Technical Thursdays - Toolbox in Miniature Scale archive

Thursday 9 October 2014

In The Anarchists Tool Chest Christopher Schwarz builds a tool chest to store all the necessary hand tools for traditional woodworking. A symbol for the preservation of tradition, Marco Terenzi built his chest in 1/4 scale

Gallery

It's true to say that, over time, the miniaturist acquires a mindset that results in a very disciplined way of working. It doesn't happen overnight and working with wood on a miniature scale requires slightly more patience than full-scale production.

I feel this is because only a little material is removed at a time and it can take a long time to remove it carefully. Many of the operations are long drawn out processes and at a reduced scale it is easy to lose sight of the bigger picture. This way of working doesn't suit everyone but determination to reach the end product goes a long way; it will get you through very tedious tasks if you keep your mind on the prize. For me, every project starts with a clear end goal. When deciding what project you would like to build in small scale, it is important to choose something you love. You're going to spend weeks, perhaps months working out the smallest details and if you are not entirely committed to the subject, it will be impossible to pour hundreds of hours into it. The reality is that you will end up investing a lot of time on any one single piece or joint. The operations that follow on from that piece have to be well-planned and as gentle as possible to avoid you being forced back to step one due to careless handling, splitting or dents.

Miniature material selection

When making a miniature, timber species and grain orientation should be chosen very carefully. In truth, almost any timber will work, although workability, tool wear and appearance in scale vary tremendously across species. If the project would only look right using a certain species, then give it a try - you may be surprised. It is best to seek out quartersawn timbers to eliminate as much wood movement as possible. The more straight grain, the better.

Using figured wood poses a whole different set of challenges. When wood is milled down thin, you will find it twisting and cupping a lot more. If panels are required, then it is wise to make them out of smaller pieces for maximum stability, just as you would for a full-scale project. This technique will also help you to remain true to the original subject but in miniature. If panels are glued up on the full-size piece, then glue them up on the miniature version, even if you have a single board that is the required width. I like to record my work with detailed photography as it progresses and I've noticed that without an immediate visual trigger to suggest the scale, it is often hard to tell the miniature from the full-scale object. This is most evident when using timbers with natural features that work on a smaller scale.

Working with softwoods

Some softwoods, such as the white pine (Pinus spp.) used for this project or basswood (Tilia americana) are excellent for the production of miniatures. They are easily worked, easy on cutting edges and consistent in texture across the annular of the timber rings. They also hold great detail, especially around exposed joinery but are harder to keep clean throughout the project. When many operations have to be performed on the same piece of wood, there is much more risk of denting or chipping. Clamps that are not soft or just too heavy should also be avoided for this type of work.

Some woods to avoid

Generally speaking, open celled hardwoods, such as oak (Quercus spp.), hickory (Carya spp.) and ash (Fraxinus excelsior) have a tendency to cause problems on a miniature scale. The stringy nature of the grain also makes the finished piece look less convincing. The open structure translates as huge indents in the surface and any end grain like a pack of drinking straws. These woods are tough on the thin tools required to work small and require greater force to operate the tools precisely. If in doubt, take a scrap and test out various operations on it to make sure the material is going to hold up to what the project asks of it. The natural features of burrs and figured timbers can also be problematic for the same reasons but are more likely to work to your advantage if chosen wisely.

Handle with care

The handling of the components and work area also affects the outcome of a miniature. The material itself has to be handled carefully - just think of it as an irreplaceable object - and you will change the way you hold it. Fingernails and tweezers can easily cause dents in softwoods, making marks that may be impossible to sand out later.

It's important to pay attention to all the offcuts you produce as these little chips of wood can also be pressed into softwoods if the work area is not brushed off frequently. Small dents on a miniature piece equate to big dents if you scale up the size of the flaw, so if they can be avoided, the final outcome will be much more convincing. Since the wood is milled only a few thousandths of an inch larger than final thickness, there is little to no room to sand out blemishes without making craters. Resist the temptation to use a vacuum or compressed air line to eject unwanted particles. There's a real risk of losing a precious component or worse still, a special piece of tooling. After you get comfortable with this idea, you will sometimes find yourself avoiding problems subconsciously. In most cases, I will start with a new worktop surface at the beginning of the project. A piece of fresh MDF is ideal. The clean surface is often a convenient place to jot down dimensions or make notes along the way without having the extra clutter of a note pad or scraps of paper.

Specialist tools

Although there are a lot of really good quality tools available to woodworkers, not many of them are capable of working in the confined spaces that I require. That's not to say that they are in any way inferior but simply inappropriate for fine work. A normal 3mm bench chisel may sound small but is far too thick and wide for miniature work.

To reach into the bottom and corners of a tiny dovetail, it must be thin to eliminate wedging that will distort the walls of the joint. For this project alone, I produced several miniature tools, replicas of the full scale versions, to carry out certain operations. The first being a brass dovetail marking gauge that was milled out on my Sherline milling machine to match the 1:4 angle of the dovetails on the original chest in the book. Like any home-made tool it represents an investment in the future and will come in handy for use on future projects.

Tools to make tools

The dovetail saw to cut the joints on the chest was made specifically for this project. In keeping with the theme I decided to make it a replica of a Lie-Nielsen dovetail saw with a folded brass back and split saw nuts. It required a matching saw nut driver based on the Lie-Nielsen tool with a hardened steel tip to assemble.

Tooling for dovetails

I use a set of chisel edge hobby blades for this purpose. After they have been flat ground on one face and re-bevelled on another they are honed on a leather strop in much the same way you would a regular-sized tool. I use a strip of leather glued to a piece of flat ground tool steel, charged with honing compound. At around 12mm wide they're not much use for small dovetailing so I grind them to the width I need for a variety of applications. They fit into a large handle to give me good control over the tool. The craft knife blade is used to mark the joints before sawing most of the waste out with a jeweller's fretsaw. The custom-made miniature chisel also works but is really a show item. The bevelled sides allow me to get right into the corners of the tails.

Taping joints

Double-sided masking tape works well for holding down small pieces without causing denting or tear-out. Just make sure you test it on a scrap piece first, as not all tape is created equal. Avoid any of the clear double-sided tape. The adhesion qualities for this are often far in excess of what's required and removing the tape after it has done its job can sometimes damage the wood. If components can't be held together for gluing with just light finger pressure, then this may indicate that something has gone wrong with the construction process.

Accurate assembly

A piece of honed granite or thick plate glass with polished edges is a useful reference platform to make sure pieces are kept square and flat. Just laying the components out on the block will identify any bowed or cupped panels. At miniature scale, any stresses built into the structure through inaccurate assembly or misshaped components will gradually start to build up and possibly create problems later on in the project. Drop-in parts like the tills for this project have to site naturally on their runners. The weight of the material won't help you here. With a good try square, such as the Staratt engineering square, you can carry out most of the checks without handling the delicate parts too often. The granite plate is also a fantastic surface for doing glue ups on because it ensures a square bottom. Any excess glue can also be wiped away or peeled away before it sets hard. These reference plates used in conjunction with fine sandpaper are perfect for truing up small pieces when a hand plane may be too aggressive and a real risk of tear-out. A dark plain granite is best, especially when working with a light material such as white pine.


Briony Darnley

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Technical Thursdays , Marco Terenzi