Juki Sewing Machine Help

**Gilla** · 07-09-2008, 01:18 PM

We are having some trouble with our Juki sewing machine. It is an industrial model that we have been using to make throw bags and fix tents, packs and other gear. We got the machine last year and I got some training on it. Basically my knowledge of the machine consists of how to thread the needle, load the bobbin, and basic sewing ability.
The problem we are having is that we can't get the two threads to lock together. The fabric will be sandwiched between the two threads but they won't lock. Pretty simple problem but I don't even know where to start to fix it. I know the machine is thread correctly and that the bobbin is being loaded properly.....
Any help would be appreciated,

Gilla

**uppernotmaster** · 07-09-2008, 01:27 PM

I know absolutely NOTHING about these machines.

This guy however is the Michael Jordan of sewing. He works on our machines here @ work. He may be able to talk you through the problem.

http://www.renatossewing.com/

Also, PM Lobstameatwad, he might be able to help you. His company makes seat covers.

**Gilla** · 07-09-2008, 02:27 PM

Edit: Got the problem solved, Thanks for the help

**lobstahmeatwad** · 07-09-2008, 05:46 PM

Yeah, I am hyper trained on the mechanics on these things now, couple different models. I do all the work here that doesn't require circuit board or computer work. It's super hard to explain w/o pics. I know the guy at a major wader manfc. that trouble shoots remotely for there production center all over the globe. Lots of pics and closeups with arrows and circles. Let me know if you need any help.

**Gilla** · 07-18-2008, 08:18 PM

Alright, here is my newest problem. When I am trying to sew my throw bags the length of the stitches is to long. So when it puts the stitches into the fabric they are really loose and I am left with the top side looking like the stitches are tight and then the back side has big loops where the stitches locked off but the machine didn't seem to pull the thread tight enough. Thats the only way I can explain it really. If you need pics of what it is doing then I will take some.

Thanks

**char** · 07-18-2008, 10:33 PM

Reading the instruction manual would probably be of great help to you.

**jerr** · 07-18-2008, 11:59 PM

It sounds like your tensions aren't tight enough.

First the easy one, Stitch length: You should have a stitch length adjuster on the front of the machine. I think on your brand it's the biggest dial with numbers on it. Set it to a smaller number for a smaller stitch. For normal clothing thickness fabric you want 12 stitches per inch. This gets bigger if you're using thicker fabric.

Machine tensions can be put out as you change the thickness of fabric. It may be a as simple as this.

The needle thread tension doesn't usually go out much. Make sure you're threading it properly. Remember that the thread sometimes zig zags all over the top of the machine, even down the back on some brands. So have a good look for hidden eyes/hooks/guides. Also there is often a bar on the needle mount. It's easy to miss but the thread must be tucked behind it.

Next the bobbin thread tension is checked by loading the bobbin into the bobbin casing. Setting the thread up through it then dangle the bobbin by the thread. If the tension is correct the bobbin should just hang there. Then give it a slight shake and it should start dropping away. If it just drops away without encouragement or it won't move at all the bobbin tension is to lose or tight respectively.

Try testing the machine with a double layer of normal thickness fabric. There's a good chance it's actually set up fine but the fabric your putting through is causing the problem.

**Gilla** · 07-19-2008, 09:15 AM

Right after I learn how to read Chinese I will start referring to the instruction manual, thanks for the tip char

**char** · 07-20-2008, 08:10 PM

http://www.juki.co.jp/industrial_e/d.../manual_e.html

**bethsews** · 12-13-2010, 12:35 PM

Originally Posted by lobstahmeatwad

Yeah, I am hyper trained on the mechanics on these things now, couple different models. I do all the work here that doesn't require circuit board or computer work. It's super hard to explain w/o pics. I know the guy at a major wader manfc. that trouble shoots remotely for there production center all over the globe. Lots of pics and closeups with arrows and circles. Let me know if you need any help.

Can you help me figure out how to change the stitch length on our SC-500? We only want about 7-8 SPI.

Thanks!

bethsews

**lobstahmeatwad** · 12-13-2010, 09:18 PM

Originally Posted by char

Reading the instruction manual would probably be of great help to you.

The instruction manuals are almost worthless. they are written in japanese and then a german translates them to english, or so it would seam.

Bethsews,
sc 500?
hmmm. Do you have a dial on the front for changing stitch length?
Sometime the mechanical connection will lengthen over time. You can take the dial off and crank it down and then set the upper end to the desired spi.
We run 6-7 spi with a size 20 needle for 1000D cordura.