Adler 205-374

[llucas]

Ok, as a complete novice to leather sewing machines and stitching leather with them, I am learning far more about this Adler 205-374 than I ever wanted to know, lol. I installed the repaired parts (feed dog carrier and the unchanged cam) from Weaver and adjusted the end thrust of the cam to where the needle guard was in the right place in relationship to the needle and the needle to the shuttle hook. I managed to get it timed per service manual specs. Now I am facing an issue that was not there before: while sewing the stitch length changes. For about six to ten stitches it runs about four stitches per inch then changes to five stitches per inch, and occasionally six stitches per inch. to me as a novice it seems the tension is right as it buries the knot in the middle of the leather. Could the tension be too tight, even if "balanced"? The stitch looks good on the top except for the change in stitch length. The bottom stitch not so much.

There is another new problem that was not there before the repair: when I reverse to backstitch the stitch length doubles. It hits the holes but goes to every other one. I am using 346 nylon on the top and 277 nylon in the bobbin. The thread is also from Weaver and is new. It seems to be much better thread than I was using before. No problems with fraying or coming apart.

There is an adjustment for the 205 series wherein the middle foot is adjusted to the average thickness of material being sewn -- I have not attempted that one yet. The pressure on the double foot is adjusted to a modest pressure -- does it need more pressure? Is the leather slipping under the feet? If it is slipping, wouldn't there be greater inconsistency between the length of the stitches instead of five to six inches where the length is the same?

Suggestions?

Here is the top stitch about 4 per inch, also showing back stitching skipping every other hole

This is the top stitch showing changed length. The groove was intentional and meant to be a stitching groove that I missed, lol.

Here is the stitching on the back showing the start and the reverse backstitching:

This is the back showing the change in stitch length:

The back doesn't look as good as the top, and I am not sure why it is fracturing the leather where the needle punches through. It is older leather -- or does the needle need to be changed? I am grateful for the help I have received on this forum.

Edited February 2, 2016 by llucas

[Uwe]

Does the Twilight Zone Theme play while this is all happening? That exact double stitch length in reverse is just too freaky. Make a video of that. The only real explanation of that would be a stitch length mechanism that's WAY out of adjustment.

Is your feed dog movement correct after re-installing the cam? Check feed dog movements without any material and verify they make sense, both forward and reverse.

Test sew a piece with NO thread, forward and reverse. If stitch length still changes it's clearly not the thread that's causing it.

Does the material slip a little when the needle is above the material? That's the only time it really can slip. Perhaps the outer presser foot is not holding the material down with enough force to keep it from slipping. Thread tension does play into this to some degree. If thread tension is too high it may yank the material towards the needle a little as it's pulling the knot tight and pulls more thread from the spool.

If the material is not slipping, perhaps the transport mechanism or linkage is slipping when the going gets tough or reverses. Make sure all the screws and bolts involved in the stitch length mechanism are tight. Does the stitch length lever move when this happens? That level should stay wherever you put it and it should not move as you sew.

Edited February 2, 2016 by Uwe

[llucas]

Thanks Uwe. Today was the first day it was up and running after the repair. I wondered about the outer presser foot pressure -- in the first two photos you'll notice there are no marks from the outer presser foot, whereas most of the photo samples I have seen on leatherworker.net have at least mild impressions. The feet on this machine are harness-makers feet and I assumed I would have to buy smooth and bigger feet to minimize that issue. So I was happy today when it made no marks. I'll put more pressure on the outer presser foot tomorrow and see if it helps. Perhaps it is slipping in conjunction with the thread tension. I have had a hard time observing the actual mechanics while sewing samples as I still have a clutch motor that speeds up beyond my ability to sew (servo and speed reducer pulley will be my next purchase). But I will try to be more observant and report what I see. I did check the only screw on the stitch length lever I could see and it seems firm.

Edited February 2, 2016 by llucas

[Uwe]

Just turn it over by hand to make stitches until you figure out what's going on.

When I make major changes or adjustments I always check everything out first with hand-turned stitches before I even attempt to run it under power. A lot of bad things can happen under motor power that won't happen if you first turn the wheel by hand and observe, listen and feel how the machine works.

[dikman]

I'll second that! Whenever I fiddle with a machine I always turn it by hand first and make sure it can sew properly before powering it up. (It's scary when a needle hits the needle plate under power!!!).

