How to Make a Wooden Engraving Pantograph

A pantograph is a simple series of levers of a set length that can be used to enlarge or reduce and existing shape. Very often used for drawing, this version is a small & cheap DIY version of the typically larger and more expensive engraving pantographs that can be bought.

The engraving pantograph differs in design from a drawing pantograph (often used with pencils) in that for a drawing pantograph, either the tracing point or the pencil (depending on if you are enlarging or reducing) will coincide with one of the pivot locations. As we are using this for engraving with a Rotary Tool for engraving, this would make it much more complex, so to avoid this, I have moved the position of the Rotary Tool away from the pivot allowing us to use a very simple pivot. This changes the geometry of the levers slightly but makes the pivot design and mounting the Rotary Tool much simpler whilst still getting the same result.

A pantograph can be used to either enlarge or reduce, for this design I have chosen to make it reduce only, for a number of reasons;

1. Due to the simple pivots I'm using, accuracy won't be as good as it could be and when enlarging and errors are magnified, which depending on how loose the pivots are, might be visible in the enlarged engraving.
2. For enlarging, the accuracy you have to move the tracing point with is also increased by the magnification factor, for reducing, any inaccuracies are halved.
3. We use mechanical advantage of the levers, by reducing we move our tracing point twice the distance that the engraver will move, this effectively doubles the force, which is important as as the engraving tool cuts, you must manually resist any cutting forces it generates.

1. Timber 20x30mm 1.2m long
2. 4mm Wood Screw 50mm long
3. M6 Countersunk or Hexagon head bolts
4. M6 Washers
5. 3mm Hardboard 75mm x 75mm
6. TImber 75mm x 75mm x 50mm
7. A rotary tool

Each of the four pieces of wood need to have holes drilled certain distances apart, the position and accuracy of these holes will affect the final operation of the pantograph.

I found it helpful to mark and label each piece with the Pivot number and also the distance between each pivot. The exact length of the pieces isn't important, I chose to cut each to length, half the width past each pivot hole so the the holes visually sit centrally in each end i.e. equally from all sides.

So for example, looking the P1 - P4 piece, the distance between these two pivots is 300mm but I've added 15mm to each end, hence the cut length of 330mm

P1 - P4 330mm

P1 - P3 330mm

P2 - P4 270mm

P2 - P3 180mm

The screws/bolts that I'm using are M6 so I drilled the pivot holes with a 6mm drill bit. These hole locations and sizes need to be as accurate as possible so I used a Pillar Drill although it would be possible to do it by hand with a hand drill.

As the joints need to be able to pivot you can't tighten the nuts and bolts that are used to make the pivots. So I used a type of locking nut, called a Nyloc, so that I can tighten each one up just enough so it isn't floppy but not so much that the joints can't rotate. The Nyloc then stops the nuts being loose and undoing themselves as you use the pantograph.

Depending on the type of screws or bolts you use, you will need to either countersink or counterbore the underside to make the bolts/screw heads sit flush.

It is easier to countersink as you can do this with a common countersink bit with a handheld drill. As I only had hexagon headed bolts to hand, I had to counter bore, which is more difficult and the tool will not naturally want to self-centre in the existing hole so you will have to have a drill press as a minimum.

This is a great time for a quick test before you carry on. The pantograph should be able to move freely but without being to floppy. Before I drilled the hole for the Rotary Tool, I did a quick check to make sure I had the ratio that I wanted. By keeping the ruler steady at the 3 inch mark, you should see that when you move the tracing point (shown here at the 9 inch mark), the engraving point should move (in my case) half what you move the tracing point. So if I was to move the tracing point to be at the 10 inch mark on the ruler, the engraving point should be at 9.5 inches.

When engraving, the dust created must have a way to escape otherwise it will build up around the cutting tool, eventually clogging it. I used a handsaw to cut a 'V' notch on the underside where the Rotary Tool mounts to allow and dust to escape either side.

This step may very depending on the type of tool you want to fit. My Rotary Tool has a large plastic thread on the end so I made the mounting block design to suit this.

Firstly, fit the engraving tool you want to use and measure how far it sticks out of the machine, this will determine how tall (or deep) you mounting block needs to be. When the whole thing is assembled, the cutting point of the tool needs to be able to stick out of the bottom of the mounting block as much as you want to engrave.

I cut a notch from a block of wood that was wide than the pieces I used to make the pantograph so that one of the pantograph arms fits in this slot.

I then used a large hole saw or spade bit to drill a hole through. For me this needed to be large enough to fit the nut that normally screws onto the end of the tool.

I took a piece of 3mm hardboard and cut it to the same size as the rest of the mounting block. I drill a hole in the centre as close to the size of the outside of thread on the Rotary Tool. For me this was just a bit smaller than the thread, so it actually screwed onto the tool, I then screwed the normal nut back onto the end to clamp it tight.

I drilled 4 small holes in each corner so I could screw this hardboard to the top of the mounting block.

The pantograph needs a solid point to pivot about, as this was a temporary set up I made one from an offcut from the same wood I used to make the pantograph arms. I put a Nut & Bolt through as a pivot, in the exact same way as I did for all the other joints.

I used a 'quick clamp' to firmly clamp this to my bench. Depending on the size & shape of what you want to engrave you might need to adjust the position of the pivot so the hole thing is on your work bench.

As accurately as you can, drill a hole slightly smaller than your screw, so the screw threads can bite into the wood, but not so small that the screw will split the wood. You must drill a pilot hole, as so close to the end of the wood, it will almost always split.

Make sure the screw is long enough to pass through the wood and to just almost touch the shape to the traced. You can screw the screw in or out to adjust this.

I used a 4mm wood screw.

I found something to hand that was about the right size and had a clear outline, turned on the tool and traced the tip of the tracing screw around the outline of the shape.

I was fairly happy with the outcome for a first test, turns out my tool was blunt, hence the black burn marks, that, and I wasn't moving it fast enough. That aside, the actual accuracy was a pleasant surprise considering how crude the pivots are.