In this week's video, I needed to thin a piece of leather to a uniform thickness.
Now I wanted to show it in the video, but it was taking up so much time, that I decided to do a separate video on just
using the Schärffix machine.
Now, most English speakers will call it the "sharf fix" machine, I'm pretty sure Germans will say "share fix",
though I'm probably hurting the ears of German speakers both ways.
But I'll stick with "share fix".
The kit comes in a handy box for storage.
Comes with the machine, some extra rollers, some razor blades, and the hex driver for removing the blade.
Now you can buy them in the UK from Hewit's.
Talas in the US, Cali Anderson in Sydney, or from the manufacturer, Schmedt in Germany.
So the machine has two adjustments screws and a control lever opening the mouth of the paring section.
So I'll go through those in a moment.
It clamps to a bench.
Now my bench is too thick for the clamp, so I had to add that chunk of wood on the edge of the bench.
So you can probably tell by looking at my videos when I got this machine because that chunk of wood appeared, and that
thing always catches my sewing thread when I'm sewing.
So I've clamped it to the bench.
So the lever at the back opens the mouth up for inserting the leather.
Now, I've noticed a lot of people don't actually use that, but I always do.
Some people - they'll push the leather in pulling it forwards.
So it's pulling it away from the blade as they do it.
That's great, but I've cut so many pieces of leather doing that, that I just always open it up.
The large horizontal knob adjusts the opening, so how thick the leather will be pared to.
Now you don't want to take off too much leather at once because it causes too much drag and it will pull the leather
up and it'll cut through the leather.
I forget what they I recommend in the manual, but I wouldn't take more than a third of the thickness of the
leather off at once.
The second adjustment is adjusting the angle of the blade.
If you don't want to do a parallel cut, if you want to do edge paring, then you can adjust this angle.
Once you set the angle, whether it's parallel or at an angle - one way or the other - the machine is pretty clever
at holding that angle as you open and close the mouth.
For adjusting the opening, I put a light behind it.
Now, when I want it parallel, what I'll do is I'll start to close it up and adjust the tilt until it looks parallel, and
then I'll close it up until it's almost touching.
And I'll get a very thin line.
And you can get it very parallel this way.
A friend bought one of the Chinese knock-offs.
And when you opened it up and closed it, it never went back to the same position.
And when you opened and closed it, it wouldn't hold the angle.
So it was next to useless, really.
Let's have a look at how to change the blade, which you want to do regularly.
Now, my favorite razor is the Japanese-made Feather.
I happen to own the world's most sensitive razor sharpness tester, which is my face.
I've been using double-edge safety razors for shaving since I was 16.
So at least 10 or so years.
And over the years, the quality of razors has changed dramatically.
And currently, my favorite razor by far is the Feather razor.
I can get two shaves from these, and by far they are the sharpest blade to start with.
The only other razors I'll use at the moment is the German-made Wilkinson Sword.
The Wilkinson Swords aren't as sharp initially, however, they do maintain their edge longer.
So I can normally get three shaves out of the Wilkinson-Sword.
So they're probably the best razor for paring leather.
To change the roller - they just lift off the little guides on the side.
And you put the other ones in.
And these different widths are for doing joints, so you may have a narrow joint or a wide joint and you want to use
them. I don't really use these.
I normally pare down a complete piece of leather.
That may change in the future, in which case I'll probably be quite pleased with these.
There is a video by the manufacturer which I will put a link to which shows the use of these for doing a leather case -
and it's quite clever - as in a cased book.
The blades that come from the manufacturer, I think are near as good as these two other blades.
I wouldn't bother buying extra blades from the manufacturer.
The Wilkinson Swords are made in other countries such as India and Brazil, and they're nowhere near as sharp.
And I would avoid those.
And you can get those in Australia, for instance, so just check the packaging that you've got the German-made ones.
So let's pare some leather.
I've got some leather, that's 0.8 of a millimetre thick.
And I want to get it down to about 0.5 millimetre thick.
Now, I've put a mark on the adjustment, and I think this really helps.
And I know that about three quarters of a turn around is about 0.6 of a millimetre thick - it
sort of depends on how I've put the blade in and things like that.
But so I'm adjusting the blade to get it parallel first.
And then I'll adjust it so that it's a bit more open than where I want to end up.
Now, as I said before, you don't want to take too much off at once, but I should be able to get to this in one cut.
So I'm aiming for about a half a millimetre.
So where I'm going to adjust it to should be around 0.6 or 0.7.
So I'll open it up, I'll put the leather in, and give that to go.
And then I'll measure it and see where it is.
Now, I always start in the center.
The instructions say to start in the center.
And I think there is a reason for doing that.
And I always put my thumb in front of the blade and hold it down.
Otherwise, I do find that it is liable to ride up and cut through.
Now, always follow the instructions in the manual.
If you're not comfortable putting your thumb there, then don't do it.
But I find this works well for me, and I'm comfortable doing it.
If you're not - see how I'm using my fingers also to hold my hand steady and just stop it being pulled back with the
leather. So this first cut's gone really well, better than I expected, and it's probably actually closer to where I
wanted to be than I actually wanted to be.
So I think I've taken off almost 0.3 Of a millimetre and ...
do I measure it?
And it looks like it's down to about 0.5 millimetres - where , roughly where I wanted to be.
So now I'll work towards the edges.
Now, I think the idea is - why this works better is - once you get towards the edges, then you're cutting less leather.
And now the leather's thinner, it's more liable to stretch and distort.
So it's better that you're cutting less leather.
That's my weird theory anyway.
And it seems to work. Start in the center.
Works best for me, and it's what it says in the manual.
I have left a slight ridge, so I will try and get rid of that.
But it turns out I won't get rid of it.
And I often find this - if it's a really small ridge - and I'll talk about how to get rid of that ridge once I've got
the leather down to a uniform thickness.
So I'll keep going.
At the back, I'm pulling the leather down at maybe 50, 60 degrees, but I'm not pulling it straight down and I'm not
pulling it straight out either.
I want to pull it down to keep some pressure on the roller, but not so much that it distorts the leather.
Once I get this end thinned down, I'll spin it around and do the end that I'm holding.
So I can feel those ridges slightly and they're bothering me.
So what I'm going to do is I'm going to just close the opening ever so slightly.
And I think the Schärffix will take those ridges right off.
Now, the other option is to use a piece of sandpaper and sand them, or even a spokeshave.
But I think by just closing ever so slightly, it's just going to take those ridges off perfectly for me.
And it does.
Here's a view from a different angle.
Now, I'll demonstrate what happens when you try and cut too much leather off at once, and it's really frustrating when
it happens.
Let's have a quick look at using the different rollers.
Now, from my limited experience, my understanding is that the German approach to paring is to remove as little
material as possible.
So in the joints, instead of using a big wide spokeshave and paring a lot of material away, the idea is to be quite
precise about it.
And just to take a thin strip of material off at the joint area.
And finally, we'll go back to the wide roller and adjust the angle of the cut to do an edge pare.
So it will be much thinner at the edge.
And it won't cut on the outside.
Now, I haven't been able to cut down to a feathered edge this way.
I don't think you can, because as soon as you go through the grain side, the blade bites in and then cuts it into the
leather. So you can get it down close.
But you have to, if you want to feather edge, then you need to finish that with a paring knife.
Hopefully, I'll get this video finished for the weekend and I'll use this piece of leather in the tight-back sewn board
binding. But that's it for today.
I hope you've enjoyed this, and this has been of some use.
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And until next time, cheerio.