Re: Asian Import mills, EMCO, PRAZI, Myford, MOTORS

Hi Jeff,

Well, I'm sure that if I get the ENCO, I can do something similar for
the bearings. My old ballscrew stuff is 5/16 (perhaps metric), so
they're too light anyway for this application.

More below:


cadman@... wrote:

>
> --- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> > Hi Jeff,
> >
> > Thanks for the ENCO descriptions! I'll be following your conversion
> > closely. It is interesting to hear your comments on rotational
> > alignment, I suppose it won't matter, just a chore to measure out.
>
> Yes! I took the bearing blocks (three of them) to work and used the
> "Reneshaw" probe scanner. It made it easy to get the relation between
> the bearing hole and the mounting pins and bolt holes.
>

Are there three identical bearing blocks then? Good things to post pix
on, as well as the new motor mounts you're making! ;>)

>
> I
> > would want to use a pair of bearings, secured to the casting, and
> > preload them to take thrust. And then use a slotted flex coupler
>
> I also am planning to use angular contact bearing (two per end) and
> hold them to the new bearing block. I will use a nut on the ball
> screw to hold tension to the bearings.
>
> > (similar to the way Sherline did it). Are you going to use NEMA #23
> > motor mounts? What motors do you have? I just bought 3 180 oz/in
> > motors, intended for the Sherline. humm, might work on the "big
> mill"?
>
> I'm using servo motors. I got them from Camtronics. They don't come
> stock with a NEMA mount. I think I will use the standard bolt circle
> that is on the motor. I'm adding timming belts with a 2/1 ratio. I
> don't know for sure the size of them, I think 420 oz/in peak.

I won't be using servo motors anywhere soon, but more/bigger steppers
might be in order. I'll probably just run it by hand for a while.

>
> >
> > How long, and what dia ball screws are needed? I got my "scrap"
> ones
>
> The group has said to use 5/8" dia .2 pitch ball screws. This is what
> I plan to use as well.
>
> >
> > Good to hear that motor is not a problem. But at $200 or so more
> for a
> > US motor, I think it could be replaced later if needed. Is it a
> > standard mount/motor?
>
> I'm not sure, what is standard? It looks like the motor bolts to a
> plate and the plate has a pivot point and a locking end to keep it
> tight.

I have no idea what a standard motor would be!

>
> >
> > I don't know much about the gibbs. Aren't the gibbs tapered, so
> that
> > the ways get a little tighter as the gibbs are pushed in?
>
> Ah... yes "gibbs" that is what they are called, not "jibs". :)
> Yes that is normally how to adjust gibbs. You tighten screw that are
> pushing against the gibb and use a nut to lock the screw from moving.
> This system was not designed that way. There is ONE screw with a
> large head and is located at the end of the gibb. Not perpendicular
> to the gibb, but with it's axis, part of the large head catches the
> gibb and pushes it against another screw at the other end. I can't
> see that it does any good at all.

Maybe you just work the gibb back and forth between the screws? I'd
have to play with it. Not all that familiar with them.

More good info!

CUL8R!

Alan KM6VV

>
> >
> > cadman@p... wrote:
> > >
> > > Hi Alan,
> > >
> > > Well you know what my project is. I have taken appart the ENCO X
> and
> > > Y tables to measure everything. I'm just about finished designing
> the
> > > ball screw conversion for X and Y. I have not looked at Z yet.
> > >
> > > Some notes about "Quality" on ENCO. The iron looks like good
> quality
> > > cast iron. Can't find any pits or bubbles in the machined places.
> > > The stock machine uses "Thrust bearing" for the X and Y screws.
> They
> > > are a press fit on the shafts. This is the only thing that keeps
> the
> > > screw from sliding back an forth. (Other than the pinned collar at
> the
> > > end of the screws) The assembly procedure for these machines must
> have
> > > fixtures to hold things. While measuring the threaded holes and
> > > locating pins for the lead screw bearing blocks, I could see that
> > > every hole was placed at a random location. The only thing that
> is
> > > important is the location of the bearing hole. It must be on
> center
> > > to the lead screw. They don't care about rotational alignment,
> this
> > > is why the mounting holes and locating pins could be anywhere.
> > > The 2HP import motor runs great! Lots of power. 110 or 220 your
> > > choice. I liked the belt pulleys, they look like they were
> machined
> > > out of solid aluminum. (Thats a 10" dia bar stock!)
> > >
> > > The nuts are machined from one casting of copper or brass. The
> way
> > > they try to handle nut wear is by bandsawing a slit through the
> > > threads and placing a screw to "pinch" the thread if slop devlops.
> > >
> > > I'm not too concerned with the stock bearing and nuts since I will
> be
> > > replacing them with ball screws. What bothers me is the "Jib
> > > adjustment" They only give one screw to tighten the ways. It is
> > > located at the end of the jib (If you can believe that). I am not
> > > sure if it does anything at all. The only real jib tightning is
> done
> > > by the way clamps. You know the ones that you tighten to lock the
> way
> > > from moving.
> > >
> > > CADMAN
>
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