BEHAVIOUR OF LEATHER WHEN SEWING IT TOGETHER

[zzmikeg]

Hi Folks,

I'm perplexed.  This is not unusual, but can anyone help me get un-perplexed re: below?   Using the pictures, here is the best way I can explain it:

I'd like to marry two pieces of belt leather to create one very thick belt (and maybe even a dog collar).

When I take two pieces of belt leather, and put them together in a curved fashion, as shown below in picture A (using no glue, no sewing, no tape, etc.) it looks good, however; if I firmly hold the two pieces together, and pull them out straight, I get that gap in picture B. 

If I pull these two pieces out flat and straight, glue them down, and sew them together, will I have trouble getting the project to bend when I put it on?

Hope this makes sense: I've got dyslexia and I often unwittingly  make things more confusing than they need to be.  Sorry for whenever I do this.

Thanks in advance for any insight.

 

[Hildebrand]

Glue them then stitch together, you won’t see the separation. This is a very common method of creating heavy duty belts. 

[Hardrada]

To add to your worries, maybe, I've been wondering whether you'd run into problems if you mix tannages. Will something ugly happen if I glue a chrome tan liner to a veg tan belt?

[TomG]

As Hildebrand said. This is normal. Let me see if I can remember how it was explained to me.
Picture a doughnut. If you measure the diameter of the outside and of the inside, they are different, of course. Say that the outside is 3" across and the inside is 2" across. Using the formula for the circumference, c=pid, the outside circumference is 9.42" and the inside is 6.28".
And, since the circumference is equivalent to the "length" around the circle, you see that there is a 3.13" difference in length.
In practical matters, you'd have to figure the diameters based on the thickness of the leather - if I remember right, it's something like outside diameter - thickness x 2.
As for mixed tannages, people glue Chrome to Veg all the time.
BUT, regardless of tannages, measure and glue everything up flat, not curved.

 

[zzmikeg]

Thanks for the replies.

On 11/12/2019 at 7:50 AM, TomG said:

As Hildebrand said. This is normal. Let me see if I can remember how it was explained to me.
Picture a doughnut. If you measure the diameter of the outside and of the inside, they are different, of course. Say that the outside is 3" across and the inside is 2" across. Using the formula for the circumference, c=pid, the outside circumference is 9.42" and the inside is 6.28".
And, since the circumference is equivalent to the "length" around the circle, you see that there is a 3.13" difference in length.
In practical matters, you'd have to figure the diameters based on the thickness of the leather - if I remember right, it's something like outside diameter - thickness x 2.
As for mixed tannages, people glue Chrome to Veg all the time.
BUT, regardless of tannages, measure and glue everything up flat, not curved.

 

I read and contemplated the above solution, accepting the formula as correct, and my brain shit itself.    I think I'll just glue and sew, as suggested by Hildebrand, and see what happens.  I do, however, appreciate the effort. 

Good question by Hardrada, too.

 

 

 

 

[Kcstott]

On 11/17/2019 at 4:08 PM, zzmikeg said:

Thanks for the replies.

I read and contemplated the above solution, accepting the formula as correct, and my brain shit itself.    I think I'll just glue and sew, as suggested by Hildebrand, and see what happens.  I do, however, appreciate the effort. 

Good question by Hardrada, too.

 

 

 

 

to put it simply the belt on the outside of the curve has to travel farther to end at the same place as the inner belt. when sewn flat they are fine, when wrapped around something the outer belt will be in greater tension that the inner belt. Thing is it don't mean a hill of beans when you glue and stitch. Leather will stretch as needed in these instances.  

Now if you had Dinosaur leather say of the 128 oz variety and glued and stitched two belts back to back, that would be thick enough to cause a problem. thing is I don't think you can get a #500 needle and #4000 thread let alone the Cobra Class 1 with optional Diesel engine. 

[zzmikeg]

On 3/8/2020 at 7:13 PM, Kcstott said:

to put it simply the belt on the outside of the curve has to travel farther to end at the same place as the inner belt. when sewn flat they are fine, when wrapped around something the outer belt will be in greater tension that the inner belt. Thing is it don't mean a hill of beans when you glue and stitch. Leather will stretch as needed in these instances.  

Now if you had Dinosaur leather say of the 128 oz variety and glued and stitched two belts back to back, that would be thick enough to cause a problem. thing is I don't think you can get a #500 needle and #4000 thread let alone the Cobra Class 1 with optional Diesel engine. 

I missed this response.  Thank you.  Perfect timing to get a reminder, gonna do one of these next week. 

Last time I had 128 oz dinosaur leather I had to run it through a log planer. Diesel, of course. That unique, pungent smell of freshly cut dino skin usually clears the room out, but it doesn't bother me.  It just me hungry.

[Sturme]

just make the inside strap of the belt as long as you want and clip the ends together. then you can wrap the outside of the belt around the inside to get its length. sewing the belt is similar. once your tooling and dying is done, you start gluing one end make your loop and fit it all together once glued start sewing as soon as you get far enough along to loop it together and clip it to hold keep sewing. end result is a nice curved belt with no wrinkles, crinkles or binding. i love redneck science