Thursday, 14 July 2022

Tool time: Drill guides

I got a drill guide and a doweling jig, after a situation where these might have been useful. But I can at least blog about them.

In the past I have managed with drilling through a wooden block and using that as a guide, but these ad hoc pieces easily get lost and mixed up.

When ordering from the internet, half the trouble is knowing the Finnish words for some items. Again, when writing this blog, there's the added trouble of finding the English words.

So:

Wooden dowel pin : Poratappi
Drill Guide : Porausohjain
Drill Stop/Depth Stop: Poraussyvyyden rajoitin(!)
Dowel joint: Tappiliitos, Poratappiliitos
Doweling Jig/Dowel Gauge : Tapitusohjain
(Dowel drill) centre point : Tapituskeskitin
Hex key/Allen key/Allen wrench :  Kuusiokoloavain

Often Google Translate can't figure these out correctly, and the terms are not certain to begin with. According to GT, tapitusohjain is "Tap Controller", and poratappi is "Drill Pin".

Looking at item lists of complete doweling kits was the easiest way to reveal the terminology.

Dowel joints aren't exactly the state of the art, but they can be done at home without huge tools. At least somewhat precise positions and 90 degree angles are needed, so guides like these can be handy.

First, the Wolfcraft Dowelmaster jig:

This jig has an adjustable/removable block that helps position the jig against an edge. Then I can drill 6mm holes through the device.

The drill stop is almost necessary for preventing accidentally drilling through the material. The stop is tightened in place using a tiny Allen key. It did keep falling out, though, it would work better on the non-bladed area of the drill.

At this position drilling the right hand side was rather easy. To make a 6mm hole at the left side was trickier because the tool can't be mirrored. (The holes are for 6, 8 and 10mm pins respectively)

Drilling the holes through the edge was little harder, it would be helpful to have the piece attached somewhere.


As can be seen my test joint is not very precise. But the result was ok considering the wood was not very even or cut very accurately, I wouldn't blame the jig here.

The idea of keeping the device at place with your hands is fast, but also kind of crap. Especially here when working with small pieces I kept trying to find a good position.

There are more straightforward jigs that can be clamped to the piece. But the Wolfcraft jig has a few tricks up its sleeve. The contraption can be held diagonally against the edge of the wood, the edge held firmly within the "X" shape of the jig. There are two ways to do this depending on the thickness of the wood. The pinhole position can't be adjusted but at least the holes will be equidistant.

I liked the simple drill guide. ("accumobil Mobile Drilling Aid") It's not specifically made for dowel pins, but it does have the 6,8,10 sizes.

The device is better used upside-down, because what looks like the top works better for the special cases of drilling into a corner or a round object.


There are also marker lines around the guide. If you want to use them you have to mark your boards very generously because otherwise they are not very easy to see. 

Here the wooden piece is so small I couldn't even check the lines from all directions. It may be a better to make ~2mm deep initial drillhole and then finish the job with the guide.

Here I also made use of the drill centre points, these small metal pins.

The idea is that the drill hole positions don't need to be super-precise. Drill holes into the first board, then put the centre points in the holes. The second board (edge) is pushed agains the pins and the drill locations will be correctly marked.

For the edges, I again used the doweling jig, and I wasn't very comfortable with it but the result was fine. It would work much better if I had gone through the trouble of clamping and positioning the parts with more care.

So, altogether these felt robust enough for my purposes.

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