Leather marks?

[palvim]

Hello All,

I've purchased a LS-1341 type machine and trying to get it dialed in perfectly. I am not sure however why this happens on the underside. Please see the images attached. 

I've loosened the presser foot tension to its highest position. Any more turns and it'll pop out entirely. 

Any help is greatly appreciated. 

Thanks

Vimal. 

 

 

 

And here is the problematic underside. 

[Wizcrafts]

That is how leather looks on the bottom with most walking foot machines. The inside foot is small and surrounds the needle. That's what causes the bottom to pucker around the needle holes. If your machine has a separate adjuster screw over the inside foot, back it out as far as it will go and just use the outside foot to hold down the work.

Getting the foot pressure right can be a balancing act. Too little pressure allows the leather to lift up with the ascending needle. This causes skipped stitches and rats the thread. Too much pressure leaves marks on top and puckers on the bottom.

[palvim]

Hi Wizcraft, 

Correct me if I'm wrong. The top part looks ok. That's where I've made the springs loose for the presser feet as well as the center foot. The bad part is happening I guess due to the feed dog (under the leather being stitched). Did you mean there is some spring also for the feed dog or some way I can make it loose? 

[Wizcrafts]

11 hours ago, palvim said:

Hi Wizcraft, 

Correct me if I'm wrong. The top part looks ok. That's where I've made the springs loose for the presser feet as well as the center foot. The bad part is happening I guess due to the feed dog (under the leather being stitched). Did you mean there is some spring also for the feed dog or some way I can make it loose? 

No, you have it wrong. The marks on the bottom aren't just from the feed dog hole. While the size of the hole is important for letting the needle pass through it without binding, the hole itself does not cause the bottom to pucker. It is the spring pressure on the inside foot that surrounds the needle that pushes the leather into the dog's needle hole. If your machine is equipped with a separate adjuster over the inside foot, backing off the pressure on that part will reduce the puckering on the bottom.

Look at the left side of the head of the machine. Is there a screw adjustment inline with the inside foot? It would be between the needle bar and presser foot bar. On machines having that adjuster, it could be a thumbscrew, or a simple screwdriver adjustment that is close to the top of the head until screwed down. Consult your owner's manual, or open the faceplate and see if there is a coil spring around the inside vibrating foot bar. If there is an adjustment screw it will be directly over the bar and spring.

This is a separate adjuster than the main presser foot pressure adjuster. If your machine only has one pressure adjuster, you will have to try to optimize it so it just holds down the leather as the needle ascends while exerting the least required pressure on the inside foot. Otherwise, live with the bottom appearance, or try using a different needle point shape.

As a rule, the larger the needle, the more pronounced the bottom pucker around the hole where it presses into the feed dog hole or slot. This is how it is with walking foot machines that have a middle/inside foot.

[Handstitched]

Looks pretty good to me, thats how my sewing looks    You're going to get some marks at least. I don't dare touch the presser adjustment screw anymore than I have in case it goes through the roof , I really have no idea how much pressure there is on the spring, I'm not going to risk it.  When my machines are working fine  I leave them as they are   . 

Nice work tho  

HS

[palvim]

Yes. It seems there is another spring that is adjustable for the center foot (see image. The screw is pointed with red arrow). I'll make that as loose as possible too. I have also been using the D point needle which probably makes bigger marks. I'll use the LR needles which should cut more smoothly. I'll try these two things and let you all know how it goes. Thanks for the help so far. 

[RemingtonSteel]

On 3/25/2021 at 6:07 AM, palvim said:

I've purchased a LS-1341 type machine and trying to get it dialed in perfectly

Perfection in Leatherworking... Many strive for this, but few ever achieve it.  As Wizcrafts and Handstitched have mentioned, not enough pressure, and the leather will lift off the needle plate on the upstroke (not good) while too much tension can leave unsightly marks on both the front and back of your leather.  IMHO, the best you can hope to achieve is no marks on the top, and minimal marks on the bottom. Regardless, you are most likely going to have some marks on the bottom left by the machine.  The only way I can sew and not leave marks is to hand stitch, but that defeats the purpose of getting a machine.

Having said that, my first attempts at using my machine yielded results that look like your bottom stitch above, but my marks are left buy the needle plate.  After I found that happy compromise between not enough and too much pressure on the presser spring, I was able to virtually remove all marks from the top side (still there but you have to really look hard to see), and have minimized the marks on the bottom side.  In my personal experience (others can chime in on this with their experience) the needle you use can also impact the amount of marking on the back of your leather piece. The below photo shows two samples of stitching two layers of 7/8 oz. leather together. Both pieces were sewn on the same machine (441 clone) with the same feet, and presser spring settings. You can clearly see that the top piece which uses a #23 LR point needle had less marking on the bottom than the piece sewn with an #24 LL point needle.

 

You also might try tapping on the seams with a cobblers hammer, or using a modeling spoon (which I did not do on the samples) to minimize/remove the marks left by the machine. I personally am not a big fan of the cobblers hammer technique as it can make the stitching look a little mushy for my taste.

FWIW, I find it useful to sew some samples with different weight threads, every time I try a new needle size or needle point style. I clearly mark the back side with the Brand, Size, Part Number and Thread for both top and bottom. That way I have a clear reference to look at when deciding what type of needle and thread I want to use on a project.

That is a beautiful machine you have. Good Luck with it and enjoy!  

[palvim]

I have managed to get decent results with loosening the center foot and presser foot tension. Now I have virtually no marks on the top and very light marks on the bottom which is totally passable. Also the results with LR needle were much better compared to the diamond point needle which is really meant for textile as I understand. LR needle point is like a chisel. 

Hope this helps anyone else having issues with leather marks on their machine.