THE MICRO CALIPER

THE MICRO CALIPER

About the next thing that I want to show you, I’m not sure, if it’s really a useful tool, or more a kind of tool-fetishism. So it’s up to you to decide if it’s the one or the other.

The use of callipers is quite common in life size sculpting. It is used as a sculpting aid to check proportions and to transfer sizes onto the sculpting. On the following photo you can see such typical sculpting calipers (pic. 1).

I thought, even though we do quite small sculpts, such a tool might be also useful for us miniature sculptors, so I made this miniature-version of a caliper. You can see this caliper on the next photo (pic. 2).

With this, you can check the proportions of your sculpture (for example: have both arms the same length? Is the left biceps thicker than the right one?) or you can transfer the correct length from a ruler to the sculpt or in reverse, check the exact size of a sculpt-part by putting it between the caliper "claws" and then checking the length on a ruler (pic. 3).

It’s not difficult to build such a caliper. In short words, you just need to cut out the two "claws" of the caliper from a sheet of metal and to fix them with a bolt and nut. And that’s how it goes:

Material:
You need a sheet of brass with a material strength of 1mm. A piece 10cm x 10cm would be enough. There are different qualities of such brass sheets out there. You should take the "hard" quality so your caliper won’t bend too easily. Theoretically you could use other metal for that, but 1mm aluminium would be too soft and therefore would bent too easily and steel would be really hard to cut, so I recommend the brass. This kind of brass can be found in hardware stores or building centres or in model craft and hobby stores.

Then you need a bolt and a nut with m3 size of . Be sue to choose a bolt with a flat head, otherwise it might stand in the way when you hold the caliper later. You also need a special nut, a self-locking nut. This kind of nuts has some sort of plastic inside that prevents the nut and bold to accidentally unscrewing. The thread of the bolt would stick into this plastic. This kind of nut is important for your caliper to work properly. These nuts can be found in every hardware store or building centre. If you are not from Germany (and I guess, most of you are not) you don’t have to search for those nuts and bolts with metrical system. Just get those small nuts and bolts that you can find. The correct size isn’t that important here. You can also use bolts (screws) from the computer store (see below). You just have to be sure, that the hole that must be drilled in the calliper claws have the same size as the bolt you use.

Another thing you’ll need to get your caliper work properly is a special kind of washer. It will be placed between the two "claws" of the caliper and prevent the two "claws" from scratching on each other and that guarantees a smooth movement of the caliper "claws". So the washer you should use has to be very thin and not to be made from metal (scratching!). So I found that the washer that works best are one of those that comes in connection with the screws (Bolts) for the computer cases and components. These red or orange washers are made of some kind of plastic and they are very thin (see pic. 4).

Beside that you’ll also need two ordinary washers made of metal that are made for m3 screws (see pic. 4).

Needed tools:
As tools you’ll need a jigsaw with fine saw blades made for cutting metal (pic. 5).

Power drill:
You’ll also need an electrical drilling machine (power drill) and a 3 mm metal drill. Also a small metal file and fine grinding paper will be needed.

PC and printer:
Then you need a computer (we’re getting high-tech now) and a printer that is able to print on sticker-foil-paper (nearly all printer can do that) and of course a sheet of transparent sticker-foil-printer paper. I mean these transparent foils on paper that are made to be printed with a pc-printer. Than you can peel the paper off and the remaining printed foil has a sticky side, so you can stick it on any surface you like. The official english term for that paper is "transparency film, self adhesive". At least that's what is printed on the box. You’ll get this kind of "printing-paper" in every shop, were you can by the ordinary printing paper for pc’s.
　
How to build the caliper:
The base idea is to construct the right shape for the caliper-claw in your pc then to print it out as a template with your printer on sticking-foil, stick the foil onto your brass sheet and cut out the brass around the shapes you see now on the brass with the sticker.

If you want to construct your own caliper shape, I recommend using the software called INKSCAPE. It is freeware and a very good vector-graphics-program for this kind of work.

You can find it here: http://www.inkscape.org/

But maybe not all of you have the nerve to draw their own caliper shape, so if you like, you can use the shape I’ve made for my caliper and that you see on the next picture.

I made my caliper with two pairs of claws (one longer side and some shorter one).
I found, this will give it more variations to use it and -as a side effect- you can hold it in your hand much easier.

So first you have to print out the calliper shape on printable sticky foil paper.
To avoid problems with the printer settings, be sure that the printed shape has a length of about 4,8 cm. Do a test printing on ordinary paper and check if the size is correct before printing on the printable-foil-paper (pic. 8). Remember: You need two of these caliper-claws to make one complete caliper, so you have to print two of these shapes on your foil-paper.

After printing out the shapes correctly, just cut out the printed part of your foil-printing-paper roughly, peel off the paper and stick the remaining "sticker" to a corner of your brass sheet (see pic 8a-e).

Then, before cutting out the shapes with the saw, just drill in the holes in the middle part of the caliper "claws". For that, you’ll find in the middle of the little circle a tiny black spot that shows where the hole has to be (pic 9). This spot marks the centre point where you have to place the drill.

The reason for me to recommend drilling before cutting out the rest is that the "cutting out" is quite a bit of work. So if you would do the cutting first and the later drilling went wrong, all the cutting-work with the saw will be lost. So I guess it’s better to start with the holes.

Now after drilling the holes, you can start cutting out the shapes with the saw. You might find that the cutting will go on boring slow, but just be patient. Ah, and if your saw blade break at some point, don’t worry, that is quite normal. Just take another saw blade and go on.

After cutting out the two shapes, just refine the edges with a file and grinding paper and round them up except for the small edge at the top, where the two caliper claws meet. This edge should be left "sharp".

Now, all that’s left to do is to screw all the parts together. In the middle is the red plastic washer, than comes a caliper-claw on each side, followed by a ordinary metal washers on each side and then the nut from the one and the bolt from the other side (pic. 11).

Because the ends of the two caliper claws are not exactly at the same level, you have to bent the two "claws" slightly to each other, until the points exactly meet at the same level (see pic. 12).

Screw the nut and bolt as tight that there is some resistance while opening and closing the calipers claws while they can still be moved smoothly.

That’s it. Your caliper is ready to be used. I hope you’ll like it. As I told you before I’m not so sure about its real worth for getting better sculpts, but at least this little brass thing looks really cool, no?