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MtlBiker

Cutting Curves?

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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...

 

IMG_8561.jpg

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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...

 

IMG_8561.jpg

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

 

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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  

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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.

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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".

 

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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!
 

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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.

 

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1 minute ago, mike02130 said:

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.

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31 minutes ago, MtlBiker said:

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".

 

Search Google and YouTube for 'Japanese leather knife' and 'Japanese skiving knife'; --two names for the same thing; there are several videos

Note that there are left - & right - handed versions. For cutting you hold them more or less vertically in your fist, sometimes with your thumb on the top of the handle, so that the bevel faces away from your palm, and the trailing edge of the asymmetric blade faces away from your body. This might seem odd, but it is actually a bit of a strain to hold the knife perfectly vertically, if you hold your hand & wrist in a normal relaxed manner  the top of the knife will slope outwards, which makes the bevel vertical  - just watch a few videos of one in use

I'm sure other forum members can suggest a supplier in the USA or Canada; or you could try Etsy 

Edited by zuludog

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38 minutes ago, MtlBiker said:

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".

 

This is the exact one i purchased...yep, $10 and it was sharp when it arrived.  Have only stropped it.

 

https://www.amazon.com/BANYOUR-Leather-Cutting-Working-Leathercraft/dp/B07LD4PC2D/ref=sr_1_1_sspa?dchild=1&keywords=leather+knife&qid=1631115906&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzUzFJN1BQSzZMTDVKJmVuY3J5cHRlZElkPUEwMzQ0MTIyMlA3NE5ISTI3RTU3TSZlbmNyeXB0ZWRBZElkPUEwNzAzMzQzMTdWNEdaWTRGVU1VSyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

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39 minutes ago, PastorBob said:

I have one of those knives, and it's surprisingly good for the price, but I have improved it by scraping & sanding the paint off the handle, back to the wood, which is more comfortable and, I think, more attractive. Also sharpening the blade on a couple of oilstones then a strop to give a longer bevel, about 5mm .

Edited by zuludog

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1 hour ago, PastorBob said:

Thank you!  I found that exact same knife on the Amazon Canada website but it says delivery estimated to be Nov 5th to 18th!!!  (But I want it NOW!!!  :) )

The search goes on...

 I found a supplier (not quite local but in Canada) which has two different Osborne knives... one is called a 5" Round Blade and the other 4 1/2" Head Knife.  From the photos (especially as a novice) both knives look extremely similar.  Can you or someone else tells me what the difference might be and which you'd recommend?  Both are the same price.

They also have an Osborne Skiving Knife but the width isn't specified.  Their product code (might not be Osborne's) is MR-469a.  The website is: Cuir Desrochers

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I mark the curve on the flesh side with a ball-point ink pen then I cut the curve with my leather scissors. They'll cut at least up to 4mm nicely. If necessary a swipe or wee bit of sanding with a coarse grade sand piper tidies the cut

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He are a couple of videos showing how to use the single head and a round knife they maybe of interest to notice how easy it is to cut curves yes it does take some practice but worth it in the end. As you will also hear the round knife can do so much more.   

https://www.youtube.com/watch?v=zkEXU-RYrjg

https://www.youtube.com/watch?v=CUgZjMPw0AA

He is a link to Aaron Martin they are in Canada.

https://aaronmartin.com/product.php?cat_id=935&submit=View&catview=20&s=Harness Maker Tools & More&catview2=&catview3=&s2=&s3=

This is a member on here selling a single head made by Vergez Blanchard, i know he says only shipping within America but might be wort giving him a shout after all he is your side of the pond.

I can give you some links over here if you want but sounds like time is a factor, also the single head knife has an easier learning curve than the round knife but can do everything a round knife can do. 

Hope this helps

JCUK

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1 hour ago, MtlBiker said:

Thank you!  I found that exact same knife on the Amazon Canada website but it says delivery estimated to be Nov 5th to 18th!!!  (But I want it NOW!!!  :) )

The search goes on...

 I found a supplier (not quite local but in Canada) which has two different Osborne knives... one is called a 5" Round Blade and the other 4 1/2" Head Knife.  From the photos (especially as a novice) both knives look extremely similar.  Can you or someone else tells me what the difference might be and which you'd recommend?  Both are the same price.

They also have an Osborne Skiving Knife but the width isn't specified.  Their product code (might not be Osborne's) is MR-469a.  The website is: Cuir Desrochers

I have the round knife.  I have seen videos of folks cutting curves, but I have not mastered it yet.  For me, the skiving knife by Osborne would be the one I would get.

