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rtr@...
I'de like to order a couple of boards. How much should I send, and where
should I send it? I just got on this list so I missed the preliminaries.
I guess a schematic and parts list would be awfully helpful.
Thanks,
Ted Robbins



----------

From: Dan Mauch <dmauch@...>
To: CAD_CAM_EDM_DRO@...
Subject: Re: [CAD_CAM_EDM_DRO] DRO boards.
Date: Monday, May 24, 1999 6:21 AM

From: "Dan Mauch" <dmauch@...>

I have gotten enough email to decide to go ahead and order the boards for
the 4 axis DRO. I will have 30 made even tho I only have orders for 20.
There will be other newsgroups that will be interested.
Dan


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discussion of shop built systems in the above catagories.

Poured lead or type-metal bearings are still used extensively on some
older-type industrial machinery and they are very successful - hence
there are machines around here still running with them which are over > a hundred years old.

I am going to try something semi-related to this topic. My CNC is
fairly stiff for what I am doing, but I have a huge problem with
vibration. I am using aluminum and steel extrusions and box channel for
the frame. These hollow members are very underdamped in nature. 2 ways
to decrease the amplitude of vibrations is to either increase the
damping coefficient of the material, or increase the mass of the
system. I was lucky to spend a day with Dan Huggins, programmer of
Dancad, and he gave me the idea of making a precast concrete frame
components. Then I saw a company at a trade show (Philadelphia resins)
who make a slurry of granite particles in epoxy, and form it into a
composite that has much of the vibration damping properties of solid
granite. Davenport actually makes an entire lathe bed using this
process. They also fill structural members with this goo to help damp
vibrations in machines. Unfortunately, their stuff is too expensive for
a hobbyist like myself. But, I think I am going to try to fill my
hollow structural parts with a reinforced polymerized concrete. This
will make my machine heavy as hell, but should also decrease the
amplitude of the vibrations radically. I will let you all know how it
works.

-Mike Romine

Tom:

I am just new to the list so I missed out on some earlier discussion of
your DRO project. I scanned your WEB page, I think it was yours, But I
seemed to have missed what type of encoders you are using and or
support. How about building your own using a type setter to make a film
grid.

Thanks
--
James Buchanan
Lexington, Kentucky (The Blue Grass State) USA
Two Truck Climax Locomotive Operator & Builder

Hi Don,

I don't have a lot of experience with lead bearings except the one in my
fly-press but I have seen them used a number of times. I agree that, as
with all techniques, this one has its own place and I suppose there
would be design considerations which may preclude its use in certain
situations. Presumably, the screw working with such a bearing would need
to be at a coarser pitch than for say a bronze bearing and the nut may
need to be several times as long to get enough load spreading. I
certainly won't be using this type of feed nut in the miller I'm making
now, it will have a split nut - either split on the diameter with a
pinch screw if I decide to use a 'V' thread or split t'other way with
pinch screws to draw the two parts together if I go with a square or
acme thread. This way both the shake and friction can be adjusted
whenever necessary.

Ian

Don Hughes wrote:

From: Don Hughes <pencad@...>

Ian:

In response to your post here about babbit bearings, I have worked in
the past most extensively with babbit.
My comment is this. Having worked so much myself with babbit, you must
have the lead at the right temp. to pour and make a "good" bearing. I
believe we used to pour at around 350deg C to ensure a solid pour for
the bearing and the consistency. The machines that we had the babbit
bearings on were larger engine lathes, swinging approx. 60+ inches and
located in the headstock where we weren't turning the spindle all that
fast. Truthfully, after seeing the amount of rigidity that is required
for CNC applications in the rigorous movement of the axis' at the given
feed rates, I don't feel babbit is the best way to go.

Best wishes

Ian

--

Ian W. Wright LBHI
Sheffield Branch Chairman of the British Horological Institute.
Bandmaster and Euphonium player of the Hathersage Brass Band. UK.
See our homepage at:- or


'Music is the filling of regular time intervals with harmonious
oscillations.'

Andrew Werby wrote:

[Well, MaxNC has a retrofit kit for Sherlines I could sell you for $415,
which includes
mounting plates, lead screws, nuts, and miscellaneous hardware, plus the MaxNC
motion control system. If you really didn't want the control software, it
could possibly
be even cheaper, but I'd say get it if you can, if only for comparison's sake.]

