Recommended DRO Scales

To avoid unnecessary markups and shipping costs, we don't sell DRO scales directly. Instead, you can purchase the scales directly from the supplier. Based on our experience, testing, and the feedback from TouchDRO customers, we have compiled a list of recommended scales and suppliers.

Please see the DRO Scale Selection Guide for more in-depth comparison of different DRO scale types.

Table of Contents

• Recommended Glass Scales

  • Ditron
  • Sino
  • Aikron
  • Generic Chinese Scales

• Recommended Magnetic Scales

  • Electronica/EMS
  • Ditron
  • Aikron

Recommended Glass Scales

Optical DRO scales (also called "Glass Scales") use a precision glass encoder strip that is read with an infrared sensor. They are commonly available with 5µm and 1µm resolution but can be specially ordered with a sub-micron resolution. The effective resolution is the same as nominal resolution. Glass scales offer excellent balance of price, accuracy and reliability, and are virtually maintenance free if installed correctly.

• Recommended for most digital readout setups.
• Not recommended for setups where high pressure flood coolant is used, or where the machine is subject to extreme vibrations.

The limiting factor for the optical DRO scales is the size. The scales are bulkier than other types, and can be challenging to mount in some situations. Conversely, maximum travel length is around 2 meters.

Recommended Resolution

• Milling machines - 5µm scales on all axes.
• Lathes - 5µm scales on the carriage movement and 5µm scale on the cross slide for most lathes. A toolroom lathe can benefit from a 1µm scale on the cross slide.
• Surface grinders and jig borers - 1µm scales on all axis movements.

Recommended Brands and Suppliers

Ditron

Ditron Measuring Co, Ltd. is a well established DRO manufacturer from China, and was one of the first to offer affordable DRO scales. Their quality control and after-sales support are very good.

We had very good experience purchasing directly from Ditron via eBay, but they have an Amazon store as well.

• Slim optical scales: Buy on eBay Buy on Amazon

All Ditron scales are compatible with the Pre-Assembled TouchDRO Adapter "Option B"
Common pinouts are as follows:

Note: Ditron is a well known brand, so naturally, there are numerous counterfeit Ditron scales; so, it's recommended to buy from a known seller.

Sino

SINO Digital Readout Co., Ltd. is another reputable Chinese DRO brand that has been on the market for over 20 years. In all practical regards, their scales are identical to Ditron scales.

Sino doesn't appear to have an online storefront, where they sell directly to the public. We've had good experience with eBay seller sino-sd. The seller is very responsive, and provides very good after-sales support.

• Standard optical scales: Buy on eBay Buy on Amazon

All Sino scales are compatible with the Pre-Assembled TouchDRO Adapter "Option B"
Common pinouts are identical to Ditron (see above)

Aikron

Aikron is a reltively new supplier of DRO kits and scales. The scales appear to be of very good quality, and many TouchDRO customers reported receiving good after-sales support. Their DRO consoles look very similar to Ditron units, and the pinout is the same as Ditron and Sino.

• Standard optical scales: Buy Aikron AKM
• Slim optical scales: Buy Aikron AKS

Aikron scales are compatible with the Pre-Assembled TouchDRO Adapter "Option B"
Common pinouts are identical to Ditron (see above)

Other Chinese Optical Scales

There are hundreds of smaller DRO brands that sell DRO scales at a steep discount. Unfortunately, the quality of these scales is very inconsistent, even within the same brand. Some are as good as the better known brands, and some are outright not usable. Furthermore, many discount sellers offer little or no after sales support or warranty, but if you purchase these scales from Amazon, eBay or a similar marketplace, you will be able to take advantage of the buyer protection offered by the platform.

Vevor scales are compatible with the Pre-Assembled TouchDRO Adapter "Option C" and have the following pinout:

ToAuto are rebranded generic scales sold on Amazon. Their build quality is better than some other generic Chinese scales, but some customers reported receiving defective scales.

