Leather cup stitching problem!

[toxo]

Still working on my tea cup koosie/kuzie and I've run into a problem. If you use the same punch/chisel for the main body and the bottom piece you are going to run into trouble because the main body has a bigger diameter/circumference than the bottom piece so if you don't allow for it by the time you run out of stitch holes in the bottom piece you still have some left on the main piece and a big bulge as well.     

Now being a bit mathematically challenged I turned to YouTube. I could only find one vid that advocates sort of dropping stitches when the holes are no longer opposite each other and I think I remember Armitage saying the same thing years ago. This doesn't work because when you start out the holes ARE opposite each other and the problem doesn't arise until it's too late to do anything about it.

I know the answer is somewhere in the PCD math (Pitch Circle Diameter) but I don't have the noodles to be able to work it out. BUT there are not many problems that Paulie can't work out eventually and I've come up with a cunning plan. I know the answer is to have the same amount of holes in both pieces which means the holes in the bigger piece have to be farther apart so todays plan is to use the sewing machine. I'm gonna draw the bigger circle and because I already know how many holes there are in the bottom piece I'm gonna change the stitch length on the machine until I have the same amount of holes.

If there's someone out there who knows how to work this out using to math please let me know.

[chuck123wapati]

1 hour ago, toxo said:

Still working on my tea cup koosie/kuzie and I've run into a problem. If you use the same punch/chisel for the main body and the bottom piece you are going to run into trouble because the main body has a bigger diameter/circumference than the bottom piece so if you don't allow for it by the time you run out of stitch holes in the bottom piece you still have some left on the main piece and a big bulge as well.     

Now being a bit mathematically challenged I turned to YouTube. I could only find one vid that advocates sort of dropping stitches when the holes are no longer opposite each other and I think I remember Armitage saying the same thing years ago. This doesn't work because when you start out the holes ARE opposite each other and the problem doesn't arise until it's too late to do anything about it.

I know the answer is somewhere in the PCD math (Pitch Circle Diameter) but I don't have the noodles to be able to work it out. BUT there are not many problems that Paulie can't work out eventually and I've come up with a cunning plan. I know the answer is to have the same amount of holes in both pieces which means the holes in the bigger piece have to be farther apart so todays plan is to use the sewing machine. I'm gonna draw the bigger circle and because I already know how many holes there are in the bottom piece I'm gonna change the stitch length on the machine until I have the same amount of holes.

If there's someone out there who knows how to work this out using to math please let me know.

just use the chisel on the main body glue the bottom on and finish the hole through with an awl. No math is needed friend.

bevel the edges so the two pieces fit together properly before glueing.

 

[chuck123wapati]

the best way is to just mark your holes on the main piece then use an awl through both pieces after glue up. bevel both pieces at 45 degrees and your thread should not show inside the cup but go through the beveled area only.

[chuck123wapati]

i should turn some wood and makes some koozie forms for folks, i just grabbed a tree limb and cut off a piece one day for a sewing form but a nice turned one the right size would be better.

[toxo]

33 minutes ago, chuck123wapati said:

just use the chisel on the main body glue the bottom on and finish the hole through with an awl. No math is needed friend.

bevel the edges so the two pieces fit together properly before glueing.

 

Works fine on 3mm firm veg tan. Not so much on 2mm soft chrome. This is just a holder. Doesn't have to be watertight. I could just put a cross on the bottom.  It's the principle I'm after.

[chuck123wapati]

18 minutes ago, toxo said:

Works fine on 3mm firm veg tan. Not so much on 2mm soft chrome. This is just a holder. Doesn't have to be watertight. I could just put a cross on the bottom.  It's the principle I'm after.

It works the same if you have a form to sew on.

If the leather is that thin then the difference in circumference isn't very much between the two pieces but your making it way to hard for no need. 

Another way, get a compass and draw a circle the same size as the bottom circumference. Draw a second circle the size of the main body circumference.  mark your intended holes on the inner circle then with a ruler mark lines from the  center of the circle through your intended stitching pattern to the outer circle. this will give you the measurement you want. easily and quickly. The problem with finding that "principle" is that the distance from the edge of the leather to the hole is part of the equation as well as the thickness of the leather so you have more than one variable to the equation. you will see and understand this problem better when you make the above template.

[chuck123wapati]

44 minutes ago, toxo said:

Works fine on 3mm firm veg tan. Not so much on 2mm soft chrome. This is just a holder. Doesn't have to be watertight. I could just put a cross on the bottom.  It's the principle I'm after.

