Seam Strength on Holster/sheaths

[AlZilla]

So, the usual rule around here is to use 277 thread for duty holsters or anything that's going to see heavy use.

The formula for seam strength for the lock stitch is:

Stitches per inch x thread strength x 1.5 = seam strength.

277 thread has a breaking strength of 45 pounds. 138 is rated at 22 pounds.

The question I have is, why couldn't I use 2 seams, closely spaced side by side on the outside edge of a piece using 138 thread?

Purely an aesthetic question.

[fredk]

Interesting

I just use thick thread for heavy duty, thin thread for light duty. I've never even thought about the thread strength

Considering that tent and tilt and truck curtain makers use a double run of stitching and their thread doesn't look overly thick I reckon you could use two stitching runs. Spaced well apart and maybe with the sewing holes staggered, and maybe threads of different colours?

[AlZilla]

1 hour ago, fredk said:

Interesting

I just use thick thread for heavy duty, thin thread for light duty. I've never even thought about the thread strength

Considering that tent and tilt and truck curtain makers use a double run of stitching and their thread doesn't look overly thick I reckon you could use two stitching runs. Spaced well apart and maybe with the sewing holes staggered, and maybe threads of different colours?

This pic is part of my desktop and what got me thinking about it. It's a wild bunch 1911 holster.

I'm machine sewing but I could stagger the seams a bit.

 

[Dwight]

Jump on up to 346 and you can forget all them there worries.

I did.

May God bless,

Dwight

[BruceGibson]

Like Dwight, I use #346 on top.  I also use #277 in the bobbin as that combination pulls my stitches up consistently the way I like to see them.  I wouldn't go lighter than #277 on top, but again, most of this is personal preference.  Double rows of stitching is fine, but the primary row closest to the gun is the important one.  The outside row is strictly aesthetic.  I like my stitch length to be somewhere the 6 to 6.5 SPI range.  Stitch lengths in the neighborhood of 5 SPI look too mass-produced/unrefined in my view, but most of this is my own obsessive/compulsive way of looking at things.    

[Hags]

I normally use 277 top and bottom, double stitch near the gun, single on the outside. Never really felt the need to go heavier. Might revisit that  now.