Thread breaking Seiko SK-2B-1-20

[MaryelR]

I have a new (to me) Seiko SK-2B-1-20, long arm walking foot machine and have trouble-shot everything I can - set the hook timing, needle bar height, adjusted feed dog & presser foot. It's working okay. This is my first time using an industrial machine - I have used many small machines. I'm using this machine for sewing books - sewing through about 3/8" thick paper. I can do this work on my old Singer, but the stitch length isn't variable, and I needed longer stitches. I also wanted working space for wider books.

My question is regarding thread tension and thread weight. I'm trying to use Chinois linen thread, #532 and it keeps breaking. It's very hard to pull the thread through the machine, there's just so much tension. If I set the tension any looser, I get loops on the back of my work.  I have to use two hands to pull the thread through before starting or at the end of my piece. The mechanisms are all about the same as those on my old Singer, so I don't know why it would require so much more tension to work. I have adjusted the bobbin tension - it's as tight as can be, though the bobbin thread is much looser than the top thread.

Is it possible to use this machine with lighter weight thread or does it have to be very thick thread? I'm worried I may have bought the wrong machine.

Any help or advice would be much appreciated. Thank you.

[DrmCa]

Yes you can use smaller thread in the #24 needle, but how small you can go can be only found by trial and error.

Isn't #532 too large for #24 which this machine takes? I thought that #24 was good up to size 300.

[Wizcrafts]

I looked up your thread and found that it is a little over a half millimeter in diameter. Your size 532 hand sewing thread is about the same as #277 bonded nylon. This calls for a #25 needle. In your case, you may need to move up to a #26 needle to poke a large enough hole for the take-up system to pull the lockstitch knot into the stack of paper.

Lockstitch sewing machines with a standard closed eye needle are not meant for use with any prewaxed thread. The thread path, guides and tensioning disks are not optimized for sticky thread. Use bonded nylon, bonded polyester, or even heavy cotton or poly core button hole thread.

[Wizcrafts]

I found the pdf with the specs for your machine. It is not clearanced for that size of thread and is only rated for up to a #24 needle. You must use smaller thread than 1/2 mm. I would go down to 3 cord linen (Chinois #832), or #207 bonded nylon.

[Wizcrafts]

If you must use 1/2mm thread (aka: 4 cord, or #277), you'll need a machine meant for heavy thread, like the Juki TSC-441, or the Cowboy, Cobra and Techsew 441 clones, or the Adler 205 heavy stitchers, or a Union Lockstitch, or Campbell Lockstitch machine, or even a Puritan chainstitch machine. The latter three machines are actually built for use with linen thread.

If you need a flatbed machine, look for a used Adler 204-370 (long out of production, but out there), or a new Cowboy CB243 - both of which sew at least 3/4 inch with thread sizes up to #415 (.7mm), using needles up to a #27. These machines have an open frame shuttle and huge cylindrical bobbins.

[MaryelR]

Thank you so much for all your responses! I just ordered some bonded nylon thread in size 92 and 138. Maybe that will also reduce the overall friction enough so I can pull the thread through the machine more easily?

The Fil au Chinois linen isn't actually waxed, but glazed with potato starch and has a tight Z (left) twist. I was hoping it would be a good machine alternative to typical linen bookbinding thread. Is it possible to use linen thread successfully with a machine - or is linen simply too weak?

Quote

In your case, you may need to move up to a #26 needle to poke a large enough hole for the take-up system to pull the lockstitch knot into the stack of paper.

This explains a lot. I've been using too small a needle for the knot to pull through, and as a result I probably have the tension too high to compensate. I've found that with some adjustments, the machine can take anywhere from #21 to #27 needles. I will try again with a larger needle and see what happens.

I can't thank you enough. I've been struggling with this for many weeks - it's such a relief to have some input! 

 

[Wizcrafts]

5 minutes ago, MaryelR said:

This explains a lot. I've been using too small a needle for the knot to pull through, and as a result I probably have the tension too high to compensate. I've found that with some adjustments, the machine can take anywhere from #21 to #27 needles. I will try again with a larger needle and see what happens.

Please, for the love of God, do not put a #27 needle in that machine. It is meant for use with a #24. You may be able to squeak in a #25, but watch out for impacts with the feed dog hole and hook. If you break the machine it will be very costly to ship and repair it.

The hook clearance is insufficient to pass 1/2 mm thread of any kind. Your idea of buying #138 thread is fine. It may even handle #207, which is what the #24 needle is sized for.

[MaryelR]

Not to worry! The machine is not Seiko brand, but one of many equivalents - its documentation has it listed as #25 - #27 and it shipped from the manufacturer with a #27 needle. 

I just loaded some nylon upholstery thread with a #21 needle, and it works perfectly. I can't believe my problem was the thread! Feeling very silly.

Thank you so much.

[DrmCa]

1 hour ago, MaryelR said:

it shipped from the manufacturer with a #27 needle. 

Too bad we left crystal balls at home.

[Wizcrafts]

2 hours ago, MaryelR said:

Not to worry! The machine is not Seiko brand, but one of many equivalents - its documentation has it listed as #25 - #27 and it shipped from the manufacturer with a #27 needle. 

I just loaded some nylon upholstery thread with a #21 needle, and it works perfectly. I can't believe my problem was the thread! Feeling very silly.

Thank you so much.

Okay, no harm done. Buy some #23 needles (round point!) and use #138 bonded nylon (22 pound test), or bonded polyester (21 pound test). That should hold a 3/8 inch stack of book papers together. If you need more strength, buy #207 (aka: T210) bonded thread and use the #24 needle you already have. Just make sure you use round point needles, unless the covers are of leather.

[MaryelR]

I wouldn't have thought to use a round point. The covers are heavy paper. A minor problem I'm having is that the holes on the back of the sheet (bobbin side) are very large - the needle appears to be tearing through the pages. Would round point needle help with that?

[Wizcrafts]

2 hours ago, MaryelR said:

I wouldn't have thought to use a round point. The covers are heavy paper. A minor problem I'm having is that the holes on the back of the sheet (bobbin side) are very large - the needle appears to be tearing through the pages. Would round point needle help with that?

Yes. The hole will be round, not slot shaped, or oval, or triangular. Round point needles are meant for paper, canvas, cotton, denim, vinyl and most other non-leather materials. Leather point needles are specifically designed to penetrate leather for the best results in otherwise difficult material. A benefit of using round points is that the stitches will lay flatter on the top and bottom surfaces, rather than getting pulled in on the leading and trailing edges, as slicing needles tend to do.

[DrmCa]

Round point is not to be confused with ball point used on knits only.

[MaryelR]

Thank you both. New thread arrived today, I seem to be up and running! Really appreciate all your help.