Particularly useful tools

Over the past while I’ve come across, or rediscovered, various tools that I’ve found quite useful in making models. Here are three I find pretty cool. I’ll probably add to this list as time goes on.

Offset knife blades

A complete list of blades made by the American X-Acto line is oddly difficult to find.

Standard X-Acto style blades are commonly equipped with the classic #11 blades. These are the pointy triangular types. I find them less than great, mainly because they have such a tiny slender point. This makes them really fragile, so they’re always breaking at the tip. That’s great for the manufacturer, but less so for my wallet.

A blade I find more generally useful is the #16 offset “scoring” blade. This type has a small bit at its tip, which means it’s less pointy. But it’s good for cutting as you can hold the cutting edge pretty flat without going at an awkward angle. The angle of the tip is less acute, which is also why it’s less fragile. The fact that the offset cutting edge is short may seem crazy, but in reality how often do you use the entire length of a #11 cutting blade? Maybe for whittling or scraping actions, I guess.

Another useful one is the #2 which is similar to the 11, but which has a thicker base and a slightly squared off tip. This type is sturdier than the 11 and takes a bit more abuse than its more fragile cousin. Up to a point, of course.

Digital calipers

Measuring fine details can be tricky. Even if you can stick a ruler somewhere the marks can be quite wide or hard to read. You also have to make sure you’re not looking at the thing at an angle, since that can throw off your measurements thanks to parallax.

The answer is a pair of digital calipers. These are devices with a ton of tiny parallel wires embedded in a ruler. A little sensor detects these wires using capacitance as you slide the measuring section along, giving you extremely good accuracy - down to a tenth of a millimetre, typically. The results are shown on an LCD screen. The information is retained when the device switches off, so you can go back and look at the figure.

High quality machinists’ tools can be mind-manglingly expensive, but there’s also a ton of super-cheap ones on the market. However I don’t know how reliable the cheapies are. I do know that I bought a pair at bargain basement prices that only lasted a couple of years of pretty light use. Then the calibration went out of whack, rendering the whole thing useless. Are they all that lame? No idea.

I looked for a hopefully sturdier set. However I noticed a lot of different brands and models all seemed to share the same plastic housing and LCD/button arrangement, suggesting they’re all electronically identical inside. So I went for a very different looking one with a larger screen, on the theory that a different make or model must be involved. It also had steel jaws and handles, which are harder to chip than the plastic ones. So far so good.

Fine razor saw

Most razor saws aren’t actually razor-thin at all! Most are surprisingly thick. The usual X-Acto, Expo, and Zona blades are fine for cutting larger objects, but they suck for tiny things. The problem with thick blades is that you lose a ton of material where the blade cuts through. In other words, most blades have a very thick kerf.

However, a little known Czech company called JLC makes very nearly razor-thin saws. These are impressive for cutting details out of objects without sacrificing too much material. Of course, the blades are fairly small - about the size of an actual replaceable razor blade - and so aren’t any good for cutting larger pieces. But I find them perfect for trimming tiny models 3D-printed using brittle acrylic plastic resin.

The blades are almost paper thin, and have two cutting edges. One has 20 teeth per centimetre and the other an incredible 34! (that’s 51 and 86 teeth per inch for non-metric people in Myanmar and Liberia) Compare that to around 30 tpi for typical “razor” saws.

JLC sell optional wooden handles, though for very slow and precise details you could hold the blade by hand. The handle is recommended though, since it gives you more control and minimizes blade breakage owing to flexing. They also sell spacers that can fit between blades. I’ve never needed these, but the idea is that you can cut precisely parallel cuts by stacking more than one blade together into a sandwich.

Of course the blades have a low height and this limits the depth of the cut possible, to around 6mm if you use the handle. And the thinness and brittleness of the blade does mean you can’t hack away with wild abandon - the tool is fairly fragile.

Incidentally the saw is available in an “anniversary” set that includes a sturdy plastic case, the handle, and a bunch of spacers.

Super-fine chisels

I have a set of really tiny steel chisels. These aren’t used in a hammering chiselling kind of way, but dragged backwards across a plastic surface to scribe it. They’re the best tool for making recessed panel lines on 3D printed resin or styrene. Wider chisels are useful for precise reshaping of resin or styrene objects. You can get them in sizes from 0.1mm wide to 2-3mm wide.

The chisels are not super cheap, though very inexpensive Chinese ones are widely available. But they do a much better job of scribing lines than craft knives or whatever. They also result in perfect flat-bottomed straight-sided grooves, rather than triangular troughs.

Embossing labelling tape

This is the self-adhesive plastic tape used in old-fashioned Dymo embossing label makers popular in the 1970s. It’s relatively thick plastic tape, typically around 9mm wide. If you were alive back then you’ll remember those awful plastic strips, with their raised white letters, curling up and falling off anything you put them on!

But I don’t use the tape for labelling! Instead it serves as a perfect guide for panel scribing. Apply the tape and you have a solid and firm guide edge for the chisel to slide against. For this reason it has to be the thick embossing tape material – thin adhesive label tape is useless for this!

Tiny sanding blocks


Detail sanding is tricky. It’s a balance between getting a smooth unblemished surface, particularly on a 3D print with stairstepped lines, and obliterating details.

Machined aluminium sanding blocks are perfect for fine detail work. They rely on self-adhesive strips of sandpaper, which are a bit expensive but which last quite a long time when used for wet sanding. They tend to clog up quickly when dry sanding, which is also worse for kicking up lung-wrecking dust. I have three separate blocks, so each can be loaded up with different grades of sandpaper.

A key thing about these sanding blocks is that they’re totally flat and have no foam padding, like the ones used for woodwork. As a result they work well for precision work where a flat finished surface is needed. They’re also thin machined metal on the edges, barely 1mm thick, again helping with precision work.

There are a couple widely available miniature sanding blocks out there from Chinese manufacturers - Galaxy Tools and the oddly named and hard to spell DSPIAE. But it turns out, while they look really similar, the blocks are of different sizes! And DSPIAE brand self-adhesive paper is the easiest to source, but slightly too big for the Galaxy sanders at 25mm x 75mm in size. Galaxy products are 21mm x 72mm. Meanwhile the DSPIAE papers are bizarrely 1mm too short for their sanding blocks on the long axis. The USTAR paper is another product, and it doesn’t fit either size block at 19.8mm x 75mm.

So I guess buying slightly larger paper and then cutting it to fit your sanding block, once it’s been stuck to the block, is one way to go. Just remember to set aside a knife that you don’t mind getting dull very quickly when slicing through abrasive paper!

Carbon fibre sanding sticks

A couple companies make thin flat sticks, cut from carbon fibre sheet. You then use self-adhesive sandpaper and fasten it to one of the sticks. This lets you make tiny and precise sanding tools, sort of like miniature files. The reason they’re made of carbon fibre instead of, say, styrene sheet is because the sticks don’t bend easily.