We sometimes get asked what drill machines we can recommend for drilling the probe plate.

If you have a small floor-mounted or bench-top pillar drill, it will likely be suitable so long as it is in reasonably good condition. Lack of precision can be a problem with larger machines, cheaper models, or with older, worn machines. But if you already have a machine it is certainly worth trying it out. Our fixture kits include a small piece of probe plate material to practice drilling on, so you can test without damaging your kit.

If you are going to buy something your choices are essentially a high-speed rotary tool (such as a Dremel tool), a small bench-top pillar drill, or a small bench-top mill.

High-Speed Rotary Tool

The cheapest option is undoubtedly a high-speed rotary tool. You will also need a matching drill press accessory. This is essential - you will not be able to drill straight and true without it. Most tool manufacturers have such an accessory to suit their popular tools. The combination should cost around a hundred dollars.

We have had success with the Dremel model 395 tool and Dremel model 212 drill press stand. This is about the cheapest combination capable of producing good results. That stand is not great but it is adequate if used with care. At about the same price Dremel also offers the 220-01 Rotary Tool Work Station which is a newer product with more flexibility.

An alternative that gets some good reviews is the MICROMOT system from German company Proxxon. The combination of Proxxon IB/E Professional Rotary Tool and Proxxon MICROMOT Drill Stand MB 140/S is closer to two hundred dollars but appears well made.

Proxxon also have cheaper models of high-speed rotary tools; the FBS 115/E is a mains-powered tool functionally similar to the IB/E, and the 50/E is a 12V tool that requires a matching power supply unit. These tools don't get as good reviews as the IB/E Professional series tool.

Bench-top Pillar Drill

Next up are small bench-top drills intended for modelling work. These are all-in-one units (the drill is not separate from the stand), and they typically have a pulley and belt drive mechanism which runs at lower speeds than the high-speed rotary tools.

A popular unit is the Proxxon TBM Bench Drill Machine which will set you back about two hundred fifty dollars. It comes with a set of collets including one suitable for 1/8" shafts, and there is an optional adjustable chuck. A very similar-looking, similarly priced tool is the MicroLux 3-Speed Mini Drill Press from Micro-Mark. This is apparently made in Japan and comes with an adjustable chuck.

Don't be fooled by the scale of these pictures; these units are small, around eleven inches tall.

Accessories for these drills include a vice and a compound (X-Y) table which opens the possibility of drilling holes purely by measurement, rather than using a scrap bare board as a drilling guide.

There are also a huge number of made-in-China products of this type on the market, at various price and quality levels.

Bench-top Mill

At the high end your options include bench-top milling machines.

The main advantages over a drill are a more rigid and accurate construction, and an X-Y table that is part of the machine rather than an add-on. Typically the X-Y table can be fitted with a digital readout which is hugely more convenient and less error-prone than counting revolutions of handwheels.

We have used a Sherline 5400 to drill probe plates and pressure plates with excellent results. This made-in-USA machine costs around a thousand dollars, depending on options.

Taig is another US supplier of similar machines at similar prices. We don't have any experience with these ourselves, but have heard good reviews.

A mill can be used for more than drilling of course, and one of these machines is an excellent addition to a small workshop, or a workshop area in a lab. They don't take up much room on the bench and are amazingly useful. Once you have one you won't know how you did without it.