Help me undestand

[KennethM]

Hello everyone.My name is Kenneth and I am new here and new to leatherworking..Orginally a blacksmith/Bladesmith that has been struck by the beauty of leather working craft..I have a question.I been practing making bi fold wallets which has been fun.I am using an acrylic template..I hold down the template onto my veg tan leather and trace around it with a scalpel knife..sometimes when I inspect the leather aftwr words I noticed bits of it is undercut .Sorter then the template and sorter in some areas then others..

 

I was thinking maybe I am apply to much pressure onto the template as I hold it down?Or maybe a dull blade .I wanted to seek you leather gurus advice before I keep making this mistake lol.I really want to learn and improve.Thank you for taking time to read this!

[battlemunky]

Sounds to me, from having done it a hundred times myself, like you aren't keeping your knife completely straight. The good news about it is when you do your edge work it should remove most errors like that. A little bit of edge beveling and some sanding and slicking and you won't see it anymore. Also, cutting more and more leather will help too but I don't know if you'll ever really get away from small deviations from hand cutting.

If you are capable enough with your blacksmithing and have a press, you could always made a set of dies that you can then press out some pieces and it'd get you all uniform all the time.

Welcome to the forum!

[KennethM]

Thank you for the reply brother!You know that makes total sense.I dont know why I didnt think of that.I have noticed hand curting the pattern HAS been the hardest part so far lol!

 

Another question..Do you have a certain knife you find work better?I have alot more practice to do with the scaple to get good At it.I was curriors if those rotary cutters were better?

[battlemunky]

You are welcome!

I have a rotary cutter and a few other types of knives but honestly what I end up using more than any of them is an Olfa snap blade knife. I guess Exacto would be very similar. I also use a regular old Stanley utility knife but do prefer the snap blade knife to that. Link to that knife is below.

And the scalpel being a pretty fine blade likely flexes a bit as well and that'll lead to some variance but quite a few people use them. There isn't a huge need for a high dollar knife if/until you get deeper down the rabbit hole or you just want to. As long as the leather is getting cut and it isn't messing up your work is all that needs to happen.

https://olfa.pl/en/product/olfa-a-1-1793283183

[NVLeatherWorx]

I have also used a scalpel for some cuts and have found that the blades do indeed flex as @battlemunky has suggested so I only use the scalpel for my detail work when doing Filigree backgrounds.  My standard cutting knife of choice is a #2 X-acto knife as it is a beefy blade and very sturdy.  I have recently started using the Z-blades that they make and they are very sharp; can get a cut through 9 to 10 oz. leather on the first run smooth as can be.  It also sounds like you may also be tipping your knife slightly so that can exaggerate the amount of undercut that you end up with but those do work themselves out once you get into the edge finishing process.

[zuludog]

I use scalpels for making model planes, but I think they're a bit too light for all but the thinnest leather

Xacto knives are a bit heavier, and seem to be more popular in USA than Britain

An obvious choice is a craft knife, often known in Britain as a Stanley knife, even if it isn't actually made by Stanley. I think you call them box cutters in USA The blades can be improved by sharpening on a fine stone and a strop. This lowers the shoulder of the bevel and polishes it. In fact once you get away from disposable blades to a fixed blade, you'll need a fine stone & strop anyway

After that you're looking at specifically leather working knives. Search Google & YouTube for - Clicker Knife; Kiridashi; Japanese Style Leather Knife; Head Knife; Round knife; and you'll see the sort of things that are available. Be warned - some of them are expensive, but perhaps you could make your own?

Also search YT for Beginners Leather Tools

As mentioned by battlemonkey, one of the cheapest and easiest knives to start with is a snap blade knife

Whatever you settle on, you will need two knives. The first is for cutting leather. The second is for sharpening pencils, opening parcels and so on; it's purpose is to make sure you use the first knife exclusively for cutting leather

I think you'll find this video interesting - 'How to make a Simple Hand Made Leather Wallet' by Nigel Armitage. The knife he's using is a clicker knife

Edited September 29, 2018 by zuludog

[alpha2]

I still sometimes use a rotary cutter for long straight cuts, especially with thin leather. It cuts downward instead of pulling the leather. It's also easy to see if the blade isn't vertical. Not that good for corners, though. 

[Sheilajeanne]

Yeah, the rotary knives are the best for thin leather, which stretches when you are cutting it. Sometimes the pressure of the knife will cause just enough stretch that you don't get a nice straight cut. The rotary cutter does away with this problem.

[KennethM]

1 hour ago, battlemunky said:

You are welcome!

