Re: Newbie Questions

Hi C.S.,

Firstly I have a concern about your band saw and mill stands.
Although your welds look very good, you still should consider adding
braces to the legs! As you raise and lower your saw head you're
going to cause metal fatigue in those joints. This is especially
going to be a problem if you convert your mill to CNC. Given that
the inertia of the table will be repeatedly torquing your stand. All
you need to do is throw in some 45-degree braces or the like.

As for questions about the Rong Fu mill, there is a Yahoo group
that specifically covers this mill.

Go here: http://groups.yahoo.com/group/mill_drill

That's what I know! Now let's talk about what I don't know. I
also have a Rong Fu mill drill ( RF31 ). Parts created zero and my
CNC conversion knowledge is minimal. So, I'm sort of in the same
boat as your self. I just started collecting tooling as I just got
the mill a few weeks ago. But as far as indexing the head, I plan to
do something along the lines of a laser from the head to the base
rather than the popular head to the wall method. Problem with the
later is I plan on building a stand with casters. I'm thinking of
some kind of microscopic sensor of some kind. But haven't drawn any
plans yet. Take a look at a program under development called Mach 1
formerly known as Maser5.

Go here: http://groups.yahoo.com/group/Master5

And here: http://www.artofcnc.ca/

I'm not certain, but think Mach 1 will read your rotary optical
encoders and give the readouts on your computer monitor. This in
addition to acting as a software based controller for G code
interpretation and motion control.

Well that's about all I can think of for now. I hope you continue to
enjoy your new shop!

All the best,
James

--- In CAD_CAM_EDM_DRO@y..., C.S. Mo <cs@v...> wrote:
> I'm pretty new to machining, so please forgive me if my questions
have
> already been re-hashed ad nauseam. I have a Rong Fu Geared Head
> Mill/Drill from Enco. So far I've only made one part!
>
> http://www.smidgie/928/machineshop (nothing about machining until
the
> very end)
>
> At any rate, I've discovered that I really can't stand using the
dials
> and I want to reduce the backlash of the machine. I've also started
> working on converting the machine to CNC. So, here's my questions:
>
> 1) I have roughly .015" backlash in my X and Y travels. I've heard
talk
> about "double-nutting" in order to reduce backlash. Has anyone done
this
> to one of the little Mill/Drills? Any advice on how to go about
doing it?
> I've considered going to ball screws but my understanding is that
ball
> screws make it so that the machine can not be used for manual
milling -
> is that correct?
>
> 2) Judging by others' comments, it appears that one of the biggest
> disadvantages to the little Mill/Drills is that you lose your
position
> when you move the head up and down. Has anyone done anything to
address
> this?
>
> 3) I don't expect to have the machine converted to CNC anytime in
the
> near future, in the meantime I'd really like a DRO for at least the
X and
> Y axis.
>
> The least expensive method (once you factor in the cost of the
> PC/Monitor..etc) and the quickest to get setup seems to be to use
> digimatic scales (the ones that are kind of like digital calipers
without
> the caliper part) with SPC output to an external 3-axis readout.
WTtool
> sells the readout for $249 and the individual scales are available
for
> roughly $200 for three, so call it $500 once I make the
> brackets/shipping..etc. The disadvantage to this is, as far as I
know, I
> can't get the SPC outputs into a PC.
>
> I'm planning on using servo motors (already have two) with Gecko
drives
> for my CNC upgrade. The servo motors have encoders attached so in a
sense
> the external DRO would be redundant. So, I *could* get the X/Y
motors
> hooked up (which has a lot of other advantages, but will be very
> expensive because all of a suddenly I will have my credit card out
and
> will be calling Gecko for drives, and getting a power supply
> and...and..and..) and use the encoders on the motors with one of
the free
> DRO software utilities. One disadvantage to this is the servo
encoders
> will have to compensate for backlash which may or may not be a
problem. I
> assume it isn't a huge problem because it appears to be common
practice.
>
> The other method would be to build my own rotary-to-linear encoder
system
> which certainly has appeal and could have better resolution than
either
> of the two previous methods. However I don't know that it is
necessary...
>
> So, bottom line, is there an advantage to having two DRO systems on
a
> single mill? If I put on a digimatic scale system will I end up
junking
> it once I get my CNC stuff completed?
>
> Thanks!
>
> --C.S.