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Thank you very much for your insightful opinions, I appreciate it.

greybeard -

so would you say it would be easier to do work on a bridgeport rather
than a cheap RF-31 milldrill because of the rigidity?

It is always benificial to have the largest, most powerful machine that will
fit in your space, is within your budget, and will hold the part you're
machining.

A bridgeport is ideal for your work. A mill/drill is a compromise (less
rigidity and smaller capability in exchange for less money and smaller
footprint).


And is a DRO absolutely accurate? (ie reading on DRO always corresponds
to table distance..)

As far as the work you're doing is concerened, yes.


Also, how would you cut complex shapes without CNC? with a rotary
table?

What kind of "complex" shapes are you producing? Can you specify examples?


We've used bandsaw, lathe at RC's shop but not a mill. How much more
dangerous would a mill be? (fly cutters do look dangerous..).

It's not a matter of degree. A bandsaw will cut your finger off while a mill
may pull your finger off. Neither are ever acceptable. Both machines require
respect and proper training.


6x4 1 mil of tolerance is easily doable? or is it a fairly difficult
task? I'm trying to gauge the relative difficulty of the work we do.

Truly +/-.001" on a bridgeport is pretty tight, but certainly attainable.
What kind of work are you doing that requires such a tolerance?


And our build season is already over this year (we shipped our robot on
tuesday). I intend to learn how to use a mill (regardless of whether or
not we acquire one) over the next year. (any suggestions? I've been
thinking about volunteering at a machine shop..)

Here's a rule of thumb: 1st and 2nd year apprentices are considered losses
(pay and overhead versus output). 3rd year apprentices might break even. 4th
year apprentices should make the company money.

If you happen to find someone willing to let you work in their shop (costing
them money! even if they never give you a dime), ask as many questions as
they'll allow, do your best always, and always be respectful of that
person's sacrifice as well as their experience and capability compared to
yours.

As for tooling, a graduating member is willing to donate to us R8
collets , vises, indicators and end mills. Of course we'd still have to
buy alot of tooling, but I think we can get buy most jobs with end
mills and a boring head (of course I could be terribly mistaken..
please correct me if I underestimate this)..

*Important advice below*

Make a point of designing parts around the tooling you have. Cutters get
expensive *very* quickly and you will inevitably run out of time. If you
want to keep the price and complexity of your parts low, Keep It Sweet and
Simple (KISS).


Also, what other good ways of learning (for highschoolers..) do you
know of?

You're in a rough position.

In high school, I entered two Canada-Wide Science Fairs with projects I had
built in machine shops. I was lucky because of the people and facilities to
which I had access. I'm sure you've seen that there are many skills that you
have to master to be successful in large projects like a robotics
competition. Time management is huge. Conceptualization, design, fabrication
and assembly of the project. Perhaps a write up. Computer programming. The
list is endless. Adding machining is a big jump, but if you can pull it off
you'll be far ahead.

Good luck with everything. Enjoy this time, as you are working towards your
own goals. Once you start making parts for other people, it'll never be the
same.

(Go for the Bridgeport, if you can)

Regards,

Robin