Attaching Dee Rings And Stitching

[JamesR]

Hello,

I want to make some shoulder bags for people who want to lug around text books and other weighty items.

I am concerned about attaching the dee rings.

What would be the strongest way to stitch them to the side of a bag? I am using 6SPI with 6 cord.

Does increasing the SPI make a stronger connection?

Is there some optimum combination between SPI and cord size if strength is the main consideration?

Thanks

Jim

[harnessman]

Hello,

I want to make some shoulder bags for people who want to lug around text books and other weighty items.

I am concerned about attaching the dee rings.

What would be the strongest way to stitch them to the side of a bag? I am using 6SPI with 6 cord.

Does increasing the SPI make a stronger connection?

Is there some optimum combination between SPI and cord size if strength is the main consideration?

Thanks

Jim

Here are just some misc ramblings on your questions.

Since you are talking "cord" Can I presume you are using linen thread? If yes, then the 6 cord is probably plenty strong and you will cut the leather before you get thread failure. Personally if you are concerned about strength I would use 277 Nylon or Poly thread, or larger if you are after the cosmetic effect, and the thread will be stronger than the leather that it is attached to, unless you are stitching heavy sole leather. Needle and awl hand saddle stitching the rings on will be a better lasting, though ultimately no stronger, than machine stitching. It is a time trade off thing. For the strongest connection hand saddle stitch and rivet with solid copper post and burr rivet through the center of each ring billet. Split or rose head type rivets, hollow rivets, pop rivets are all worthless and should be considered strictly cosmetic if you are concerned about strength.

As to the SPI 6 is about all you are going to get with 6 cord without getting the holes to close together and risk ripping out between holes.

finer stitching requires finer awl and finer thread. For strength it is a balancing act between cosmetics, durability and strength. Figure everytime you pierce the leather you are weakening it somewhat so more holes, higher SPI equals weaker leather. I have seen beautiful 16SPI stitching in fine harness work rip out right around the stitch line. Never, ever stitch across a strap is strength is a concern!

With a really heavy duty bag you will find that the leather of the bag itself will probably give way before the ring billet does. For extra weight capacity wrap the strap completely around the bottom so you are carrying weight on the strap, not a stitched billet. That way you can also just replace the strap rather than having to restitch a torn billet or side panel.

Good luck with your project

Jim D.

[JamesR]

Here are just some misc ramblings on your questions.

Since you are talking "cord" Can I presume you are using linen thread? If yes, then the 6 cord is probably plenty strong and you will cut the leather before you get thread failure. Personally if you are concerned about strength I would use 277 Nylon or Poly thread, or larger if you are after the cosmetic effect, and the thread will be stronger than the leather that it is attached to, unless you are stitching heavy sole leather. Needle and awl hand saddle stitching the rings on will be a better lasting, though ultimately no stronger, than machine stitching. It is a time trade off thing. For the strongest connection hand saddle stitch and rivet with solid copper post and burr rivet through the center of each ring billet. Split or rose head type rivets, hollow rivets, pop rivets are all worthless and should be considered strictly cosmetic if you are concerned about strength.

As to the SPI 6 is about all you are going to get with 6 cord without getting the holes to close together and risk ripping out between holes.

finer stitching requires finer awl and finer thread. For strength it is a balancing act between cosmetics, durability and strength. Figure everytime you pierce the leather you are weakening it somewhat so more holes, higher SPI equals weaker leather. I have seen beautiful 16SPI stitching in fine harness work rip out right around the stitch line. Never, ever stitch across a strap is strength is a concern!

With a really heavy duty bag you will find that the leather of the bag itself will probably give way before the ring billet does. For extra weight capacity wrap the strap completely around the bottom so you are carrying weight on the strap, not a stitched billet. That way you can also just replace the strap rather than having to restitch a torn billet or side panel.

Good luck with your project

Jim D.

Jim D

Thank you very much for such an informative reply. I was really hoping someone would help steer me through this and you did.

I really like the idea of extending the strap all the way around the bag for really heavy loads.

"Ring billet", I now know what they are called and since I recently purchased copper rivets I will take your advice and use them in addition to the stitching.

Thanks again for the valuable help.

Jim