Why Two Differnt Thread Sizes On A Machine

[Kustom]

I was wondering why people sew with say, 277 on top and 207 on the bottom? What's the benefits?

Thanks, Steve

[TwinOaks]

If you use a large enough needle, you can use the same size top and bottom. Smaller needles mean smaller holes...more attractive. Generally, you use a smaller size on the bottom because you can only get a certain amount of thread in the hole made by the needle. Most leather sewing machines create a lockstitch, which means there are 4 thread diameters being squeezed into a hole. (you count both sides of the loops).

By using the smaller thread on bottom, you can get by with a smaller needle (thread doesn't need as much room).

[Kustom]

If you use a large enough needle, you can use the same size top and bottom. Smaller needles mean smaller holes...more attractive. Generally, you use a smaller size on the bottom because you can only get a certain amount of thread in the hole made by the needle. Most leather sewing machines create a lockstitch, which means there are 4 thread diameters being squeezed into a hole. (you count both sides of the loops).

By using the smaller thread on bottom, you can get by with a smaller needle (thread doesn't need as much room).

Thanks for the explanation TwinOaks. So you would use the needle size that's right for the bottom thread? Like for a 277 top 207 bottom combo you would use a 180 needle?

[Art]

The "Right" needle size is whatever works. I run as small as a 19 when sewing 138/138; just what I can get away with and I like the look. One thing about running smaller thread in the bobbin is the stitches are a bit tighter, but another is that you can get more thread on the bobbin; not a big problem on the 441, but it makes a difference on the 618.

You can also make it "look" like you used a smaller needle by closing-up the needle holes after sewing. You can use a bouncer or some other type of slicker to close up the holes and remove any presser foot marks. You can do it with or without spraying with a little water.

Art

Thanks for the explanation TwinOaks. So you would use the needle size that's right for the bottom thread? Like for a 277 top 207 bottom combo you would use a 180 needle?

[Kustom]

The "Right" needle size is whatever works. I run as small as a 19 when sewing 138/138; just what I can get away with and I like the look. One thing about running smaller thread in the bobbin is the stitches are a bit tighter, but another is that you can get more thread on the bobbin; not a big problem on the 441, but it makes a difference on the 618.

You can also make it "look" like you used a smaller needle by closing-up the needle holes after sewing. You can use a bouncer or some other type of slicker to close up the holes and remove any presser foot marks. You can do it with or without spraying with a little water.

Art

Thanks Art. I sew a lot of 138 top and bottom. Right now I use a 22 needle, I'm going to have to get some 19s and give it a try. I would really like the bottom hole to look smaller.

[Art]

First just try the "flounder" end of a fitters hammer and just run it down the stitches after sewing; you will really like how it closes the holes up. The 19 is something that works for me in a certain application, your results may be different. Try just closing up the stitches first.

Art

Thanks Art. I sew a lot of 138 top and bottom. Right now I use a 22 needle, I'm going to have to get some 19s and give it a try. I would really like the bottom hole to look smaller.