 

I did find one in stock at Weaver Leather supply...a lot cheaper (I Think...not sure on the conversion rate CDN to USD)

https://www.weaverleathersupply.com/catalog/item-detail/65-2864-36/flat-leather-knife/pr_58899

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Here is a video I had my granddaughter film while using the knife.  Apologies for the messy workbench.  And yes, I am a southpaw :-)

 

 

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29 minutes ago, jcuk said:

He are a couple of videos showing how to use the single head and a round knife they maybe of interest to notice how easy it is to cut curves yes it does take some practice but worth it in the end. As you will also hear the round knife can do so much more.   

https://www.youtube.com/watch?v=zkEXU-RYrjg

https://www.youtube.com/watch?v=CUgZjMPw0AA

He is a link to Aaron Martin they are in Canada.

https://aaronmartin.com/product.php?cat_id=935&submit=View&catview=20&s=Harness Maker Tools & More&catview2=&catview3=&s2=&s3=

This is a member on here selling a single head made by Vergez Blanchard, i know he says only shipping within America but might be wort giving him a shout after all he is your side of the pond.

I can give you some links over here if you want but sounds like time is a factor, also the single head knife has an easier learning curve than the round knife but can do everything a round knife can do. 

Hope this helps

JCUK

Yes it helps.  Thank you.

Time isn't really a factor... but two months for delivery is pushing it.  A week, no problem, even two, but two months??

I found the Osborne round knife in Canada (Quebec) and I linked the site a couple of posts up.  Aaron Martin wants 50% more for the knife PLUS shipping than Cuir Desrochers.  I was going to order that, plus the skiving knife, but they're out of stock on the skiving knife so I'm holding off ordering for a week (still better than two months!) until their supply arrives.

 

@PastorBob - That's really great!  Thanks very much.

 

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1 hour ago, fredk said:

I mark the curve on the flesh side with a ball-point ink pen then I cut the curve with my leather scissors. They'll cut at least up to 4mm nicely. If necessary a swipe or wee bit of sanding with a coarse grade sand piper tidies the cut

I've got really good Gingher fabric scissors which I've been afraid to use on leather in fear of ruining them.  I guess leather scissors are different.

To get my curve pattern I use a drawing program on the computer and form a bezier curve exactly as I need and print it out.  Then cut it out (using paper scissors :) ) and position it carefully on the flesh side of the leather.  I don't use a pen to mark it but rather just an awl, which leaves an easy to see line.  Follow the line to cut however, has been challenging for me.  Scissors would probably be easier.

 

 

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Cut it close and sand to shape...

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4 hours ago, MtlBiker said:

I've got really good Gingher fabric scissors which I've been afraid to use on leather in fear of ruining them.  I guess leather scissors are different.

My 'leather' scissors are not the speciality type sold by leather suppliers but just very tough high quality scissors. They are by Mundial^. They cost me £12 each and I've ended up with 3 (don't ask). These scissors can cut through thin sheet metal as well.

For curves I don't do anything fancy, I just grab a plate, a bowl, a lid, anything that has the right curve to it, or even just fold a bit of card in half and cut a curve by eye, trimming it to tidy it maybe*. Then draw around it. Using a pen to mark the leather gives me a more solid line to follow. Also, as I'm very colour blind I cannot actually see a scratch mark on leather

* if I'm going to make more of the same item I keep that card pattern shape

^ similar

https://www.amazon.co.uk/Mundial-2-inch-Red-Dressmaker-Shears/dp/B0009VEM54

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All I use for curves is a Don Carlos round knife. Before that knife curves were a dreaded nightmare, now they're a zinch and even enjoyable to cut.

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Learning to use a round knife changed my life.  Very versatile.  Tight curves, long straight cuts without a straight edge, skiving, trimming...  I have an old Midas Leather round knife I inherited and a Master Tool from Weaver.  I have been happy with both.  

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I will have to add the last Osborne round knife i got in exchange for a older one which got damaged is not a patch on the older one i had, good to use when it has been sharpened and stropped but will not hold a edge for very long so i was spending more time on keeping the edge in top order than on my leather work. I am not the only on here who thinks Osborne quality may have dropped which is a real shame. Have said this before think they are trying to compete with cheaper imports from the far east, think thats what did it for Dixons ( a old British maker of no nonsense Saddlers tools that did the job they were made for)  their quality dropped towards the end.

Glad to see George Barnsley are trying to buck the trend over here again no nonsense tools that do the job their single head might be a good knife to get not sure about shipping costs and import duties may make it way expensive. You might be lucky someone that side of the pond may stock them. 

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