The scales use one of the standard generic Chinese scale pinputs shown below, and are compatible with Pre-Assembled TouchDRO Adapter "Option D".

Recommended Magnetic Scales

Magnetic DRO scales use a magnetic encoder tape that is read by an array of Hall effect sensors. They are commonly available with 5µm and 1µm resolution, but can be found with 10µm and even 20µm resolution. Magnetic scales are inherently less accurate than glass scales. Actual resolution is usually lower than nominal due to interpolation errors. Furthermore, magnetic scales are very sensitive to misalignment, and small ferrous chips that get between the reading head and the encoder tape can throw off the readings.

• Recommended for the machines where optical scales can't fit due to the size constraints, or a measurement distance over 2m is needed. Since these scales are immune to coolant and a lubricant contamination, they can be used with the high pressure flood coolant.
• Not recommended for the machines where standard glass scales can be used.

IMPORTANT: After the installation, magnetic scales have to be thoroughly checked to ensure their accuracy. Instructions are provided in the TouchDRO calibration video.

Recommended Resolution

• Lathe - 1µm on the cross slide. Glass scales are recommended for the carriage.
• Milling machines - 1µm on all axis movements where a glass scale can't be fitted.
• Surface grinders and jig borers - not recommended:
  • Effective [reliable] resolution is too low for a surface grinder or a jig borrer
  • Ferrous dust will be attracted to the scales and can throw off their reading

Electronica

EMS (Electronica Measurement Systems) offers excellent entry-level magnetic scales with effective resolution approaching comparable glass scales. The scales come with 5µm and 1µm resolution. Electronica offers standard scale models, Magna S1 and S2 (the difference is in the magnetic track aluminum extrusion), and MagneSium that use a miniature reading head and low profile track. The scales have some cyclic and non-linear error. The manufacturer states that 1µm and 5µm scales are accurate to +/- 10µm over 1m of travel. Due to the nature of these scales, the 1m travel distance is irrelevant, and you should treat them as 20µm scales.

In the USA, EMS scales are sold by DRO Pros and Carl Staehle Corporation.

DRO Pros have a very good track record, and offers excellent after-sales support and warranty.
Some customers reported that DRO Pros didn't have readheads or tape in stock.
Their contact information is as follows:
Phone: 707-452-8434 Website: www.dropros.com Email: sales@dropros.com

Carl Staehle Corporation is a distributor for many high-end DRO brands. Electronica/EMS appears to be their "budget" line.
They appear to have more scale in stock; the prices are comparable to DRO Pros. More importantly, they sell EMS magentic tape in bulk (pricing is by an inch).
Their contact information is as follows:
Phone: (847) 573-8200 Website: www.carlstaehlecorp.com Email: mikes@carlstaehlecorp.com

EMS scales are compatible with the Pre-Assembled TouchDRO Adapter "Option A" and use the following pinout:

Chinese Magnetic Scales

A few Chinese DRO manufacturers offer magnetic scales that cost 30-50% less than EMS scales. Unfortunately, Chinese magnetic scales have much higher non-linear error than even EMS scales that is especially pronounced with 5um scales. In our testing, we saw a cyclic error that exceeded +/-0.0025" (+/-60 micron) with 5µm reading heads, and +/-0.0006 with 1µm models. Full size 1um scales seem to peform better than the slim version. We have received similar feedback from other TouchDRO customers.

Ditron offers standard profile scales with dimensions similar to Electronica S1 scales, and smaller "slim" scales that use narrower track and smaller head.
Ditron magnetic scales can be purchased from their eBay or Amazon store. The eBay listing has only one option for slim scales, but you can contact the seller to customize the length or upgrade the resolution.

Even though 1µm models are slightly more expensive than their 5µm counterparts, we strongly recommend upgrading to 1µm if you decide to use a Chinese magnetic scale in your setup.

We contacted Ditron regarding the observed error, and they provided the following test results for a typical scale of similar length: The error shown in the graphs is significantly lower than our results.