Help adjusting Back-stitch length

[lSherlockl]

Hello,

 

Think this post fits here and meets requirements. Been a bit of a lurker but got my first walking foot machine and there seems to be a very knowledgeable community.

I was hoping someone could help me or point me in the correct direction of how to adjust the backstictch length on my machine, currently approximately half of forward stitch at all lengths. Its a Chandler Chandsew 100RB which i know must be a clone of something no clue what ofthough. I have a "manual" for it/ the DY377 which does not cover stitch length tuning.

So far I have cleaned and relubed everything and re-timed the machine per manual, forward works and stitches well, backstitch can seem to make the thread fray and its significantly shorter (verified using cardboard). I have also carefully examined to make sure that it wasn't some synchronization issue between the presser foot and feed dogs but they seem in perfect sync forward and reverse.

I have also read about every post on here i could find about adjusting backstitch and couldn't find anything relateable.

HERE is a album of the head: http://imgur.com/a/eSwbR

Thanks for any info and or any help

 

Edited April 4, 2018 by lSherlockl
adding more info

[Uwe]

Your machine appears to be a close relative of a Rex 11-155R and they may both be re-badge jobs of some other machine made by a contract manufacturer. My machine has a plate that says it was "Made exclusively for Rex by Nakajima."

Many factors contribute to the real-world forward and reverse stitch length. The actual stitch length and reverse mechanism is one of them, but feed dog movements and walking foot linkage are also factors.

I made a video some to ago about the stitch length and reverse mechanism on my Rex 11-155R. That "butterfly" part plays a central role in both stitch length and reverse functionality.

One easy check is to see if the butterfly part is properly centered. Set the stitch length dial to "0" and verify that A: that the pin really does sit in the valley of the butterfly wings (reverse level has minimal or no movement at all) and B: that there really is no front-to-back- movement of the feed dog or walking foot when you turn the hand wheel. If A or B is off, then your forward and reverse will not match for sure. 

Other easy visual checks are:

1. The feed dog needs to move all the way to the front before it comes up and all the way to the back before it goes down (and obviously the opposite for reverse.)

2. Descending needle, descending walking foot and rising feed dog should all meet at the throat plate level at the same time. 

Check those things and report back.

 

In general it's better to upload pictures directly here on LW. It's a bit of a pain, but worth it in the long run. Those external picture hosting services have a tendency to turn nasty or greedy. 

 

 

 

Edited April 4, 2018 by Uwe

[Gregg From Keystone Sewing]

Is this a possible adjustment on the machine?  

[lSherlockl]

4 hours ago, Uwe said:

Your machine appears to be a close relative of a Rex 11-155R and they may both be re-badge jobs of some other machine made by a contract manufacturer. My machine has a plate that says it was "Made exclusively for Rex by Nakajima."

Many factors contribute to the real-world forward and reverse stitch length. The actual stitch length and reverse mechanism is one of them, but feed dog movements and walking foot linkage are also factors.

I made a video some to ago about the stitch length and reverse mechanism on my Rex 11-155R. That "butterfly" part plays a central role in both stitch length and reverse functionality.

One easy check is to see if the butterfly part is properly centered. Set the stitch length dial to "0" and verify that A: that the pin really does sit in the valley of the butterfly wings (reverse level has minimal or no movement at all) and B: that there really is no front-to-back- movement of the feed dog or walking foot when you turn the hand wheel. If A or B is off, then your forward and reverse will not match for sure. 

Other easy visual checks are:

1. The feed dog needs to move all the way to the front before it comes up and all the way to the back before it goes down (and obviously the opposite for reverse.)

2. Descending needle, descending walking foot and rising feed dog should all meet at the throat plate level at the same time. 

Check those things and report back.

 

In general it's better to upload pictures directly here on LW. It's a bit of a pain, but worth it in the long run. Those external picture hosting services have a tendency to turn nasty or greedy. 

 

also noted on pictures

 

Wow thanks,

 

Looks incredibly similar.

 

So based upon your notes and video

 

I had traced the guts to the "butterfly" as you call it and yes to the best of my ability its pretty well centered. and both "wings" if you will are enganged when all the way released and all the way engaged. with stich length set to zero there is a little play in the reverse lever and  just under 1mm of movement from the feed dogs/presser it places holes in carboard literally adjacent so it cuts a "slot" imagine this has some effect but may not be the whole story

 

1.) at max stitch length the feed dog is all the way forward as it comes up and not technically all the way backward but at the furthest position of its reward travel before it goes down when the machine runs forward. Whith the reverse lever held down the same is true however both the presser foot and the feed dog do not move as far back but the pick up/down at the apex of movement like they should. its just the apex is in the wrong spot

2.) Descending needle hits the plate at the same time the feed dogs begin their descent. and the presser foot lifts at the same time. I think this makes sense or is correct as its not compound walking foot so the needle goes up and down in the space where the feed is being reset. otherwise the needle would get pulled and snapped when advancing the fabric/material right?

