How to account for a circumference increase for bracelets or collars when layering or padding leather?

[Sarina]

I have been mostly working on bracelets but want to start working on collars too. With a lot of projects I've been layering leather on top of other leather, for example I'll make the wide base of the bracelet and then on top of that I need a thinner piece that will go into a buckle. The issue is that when I make these items, I'm making them flat. But when I try to put them on, they need to be round. Since the two layers of leather are the same length it doesn't fold into a circle very well.

I've been practicing with adding a little bit of length to the top layer to account for that, but it's mostly a guessing game.

So let's say I start with a wrist that is 12cm in circumference. If I use a 1/8th inch thick strip of leather as the base layer, the new circumference that the outer layer of leather needs to cover becomes approximately 14cm. But if I cut the outer leather piece to be 14cm in length I have a hard time fixing the two layers together while it's flat. And if I cut both pieces to be 12cm then the outer piece of leather doesn't stretch to fit the new circumference when I try to wrap the finished product into a circle.

I couldn't find any good guides on this online but I might be searching with the wrong terms. Does anyone know what the best way to handle this is?

I've generally been able to make it work with layering leather but I want to start adding foam and lining some pieces, and I'll be adding a lot of width to the items so I'm worried just accounting for a little bit of extra length in the circumference won't work anymore.

[DieselTech]

I believe Chuck Dorsett has a video on this. It's a vid for making bracers & bracelets. 

[TomE]

I thought it was only me...

I recently was figuring out the allowance for padding a dog collar.  I think of it as comparing the circumference of 2 circles.  One circle is the unpadded collar and the other is the collar enlarged by the thickness of the padding.  In the example below, the circumference of the unpadded collar (L1) is the measured length of the collar from the buckle tongue to the hole it fits into.  We know that the circumference of a circle is Pi multiplied times the diameter (d1).  We solve for d1 then add twice the thickness of the padding to calculate d2, the diameter of the padded collar.  Knowing d2 we can solve for L2, the circumference of the padded collar, which is the length of a strap that fits over the padding.  After calculating L2 we can calculate the difference L2-L1, which is the padding allowance for a collar that is padded over the full circumference of the circle.  I figure that my collars are padded over ~2/3 of the length, so the padding allowance is 2/3 of the difference (L2-L1).

I make padding with 1/8" neoprene wrapped with 3-4 oz leather, which ends up being about 3/16" thick.  In the example below, for a measured length (L1) of 15" a fully padded collar would be 16.2" long.  Since only the middle 2/3 of the collar is padded I would add an allowance of about 3/4" for the padding = 15.75"  Not much change.  Hope this helps.     

 

     

[Dwight]

You can play the math game . . . or you can do it the easy way . . . 

Determine what would be the smallest you would probably make . . . cut out yellow pine circles that size.

Measure and cut the bottom layer . . . then use a dress makers cloth tape measure to measure the outside of that piece.

Cut the filler . . . lay it around the piece . . . measure it . . . cut the top piece . . . glue em together around your circle.

You don't have to make one of every possible size . . . you could make say a 7 in dia . . . 8 in dia . . . 10 inch dia . . . 12 inch dia . . . and the 12 could be used for anythng between 10 and 12.

Easy peasy.

May God bless,

Dwight

[SUP]

@TomE unless you stick the pieces together around whatever you are making or something of the same diameter as @Dwight  explained above, how will you stich a piece of 15 inch leather to a piece of 15.75 inch piece of padding and get the edges to align?

@Dwight that sounds like a good  technique but will the outermost leather not crease when straightened?

[TomE]

7 minutes ago, SUP said:

@TomE unless you stick the pieces together around whatever you are making or something of the same diameter as @Dwight  explained above, how will you stich a piece of 15 inch leather to a piece of 15.75 inch piece of padding and get the edges to align?

@Dwight that sounds like a good  technique but will the outermost leather not crease when straightened?

I was answering the question of how long to make the strap in order to account for padding underneath, compared to an unpadded strap.  The padding will be shorter than the strap, typically spanning between the buckle return and where the buckle holes begin.  In my example, the pad is 2/3 the measured length of the collar.  The padding is glued and sewn to the strap, and conforms to the strap when buckled.

I could make a chart of padding allowances for different length straps, but it depends on the thickness of the padding and how much of the strap is padded.  At the end of the day, it is a small allowance (15.75" strap vs. 15" unpadded in my example).   For my padding thickness, I can guestimate the allowance from a few reference calculations I made.  For example I'd add about 0.5" to the strap length for a dog collar with a measured length of 10".  Of course, if the leather stretches then it's a moot point.

Why does this matter to me? For a made to order collar or cavesson (bridle nose band) I want it to fit on the middle hole.  It is a point of pride.    

 

 

[SUP]

4 minutes ago, TomE said:

The padding will be shorter than the strap, typically spanning between the buckle return and where the buckle holes begin.  In my example, the pad is 2/3 the measured length of the collar.  The padding is glued and sewn to the strap, and conforms to the strap when buckled.

So as long as there is no requirement for padding from end-to-end, this works great.

Thank you for explaining.

[TomE]

5 minutes ago, SUP said:

So as long as there is no requirement for padding from end-to-end, this works great.

Thank you for explaining.

The calculation is for full length padding then I "discount" the allowance based on the fraction of strap length that is padded.  In the 15" example, the full allowance is 1.2" and I would add about 0.75" to my strap because only 2/3 of the strap length is padded.

[SUP]

9 minutes ago, TomE said:

he calculation is for full length padding then I "discount" the allowance based on the fraction of strap length that is padded.  In the 15" example, the full allowance is 1.2" and I would add about 0.75" to my strap because only 2/3 of the strap length is padded.

SO when you use a shorter piece of padding, will that prevent creasing when the final piece is straightened? 

Edited March 4, 2024 by SUP

[TomE]

55 minutes ago, SUP said:

SO when you use a shorter piece of padding, will that prevent creasing when the final piece is straightened? 

The pads made from 1/8” neoprene wrapped with 3-4 oz chrome tanned leather are quite  flexible there are no major wrinkles.  It will depend on thickness/firmness of the pad and the radius of the bend. The dog collars I’ve made are for large dogs.