Folk considering a DIY DRO system might be interested in the latest issue of Elektor Labs magazine. It includes a project for a 4 axis system using the common "digital calliper / readout on a stick" devices in conjunction with the Elektor Platino micro controller board. Issue is number 7/2018 contents here :- **LINK** and project description here :- **LINK**
Elektor Labs magazine is a recent re-name of Elektor magazine. No longer subscribe, although I still get the E-Mail notifications, so don't have any more details. Historically the projects have always been a bit on the pricy side but well documented with professional PCB's available. Almost invariably work pretty much straight out of the box too.
I took it for many years before realising that I was pretty much never building anything and was no longer that interested in keeping up with electronics. Especially after most stuff went micro controller based. Dipped back in last year when a silly low subscription and Arduino micro board and book coincided offer with a (temporary) impulse to learn about such things.
One nice bonus with a subscription is that you get download rights to PDF format contents of pretty much every issue back to to the mid 1990's.
Clive.