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 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. 

[Dwight]

6 hours ago, TomE said:

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

I'm not sure what you mean by creasing . . . of you are making nose pieces . . . collars . . . etc . . . they are made to be round or rounded . . . they are not made to be straightened.

The whole function of the technique I told you about it to make sure the pieces fit . . . it stays rounded . . . and it does not wrinkle on the inside most piece.

May God bless,

Dwight

[SUP]

49 minutes ago, Dwight said:

I'm not sure what you mean by creasing

See, any time 2 layers of leather are stuck together, there is potential for creasing on one side or the other, depending on how the leather is folded, especially if the leather is not firm.

 e.g.  I plan to use some filigree stamps on a bracelet, with  filigreed leather on the uppermost surface, the colored lining and the inner lining which will be the same as the filigreed leather but without filigree. But it is soft leather, not firm leather and it will not be molded into a specific shape. I can stick this flat, in which case, when I curve the bracelet to wear it around my wrist, will not the innermost layer crease?

 

[TomE]

3 hours ago, Dwight said:

I'm not sure what you mean by creasing . . . of you are making nose pieces . . . collars . . . etc . . . they are made to be round or rounded . . . they are not made to be straightened.

The whole function of the technique I told you about it to make sure the pieces fit . . . it stays rounded . . . and it does not wrinkle on the inside most piece.

May God bless,

Dwight

I think @SUP was commenting about creasing and I quoted her.  I make padded straps flat and they mold to a round shape with use.  Wrinkles and creases aren't an issue in my experience.  It would be difficult for me to hand sew them when curved because the jaws of my stitching horse are flat. Here's a noseband that is constructed of 2 layers of 9 oz leather and a neoprene pad wrapped in chrome tanned leather.  The 9 oz pieces are skived on the edges, shaped in a rounding block to create the swell, then glued and sewn together with the padding while flat.  The noseband readily shapes around a horse's nose.  You can see a few wrinkles in the pad but those smooth out with use and are of no concern to the clients I make bridles for. 

Regarding my original comment on this post, I don't have a wood shop but I do have a calculator on my phone.  I had wondered if padding a strap changed the measured size and the answer is -- not much but you can make a small allowance for it, if desired.

 

 

[SUP]

50 minutes ago, TomE said:

Wrinkles and creases aren't an issue in my experience.  It would be difficult for me to hand sew them when curved because the jaws of my stitching horse are flat. Here's a noseband that is constructed of 2 layers of 9 oz leather and a neoprene pad wrapped in chrome tanned leather.

I think that maybe the 9oz. leather does not crease - too thick to do that. When I make bracelets or straps for bags, it is thinner leather and that is why I probably face that issue.  And I agree, stitching horses have jaws that hold the leather flat. I wonder if we get curved ones. It would be of so much of help to all of you who sew larger items in different shapes.

Maybe someone with expertise in woodworking will come up with one. 

[Haraldsson]

Run the leather upright through the jaws. That way the jaws are holding onto a shorter bit of the curve. 

This pony's clamp-face is almost square, mine is 3 inches long but only has an inch tall surface. If you run the strap vertically, or at an angle, you can glue the straps together as both Dwight:

On 3/4/2024 at 5:20 AM, Dwight said:

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

and TomE did...

On 3/4/2024 at 5:46 PM, TomE said:

skived on the edges, shaped in a rounding block to create the swell 

And the pony wouldn't (shouldn't?) put undue pressure to push the strap flat again.

At least, I think that is what TomE was getting at...

I am stealing Dwight's method for my next gunbelt. I'm happy as a clam to find him still here after all this time! I last poked around here about 5-7 years ago; I'm not good with the passage of years.

[Dwight]

1 hour ago, Haraldsson said:

 

I am stealing Dwight's method for my next gunbelt. I'm happy as a clam to find him still here after all this time! I last poked around here about 5-7 years ago; I'm not good with the passage of years.

Yep . . . still here . . . glad to have ya back . . . 

May God bless,

Dwight

[Sarina]

I didn't realize I had notifications turned off for this post.

@TomE
Thanks for the detailed explanation! I think that formula makes sense, that's generally what I've been using. Your formula says, make everything flat, you just want to ensure that when it's formed into a circle that the innermost part of the circle is the circumference you expect. And the formula does just that. But perhaps my leather isn't quite as stretchy since when I try to form it into a circle it has a hard time actually forming a circle, especially if I have hardware like a rivet connecting two layers.

