 bonded nylon thread and size 18 and 19 needles (Organ DPX16DIA Ti coated) and a left zipper foot. 

At this point I don't know if I have the tension balance wrong, I'm doing something else wrong, or if it's the natural behavior of the leather I'm practicing with (remember, I'm a newbie at this) but I am seeing the stitches looking kinda weird. Don't know how to describe it, but it's as if the needle pushes/pull the leather and creates domes around the stitches. I tried to capture this in the pictures, but it's hard. I know dark brown leather and black thread might not be the best combination to illustrate my concerns, but that's what I have at the moment.

I'd really appreciate your opinions, help and criticism. Left stitches on the pics were done with a 19 needle, right stitches with 18. Stitch length is set at #5 on my machine. I'm currently working on wallets.

Sorry if this was posted on the wrong side of the forum. 

Best,

Mike

 

[Wizcrafts]

The puckers on the bottom are typical of a compound feed walking foot machine. It is caused by the pressure on the inside foot pressing down right over the feed dog. See about getting some Schmetz S point needles that slice inline with the stitch line. The only other way to minimize this is to reduce the top and bottom thread tensions to the bare minimum that forms a decent stitch, then back off the foot pressure to the minimum required to hold down the leather on the upstroke. If your particular machine has a coil spring on the inside foot and also has an adjuster on top, back it off as far as necessary to reduce the puckering. If the leather lifts with the ascending needle, increase the outer foot pressure.

As a rule, the smaller the needle and thread, the less prominent the puckering on the bottom, and vice versa.

[DasMike]

46 minutes ago, Wizcrafts said:

The puckers on the bottom are typical of a compound feed walking foot machine. It is caused by the pressure on the inside foot pressing down right over the feed dog. See about getting some Schmetz S point needles that slice inline with the stitch line. The only other way to minimize this is to reduce the top and bottom thread tensions to the bare minimum that forms a decent stitch, then back off the foot pressure to the minimum required to hold down the leather on the upstroke. If your particular machine has a coil spring on the inside foot and also has an adjuster on top, back it off as far as necessary to reduce the puckering. If the leather lifts with the ascending needle, increase the outer foot pressure.

As a rule, the smaller the needle and thread, the less prominent the puckering on the bottom, and vice versa.

@Wizcrafts I'll work on it asap with the information provided. Really appreciate your help. 

Is there a "minimum" combination of thread+needle relative to the thickness (or layers) of leather or is it just a matter of aesthetics? Or both?

I mean, if I'm working on a 4-5 layers of 2oz wallet, from a functional and practical perspective (durability), is it a good practice to use #69 thread with an 18 needle to minimize the puckers or should I stick to #92/19? I'm asking because I'm realizing it's a balance of many elements: Leather type, thickness, thread, needle, tension, etc. Very interesting btw. I'm presuming that leatherworkers have their preferences when it comes to thread+needle choice for a specific project, but is there a starting point on that? Sorry if this has been asked before.

Thanks again for your time and help.

[Wizcrafts]

I use #69 thread with a #18 needle for thicknesses up to about 4 or 5 ounces. for 6 to 8 ounces I use #92 with a #19 needle. Beyond that I move  up to #138 or #207 thread with the appropriate needles.

[DasMike]

 

5 minutes ago, Wizcrafts said:

I use #69 thread with a #18 needle for thicknesses up to about 4 or 5 ounces. for 6 to 8 ounces I use #92 with a #19 needle. Beyond that I move  up to #138 or #207 thread with the appropriate needles.

Thank you for your help @Wizcrafts