I have a rotary cutter and a few other types of knives but honestly what I end up using more than any of them is an Olfa snap blade knife. I guess Exacto would be very similar. I also use a regular old Stanley utility knife but do prefer the snap blade knife to that. Link to that knife is below.

And the scalpel being a pretty fine blade likely flexes a bit as well and that'll lead to some variance but quite a few people use them. There isn't a huge need for a high dollar knife if/until you get deeper down the rabbit hole or you just want to. As long as the leather is getting cut and it isn't messing up your work is all that needs to happen.

https://olfa.pl/en/product/olfa-a-1-1793283183

Thank you for the link brother ima check this out..I thought about the box cutter knife also..my self healing cutting mat is supposed to be here today..this kitchen cutting board I think is filling my blades fast

1 hour ago, NVLeatherWorx said:

I have also used a scalpel for some cuts and have found that the blades do indeed flex as @battlemunky has suggested so I only use the scalpel for my detail work when doing Filigree backgrounds.  My standard cutting knife of choice is a #2 X-acto knife as it is a beefy blade and very sturdy.  I have recently started using the Z-blades that they make and they are very sharp; can get a cut through 9 to 10 oz. leather on the first run smooth as can be.  It also sounds like you may also be tipping your knife slightly so that can exaggerate the amount of undercut that you end up with but those do work themselves out once you get into the edge finishing process.

Thank you for the reply brother!Now that you guys point it out I do notice the flex in the blade.Ill look into the beefy blades!

[KennethM]

1 hour ago, zuludog said:

I use scalpels for making model planes, but I think they're a bit too light for all but the thinnest leather

Xacto knives are a bit heavier, and seem to be more popular in USA than Britain

An obvious choice is a craft knife, often known in Britain as a Stanley knife, even if it isn't actually made by Stanley. I think you call them box cutters in USA The blades can be improved by sharpening on a fine stone and a strop. This lowers the shoulder of the bevel and polishes it. In fact once you get away from disposable blades to a fixed blade, you'll need a fine stone & strop anyway

After that you're looking at specifically leather working knives. Search Google & YouTube for - Clicker Knife; Kiridashi; Japanese Style Leather Knife; Head Knife; Round knife; and you'll see the sort of things that are available. Be warned - some of them are expensive, but perhaps you could make your own?

Also search YT for Beginners Leather Tools

As mentioned by battlemonkey, one of the cheapest and easiest knives to start with is a snap blade knife

Whatever you settle on, you will need two knives. The first is for cutting leather. The second is for sharpening pencils, opening parcels and so on; it's purpose is to make sure you use the first knife exclusively for cutting leather

I think you'll find this video interesting - 'How to make a Simple Hand Made Leather Wallet' by Nigel Armitage. The knife he's using is a clicker knife

Thank you for the info brother!Ill have to forge a kardishi ..I need one anyway they come in handy when I'm doing wood work for my katana handles.

10 minutes ago, Sheilajeanne said:

Yeah, the rotary knives are the best for thin leather, which stretches when you are cutting it. Sometimes the pressure of the knife will cause just enough stretch that you don't get a nice straight cut. The rotary cutter does away with this problem.

Awesome thank you brother

[KennethM]

35 minutes ago, alpha2 said:

I still sometimes use a rotary cutter for long straight cuts, especially with thin leather. It cuts downward instead of pulling the leather. It's also easy to see if the blade isn't vertical. Not that good for corners, though. 

For sure,I didn't think they would be good for corners

[battlemunky]

Make two kiradashi if you do @KennethM, you don't want to use the leather one for wood or else you'll be busy fixing the edge all the time. You want your leather knife edges (of all kinds) polished mirror smooth and scary sharp.

[Sheilajeanne]

Yeah, I still laugh at that story about the guy who decided to test the edge of the leather worker's round knife, after he'd cut out a holster for him... 

 

Edited September 29, 2018 by Sheilajeanne

[Big Sioux Saddlery]

I don't remember seeing that thread before ("Things I've Learned From Leather Working")  Lots of goodies in there, and I've done them all!  I have put a barrier up in my shop to prevent the public from going back into my work space.  If someone wants to see that area, I'm happy to give them a tour, but I don't want people, (especially children whose parents are constantly oblivious to what their children are doing at any given time), wandering back there and picking up sharp objects. 

[Mattsbagger]

I trace acrylic templates with a scratch awl. Then use a metal straight edge and rotary cutter on straight cuts and a clicker knife or exacto on other lines. I find holding a template with one hand and cutting around it with another impossible for me.

