Cutting Questions

[RobC01]

I'm just getting started in leather working and I've got questions about cutting. Some of the shapes I'm needing have curves and angles. I'm using 8-9oz leather and a husky razor knife. I'm having trouble following my trace and leaving little cut "burrs" when I have to re-cut over a line due to thickness or not staying in the line.  

1. Can someone recommend a different tool or method?

2. Will an edge slicker sufficiently smooth those cut burrs? 

Thanks for any help.

[fredk]

1a. I've never heard of a Husky Razor Knife; but by the sound of it its too light duty for the job. A heavier knife with a thicker/wider blade is needed. A handy one would be a box-cutter type with 18mm wide snap off blades

1b, run over your tracing with a blunt awl first; even wetting the leather then following the tracing with an inked-out ball-point pen, to mark your cutting line first. Cut slowly and steadily. Cut away from corners, not into them. Cut half-way around a curve, then cut from the other end towards that half-way point, finishing the cut. Do it in small stages, try not to do it all in one big cut

2. you may need to sand the edges to even them up before using a slicker

[Grumpymann]

sandpaper. Works for me.

[bikermutt07]

A husky is fine to start out with (standard utility knife for Fredk sold by home Depot).

Make yourself a leather strop with Jewelers rouge. Then strop your blade. You will see a world of difference in those throw away blades.

Then follow Fred's steps outlined above.

This will increase your ability a good bit.

[zuludog]

I've found the Husky knife via Google, it looks like a replaceable blade craft knife. In Britain we often call these Stanley knives after the best known brand. I think you call them box cutters in USA

I notice it is a folding knife, which would make it bigger and probably clumsier. I suggest you get a fixed blade model such as the Stanley 199 or 199A, though there are other makes

The blades are sharp, but can be improved by sharpening them yourself, because you will polish them, and reduce the shoulder of the bevel; in fact the more you sharpen them the better they seem to get

You will need a fine stone; oil, diamond or water/ceramic, whatever you fancy, and a strop. Make your own from oddments of wood & leather, this will be just about the easiest piece of leatherwork you will do. Get some jeweller's rouge or proper honing/stropping compound; it's not that expensive, and a bar will last for ages. There is loads of advice about sharpening & stropping on this forum and on YouTube. In fact the key to good leatherwork is to have razor sharp knives, whether fixed or replaceable blades

You could also consider other knives, like a clicker knife or a Japanese style kiridashi - search Google and YouTube. There are other types, it's a bit of trial and error really to find what suits you

Whatever you get, you will need two knives - one just for leather, and a general one for opening parcels, sharpening pencils and so on; it's purpose is to make sure you use the first knife exclusively for cutting leather

Mark out the pattern with a scratch awl, followed by a light cut with the knife. Concentrate on getting the shape correct, not on a seriously deep cut. Once the shape or outline has been set you can then make deeper cuts, and the blade should follow the pattern you have made. You may need to tidy up the edges with sandpaper

I assume you are using a proper cutting mat

I started out using a Stanley knife and resharpened the blades as they became blunt. Over the past few months I've been using a Japanese style leather knife for straight cuts & gentle curves, and a kiridashi for tighter curves

[RobC01]

Thanks to all! Sorry, I should have been more descriptive on the razor knife. 

What grit sandpaper do you recommend?

[zuludog]

Sandpaper - about 80 grit, that's fairly coarse

But before that you can trim the edge just by running the knife almost flat along the eddge

[RobC01]

47 minutes ago, zuludog said:

Sandpaper - about 80 grit, that's fairly coarse

But before that you can trim the edge just by running the knife almost flat along the eddge

Excellent, thanks! 

[JKHelms]

On 12/10/2017 at 0:24 AM, bikermutt07 said:

A husky is fine to start out with (standard utility knife for Fredk sold by home Depot).

Make yourself a leather strop with Jewelers rouge. Then strop your blade. You will see a world of difference in those throw away blades.

Then follow Fred's steps outlined above.

This will increase your ability a good bit.

The best razor knife blades I have found are Lenox titanium. Still have to strop them ,but will cut 8-9oz like butter. 

[bikermutt07]

Yeah, I have a Lennox for work. I have kind of moved away from the razor knives for my leather stuff.

