Stitch Length Difference Between Two Junker & Ruh Sd28 Stitchers

[Vinculus]

A while ago I acquired two Junker & Ruh SD28 outsole stitchers. I first bought one refurbished actual Junker & Ruh from eBay Germany that came with lots of misc. accessories; and then discovered a Pedersen model 308 locally that I also went and got for €200. I wasn't sure what state the Pedersen it was in, but figured I'd use it for spare parts. As it turns out, they are both in great shape and fully operable! The screw that holds the rod the top thread spool sits on was broken on the Pedersen and I couldn't adjust the tension, but after I drilled it out and rethreaded the hole it's all good. Here they are.

Now, I have one issue. The Pedersen's max stitch length is considerably shorter than that of the Junker. In the following picture the top row of stitching is the Pedersen and the bottom row is the Junker:

Since I have two of these it doesn't really matter that much, but it would be nice to be able to for example have two different thread colors or thread thicknesses on hand without having to fiddle with the top and bottom tension on one single machine every time I want to use a different thread. The Pedersen also makes slightly nicer stitches, so it would be cool to have it be able to match the Junker also in terms of stitch length.

Does anyone know what might cause this? Any parts I should inspect for wear? And yes, I have of course tried using the stitch length adjustment screw to no avail, haha.

Also, does anyone have a needle plate for a size 7/8 needle they want to trade for one of the size 5/6 plates I have? I run size 7 needles and 1 mm. Tiger thread, so I really don't have much use for a 5/6 plate. Would also be interested in a stitching plate with the raised lip for stitching soles.

[sandyt]

Does the needle of the pedersen go all the way to the right in the needle plate?

Are you sure you backed the 'nut' on the stitch regulator all the way? Sometimes these will seize by gunk ore rust over time.

[Vinculus]

It actually seems like the needle does not travel to the extreme right on the Pedersen.

Junker:

Pedersen:

The "disc" on the regulator is indeed backed all the way unto the thumb nut and the thumb nut screwed clockwise as far as it goes, I have cleaned it to make sure there's no crap there. This is a bit of a mystery really.

[sandyt]

Strange. I guess the arm that moves from right to left goes all the way back to right? There should be no gap between the bushing on the main lever and that arm. But I guess you checked that al ready. 

I presume the needle does go all the way to the left?

That clearence to the right you have, do you also have that clearence between the slot where the needle goes in under the needle plate?

Sorry for my bad English. I hope you get what I mean. 

[Vinculus]

I think I might have found the problem. The leading edge of the stitch length regulator screw is worn down, so it's not going to push the needle arm as far right as it's supposed to.

 

 

Guess it's easy enough to find a matching screw since I have one that is not worn down to compare the length to.

However, after I was fiddling with the machine for a while, it won't even stitch anymore. It's not picking up the bobbin thread. No idea what I might have done to cause this. Hnnnng.

[sandyt]

That regulator being to short would indeed explain the needle not going to the left all the way. Without that regulator the stichlength is zero.

Have you checked where the needle misses stichlength? 

Starting point or at the end. 

Picture of the end point.

[sandyt]

Picture of the starting point.

 

[Vinculus]

It's at the starting point, as the needle does travel all the way to the left. I'll make a new regulator when I find some time. Reckon I can just find a wingnut screw with the same thread, cut it to length and grind off the thread at the end with a bench grinder to make the tip roughly the same shape as the original one I have in the other machine that is not worn.

[sandyt]

Make sure you polish the tip well. It could scratch the surface of the piece where it rubs against to.

[Vinculus]

Okay, so I made the new stitch length regulator. It did not make any difference, as it only seems to affect how far left the needle travels. I'm at a loss here now, as I can't figure out why the needle won't return all the way to the right. Here is a short video showing how the needle currently moves:

http://gfycat.com/EllipticalColorlessBergerpicard

This is getting dangerously close to entering the boat anchor category.

Edited April 5, 2016 by Vinculus