Looking For Tips On Cutting Perfectly Square

[jenkins]

Hi all, first time posting, so apologies in advance for what is surely duplicate content or some grand faux pas I don't have the context to realize I'm making

I'm just beginning to learn hand stitching, and while every single part of the process is challenging for me, the one I'm having particular trouble with is cutting perfectly straight and square into a piece of leather.

I've been lightly outlining a guide into my leather using a template and a scratching awl (I believe it's called) without too much issue. But when it comes time to cut, I have the hardest time keeping my straightedge from slipping as I cut with a utility knife. I've also tried using a knife that was recommended at Tandy but the utility knife seems to cut much better. Does anyone have any best practices for keeping the straight edge on the leather without it slipping?

Additionally, once I do get a somewhat square piece of leather cut, and I fold it over to punch holes into it (using a pricking iron / punching iron / four pronged sharp thing) the leather has a tendency to skew and the pieces become mis-aligned and I end up ruining the whole project by punching holes bad holes into the project.

Any tips on those two particular issues would be very much appreciated. Thanks!

[Matt T]

Use a rotary cutter and a straight edge

[jenkins]

The issue is more around keeping the straight edge from moving, I'm not sure a rotary cutter would change that much.

[TXAG]

Yeah, I have a really nice Gingher rotary cutter and it doesn't work for $#@# on cutting a straight line on my leather. I have the same problem with the utility knife too. I usually end up scoring it with the utility knife and then bending it and cutting the rest of the way. (This is with a brand new blade also, so it's not that.)

I should probably just invest in a good round knife and be done with it...maybe if someone would ever buy any of my stuff, I'll be able to invest in such things.

[dirtclod]

You can try a stainless steel cork backed ruler. The ones i have i found at a office supply store. The cork is supposed to keep it from slipping, but i never have tried it. 15 inch rulers are the handiest for me.

[Jax]

Make sure your knife is really sharp, mark your line with a scratch awl or similar, then follow the line with your knife, takes some practice but is easier in the long run, in my opinion

[impulse]

It is a common problem that rulers slip. In cutting straps from a new hide, I must first start with a perfectly straight edge. I solve the ruler slip by clamping each end of my 1mtr long steel rule over the leather onto my cutting bench, using standard woodworking clamps. The sharpest tool to use and easiest to guide along the ruler is a surgical scalpel. These are quite inexpensive and usually available from eBay. For cutting square shapes use a steel set square (again clamped) to get accurate angle. If the leather is thin, stabilize it by temporarily lining the back with self adhesive shelf lining. Any residual adhesive can be removed with white spirits.

Hope this helps.

[Dwight]

Dirtclod's answer (cork backed s/s rulers) is about 60% of the answer to your problem. These rulers (I have an 18 and a 48) are worth their weight in gold for the leather worker.

The other 40% is the knife. Personally, . . . the carpenter's utility knife is my favorite for anything above 4 oz leather, . . . a 50mm rotary cutter does the 4 and below stuff very nicely, . . . especially any fringe I want to cut. Every brand new blade right out of the package first goes to my strop before it ever touches leather. Then strop it every time before you use it. Leather demands either sharp tools or blood sacrifice on your part, . . . and it is your choice. Dull blades will get you the blood sacrifice.

For absolutely square pieces, . . . you need a table with a flat & square edge, . . . and a triangular "rafter" square, . . . it looks like a 6 inch by 6 inch aluminum triangle with a lip on one side, . . . lay the leather along the edge of the desk, . . . put the square on it, . . . cut the perpindicular edge, . . . voila, . . . exact squares.

Final tip, . . . you cannot cut leather well when you are sitting on your duff. Stand up, . . . look straight down on what you are cutting, . . . and give it your total concentration. And again, . . . I cannot emphatically urge you too much to make sure your blades are SHARP !!!

May God bless,

Dwight

[jackd942]

Dirtclod's answer (cork backed s/s rulers) is about 60% of the answer to your problem. These rulers (I have an 18 and a 48) are worth their weight in gold for the leather worker.

