Debian 10 Dependencies

Try the Stretch repository, they should be OK. Stretch Backports may have something later.

If you have all the dependencies you might try a build-bot installation.
Worked for me on debian 10. Advantage apt-get update for linuxcnc possible.

I tried for an experiment, to build those packages for Buster from Stretch sources, builds completed successfully.
One thing that maybe an idea is to use apt-hold to mark the packages mentioned by phli so they are not upgraded. I know this works well when using apt or apt-get to do upgrades.

Can report back that everything went smoothly with the packages I built from Stretch sources for Buster, and the install of Linuxcnc went ahead smoothly. I did mark those self built packages as hold so as not to be updated. Mind I did download and install manually.

Could the packages needed (once built against Buster) be placed within the buildbot repo ? Theoretically that should pull everything in with one go.

Just in case a link to linuxcnc buildbot
Buildbot 2.9

Well the buildbot main page. Thought that was a bit better than just a bump.

BeagleBrainz wrote: Could the packages needed (once built against Buster) be placed within the buildbot repo ? Theoretically that should pull everything in with one go.

(I haven't really had time to look at the forum for the last month)

That is a possibility. You can see that we already back-port some packages on the main repo to provide dependencies to Wheezy.
www.linuxcnc.org/dists/wheezy/base/binary-amd64/