Trouble cutting leather

[allenayres83]

Im having problems with the simplest of things. I am trying to get smooth cut lines. Are my cut lines ever going to be perfect and right on my template lines? I seem to drift off a little. Also when I am making curved cuts they tend to look choppy instead of smooth. I try to sand it down to where it looks like a smooth profile but when I bevel my edge it is very obvious that there is still same jaggedness to my cut. Any pointers on what I could do to improve? I am using a #2 Xacto knife if that matters.

[Jorge700]

La práctica ase la bb perfección

[fredk]

19 minutes ago, allenayres83 said:

Im having problems with the simplest of things. I am trying to get smooth cut lines. Are my cut lines ever going to be perfect and right on my template lines? I seem to drift off a little. Also when I am making curved cuts they tend to look choppy instead of smooth. I try to sand it down to where it looks like a smooth profile but when I bevel my edge it is very obvious that there is still same jaggedness to my cut. Any pointers on what I could do to improve? I am using a #2 Xacto knife if that matters.

I think your blade is too small. Its cutting only a few mm at a time so it can wander easier. The wider the blade the more it cuts. Even a box cutter blade is better

Use a good straight edge for the . . .  errr . . . .straight cuts. When I cut a curve I tend to not only draw the blade around but also to turn the leather. Often, on outside curves I use leather scissors/shears

[zuludog]

Could be that an Xacto blade is too small. A Stanley/box cutter/utility knife has a bigger blade; the handle is bigger/fatter so you get a firmer grip; and they're not very expensive.

You could also consider a clicker knife, with the interchangeable straight and hooked blades, which is a bit more expensive, but not impossibly so. Straight blade for straight cuts; hooked blade for tighter curves

As mentioned by FREDK, if you hold the handle flatter you will get more of the cutting edge in contact with the leather

Firstly mark out the shape of the piece with a scratch awl/round awl; then make a light cut around the template; then deeper and deeper cuts, staying in the same groove all the time till you've cut all the way through

Even new Stanley knife blades work better when they've been stropped

Have a look at YouTube videos for people making the sort of things you're interested in and you'll see how they do it 

[LumpenDoodle2]

My preferred way is to use a leather silver marker around the template, then with the template removed, follow the line with a round awl, then either use a round knife, or for lots of curves, I use a small Stanley knife.   Doing it this way allows me to tweak patterns a little bit for a bit of personalisation for each item, but it also stops me getting into a bit of a rush,, and so not wander off the line.

I also think that it’s important to make sure that whatever knife you choose, it fits comfortably in your hand.   It’s way easier to follow the  curves if you have full control of the knife, and it’s proper sharp.   Stanley knife blades are disposable for a reason, and starting out with a few minutes stropping my round knife is quite relaxing.

Edited January 19, 2021 by LumpenDoodle2

[Hardrada]

Xactos are just one cutting tool to have and they're not suitable for everything.

What weight is the leather you're cutting?

If you have to make several passes with the knife, you're increasing the chances of going off with each pass.

Methinks you need to get additional cutting tools, such as a half-moon knife, a Japanese skiving knife, and an Olfa snap-off utility blade. The latter is probably the cheapest and more accessible and easier to use option for you right now (not that that means you shouldn't procure the others): if you're cutting thick leather you can pull more blade out (I normally pull out the blade(s) up to two notches when cutting >8 oz leather).

https://www.olfaproducts.com/olfa-l-5-fiberglass-rubber-grip-utility-knife-18mm.html

[Webicons]

In addition to the comments above I cannot stress the importance of a strop to polish your blades.  Exacto blades are pretty sharp but a few passes on a leather strop will make it scary sharp.  
Its an easy project too.  Just mount (glue) a piece of vegtan onto a piece of wood.  Load it up with green compound and polish all your blades.  You’ll be amazed the difference it makes. 
 

I’ve used many different blades, some pretty expensive, but I make 80% of my cuts just using a Japanese style skiving knife in aogami blue steel.  You can find them reasonably priced around 40 bucks.  Just my 2c.

[AzShooter]

I normally used a Stanley Knife but lucked into buying a Head Knife from Tandy.  I know, there are better Head Knives but I wanted to test the waters first.

Most important is to keep it sharp.  Stropping is the key but a good set of stones also helps. The reason for the Head Knife is that I can cut curves very easily compared to a straight knife.

I'm still learning how to use it and what platform to cut on.  Self Healing matts work but the knife will get stuck sometimes.  A hard plastic cutting board works but when I'm doing a large cut the head knife is the key.

[Tugadude]

For long, straight cuts, especially on stretchy leather,  I like to use a rotary knife.  I find that you can eliminate almost all of the "pull" that can cause leather to deform as you are cutting it.  If you haven't tried it, I recommend you give it a shot.

[allenayres83]

19 hours ago, Hardrada said:

Xactos are just one cutting tool to have and they're not suitable for everything.

What weight is the leather you're cutting?

If you have to make several passes with the knife, you're increasing the chances of going off with each pass.

Methinks you need to get additional cutting tools, such as a half-moon knife, a Japanese skiving knife, and an Olfa snap-off utility blade. The latter is probably the cheapest and more accessible and easier to use option for you right now (not that that means you shouldn't procure the others): if you're cutting thick leather you can pull more blade out (I normally pull out the blade(s) up to two notches when cutting >8 oz leather).

https://www.olfaproducts.com/olfa-l-5-fiberglass-rubber-grip-utility-knife-18mm.html

I am cutting 5-6 oz leather. I will definitely try out all of your suggestions and hopefully see some improvements with practice. So will these techniques help to the point where my curves wont be choppy? Or is some sanding to round things out to be expected?