@Dwight

Your explanation makes sense as well, seems it's the opposite of TomE's explanation. You are making the leather as a full circle to begin with, so the stretching would happen when it's formed flat. Although how do you do things like punch holes for rivets or stitching and such when the leather is formed into a circle?

I think my goal is to be somewhere in the middle of the two solutions, so the leather stretches out just as much being flat as it does formed into a circle, but at rest it's concaved. But I still run into the same problem of how I can punch holes in the leather and have them line up,  since the leather needs to be flat to punch holes in it.

Edit: Actually the more I think about it the more I realize that there can't be an exact formula and that the way Dwight says is the only way to get it exact. Depending on the firmness and thickness of the leather, when you bend it into a circle the circumference of the inner part shrinks as it gets squished but also the circumference of the outer part grows some as it stretches. The exact amount depends on the type of leather and how big the circle is, so you can't make a formula that calculates it exactly.

Edited March 21 by Sarina
Realized why you can't use a formula to be exact

[Dwight]

3 hours ago, Sarina said:

I

Edit: Actually the more I think about it the more I realize that there can't be an exact formula and that the way Dwight says is the only way to get it exact. Depending on the firmness and thickness of the leather, when you bend it into a circle the circumference of the inner part shrinks as it gets squished but also the circumference of the outer part grows some as it stretches. The exact amount depends on the type of leather and how big the circle is, so you can't make a formula that calculates it exactly.

Actually, Sarina . . . I would only do that for a circle that I knew would be say 14 to 18 inches in diameter . . . or less . . . and only if I knew that the wrinkles on the inside would be a problem for the user or wearer.

For example . . . if my customer wanted a "stuffed" nose piece on a bridle or halter . . . a showy piece . . . I would get the measurement from the horse . . . make a round piece that width and that diameter . . . because I know the nose of a horse is tender . . . and if I made the piece and there were several large wrinkles inside it . . . they could rub and irritate the animal . . . which I would never allow if at all possible.  I'm a horse lover guy.  It would probably be less of a problem for a collar for a small dog . . . but in that case . . . it would be an ugly and "not professional" looking product . . . so again I'd make the model . . . so my finished product looked really nice if at all possible.

I have access to power tools and lumber . . . so for me to make a circle that is 13 inches in diameter is a piece of cake . . . taking me all of 25 to 30 minutes . . . I would staple or otherwise fasten the inslde piece of leather to the wood model . . . form the rest of the pieces . . . and then using an awl . . . punch thru the leather . . . into the wood . . . for the stitching.  

Once the pieces are made  . . .  I then glue them together with Weldwood contact cement . . . and they are easily stitched using my Cowboy 4500 or in some cases . . .  sewing it by hand . . . with a stitching pony.

For rivets . . . I just do the same thing . . . punch thru the leather into the wood . . . and not worry about it . . . I've done it many times.

Not being able to do it any other way . . . I find that "necessity is the mother of invention" . . . and needing it done makes me invent a way to do it.

May God bless,

Dwight

[TomE]

11 hours ago, Sarina said:

I didn't realize I had notifications turned off for this post.

@TomE
Thanks for the detailed explanation! I think that formula makes sense, that's generally what I've been using. Your formula says, make everything flat, you just want to ensure that when it's formed into a circle that the innermost part of the circle is the circumference you expect. And the formula does just that. But perhaps my leather isn't quite as stretchy since when I try to form it into a circle it has a hard time actually forming a circle, especially if I have hardware like a rivet connecting two layers.

@Dwight

Your explanation makes sense as well, seems it's the opposite of TomE's explanation. You are making the leather as a full circle to begin with, so the stretching would happen when it's formed flat. Although how do you do things like punch holes for rivets or stitching and such when the leather is formed into a circle?

I think my goal is to be somewhere in the middle of the two solutions, so the leather stretches out just as much being flat as it does formed into a circle, but at rest it's concaved. But I still run into the same problem of how I can punch holes in the leather and have them line up,  since the leather needs to be flat to punch holes in it.

Edit: Actually the more I think about it the more I realize that there can't be an exact formula and that the way Dwight says is the only way to get it exact. Depending on the firmness and thickness of the leather, when you bend it into a circle the circumference of the inner part shrinks as it gets squished but also the circumference of the outer part grows some as it stretches. The exact amount depends on the type of leather and how big the circle is, so you can't make a formula that calculates it exactly.