 

[Frodo]

You have 2 parts. The outside piece of leather and the inside piece of leather

4" circles circumference is 12.56"

so the back side of the outter piece is 12.56"

the front side of the inner piece is 12.56"

that's is assuming your bottom is fitting inside the top 

That is how I figured this jewelry box

i used my sewing machine with out thread to make the holes in both pieces  

glued the plug inside the outter piece  using bits of wire to align holes  while glue set up

then sewed it,  using an awl when needed 

 

[chuck123wapati]

15 minutes ago, Frodo said:

You have 2 parts. The outside piece of leather and the inside piece of leather

4" circles circumference is 12.56"

so the back side of the outter piece is 12.56"

the front side of the inner piece is 12.56"

that's is assuming your bottom is fitting inside the top 

That is how I figured this jewelry box

i used my sewing machine with out thread to make the holes in both pieces  

glued the plug inside the outter piece  using bits of wire to align holes  while glue set up

then sewed it,  using an awl when needed 

 

excellent work!! and now brings up the question how are you connecting the two pieces?? . Butted up together like with thicker leathers , formed inside like Frodos,  formed opposite of Frodos or some other method ? maybe a pic of what you are trying to do would help.

[toxo]

1 hour ago, chuck123wapati said:

 

Well done Chuck. That'll do it.

[toxo]

1 hour ago, Frodo said:

You have 2 parts. The outside piece of leather and the inside piece of leather

4" circles circumference is 12.56"

so the back side of the outter piece is 12.56"

the front side of the inner piece is 12.56"

that's is assuming your bottom is fitting inside the top 

That is how I figured this jewelry box

i used my sewing machine with out thread to make the holes in both pieces  

glued the plug inside the outter piece  using bits of wire to align holes  while glue set up

then sewed it,  using an awl when needed 

 

Well done Frodo. That's similar to how I do some bags.

[Frodo]

There are 2 other ways I use to make a cup

turn that plug in the picture over.  See it from the outside 
 

and the other is to bend the cup side out at the bottom on a 90 degrees, then sew to a flat piece ,  this comes in handy if making a stein that needs a bigger bottom for stability

[dikman]

I'm guessing that Toxo is talking about making it like a toeplug in a holster, which is usually done by marking out the holes on the outer piece, scribing a guide line on the plug, gluing the plug in and then using an awl to punch the hole so it comes out on the guide line. The spacing on the plug is determined by where you punch the awl through. I think this is what chuck is talking about.

His method of drawing out the two circles is probably the only accurate way of doing it, if a little time consuming, but there's no margin for error if it doesn't line up exactly when you assemble it.

[TomE]

The math is analogous to the question in the post below - how to calculate the allowance for padding a collar - with the additional consideration of hole spacing that is proportional to the 2 circumferences.  That said, it will be a small difference and difficult to accurately mark on the 2 pieces. I'd use an awl.

 

 

[toxo]

I didn't give any thought to it initially. just punched the body and the bottom with the same punch and started thinking about it near the end when I had this bubble that I knew wasn't gonna go away. Chucks drawing is an easy way to see it. I still don't know if it would be better to lose a stitch or use a wider spacing for the bigger circumference.

[TomE]

7 hours ago, toxo said:

I didn't give any thought to it initially. just punched the body and the bottom with the same punch and started thinking about it near the end when I had this bubble that I knew wasn't gonna go away. Chucks drawing is an easy way to see it. I still don't know if it would be better to lose a stitch or use a wider spacing for the bigger circumference.

The diagram is easy to see but it's not easy to calculate stitch spacing from the angles shown.  I think it's easier to calculate the inner and outer circumferences then convert the spacing of the outer piece to that for the inner piece as the ratio of circumferences.  My point is you will end up with something like 6 and 5.5 stitches per inch for the 2 pieces and I don't know how to accurately mark 2 spacings with a small difference.  Won't have to do this with an awl.  Skipping a hole doesn't fix the spacing.

[toxo]

49 minutes ago, TomE said:

The diagram is easy to see but it's not easy to calculate stitch spacing from the angles shown.  I think it's easier to calculate the inner and outer circumferences then convert the spacing of the outer piece to that for the inner piece as the ratio of circumferences.  My point is you will end up with something like 6 and 5.5 stitches per inch for the 2 pieces and I don't know how to accurately mark 2 spacings with a small difference.  Won't have to do this with an awl.  Skipping a hole doesn't fix the spacing.

OK here is what I was trying to do in the first place. As I've said, I don't think skipping stitches is the proper way to go even if this guy get's away with it. Another consideration is whether you're going with hole punches, chisels or awls. I got into trouble because I used punches which can be problematical unless you happen to have the corresponding set of punches with the wider spacing for the bigger circumference so unlikely to be the way to go especially if you want the 45 degree holes. I did see something a long while back where someone (might have been Leodis?) where he made a wooden 45 degree gadget so you could chamfer the edges and use punches but I digress, anyway, I'm loving this conversation and I'm trying to keep up even though my hair stands on end when I see a scientific calculator but I love that every day is a school day.