[LumpenDoodle2]

I’m no great expert, but I cut 3.4mm (about 8-9oz?) leather all the time, and any choppy curves are usually caused by me stopping and starting a cut, rather than keeping the ‘flow’ going.   That, and on the odd occasion, convincing myself I’m too busy trying to cut the leather, rather than be sensible and stop to sharpen the blade.

[Woodshed]

Something that has help me is much better lighting (I'm using a total of 240 watts close to and directed at the cutting board), and also working very deliberately to focus my vision in front of the blade at where I want the blade to go as I cut. I found that I had a tendency to want to look at where the blade had been to see if the cut was staying on track, which wasn't helping at all.

[Hardrada]

On 1/20/2021 at 11:43 AM, allenayres83 said:

I am cutting 5-6 oz leather. I will definitely try out all of your suggestions and hopefully see some improvements with practice. So will these techniques help to the point where my curves wont be choppy? Or is some sanding to round things out to be expected?

Ahh, curves. Now I see why you're using an Xacto. For curves, the best knife is the half-moon knife, really. You're gonna need to practice with that knife a bit, though, before you can master it; but it's not as scary as it sounds (or as it looks), if you watch the proper technique and then replicate it, you can be up and running pretty quickly. I was cutting smooth curves with mine in no time (same day, basically).

 

Here's another one with techniques. I disagree on the sharpening approach with this fellow, but his cutting techniques are spot on (jump to the ~3:00 mark to see the S-curve cutting):

 

What they mention there is paramount, though: the knife has to be very sharp. Always.

This is true of any knife, anyway, not just the half-moon. A dull knife will force you to make several passes and it's also more dangerous than a scary sharp knife, as you'll try to use more force/pressure and if it slides or bounces on you or if your finger or limb is in the way, God help you.

Lacking a half-moon knife, you can cut curves with a straight knife such as the Japanese skiving knife by successive straight cuts. Start at 45°, cut, then cut the newly made 'pointy' ends at 45°, and so forth till you've a curve.

RE: sanding, I never sand my edges, if they need evening out I glass them with the knife instead.

Here're two more references. In the first one several cutting choices are discussed and shewn, and sure enough, he does say that a craft knife (Xacto) is not the best to cut leather with and why; the second one concerns clean edges, so that might be useful to you.

 

 

Edited January 22, 2021 by Hardrada

[Woodshed]

On 1/19/2021 at 12:48 PM, allenayres83 said:

Im having problems with the simplest of things. I am trying to get smooth cut lines. Are my cut lines ever going to be perfect and right on my template lines? I seem to drift off a little. Also when I am making curved cuts they tend to look choppy instead of smooth. I try to sand it down to where it looks like a smooth profile but when I bevel my edge it is very obvious that there is still same jaggedness to my cut. Any pointers on what I could do to improve? I am using a #2 Xacto knife if that matters.

Another thought popped in, hope its a helpful one. Really, cutting leather accurately isn't necessarily a simple thing. It can be very challenging. One slip can be an expensive mistake. So lately I've been making templates using picture frame mat board from Hobby Lobby and heavy paper. Somewhere on this site a video link showed a seriously skilled maker making templates for a wallet this way (I think from Iceland?). I figured it could only help me to borrow from his techniques.

So now, after carefully drawing whatever parts will be needed on paper, I use knives to cut away the excess paper, then glue the shapes to contrasting color mat board, and finally use knives (again) to cut out working templates along the edges of the glued-on paper objects. Before any leather is cut, there have been two practice runs and a lot learned about what knives and what directions of cut work for any given feature. It's a lot less expensive to practice on paper and if the template comes out right, it's re-usable for any do-overs.

I have so far added several knives as a result, and will likely add a few more over time. All the best, hope this is helpful.

[AzShooter]

2 hours ago, Woodshed said:

Another thought popped in, hope its a helpful one. Really, cutting leather accurately isn't necessarily a simple thing. It can be very challenging. One slip can be an expensive mistake. So lately I've been making templates using picture frame mat board from Hobby Lobby and heavy paper. Somewhere on this site a video link showed a seriously skilled maker making templates for a wallet this way (I think from Iceland?). I figured it could only help me to borrow from his techniques.

 

What a wonderful idea.  This I've got to try.  I keep all my paper templates but sure would like something permanent.  I'm going to try Michaels tomorrow.

[327fed]

I have found these hook utility blades really great, especially on curves. Hard to keep vertical and hard to find. I think these came from Lowe’s. I also use a wheel fabric cutter a lot on straights, but the steel ruler ruins them pretty quick. I also picked up a $6 led desk lamp at Walmart. Small, easy to move and pinpoint. 

Edited January 27, 2021 by 327fed

[$$hobby]

i didnt read all of the replies...

but imo, what it comes down to will is what you are trying to cut, how thick and what you are using.

if you are going to use any of those disposable type blades, then dont be cheap and keep on using 1 for months on end.  Replace with new often.  how often?  well you will figure that out as soon as you replace with a new one.

when i started in leatherwork it was in Jr High.  My instructor had a really nice and SHARP head knife.  NO ONE was allowed to touch it since it was his personal tool.  but when it came to cutting the leather, it cut it like butter.  It looked effortless and he knew how to use it too.  So, if you want to, get one and put a good edge on it and learn how to use it.  Also, if you go that far as to buy one, then learn how to put an edge on it anyway since a tool like that works best when its sharp.

also, not sure what you are making and how important the cut/line is, but no one really knows you screwed up except yourself.   

But with your description of your "choppy" it appears you are starting/stopping alot?.   again, try using a new blade every so often and go from there.  

last comments....

 > how's the lighting in your work area?  If you have harsh direct lighting, you may have shadows to deal with.  

 > cutting surface?  depending on what you are cutting on, it may catch your knife point too.