The other 40% is the knife. Personally, . . . the carpenter's utility knife is my favorite for anything above 4 oz leather, . . . a 50mm rotary cutter does the 4 and below stuff very nicely, . . . especially any fringe I want to cut. Every brand new blade right out of the package first goes to my strop before it ever touches leather. Then strop it every time before you use it. Leather demands either sharp tools or blood sacrifice on your part, . . . and it is your choice. Dull blades will get you the blood sacrifice.

For absolutely square pieces, . . . you need a table with a flat & square edge, . . . and a triangular "rafter" square, . . . it looks like a 6 inch by 6 inch aluminum triangle with a lip on one side, . . . lay the leather along the edge of the desk, . . . put the square on it, . . . cut the perpindicular edge, . . . voila, . . . exact squares.

Final tip, . . . you cannot cut leather well when you are sitting on your duff. Stand up, . . . look straight down on what you are cutting, . . . and give it your total concentration. And again, . . . I cannot emphatically urge you too much to make sure your blades are SHARP !!!

May God bless,

Dwight

+1

[Tree Reaper]

Try to concentrate on downward pressure more than side pressure on the straight edge.

I use a steel framing square as well, more weight less movement and you can put a knee on the end to help hold it.

Clamping for cutting long pieces works real well, I have a 4ft. aluminum straight edge for that.

Sharp blade is a must.

Edited December 9, 2013 by Tree Reaper

[radar67]

Dwight's answer is right on the money. Stand up to get the most pressure on the ruler, sharp blades, and practice.

[Chief31794]

Totally agree with dirtclod, my only other trick to cutting straight is when I start cutting I cut in shorter lengths and multiple passes, I don't try to cut the entire side at one time and I cut very lightly to keep from "pulling" the leather. That plus an extremely sharp knife and cork backed ruler should make your life less challenging. I also always check my scratch awl lines to make sure they are square before starting cutting. I do that by measuring from corner to corner, the measurement should be exactly the same.

Chief

Edited December 9, 2013 by Chief31794

[Red Cent]

The rafter square will hold the leather with the lip of the square as you push against the cutting blade.

I also use these:

http://www.irwin.com/tools/browse/clamps/hand-clamps

with the aluminum cork ruler to cut straight lines. I use a utility knife without intending to cut all the way through the leather on the first pass. Then it is easy to follow the cut for another pass.

[Ed in Tx]

The same sort of issue can occur when cutting a belt strap from a large hide. I also use clamps on the straight edge to keep it from slipping, they work like a charm. If you are using the angled knife from Tandy that uses utility blades I would recommend trying Lennox brand blades that they sell at Home Depot, they have a titanium coated edge and in my experience cut better and longer than others I have used. They cost a bit more than some of the others but I can use the same blade a lot longer than other brands. For the hand stitching issue I have used a thonging chisel to make my holes, in order to keep the aligned use a straight edge to start your holes on the opposing sides. Doing that will guarantee that you are lined up.

[MadMorbius]

I use a large ruler to lay out the line with a scratch awl, but I haven't used a straight edge or a utility knife to cut in ages. The point of the utility knife is just too small to cut a straight line... basically the same thing that makes them great at detail work makes them hard to use for long straight cuts. Consider a good quality head knife or round knife, sharpen, polish and strope it. Tilting the blade forward as you cut will make it relatively easy to run a nice straight edge, while tilting it back on the point makes it more maneuverable for curves.

[jenkins]

Thanks for the great replies. I made another effort with a new cork-backed steel ruler and it made a world of difference. Still plenty to learn, and still not cutting perfectly square (though there are some great tips in this thread I will try soon), but I'm pleased that I was able to cut a relatively straight tiny 5 inch line for the first time.

Thanks again to all of you that took the time to respond.

[gentle ben]

Do you have a cutting mat with a grid? I find it a big help to get two edges parallel with each other - just lay the one you've already cut up against a line, then line up the ends of the ruler with another. Make sure you are above so the parallax effect doesn't stuff you up.

