Seiko STH-8BLD-3 reverse/tacking question

[anvilring]

I'm using the machine noted above set up w/207 top, and 138 on the bottom, and the schmetz 37:20 AX1 needle size 23  (135x16 R TW) which is a needle w/the point sharpened at an angle to replicate an awl I guess. Sewing mostly 3/8in. of leather; making knife and pistol scabbards/holsters w/ few problems. However in reverse, it will back tack a few stitches then usually the thread breaks, even on much thinner leather. And I find there's only one "stitch per inch" when in reverse? Anyway to regulate that? There's a sweet spot where my forward stitch will match up w/the reverse stitches but sometimes I use more stitches per inch than that. Here's a pic of underneath my machine and I'm wondering if this is where you regulate reverse stitches per inch? It's the bright colored nut which can be adjusted in that slot, securing the arm going back up into the machine. I should add that one reason I'm interested in a reliable back/reverse stitch, is that I"m making/going to make some cartridge/money belts and I need that reverse so's to not have to constantly be rotating the work (which in itself is a good reason for breaking thread!). 

 

DSC09469 by rynegold, on Flickr

 

 

DSC09468 by rynegold, on Flickr

 

 

 

Edited September 6, 2016 by anvilring

[Uwe]

Since your machine doesn't really behave at all the way it should in reverse, you're either using it wrong or something may be way out of adjustment, loose or broken.

The Seiko STH-8BLD-3 manual will get you going on the right path. I highly recommend reading it carefully - it's one of the better manuals out there.

First thing to make sure is that you don't turn the hand wheel backwards to make the reverse stitches - that's just not how it works but you would be in plentyful company if you tried that.

Second thing to make sure is that the reverse lever has normal range of motion (isn't catching on anything) and that you depress the reverse lever all the way down and hold it there while sewing in reverse.

Third thing to make sure is that you don't make any changes or loosen screws unless you really understand what they do.

That screw in your picture is NOT where you adjust the reverse stitch length balance. Chapter 8-13 on page 23 of the manual shows how to adjust stitch length balance.

 

Edited September 6, 2016 by Uwe

[anvilring]

" That screw in your picture is NOT where you adjust the reverse stitch length balance. Chapter 8-13 on page 23 of the manual shows how to adjust stitch length balance. "

 

Right; got it. But; what IS that adjustment for? just curious. The one I've pictured?

Edited September 6, 2016 by anvilring

[Uwe]

I'm not positive but I believe that adjustment screw/mechanism allows matching the amplitude of the needle bar rocker frame movement to the feed dog movement. It makes sure the needle's position remains fixed inside the feed dog hole as they both move front to back. If the amplitudes don't match, there will be relative movement of the needle inside feed dog hole as they move. 

[anvilring]

Thanks Uwe!!

[Gregg From Keystone Sewing]

19 hours ago, Uwe said:

I'm not positive but I believe that adjustment screw/mechanism allows matching the amplitude of the needle bar rocker frame movement to the feed dog movement. It makes sure the needle's position remains fixed inside the feed dog hole as they both move front to back. If the amplitudes don't match, there will be relative movement of the needle inside feed dog hole as they move. 

Exactly.  A common situation that may occur is that people find that at the end of a long run of sewing material together, say 10 feet for example.  Even if all layers being sewn together are the same exact dims and we started at the same point, the piles can shift.  This is how we would compensate for this.  The best way I can describe it is that it curls the material up or down as it's being sewn.  Also, not all Consew 206RB and Seiko STH-8BL models have this adjustment available, and may be a fixed crank.

Edited September 7, 2016 by Gregg From Keystone Sewing