[zuludog]

There are loads of videos on YouTube about leatherwork. Watch as many as you have the stamina for to see how they do their cutting

'Making a Leather Knife Sheath' by Jacklore uses a Stanley knife

'Making a Leather Knife Sheath' by Ian Atkinson uses (admittedly briefly) a Stanley knife, a clicker knife, and a round knife

Cutting inside curves is difficult, which is why one of them uses a strap end cutter, but that's not necessary, and is quite expensive

A round knife is the traditional leather knife, but they're also expensive, and need practice & experience to use well

Sharpen your replaceable blades, practice, learn how to use it, and take your time. If you're still not happy think about a clicker knife, Tandy sell them as Industrial knife #3595-00. Or look at videos of a kiridashi

[Lakejumper]

Rob,

if you're located in the U.S. and need a cutting mat, Joann's Fabrics has them for a good price with their coupons. Check out their website for coupons.

[RobC01]

On 12/11/2017 at 5:30 PM, zuludog said:

Sandpaper - about 80 grit, that's fairly coarse

But before that you can trim the edge just by running the knife almost flat along the eddge

Do you wet your edges before sanding? I was thinking about using a Dremel, but it seemed to rough up the dry edge and throw a lot of 'dust'.

[zuludog]

Hello RobCO1, We're looking at two similar, but still different things here - Cutting and Edge Finishing

CUTTING

In theory, if your knives are razor sharp and you follow the outline or pattern  you want, the cut edges of the leather will be clean, neat, smooth, and exactly how you want them to be, and mate up perfectly.

Coarse sandpaper is only used to remove the occasional bump, slip, protrusion,  misalignment, ragged edge or other mistake resulting from cutting out your pieces. If you get your cutting right, there's no need to sand.

 

EDGE FINISHING

Once two pieces of leather have been mated together by clamping or tack - glueing, and tidied up as described above, the resulting edge should be level, with no overlap between the pieces. Then the procedure I use is to sew,  bevel; a light sand sometimes with a slightly finer grade of paper, say 100 or 120 grit; then burnishing with gum tragacanth, Edge Kote, and so on. Search YouTube for leather edge finishing, burnishing, and so on, there are lots of variations

I have only used sandpaper dry and only occasionally; any dust is minimal and I can cope with it; I've never considered using it wet on leather. I've only used it by hand, I can definitely see that dry sanding with any sort of power tool would produce a lot of dust

You can use power tool for burnishing, that's different to sanding, but I've heard that sanding with a Dremel can burn out the motor; to be sure you need something more powerful like an attachment on a bench grinder

Cheap edge bevellers produce a flat or straight cut, essentially taking 45 degrees of the corner; that's why I usually follow up with sandpaper to produce a more rounded corner. No problem with that, as long as you're aware of it, but they do have their place

More expensive edge bevellers have a concave underside which leads the tool onto the corners and produces a more rounded corner, hence less need for sanding.

Search YouTube for videos on sheathmaking, which often show sanding, bevelling, and burnishing leather edges, as the edges on sheaths tend to be noticeable, so a lot of attention is paid to that. The videos by Jacklore  and Ian Atkinson are in any case, first class tutorials on leatherwork. They use power sanders, but you can obtain similar results by hand, it just takes longer.

Edited December 16, 2017 by zuludog

[ChasCS]

On December 12, 2017 at 2:39 PM, Lakejumper said:

Rob,

if you're located in the U.S. and need a cutting mat, Joann's Fabrics has them for a good price with their coupons. Check out their website for coupons.

That's quite the collection of cutting mats. ;-)

http://www.joann.com/search?q=Cutting+board

Chas

[RobC01]

5 hours ago, zuludog said:

Hello RobCO1, We're looking at two similar, but still different things here - Cutting and Edge Finishing

CUTTING

In theory, if your knives are razor sharp and you follow the outline or pattern  you want, the cut edges of the leather will be clean, neat, smooth, and exactly how you want them to be, and mate up perfectly. [•••] If you get your cutting right, there's no need to sand.

EDGE FINISHING

 

You can use power tool for burnishing, ...

More expensive edge bevellers have a concave underside which leads the tool onto the corners and produces a more rounded corner, hence less need for sanding.

 

I think for future projects, I need to just start with a quality knife. Wetting the edge did help when using a Dremel to clean up cutting errors. I used  a #3 edge beveler, and I've got a set of Cocobolo burnishing wheels that I'm getting ready to try using instructions I found pinned on here by Bob Park. I'll also be checking out the YouTube sources you mentioned, I'm trying to soak up as much info as possible!

Thanks!

[Grumpymann]

I got a cheep round knife on  amazon I practice sharpening an edge and cutting with it. And after a few projects it and a Japanese skiving knife for long runs they are the things I most use. I have a few craft knives I use for fine detail but they are rarely in use as of late.