Cutting Curves?

[MtlBiker]

I'm very much a novice with leather work and I've been trying to make a little belt pouch to hold a "Secrid" metal credit card holder.  What I'm having particular difficulty with (besides making straight stitches) is how to cut the curve on the top flap.  An x-acto hobby knife (#11) is just too flexible.  Better is the 18mm utility knife with a carbon blade.  Better, but not good enough imho.

Are those curved knife blades good for cutting curves?  I'm thinking of this one from Tandy: Al Stohlman Round Knife.  Would that make it easier to cut a smooth curve?  I'm thinking that you'd rock the blade back and forth, cutting off bit by bit of the leather.

Any suggestions would be most welcome.

This is my latest attempt... far from perfect but getting better with every attempt...

 

[PastorBob]

29 minutes ago, MtlBiker said:

I'm very much a novice with leather work and I've been trying to make a little belt pouch to hold a "Secrid" metal credit card holder.  What I'm having particular difficulty with (besides making straight stitches) is how to cut the curve on the top flap.  An x-acto hobby knife (#11) is just too flexible.  Better is the 18mm utility knife with a carbon blade.  Better, but not good enough imho.

Are those curved knife blades good for cutting curves?  I'm thinking of this one from Tandy: Al Stohlman Round Knife.  Would that make it easier to cut a smooth curve?  I'm thinking that you'd rock the blade back and forth, cutting off bit by bit of the leather.

Any suggestions would be most welcome.

This is my latest attempt... far from perfect but getting better with every attempt...

 

This is how i do it.  I either use a utility knife or one of those flat bladed Japanese knives.

 

https://www.youtube.com/watch?v=ZgzMDqJcC4c&ab_channel=leathertoolz

 

[zuludog]

You have more or less identified the answer yourself

To cut a curve you need a knife with a fairly narrow, pointed blade. An Exacto knife is the sort of thing, but as you've found out, the blade is too flexible, and not really heavy enough for anything more than very thin leather....... so use a Clicker Knife with a hooked blade

Or you could try a Stanley/utility/box cutter knife; they are cheap enough and you probably have one already; they cut even better if you sharpen the blade, even a new one, on a fine stone & a strop

You can use a round knife by rocking, which removes the leather in small sections, or by tilting it so that just a point does the cutting, but note that with a round knife you push the blade, not pull it towards yourself. Other things to consider are that you need to acquire a fair amount of practice & care to use a round knife properly, though once you have it, a round knife will do most cutting jobs, including skiving. An option is to use a head knife, which is like a round knife but has only one point, which makes it a bit cheaper and less hazardous to use

I haven't used the Stohlman round knife, but I hear it's not that good. A round knife is tricky to use, and good ones are expensive, but don't let that put you off if you fancy one. 

The other thing is that to keep the costs down the makers only usually provide a basic cutting edge, and you must do the final sharpening & polishing yourself - there are videos

Search YouTube for making belt pouches; making possibles bags; Nigel Armitage has a series of videos on making pouches; using a round knife; and JH Leather's videos, she uses a head knife for most of her work  

[tsunkasapa]

A round knife is definitely the correct tool for the job. But I would suggest an Osborne rather than the one from Tandy. Once you get used to it you will wonder why you used anything else.

[Northmount]

My Tandy Round Knife doesn't keep a sharp edge.  Has to be stropped every few inches.

[MtlBiker]

1 hour ago, PastorBob said:

This is how i do it.  I either use a utility knife or one of those flat bladed Japanese knives.

 

https://www.youtube.com/watch?v=ZgzMDqJcC4c&ab_channel=leathertoolz

 

Thanks very much for that link!

Can you possibly point me to what a "flat bladed Japanese" knife looks like?  A Google search shows up hundreds of Japanese knives.  I'm not sure what you mean by "flat bladed".

 

[MtlBiker]

50 minutes ago, zuludog said:

You have more or less identified the answer yourself

To cut a curve you need a knife with a fairly narrow, pointed blade. An Exacto knife is the sort of thing, but as you've found out, the blade is too flexible, and not really heavy enough for anything more than very thin leather....... so use a Clicker Knife with a hooked blade

Or you could try a Stanley/utility/box cutter knife; they are cheap enough and you probably have one already; they cut even better if you sharpen the blade, even a new one, on a fine stone & a strop

You can use a round knife by rocking, which removes the leather in small sections, or by tilting it so that just a point does the cutting, but note that with a round knife you push the blade, not pull it towards yourself. Other things to consider are that you need to acquire a fair amount of practice & care to use a round knife properly, though once you have it, a round knife will do most cutting jobs, including skiving. An option is to use a head knife, which is like a round knife but has only one point, which makes it a bit cheaper and less hazardous to use

I haven't used the Stohlman round knife, but I hear it's not that good. A round knife is tricky to use, and good ones are expensive, but don't let that put you off if you fancy one. 

The other thing is that to keep the costs down the makers only usually provide a basic cutting edge, and you must do the final sharpening & polishing yourself - there are videos

Search YouTube for making belt pouches; making possibles bags; Nigel Armitage has a series of videos on making pouches; using a round knife; and JH Leather's videos, she uses a head knife for most of her work  

Great reply... Thanks!

As I said, my last attempt was with a utility knife.  I use knives like this all the time at work (framing shop) but I still found it next to impossible to cut an even curve on the leather following my outline.  I will check out clicker knifes.  I'm sure using a round knife would take a lot of practice, and I was ready to buy one, but thank you for steering me away from that Stohlman knife.  I will search out those videos.  I have one of Nigel Armitage's books (most recent one I think) and he shows a photo of a round knife but doesn't talk about how to use it.

Cheers!
 

[mike02130]

https://www.rmleathersupply.com/collections/skiving-cutting-knives/products/japanese-skiving-utility-knife-shirogami-smoke-razor-sharp

Sold Out but this is an excellent knife.

[MtlBiker]

45 minutes ago, tsunkasapa said:

A round knife is definitely the correct tool for the job. But I would suggest an Osborne rather than the one from Tandy. Once you get used to it you will wonder why you used anything else.

Your (and other) reply have steered me away from the Stohlman round knife.  I'll see if I can find Osborne knives from a supplier here in Canada.

 

42 minutes ago, Northmount said:

My Tandy Round Knife doesn't keep a sharp edge.  Has to be stropped every few inches.

Another vote against the Tandy.  Thank you.

 

[MtlBiker]

1 minute ago, mike02130 said:

https://www.rmleathersupply.com/collections/skiving-cutting-knives/products/japanese-skiving-utility-knife-shirogami-smoke-razor-sharp

Sold Out but this is an excellent knife.

Thank you!  Now I know what that kind of knife looks like.  Too bad it's sold out - I'll try to find one here in Canada.