Thanks for the offer Andrew but, at the moment, finances (lack of ) are
pointing me in the way I am going. I have worked out a stepper driver
system and now have motors turning and I have tweaked Stepster a bit and
things seem more settled. I'm now starting on the mechanicals - the mill
I am making is scratch-built as I have a contact with a scrap yard where
I can get any odd bar ends of new material I need - I just have to wait
a while sometimes until suitable sizes come in. Unfortunately, this
isn't always the bet way as I found out this afternoon - I spent quite a
while slitting a 14" length of hexagon steel bar to make slideways for
the mill table only to find, when the two parts finally parted, that
they sprung apart into the shape of two bananas - talk about internal
stresses! So, back to the drawing board - or, at least, the miller and
tomorrow I'll go back to the old way and mill an angle on the edge of a
couple of rectangular bars.

Best wishes

Ian

--

Ian W. Wright LBHI
Sheffield Branch Chairman of the British Horological Institute.
Bandmaster and Euphonium player of the Hathersage Brass Band. UK.
See our homepage at:- or


'Music is the filling of regular time intervals with harmonious
oscillations.'

Charlie,
I understand that only 1 G code per line is allowed. Keep up the
good work. I think DOS version will work for 99% of the people!
Dave

In a message dated 5/17/99 6:12:55 PM Pacific Daylight Time, WAnliker writes:

Here is the information on the CAD_CAM_EDM_DRO list

Yes, people can subscribe through email. ONELIST supports several commands:

listname-subscribe@... - subscribe to a list.
listname-unsubscribe@... - unsubscribe from a list.
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where listname is the name of the list.

URL for on line subscriptions:


To unsubscribe, replace the word SUBSCRIBE in the above commands.

The following will take you to the Help Center, and will answer most
questions for you. (Note ONELIST uses the same words in all URL names, but
the destination can be different, wild, I have renamed my URL's for myself,
but copy directly from ONELIST when posting.)
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This is also the URL that ONELIST sends out when I send an invitation to a
person.

I have sent invitations to all those that signed the list at NAMES, plus
sent invitations to other lists, online. Also invitations have been sent

to

persons that I have talked to in the past on these subjects. Several names
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DRO this I have restricted for a bit, have it all screwed up. Will change
ASAP.
If I can be of further help, please contact me.
bill

Ian:

In response to your post here about babbit bearings, I have worked in
the past most extensively with babbit. Before I became a toolmaker, I
was a journeyman and used to use a lot of machines that were equipped
with babbit bearings and the such. I used to pour the bearings and
machine the bearing as well after pouring.

My comment is this. Having worked so much myself with babbit, you must
have the lead at the right temp. to pour and make a "good" bearing. I
believe we used to pour at around 350deg C to ensure a solid pour for
the bearing and the consistency. The machines that we had the babbit
bearings on were larger engine lathes, swinging approx. 60+ inches and
located in the headstock where we weren't turning the spindle all that
fast. Truthfully, after seeing the amount of rigidity that is required
for CNC applications in the rigorous movement of the axis' at the given
feed rates, I don't feel babbit is the best way to go.

Each application is different for each of our uses, and if babbit will
suit your application, and give you the tolerances required, then by all
means if you see fit, use it. This was just my opinion and not criticism
in any way.

Regards,
Don Hughes

And don't let it happen again!
:)

Charles Gallo <Charlie@...> wrote:
Subject: Re: Progress!!

Ian,
Well, I have an admission to make - I'm re-writing (Maintaining)
Stepster!
The thing is, so many things could be wrong, and I'm ONLY working with
code (I don't have a CNC Mill - YET - anyone have some cheap ideas for my
Sherline)

[Well, MaxNC has a retrofit kit for Sherlines I could sell you for $415,
which includes
mounting plates, lead screws, nuts, and miscellaneous hardware, plus the MaxNC
motion control system. If you really didn't want the control software, it
could possibly
be even cheaper, but I'd say get it if you can, if only for comparison's sake.]

