Stitch Length Difference Between Two Junker & Ruh Sd28 Stitchers

[sandyt]

I guess when you don't have a gap at the arrow, someone in the past geplaced a part that wasn't excactly the same? Can't think of something else.

 

You could always have someone machine a new needle clamp. That should solve the problem.

[sandyt]

I guess when you don't have a gap at the arrow, someone in the past replaced a part that wasn't exactly the same? Can't think of something else.

 

You could always have someone machine a new needle clamp. That should solve the problem.

[Vinculus]

I have a gap there, but I'm not sure if it's wide enough. I've been in touch with the Rolf guy who fixes and sells these on eBay, so hopefully he can help me. I recorded a few videos to show how the machine operates from various angles, not sure if it helps.

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Here is the stitch length regulator from the back of the machine when the lever and needle is all the down into the needle plate:

 

And here is the new stitch length regulator I made side-by-side with an original unworn one I have in the other machine:

[mikesc]

Your "new one" ( if it is the one on the left ) does look to be a "smidge" shorter than the the original from the old machine ( on the right )..does that "smidge" correspond to the difference at the foot ? Looks to be a little less than half a millimetre "shorter", but that might be where the missing adjustment lies..what do they measure ( respectively ) if you use a micrometre to measure just the length of the part ( which you are measuring with your steel ruler ) which protrudes from the thumbscrew "head"..?

[Vinculus]

The one on the left is actually a new original part from the other (Junker) machine, the one on the right is the new one I made for the Pedersen. It doesn't really matter that I made it slightly longer, because I can't screw it all the way in anyway - the machine just jams in that case. The thumbscrews are slightly different lengths as well, so making the screws themselves identical won't help.

Rolf Saile, who has a bunch of these and refurbs and resells them, had much to comment about what is wrong with my Pedersen. Unfortunately he doesn't speak English, so the language barrier is pretty tough. If anyone on here feels like translating for me, it would be much appreciated. His quotes are in italic.

deine vilhelmpetersen hoogen 308 hatt viele problehme.

video  1  ganz hinten wo deine hand ist zum halten  ist die kleine silberplatte  an diesem halter ist eine scharze kleine schraube diese mus ca  2 bis 3 millimeter  über dem schwarzen teil raus schauen.... von hinten die konter Mutter lösen und dann die schraube etwas raus drehen ,,,,, dan die konter  mutter wieder befestigen... ich denke es müste deinem problehm helfen..

I understood this part and followed his advice. It did not make any difference in regards to the stitch length.

sonst sind viele teile verbraucht oder nicht orginal..

vorne, bei deiner stichplatte ist das loch sehr gross  einfach verbraucht... dein presser fuss hatt unten keine nassen oder druck teile  zähne mehr..

This also makes some sense. The presser foot does have plenty teeth though, but it does indeed not have enough presser force to go all the way down anymore. Not an issue when stitching thicker materials, which get adequate pressure from the foot as-is.

deine stichstellschraube ist nicht mehr orginal, ich würde die spitze die kugel besser schleifen  oder polieren.

deine halb mond platte in der hebelarm mechanik ist sehr verbraucht...

I am going to guess this "half moon" plate is where the main issue lies in terms of the stitch length, as that is what appears to move the needle arm from right to left.

auf der rechten seite hinten am hebel rm ist eine schlitz schraube  die sehr tief im hebel sitzt die solte circa  5 millimeter drausen sein..

This part I do not completely understand.

wenn die maschine richtig näht was bei dehn sehr verschlissenen defekten teilen eigentlich noch gut aussehen tut..

würde ich etliche teile normall zerlegen und reinigen und fetten und ölen. vileicht würde dir presluft schon helfen dìe gröbsten teile zu reinigen..

versuche dein glück du kanst dich gerne wieder melden.

ich habe von den alten schwarzen petersen auch noch 3 stück und eine modernere von den jüngeren maschinen in hammerschlag braun wie fast neu.

und circa  18 stück junker und ruh..

[sandyt]

I am not sure if we understand each other correctly.

I meant this gap. Does it close entirly? I guess it does. That is your stop. No adjustment for that as far as I can see.

 

I guess there are 3 fixes.

1-find out wich part is wrong and replace it. 

2-custom needle clamp.

3-if there is enough space. Remove a mm or 2 from the peace right to the double arrow. Be carefull with this one. Hard to undo it.

[mikesc]

Is it possible that it is jamming because you made it longer ? ( the threads do not look to be exactly the same, pitch looks similar, but your new one looks more coarse ) might also explain the jamming. How far can you screw the new one in before the machine jams, is it an equivalent distance to the good old one fully screwed in ? re the thumbscrew part, I didn't mean make the thumbscrew part the same, but..curious why you didn't make the threaded part of the new one identical to the threaded part of the good old one, if they were identical ( length and shape, apart from the thumbscrew head part ) at least you would not have introduced a "variable"..will the good old one fit in the machine that has a problem ?

re translation..French I'd have done it no problem, my German is not good enough to be reliable ( lack of practice )..Uwe or Constabulary ( maybe others ?) would be your best bet for translation from German to English

[Vinculus]

6 hours ago, sandyt said:

I am not sure if we understand each other correctly.

I meant this gap. Does it close entirly? I guess it does. That is your stop. No adjustment for that as far as I can see.

 

I guess there are 3 fixes.

1-find out wich part is wrong and replace it. 

2-custom needle clamp.

3-if there is enough space. Remove a mm or 2 from the peace right to the double arrow. Be carefull with this one. Hard to undo it.

Ah, right - sorry for the misunderstanding. Yes, this gap comes to a complete close with the lever and needle all the way up. Not sure if I want to grind down any non-replacable parts of the machine yet, I'll keep that in mind as a last resort!

[Vinculus]

5 hours ago, mikesc said:

Is it possible that it is jamming because you made it longer ? ( the threads do not look to be exactly the same, pitch looks similar, but your new one looks more coarse ) might also explain the jamming. How far can you screw the new one in before the machine jams, is it an equivalent distance to the good old one fully screwed in ? re the thumbscrew part, I didn't mean make the thumbscrew part the same, but..curious why you didn't make the threaded part of the new one identical to the threaded part of the good old one, if they were identical ( length and shape, apart from the thumbscrew head part ) at least you would not have introduced a "variable"..will the good old one fit in the machine that has a problem ?

re translation..French I'd have done it no problem, my German is not good enough to be reliable ( lack of practice )..Uwe or Constabulary ( maybe others ?) would be your best bet for translation from German to English

I would guess it jams because the point of the regulator screw is supposed to slide against the slanted part of the plate it rests against when you push the lever back up. If it's too long there's not enough give and it just won't budge.

I'll try and grind down my home-made screw a little more to match it exactly in length with the original unworn part from the Junker and see how that goes. I do fear that will make it too short though, as the original thumb lock nuts are not the same width on the two machines. That's why I measured the length of the screws in the picture with the ruler resting on the edge of the thumb lock nut. In the picture of the edge of the regulator screw from the back of the machine you can see how far in it will go - the head protrudes a fair bit from the thumb lock nut.

The Junker regulator screw will not fit in the Pedersen for some reason. It will only screw in a little before the threads start to resist, and I don't want to force it and strip the threads.

Edited April 7, 2016 by Vinculus

[sandyt]

Please don't be sorry for the misunderstanding. It's on me because of my poor English. Sometimes I realy stuggle with it.

My regulators don't interchange either. Different thread.

The lenght of the regulator screw doesn't affect the right movement. Only the left movement. Feed direction.