I think at the end of the day if the collar fits then you've made the right choice.  How tight/loose it fits is a matter of the owner's choice (in my experience for dogs and horses) so this is not an exacting process.  I typically measure a collar/bridle that fits to the owner's satisfaction and make mine the same size (plus padding allowance if needed).  The calculated padding allowances are small and I only recently did the calculation out of curiosity.  I haven't had a problem making dog collars and nosebands as flat straps then wrapping them in a circle.  The noseband above is made from 2 layers of 9 oz leather and I've made dog collars in a similar manner.  They close in a circle without a problem.  I sometimes bend the buckle turn with my fingers to match the curvature (3 layers thick and skived on the end).  I am using Hermann Oak regular veg tan or bridle leather.  I typically apply a light coat of neatsfoot oil followed by conditioner at the end of the project.  Perhaps you could show us pictures of a collar that isn't shaping up.

[Sarina]

On 3/21/2024 at 7:52 AM, TomE said:

I think at the end of the day if the collar fits then you've made the right choice.  How tight/loose it fits is a matter of the owner's choice (in my experience for dogs and horses) so this is not an exacting process.  I typically measure a collar/bridle that fits to the owner's satisfaction and make mine the same size (plus padding allowance if needed).  The calculated padding allowances are small and I only recently did the calculation out of curiosity.  I haven't had a problem making dog collars and nosebands as flat straps then wrapping them in a circle.  The noseband above is made from 2 layers of 9 oz leather and I've made dog collars in a similar manner.  They close in a circle without a problem.  I sometimes bend the buckle turn with my fingers to match the curvature (3 layers thick and skived on the end).  I am using Hermann Oak regular veg tan or bridle leather.  I typically apply a light coat of neatsfoot oil followed by conditioner at the end of the project.  Perhaps you could show us pictures of a collar that isn't shaping up.

I think that makes sense. For me I am making collars for people so they're a little bit larger and might be a little bit different. Here is an example of one I made, this one I made each layer smaller than the one on top of it so that I needed to form it partially rounded to fix them together and have the ends match up.

There are 3 layers, the first one is neoprene foam wrapped in sheepskin, which is stitched to the second layer of leather. The second layer is fixed to the third layer of leather using Chicago screws. The first two layers usually bend fine since they're stitched together making it more like a single piece but the second and third layer have a hard time going into a circle. For this piece I didn't give enough extra room in between rivets for the D rings either so you can see the bottom layer caves inwards.

Since for this one I did it more like Dwight explained, not flat to begin with, it ended up being mostly okay. For ones I make completely flat the leather tugs hard on the Chicago screws when it's formed into a circle, and it ends up a little bit misshapen. I don't have any pictures of that since I ended up trashing the leather and starting over.

 

On 3/20/2024 at 11:48 PM, Dwight said:

have access to power tools and lumber . . . so for me to make a circle that is 13 inches in diameter is a piece of cake . . . taking me all of 25 to 30 minutes . . . I would staple or otherwise fasten the inslde piece of leather to the wood model . . . form the rest of the pieces . . . and then using an awl . . . punch thru the leather . . . into the wood . . . for the stitching.  

Once the pieces are made  . . .  I then glue them together with Weldwood contact cement . . . and they are easily stitched using my Cowboy 4500 or in some cases . . .  sewing it by hand . . . with a stitching pony.

Having a wooden circle with the diameter you're going for sounds like it would be a lot easier. I actually considered something similar after reading your initial comment but decided it would be too much effort for each piece I'm making. I looked up to see if there was some expandable circle measurement tool, there were some but I'm not sure that they would work well. I think if I glue the pieces together in a circle (or half circle in my case) they should stay together like that long enough for me to poke holes with an awl. For punching holes I may need to clip the pieces together while they're in the circle shape, then mark with a pen through the hole in one piece where the hole in the other piece should go. 

Edited March 22 by Sarina

[TomE]

5 hours ago, Sarina said:

I think if I glue the pieces together in a circle (or half circle in my case) they should stay together like that long enough for me to poke holes with an awl. For punching holes I may need to clip the pieces together while they're in the circle shape, then mark with a pen through the hole in one piece where the hole in the other piece should go. 

I think gluing and sewing all the layers would do the trick for constructing it flat than curving into a circle.  I'd consider sewing the strap with the dee rings to the wider strap before sewing the pad on the back, unless you're OK with the additional stitching going through the padded layer.  Could add some wedge shaped welts on either side of the dee rings.  JH Leather videos show this method for the dee on a padded dog collar.  Since you're hand sewing with an awl you'll be able to jump over each dee, and possibly overstitch the dee as shown in her videos.  That's how I've been fixing the dee to the buckle turn of a dog collar.

Edited March 22 by TomE