TWO New Stitches to Elevate your Leathercraft! (youtube.com)

 

[chuck123wapati]

38 minutes ago, toxo said:

 I'm loving this conversation and I'm trying to keep up even though my hair stands on end when I see a scientific calculator but I love that every day is a school day.

TWO New Stitches to Elevate your Leathercraft! (youtube.com)

 

I fought this problem to the death on moccasin toes last month. you cant just glue up and sew those with an awl at least I couldn't figure out how to. 

 

1 hour ago, TomE said:

The diagram is easy to see but it's not easy to calculate stitch spacing from the angles shown.  I think it's easier to calculate the inner and outer circumferences then convert the spacing of the outer piece to that for the inner piece as the ratio of circumferences.  My point is you will end up with something like 6 and 5.5 stitches per inch for the 2 pieces and I don't know how to accurately mark 2 spacings with a small difference.  Won't have to do this with an awl.  Skipping a hole doesn't fix the spacing.

yup you can mark the holes on the outside piece then draw the same diagram to find the inner hole spacing measure it and you have the answer pretty close. 

On 2 mil leather it would be a very small difference on a miter joint type. That's why I didn't draw the thing to actual proportions, probably should have. 

[toxo]

Not really germane to this problem but my cup is cone shaped which brought up a whole nother set of shapes which I hadn't thought of.

I think everyone who calls themselves a leather crafter should make a conical leather cup/mug/jug.

I do think that provided you get both sets of holes lined up, it's easier to run an awl through both punched holes on the 45. Wouldn't be watertight of course but not needed in my case.

[chuck123wapati]

1 hour ago, toxo said:

OK here is what I was trying to do in the first place. As I've said, I don't think skipping stitches is the proper way to go even if this guy get's away with it. Another consideration is whether you're going with hole punches, chisels or awls. I got into trouble because I used punches which can be problematical unless you happen to have the corresponding set of punches with the wider spacing for the bigger circumference so unlikely to be the way to go especially if you want the 45 degree holes. I did see something a long while back where someone (might have been Leodis?) where he made a wooden 45 degree gadget so you could chamfer the edges and use punches but I digress, anyway, I'm loving this conversation and I'm trying to keep up even though my hair stands on end when I see a scientific calculator but I love that every day is a school day.

TWO New Stitches to Elevate your Leathercraft! (youtube.com)

 

i watched the video and you can sew that up in minutes with an awl with nothing but a stitch marker around the outside piece.  Even the video maker is making this way to hard. Make a form so you don't have to hold the thing and sew. I just had a thought for an accurate coozie form fill a can with plaster of paris or maybe even that expanding crack filler foam crap and insert a couple of pins, dowels or some such that you can clamp in your stitching pony. simply slide the sewn outer piece over it then you can easily glue the bottom in and start sewing.

Step away from your calculator very slowly and have a beer instead. remember people made this stuff before rulers were even invented.

 

[toxo]

3 minutes ago, chuck123wapati said:

i watched the video and you can sew that up in minutes with an awl with nothing but a stitch marker around the outside piece.  Even the video maker is making this way to hard. Make a form so you don't have to hold the thing and sew. I just had a thought for an accurate coozie form fill a can with plaster of paris or maybe even that expanding crack filler foam crap and insert a couple of pins, dowels or some such that you can clamp in your stitching pony. simply slide the sewn outer piece over it then you can easily glue the bottom in and start sewing.

Step away from your calculator very slowly and have a beer instead. remember people made this stuff before rulers were even invented.

 

Nice idea on the form but getting back to the video, surely if you don't mark the main body then with it upside down you use a straightedge from the bottom center, through the bottom hole you can just mark the outside hole on the main body as per your drawing, no?

[chuck123wapati]

8 minutes ago, toxo said:

Not really germane to this problem but my cup is cone shaped which brought up a whole nother set of shapes which I hadn't thought of.

I think everyone who calls themselves a leather crafter should make a conical leather cup/mug/jug.

I do think that provided you get both sets of holes lined up, it's easier to run an awl through both punched holes on the 45. Wouldn't be watertight of course but not needed in my case.

only conical lOl.

[toxo]

1 minute ago, chuck123wapati said:

only conical lOl.

And that pic shows the problem exactly. The disparity between the main and the bottom stitches. Good job on the bottle.

[chuck123wapati]

2 minutes ago, toxo said:

Nice idea on the form but getting back to the video, surely if you don't mark the main body then with it upside down you use a straightedge from the bottom center, through the bottom hole you can just mark the outside hole on the main body as per your drawing, no?

yes that would work well i think.

[chuck123wapati]

Just now, toxo said:

And that pic shows the problem exactly. The disparity between the main and the bottom stitches. Good job on the bottle.

xactly that's why the awl rules in this case over trying to figure punch holes its a no brainer with an awl. As you can see its just a matter of marking the main body holes, a guideline in the bottom as dikman said then pushing the awl through towards the dead center of the bottom.