[llucas]

I did indeed turn it by hand first to confirm the adjustments and settings. Then I powered it up. This is when I got the inconsistent stitch length and weird reverse stitching. Late afternoon I took Uwe's advice and increased the pressure on the presser foot. That helped clean the stitches up to a more consistent stitch length. It is not perfect yet, but better. I'll increase the pressure more tomorrow and see if it solves the problem. I think I may have inadvertently increased the stitch length at the start by pulling excessively on the tread from the bobbin and top as I began the stitching line. Also, it may be that I was pushing or pulling the material through the stitching process instead of allowing the machine to set the pace. I am definitely paying my stupid tax as a newbie to using sewing machines!

I checked the needle and detected a burr on the spear point. I changed the needle and that seemed to help a little on the fracturing on the backside, but the new needle also developed a burr and the fracturing exposing tiny amounts of raw leather reappeared. Do needles need to be honed?

Here is the second sample from late afternoon for the top side: a little better on consistent stitch length:

Here is the back side, a little better but not great:

This sample is prefinished leather and most of my work is in veg tan which fares a little better. The fracturing of the hole on the backside of the prefinished leather where the needle punches through leaves a lot to be desired. Normally my hand sewn stitches are laid into a grooved stitch line. These samples are not. Is it possible the stitches will improve in appearance when I manage to lay the stitch into a preformed groove?

Edited February 3, 2016 by llucas

[llucas]

I had a moment to work on the Beast again this morning. As Uwe suggested I added more presser foot pressure in the event the leather was slipping in conjunction with the thread tension. That helped. The stitches are more consistent, but not yet perfect. Perhaps more pressure is needed. The backstitching in reverse was the same result, skipping every other hole. And it did not automatically go into the same hole even using the roller guide -- it laid the stitch side-by-side. I talked to Allen at Weaver and he had me do a few tests with the stitch lever vis-a-vis the feed dog while on the phone. He suggested putting a shim behind the upper part of the black rubberized plate behind the stitch lever in the reverse area -- he suggested a shim of 1/16" to 1/8". I have not yet done that, but there is an adjustment plate in that location designed to hold the lever further out -- same as a shim. I adjusted that stop downward to hold the lever off the surface of the plate about 1/8". That helped. It put the stitch back into each hole. However, the stitch in reverse looks good on the top, but the bottom is not clean. It almost looks like a stitch that is out of tension, showing a pull-through. Puzzling. I will go with Allen's suggestion of a shim and see how that develops. Thanks for the help. It is appreciated.

Edited February 3, 2016 by llucas

[llucas]

I discovered the fracturing on the backside of the leather by the needle is not a sewing machine issue. The prefinished leather I obtained from a company that went out of business about six years ago is now dried out. The double layers stitched here are fine on the top stitch, but fractured on the bottom layer, which actually displays another "top". Does anyone know of a conditioner I can put on this prefinished veg tan that will make it supple again and not prone to fracturing where the needle punctures on the back side?

Here is the top side of the same piece showing the stitching as the needle enters. It is acceptable. As it exits on the bottom side, the dry leather finish fractures as it is no longer supple. Hoping to find an answer so I can use this leather. It is otherwise very good stuff.

Edited February 16, 2016 by llucas

[Wizcrafts]

stitching backside 2.JPG

I discovered the fracturing on the backside of the leather by the needle is not a sewing machine issue. The prefinished leather I obtained from a company that went out of business about six years ago is now dried out. The double layers stitched here are fine on the top stitch, but fractured on the bottom layer, which actually displays another "top". Does anyone know of a conditioner I can put on this prefinished veg tan that will make it supple again and not prone to fracturing where the needle punctures on the back side?

stitching topside 2.JPG Here is the top side of the same piece showing the stitching as the needle enters. It is acceptable. As it exits on the bottom side, the dry leather finish fractures as it is no longer supple. Hoping to find an answer so I can use this leather. It is otherwise very good stuff.

Try rubbing in Carnauba Creme. Let it sit for an hour or more, then buff it with wool.

[llucas]

Thanks, Wiz. I'll give that a try. I just cut out a holster from this leather to experiment with it. After I glue it up I'll try your remedy before I stitch it.

New servo and speed reducer for the Adler 205-374 arrives today! I should be a sewing maniac by the end of the week!