Andrew Werby






Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff

Bill
The selling on list seems to be a good move. Although 99.9% of what you guys
are talking about is Greek to me I will still be out there. Who knows I may
decide to use one of those fancy systems on my mill. (If it woudl fit) Are
there any books on this CAD, etc subject laying around?
Ray
Auburn, WA USA

Poured lead or type-metal bearings are still used extensively on some
older-type industrial machinery and they are very successful - hence
there are machines around here still running with them which are over a
hundred years old. One particular machine I can think of is a
file-cutting machine where the leadscrew nut is actually a split brass
block hollowed out to form a permanently in-situ mould which is filled
with lead. In production work, where the machine is subject to
continuous severe vibration as the chisel strikes the steel file blank,
these cast bearings last several weeks before needing re-casting which
is then a simple matter of cutting off the old lead and remelting and
re-pouring it - about 5 minutes work and you again have a precision
fitting new feed nut. While there obviously would be some wear over a
period of time I don't think this should be a problem as, whenever you
want to do a really precise job, you can just cast a new nut before
starting. It also has the advantage that, if you set the carriage
position before casting, you shouldn't have to readjust the machine for
screw rotation on the new nut. If you use lead, it is also somewhat self
lubricating - if you can still get lead that is, in this age of terror
over using anything useful!

Jon Elson wrote:

Anyway, what I'm wondering about is maybe pouring linear bearings
around semi precision shafting. I've thought about babbit, and just
heard about this stuff called Moglice. Any ideas?

Well, the puored bearings would wear quickly, and it doesn't sound
like there would be a way to adjust play. but, flex in the shafting
would make it a very inaccurate machine.

Best wishes

Ian

--

Ian W. Wright LBHI
Sheffield Branch Chairman of the British Horological Institute.
Bandmaster and Euphonium player of the Hathersage Brass Band. UK.
See our homepage at:- or


'Music is the filling of regular time intervals with harmonious
oscillations.'

On Tue, 25 May 1999 21:47:12 -0700, Don Hughes <pencad@...> wrote:

I do have a photoplotter with 1/2" round rails, and it has some vibration
problems that require damping. It has an optical carriage that weighs
ounces, and no cutting forces at all!

John, you're plotter, is it a flatbed plotter? If so, I am desperately
looking for one that is a "D" drafting paper size(34" x 22") or larger.
If you happen to know of such about, or if anyone in the group here
knows of one that some company or themselves have sitting around, I
would be very interested in talking with them.

I would only be running this with optics as well and driven with HPGL
drivers from the LPT1 directly.

Uh huh, OPTICS. See, exactly my point. QED.

Gar

On Tue, 25 May 1999 23:41:47 -0500, Jon Elson <jmelson@...> wrote:

Right - and you'd have a very flimsy machine, which wouldn't be able
to cut anything tougher than cardboard or modeling wax. Some people
want a machine like that. But, as a (converted) Bridgeport user, who
still has problems with rigidity sometimes, I can't imagine how something
with 1/2" or 3/4" round rails would work for metal cutting.

Yes, I think this approach to answering "what-ifs" will go along way to making
our group successful and peaceful. Because SOME PEOPLE DO want/can-use such a
positioning system to cut foam, wax, or Rayite. (or maybe even cardboard/mdf)

Also, you'll see from time2time guys wanting to ROUTE thin alum sheet to size,
but NOT to +-0.001 precision. You've just gotta appreciate that there are all
kinds of aspirations and users for this CNC stuff, and by comparing notes and
caveats, we can help each other enormously to putting boundsNbrackets on what's
doable with a given mass/stiffness/HP whatever. AND this exercise builds
comprehensive understanding.

In lieu of some "scientific" metric or engineering design for each requirement,
comments like this give each of us an idea of the rough boundaries we're dealing
with, as far as stiffness, guide and positioning precision, etc.

My vote is for us to strive to NOT pooh-pooh another's applications that might
sound either flimsy (or overkill) compared to our own interests, but instead, to
develop a "feel" for how/what might be sufficient in terms of guide hardware,
positioning screws, driver electrics, and even software programs. That way we
all get a broader view of CNC metrics.

We've got a tremendously diverse set of interests/users on this group, and a
wise person (oh please, let that be me at least :) wanting to learn the max,
could easily build a MUCH broader understanding of what works with what and for
what, by tryna see what HAS worked for people in the past, and what's being put
together for the future.

And if from time2time, someone has to be the bearer of "bad news" as far as a
particular aspiration being outside the realm of physical reality, well, we can
all learn from that too, eh?

Gar

I do have a photoplotter with 1/2" round rails, and it has some vibration
problems that require damping. It has an optical carriage that weighs
ounces, and no cutting forces at all!