 

I had also inspected and removed the stitch length dial/screw and that was all in good shape good symetrical nose on it, not much wear on the "butterfly" what irks me is it seems like i can see and trace back to the area that something is off but looking at it nothing that you could move or adjust makes sense that you could do it to fix it. (but i am very new to this, not technically things but this sewing machine is quite the interesting device)

 

also noted on pictures, ill upload here in future, past most forums prefer external links.

 

thanks!

Edited April 5, 2018 by lSherlockl

[Uwe]

2 hours ago, Gregg From Keystone Sewing said:

Is this a possible adjustment on the machine?  

I hope so. I suspected one of those looks-like-a-screw-but-isn't heads is really an eccentric adjustment bolt with a set screw. I'll have to take a closer look at my Rex. Which manual is that image from? I have nothing for my Rex yet.

[lSherlockl]

9 hours ago, Uwe said:

I hope so. I suspected one of those looks-like-a-screw-but-isn't heads is really an eccentric adjustment bolt with a set screw. I'll have to take a closer look at my Rex. Which manual is that image from? I have nothing for my Rex yet.

 

If i follow the (no offense) poor manual image these would be my adjustment? it is the area that i determined must be at fault but it didn't seem obviously adjustable. But if the left circled bolt is a eccentric cam or whatever the proper term is it would make sense. now just to figure out how the heck to get in there to adjust it as im not sure i have the confidence to remove parts (without messing something else up that is) to get it it

[Gregg From Keystone Sewing]

13 hours ago, Uwe said:

I hope so. I suspected one of those looks-like-a-screw-but-isn't heads is really an eccentric adjustment bolt with a set screw. I'll have to take a closer look at my Rex. Which manual is that image from? I have nothing for my Rex yet.

Uwe,

I got this from the Consew 205RB-1 book.  

[lSherlockl]

20 hours ago, Gregg From Keystone Sewing said:

Is this a possible adjustment on the machine?  

So i did some examination/testing based on this diagram.

 

so based on my close up with highlighted parts earlier that is not the adjustment that bolt and set screw is keyed meaning the bolt has a flat side adjusting it does nothing  and the set screw will just bring it back to its original resting spot of flat side up.

that being said between that and Uwe's comment on the eccentric adjustment bolt with a set screw i think that may be on the right track but given everything is in sync it could only be a few ones that would potentially have the power to adjust the stitch lenght balance between forward and reverse.

ill look around some more.

[Uwe]

I just got done spending some quality time with my Rex 11-155R. 

It may not be any consolation, but my Rex also has larger forward stitches (8mm) than in reverse (5.5mm). And there's apparently nothing I can do about it - that's just the way the machine was designed.

This machine is not designed to be adjustable to balance forward and reverse stitches. The shape of the butterfly part determines where it hits the stitch length dial stop pin. One could theoretically alter the shape of the butterfly part somehow, but it's not worth bothering in my book.

Later designs by Juki have a nearly identical stitch length mechanism, but they added an eccentric bushing that allows moving the stitch length adjustment pin up and down. This allows adjusting the relative forward and reverse stitch lengths. Here's a snippet of the relevant part (blue No. 10 "Eccentric Bushing") in the Juki DU-141NH parts diagram:

 

We actually had a similar discussion a little over a year ago: 

 

So, in summary, I think  your options are:

1. Live with it

2. Start shopping for a machine with a more sophisticated stitch length mechanism.

[lSherlockl]

16 hours ago, Uwe said:

I just got done spending some quality time with my Rex 11-155R. 

It may not be any consolation, but my Rex also has larger forward stitches (8mm) than in reverse (5.5mm). And there's apparently nothing I can do about it - that's just the way the machine was designed.

This machine is not designed to be adjustable to balance forward and reverse stitches. The shape of the butterfly part determines where it hits the stitch length dial stop pin. One could theoretically alter the shape of the butterfly part somehow, but it's not worth bothering in my book.

Later designs by Juki have a nearly identical stitch length mechanism, but they added an eccentric bushing that allows moving the stitch length adjustment pin up and down. This allows adjusting the relative forward and reverse stitch lengths. Here's a snippet of the relevant part (blue No. 10 "Eccentric Bushing") in the Juki DU-141NH parts diagram:

 

We actually had a similar discussion a little over a year ago: 

 

So, in summary, I think  your options are:

1. Live with it

2. Start shopping for a machine with a more sophisticated stitch length mechanism.

 

Thats a bummer but thanks for the help. At least i may have some info to go off of at least for finding parts etc as i have some other machine to go off of. 

That being said looks like i got a new problem to sort as i thought stitch length had something to do with why reverse was misbehaving (aka the thread likes to tear itself apart in reverse) but another day and probably better suited to another post than re-using this one. 

I sincerely appreciate the help though!

 

[Handstitched]

G'Day, if its of any comfort (?) , I have a Seiko STW 28 B , and I have the same problem. The reverse  stitch is half the length  of the forward  stitch.  On some leather  jobs this may be a bit of an issue, but this machine is mainly used for horse rug repairs  and canvas repairs, so I just live with it.  I could go about messing about with it to adjust it, but its going so well ( touchwood)  I don't dare touch it as I may make things worse, some things are best left alone. This machine has never let me down  ( touchwood again ...just to be safe  ) 

HS