Recommended Touch Probes and Edge Finders
The TouchDRO Adapter for Milling Machines (TDA-420) supports standard triggering [digital] touch probes and tool setters with NPN or Push/Pull output. This covers the vast majority of hobby-grade and commercial touch probes on the market, ranging in price from $50 to many thousands of USD.
In the app, a probe works through the Edge Finder function to pick up edges, centerlines, and hole centers, and each instrument's tip diameter and offsets are stored in its probe profile.
Our Recommendations
For most people running a TouchDRO-equipped mill, we recommend the Drewtronics s5000LED wired for the TDA-420. When set up correctly, it repeats to within one encoder count and has generous overtravel protection, which puts it in the same territory as probes that cost several times more. This version ships with the probe cable already made up, so there is nothing to wire. Drewtronics is a small US shop that stands behind what it builds.
For EU customers, we recommend the Slavtec probe. It's a bit more expensive than Drewtronics, but once you factor in shipping and tariffs, the prices are very similar.
Note on Chinese Touch Probes
The most important touch probe parameter is repeatability. Even though a kinematic triggering touch probe is a very simple device, to achieve good repeatability it must have very precisely spaced contact points and spring rate matched to the stylus length and rigidity.
There are many touch probes on eBay and AliExpress in the $50-$100 price range. This is a very appealing price, but based on our testing and feedback from our customers, these low-cost probes are very inconsistent from unit-to-unit, and overall quality control appears to be non-existent. Some had excellent repeatability, and others (some times from the same batch) were completely unusable.
Recommended Touch Probes
| Models | Rating | Price Range | Notes | |
|---|---|---|---|---|
| Renishaw | Wired mechanical probes | $$$$ | Renishaw probes are the gold standard. New, they are prohibitively expensive, but mechanical CMM-class probes (TP2, TP6, TP20) can be found on the secondary market for $400-$900. Recommended CMM/digitizing setups; overkill for machine shop use. |
|
| Acu-Rite Heidenhain |
Edge Finder - KT3D | $$$$ | KT3D is a high-end conductive edge finder. New, it's very expensive, but can be found on the used market for $300-$500. |
|
| Drewtronics | s5000LED | $269 | Drewtronics is a small shop located in Texas; probes are made in the USA. This version ships with a cable already wired for the TDA-420, so it plugs straight into the adapter's probe input. Repeatability is within one encoder count, with generous overtravel protection; that puts it in the same territory as probes that cost several times more. Build quality and after-sales support have held up well in our experience. Our top pick for USA and North American customers. |
|
| Slavtec | Waterproof 3D Probe | $309 | Slavtec is based in Poland (EU); the probes are made in Poland. Slavtec touch probes offer excellent repeatability of ± one encoder count. The probes use standard 2mm threaded styli. The company has very good support via email. Our top pick for EU customers. |