John, you're plotter, is it a flatbed plotter? If so, I am desperately
looking for one that is a "D" drafting paper size(34" x 22") or larger.
If you happen to know of such about, or if anyone in the group here
knows of one that some company or themselves have sitting around, I
would be very interested in talking with them.

I would only be running this with optics as well and driven with HPGL
drivers from the LPT1 directly.

Regards,
Don Hughes

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Geoff Roehm wrote:

From: groehm@... (Geoff Roehm)

Hi! Just got switched over to digest - thanks, Bill - Great list!

I've been sneaking up on this CNC thing for a few years, and have
the electronic part more-or-less less figured out.

What I'm having a problem with is the mechanicals, specifically
whether to design and build a machine, or just buy an old CNC mill
and retrofit it. From the prices I've seen for accurate linear
bearings, shafts, ballscrews, and machining, the cost would be
about the same.(?)

Right - and you'd have a very flimsy machine, which wouldn't be able
to cut anything tougher than cardboard or modeling wax. Some people
want a machine like that. But, as a (converted) Bridgeport user, who
still has problems with rigidity sometimes, I can't imagine how something
with 1/2" or 3/4" round rails would work for metal cutting.

I do have a photoplotter with 1/2" round rails, and it has some vibration
problems that require damping. It has an optical carriage that weighs
ounces, and no cutting forces at all!

Anyway, what I'm wondering about is maybe pouring linear bearings
around semi precision shafting. I've thought about babbit, and just
heard about this stuff called Moglice. Any ideas?

Well, the puored bearings would wear quickly, and it doesn't sound
like there would be a way to adjust play. but, flex in the shafting
would make it a very inaccurate machine.

Jon

Anyway, In the past year I have accumulated quite a bit of linear motion
stuff (THK Rails and bearings, linear shafting and bearings, motors,
controllers etc.) and
was wondering if for sale ads are allowed here (on topic of course). I
need to sell
some of this stuff to buy some nice lead screws for my new machine. If
not, E-Mail
me at the address below and I will send you a list of items. If ads are
allowed I will post a list of items here.

ps I am NOT running a business, Just a hobby

Thanks

Bill Scalione
scalione@...

I think CNC related parts for sale listings would be a benefit to this
group (IMO). Sure beats hanging out in industrial surplus shops. But I
might suggest we use a 'depository' for detailed listings at one of the
free web site services (like Geocities). That way you would only need
to make a general announcement that you have things for sale on the
list, and let interested parties browse the web page for detailed
information. This would not waste the bandwidth of those not interested
in buying. You web add could have digital pictures too. I have seen
newsgroups collectively create similar web depositories.

I have been trying to make space in my garage the last few days and have
discovered I have a ton of stuff I need to get rid of as well. Mostly
THK, IKO and Thomson linear bearings. I would be more interested in
trading for things I need than selling though.


-Mike Romine

Hello Guys, the mail for selling to the group is almost unanimous in favor,
in fact only two against. Here are the comments and suggestions given.

1. Subject to be F. S. , USA or UK, AUST, Etc., The country will help those
that do want to screen for ads. that are out of country.
2. Limited to 12 items per posting, for larger lists it is suggested that
direct e-mail upon request be used. You can post an additional post the next
day or two.
3. All for sale items to be related to the subjects covered by this list.
4. No for-sale postings by non-list members.
5. If you are selling, please post the URL for your sales area.
6. All sales correspondence to be off list.
7. Handle your own complaints.
8. I feel that from the tone of the posts to this list that the above would
be a good and fair guide lines for the group. If it becomes a big problem,
we will look at it again.
Hope most of you are happy with the above.
bill

I'll mull that over.
Dan

Subject: Re: DRO boards.

I have gotten enough email to decide to go ahead and order the boards for
the 4 axis DRO. I will have 30 made even tho I only have orders for 20.
There will be other newsgroups that will be interested.
Dan

Have you considered getting together a group purchase at US Digital?
They do offer pretty decent discounts for volume purchases, and
considering you're looking at 20-30 LS7266 chips, you could save
yourselves a couple of bucks. In fact, if you decide to go that
route, put me down for 1 of those chips. :)

Of course, it's a major hassle handling the money side of this, so if
you'd rather not, I for one understand completely.

-Tom Kulaga