[zuludog]

6 minutes ago, Mattsbagger said:

I trace acrylic templates with a scratch awl. Then use a metal straight edge and rotary cutter on straight cuts and a clicker knife or exacto on other lines. I find holding a template with one hand and cutting around it with another impossible for me.

Yes, that's a good idea; it's what scratch awls were made for, hence the name

[Matt S]

There's a lot of great suggestions in this thread and I'm not going to repeat any of them, but I think one thing that hasn't been mentioned yet is that leather, frustratingly, can move once it's cut. Consider that a cow is, roughly speaking, spherical (ask a physicist if you're in doubt!) and a hide of leather is flat. When the tanner flattens it out they use heat, pressure and moisture to achieve this effect, which is pretty successful. However the residual stresses from this, added to the grain patterns and directions from when it was a beast, can make some odd and frustrating things happen -- but only once the piece is liberated from the hide, and those stresses are no longer held in check. As a smith and woodworker I'm sure the idea will be familiar to you. These stresses and odd grain are most pronounced in the pieces of hide which have changed the most to become flat -- neck, leg, belly, chest etc. -- and I suspect are most pronounced on the smaller beasts like goat, sheep and deer, though I work mainly in cow so don't have enough empirical evidence to say that for certain.

It's most obvious when cutting a straight strap off a side -- you can mark a line with an engineer's straightedge, cut it exactly, then tear out your hair at why the strap has a few millimetres' bow along its length. Other odd things can happen from grain. I have a bifold wallet I made earlier this year which doesn't fold straight but at an angle. I was trying to be clever and managed to squeeze the back from the neck of a side I had. The only way it would fit was at an angle. It was only once I'd finished the wallet I realised that that angle was the very same angle at which it naturally folds. Guess how clever I feel now!

Sometimes, when a specific dimension is needed, I cut it from the hide oversized and then trim or sand to the exact size, or to match another component as needed. This, with careful selection of where I cut the pieces, usually eliminates the problem.

[battlemunky]

lol

Dr: Hughes: Just approximate the chicken to be a sphere.

Good points @Matt S!

[KennethM]

7 hours ago, Matt S said:

There's a lot of great suggestions in this thread and I'm not going to repeat any of them, but I think one thing that hasn't been mentioned yet is that leather, frustratingly, can move once it's cut. Consider that a cow is, roughly speaking, spherical (ask a physicist if you're in doubt!) and a hide of leather is flat. When the tanner flattens it out they use heat, pressure and moisture to achieve this effect, which is pretty successful. However the residual stresses from this, added to the grain patterns and directions from when it was a beast, can make some odd and frustrating things happen -- but only once the piece is liberated from the hide, and those stresses are no longer held in check. As a smith and woodworker I'm sure the idea will be familiar to you. These stresses and odd grain are most pronounced in the pieces of hide which have changed the most to become flat -- neck, leg, belly, chest etc. -- and I suspect are most pronounced on the smaller beasts like goat, sheep and deer, though I work mainly in cow so don't have enough empirical evidence to say that for certain.

It's most obvious when cutting a straight strap off a side -- you can mark a line with an engineer's straightedge, cut it exactly, then tear out your hair at why the strap has a few millimetres' bow along its length. Other odd things can happen from grain. I have a bifold wallet I made earlier this year which doesn't fold straight but at an angle. I was trying to be clever and managed to squeeze the back from the neck of a side I had. The only way it would fit was at an angle. It was only once I'd finished the wallet I realised that that angle was the very same angle at which it naturally folds. Guess how clever I feel now!

Sometimes, when a specific dimension is needed, I cut it from the hide oversized and then trim or sand to the exact size, or to match another component as needed. This, with careful selection of where I cut the pieces, usually eliminates the problem.

Thoroughly enjoyed reading this and it made sense .Being new to leather I been trying to use every peice possible .I have noticed some of the I guess weapons or wrinkles tend to not work well.I imagine maybe higher end leather works better and is easyier to deal with.

[KennethM]

I just wanted to thank everyone for the replies..All info is great and leatherwork already improving from minor adjustments

[Rockoboy]

22 hours ago, KennethM said:

leatherwork already improving from minor adjustments

Come on man! Pics or it didn't happen. Them's the rules.

[zuludog]

KENNETH M Have a look at this video - 

'Designing and Making Leather Slip Cases' by Ian Atkinson

Although it's about making slip cases and not wallets, they are similar, and it is an excellent video on how to mark out and assemble thin leather items