Cobra 26 presser/walking foot marking up leather

[AtomicLeathers]

On 4/15/2022 at 6:33 AM, AtomicLeathers said:

Yeeeeeeep That is the adjuster I tried moving. It is backed off all the way

Hey where did you get that photo? In my manual, it looks like it is from 1990 haaa There is a section for the foot adjustment but it dosent have anything about 25mm height in it.  I cut 5mm off and it still is marking the leather up. Its at 25mm from the top of the nut to the bottem and the bottom of the top nut. If I release it anymore it comes out. and right now its pressing the leather to much. Do you think the leather is too soft? or maybe the spring is just new stiff and needs to work in?

Edited April 17, 2022 by AtomicLeathers

[AtomicLeathers]

22 minutes ago, AtomicLeathers said:

Hey where did you get that photo? In my manual, it looks like it is from 1990 haaa There is a section for the foot adjustment but it dosent have anything about 25mm height in it.  I cut 5mm off and it still is marking the leather up. Its at 25mm from the top of the nut to the bottem and the bottom of the top nut. If I release it anymore it comes out. and right now its pressing the leather to much. Do you think the leather is too soft? or maybe the spring is just new stiff and needs to work in?

this is from my manual. nothing about 25mm

[TomE]

Do you tap the stitches down after sewing?  I use a small hammer with a polished face and place the leather on a granite slab.  I am sewing bridle leather, not harness leather, with a Class 4.  The presser foot marks the leather when the thickness is > 20 oz.  even with the tension setting at a minimum. Tapping the stitches helps, and the marks fade somewhat with time.

[AtomicLeathers]

2 hours ago, TomE said:

Do you tap the stitches down after sewing?  I use a small hammer with a polished face and place the leather on a granite slab.  I am sewing bridle leather, not harness leather, with a Class 4.  The presser foot marks the leather when the thickness is > 20 oz.  even with the tension setting at a minimum. Tapping the stitches helps, and the marks fade somewhat with time.

ill try that. but gosh its crazy that it marks it up that bad. I seen others that just stitch and do a real good job the first time.  crazy.  ok ill see if I can hammer them down

[jrdunn]

I have a CB4500.  I have the presser foot tension fairly low.  It is not marking the leather, the needle foot is.  I haven't found how to reduce the tension on the needle foot.  @AtomicLeathers, It looks like at least some of your marks are made by the needle foot too.  I'd be very interested  to find out how to adjust it.  I haven't had my Cowboy long either.  Watching.

Jim

[Silverd]

Certainly the Presser foot marks can be eliminated by placing a strip of leather under it during the sewing process.  It's kinda a challenge to do this while still keeping an eye on things but after a while it becomes 2nd nature.  Of course. Reduce the spring pressure as much as you can, but this technique completely eliminates Presser foot marks in experience.  The needle foot marks are more difficult.  Short of an adjustment to reduce its down force what I have found is a few funny techniques that seem to work mostly pretty well but not 100% all of the time in all situations.

I sometimes case (wet) the top side leather pretty well then allow it to completely dry before sewing.  When dry, the previously cased leather is usually quite hard and better resists impression marking. Try it.  At least the Presser foot may not require a protective strip under it using this technique.  

After sewing, if needle foot marks are still prevalent i will lightly case top side only and use a hammer to gently pound the stitches, i then flex and bend and kneed with my fingers and stretch the stitch zone in an attempt to decompress the impression marks.  This method works pretty well but again is not 100% effective.  It usually improves things though.  Some machine tracks we have to accept or resort to hand stitching in areas where no marking is acceptable.  Thsts the difference between the work we do with a machine and fine leather working techniques that are used on very high quality pieces.   Finally, as the finished product ages, further reduction of Presser foot witness marks often diminish naturally with time and use.  

 

Silverd

 

[Wizcrafts]

Some compound feed walking foot machines have a second spring (and an adjuster) over the inside foot. If your Class 26 has that adjuster, back it off as far as it will go. You can even eliminate the spring on that foot if the adjuster doesn't clear them. Otherwise, try to find a softer presser foot spring.

The only machines I have owned or sewn on that don't leave marks around the needle are needle and awl machines, like the Union Lockstitch and Randall Lockstitch, and shoe patchers. These are jump foot machines with one presser foot that has legs outside the needle position. Unfortunately, patchers leave tooth marks from the foot, unless you cover them with heat shrink tubing (reducing the feedability).

[chrisash]

Is it me, but it looks like the stich length is varying along the sample shown, Maybe just the angle the photo was taken at

[TomE]

11 hours ago, AtomicLeathers said:

ill try that. but gosh its crazy that it marks it up that bad. I seen others that just stitch and do a real good job the first time.  crazy.  ok ill see if I can hammer them down

Just firm tapping.  I usually just tap on the backside with the front facing the granite slab.  It helps to smooth the stitch line and even out thread tension.  The marks probably won't be removed completely, but it should help.  A shorter/weaker spring is likely to be the best solution.

[rags383]

Atomic Leathers, I know this thread is old, but I thought I would give it a shot. I just bought a cobra 26 and i am having the same trouble. Did you find a solution?  I knew there would be some markings but from all the videos I watched, my markings are a lot worse. Also, when I press on the pressure foot pedal it is barely lifting the foot? Something is definitely off but I'm not sure what.