[Tree Reaper]

It's very difficult to cut square using a ruler .

You start with a single straight cut then make the other three cuts using a square to get a perfect square cut in your leather.

With a ruler you get all four cuts the exact same length but the cuts aren't square to each other.

If you prefer to use the ruler for cutting then lay the pattern out with a square and then use your ruler to cut.

[WyomingSlick]

I see there are several replies to your 1st issue, and little on your 2nd. You are aware that many leather items are assembled with some kind of glue prior to lacing or stitching, aren't you?

For a beginner leather stitcher, I highly recommend that you get a copy of Al Stohlmans: The Art of Hand Sewing Leather. It is worth far more than it's cover price. I also recommend that you get his book on Tools.

Books on leather working will teach you far more, faster, and more clearly, than asking questions on this forum. If you have the information in the book and still are having problems, then it is certainly time to come here and ask away.

[MadMorbius]

Youtube is also a valuable resource. If you're visual-kinisthetic, it can be of enormous assistance.

[leatheroo]

hi guys, here's my solution to the problem as taught by peter main. Good CLEAR ruler with metal edge if possible. The ruler should be marked in parallel and vertical lines to help get things square. My favourite is a quilting ruler. When it comes to cutting, use what ever is comfortable and appropriate to the thickness of the leather....as long as it is SHARP.

Now comes the technique.....ONLY EVER CUT DIRECTLY OPPOSITE TO THE HAND PRESSING DOWN ON THE RULER.

So if i wanted a yard length cut, i would start with the ruler set straight, starting at the top, left hand pressing down on ruler, i would make a firm cut about 6 inches long....then without lifting the blade, my left hand snakes down the ruler and i continue cutting only when there is pressure on the ruler opposite to where i want to cut.....continue moving down the leather.

Your hands should always be opposite each other. It sounds a awkward, but many of you probably do this without thinking, and the movement gets to be quite fluid and produces a nice straight cut .

Hope this helps

cheers

caroline

[nwdetectorist]

Parralax Error and Natural Lighting (the real sunshine) or Natural Lighting Products (full spectrum)

http://www.ehow.com/how_10000073_prevent-parallax-error.html

Errors in Measurement

http://en.wikipedia.org/wiki/Parallax

The lighting that I use to help with my no-line bifocals, so that I may actually get something crafted right.

These lights can be purchased at Fred Meyers, Krogers, and other retailers.

I am also a newbie/returning to a long lost hobby of mine, and no I do not always do so well with getting clean edges and a nice square layout.

Learning to be a professional is learning how to adjust for, integrate, and hide those minor errors in fabrication:)

Thanks,

nwdetectorist

[Sturme]

I had this issue, then I switched to a cork backed ruler, and a head knife. I really feel the head knife made a huge difference. main thing is to keep your head knife sharp, and read up on proper usage of it.

[Nuttish]

I find the lack of feedback and accuracy using a ruler unacceptable. Even a clear ruler obscures the edge. It's also far too easy to make irreparable errors if the straightedge slips.

When I rarely use a ruler and rotary cutter on unfinished vegetable tanned leather, I use a heavy steel carpenter's straightedge that I glued latex strips to. They have far better grip than cork. You can get them as large rubber bands for artists's drafting clipboards at Blick. Latex will still slip on waxy or fatty tannages.

Now I lay lines out with a sharp awl and a heavy steel straightedge and freehand a very sharp round knife. I just find it easier to get better cuts this way. You can roll in and out of your cuts to avoid distorting the leather and getting bowed ends and it's easier to nibble in to correct those inevitable little deviations from the line or make them less obvious by stretching the error over a longer distance. Stand over your work so you can both get the appropriate mount of blade into the leather and cutting surface and make sure your knife is straight. Unlike the rotary cutter, which doesn't always make it easy to tell whether you've made a clean vertical cut in one pass, you get useful feedback from the round knife telling you you're doing well. YMMV.