"Alun Saunders" skrev i melding
...

But surely after you're done with turning the bottom and making the
recess, then it doesn't matter because the first thing you're going to
do when you reverse the bowl to hollow the inside is to get rid of the
first hole you made anyway ... or am I missing something here? It seems
like an unnecesary extra step to me, unless you're getting some movement
or wobble in the piece due to the nature of the bored hole which you
want to avoid when finishing the bottom?


When I use the drilled hole, I roughturn the backside, that is, I turn it
down
to _near_ the finished shape. Then I make my second hole in the bottom with
my parting tool (5mm thick)(and I have another, thinner one, for real
parting work).

Now comes the hard part: Sometimes and allways you find something inside the
wood to make you change your plans for shape and / or thickness. Sometimes I
have to hollow the bowl partly, leaving a thick stem in the middle, just to
see
what the wood looks like, and then I have to change the shape of the outside
somewhat, because of what I saw.

When I have made sure of two exactly parallell holes, I can switch back and
forth between the two sides without losing anything that I don't want to
lose.
With an uneven, not trued up hole on the other side, I get wobble each time
i turn the piece around, and the bowl is rapidly taking the shape of a
platter.

Now. When I allways true up the two holes in the beginning, it gives me
a wider range of actions afterward.

Sometimes it is a bit unneccessary, and sometimes it gives me a good result
with minimal loss of material.

That's why I do it routinely.
It works for me.

Bjarte