Owen Duffy wrote:

Tom Ring wrote in
:

...

the next hole. Move the device to the latest hole drilled as you run
out of table. To reduce errors from imperfect vertical on the device,


This violates an important technique of minimising measurement and layout
error, determine a datum such that you can lay everything off from that
datum, and then do just that.


the next hole. Move the device to the latest hole drilled as you run
out of table. To reduce errors from imperfect vertical on the device,
rotate it 180 degrees between each move.


This is a technique to compensate for moving the datum.

I am not saying it won't work, and I can see that you have done it to reduce
the size of accurate table needed to register the device.

Owen

And yet is does work. For 39 holes in my case.

I didn't say it was highly accurate, but that by following what I did,
that it would work well enough for a long boom UHF beam DESPITE that
fact. It's also cheap and easy. Unfortunately, many of us cannot
afford the best, but need still need good results. This is one way.

If I could afford equipment like you describe, I would certainly have it
and use it, but I can't. My guess is that most of the people here are
closer to my end of the spectrum than yours. Yet another unfortunate fact.

73,
tom
K0TAR