Re: [CAD_CAM_EDM_DRO] Z Axis Mechanical Layout Options - Bridgeport M Head

Graeme,
I haven't started the retrofit on my Enco mill (8 X 36) yet, but
I'm interested in your Z axis solution. If you can, either post the photos
on the Yahoo Group site, or send them to me directly.

Thanks,
Marv Frankel
Los Angeles

----- Original Message -----
From: "Graeme Murray" <graemem@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, November 18, 2002 10:30 PM
Subject: Re: [CAD_CAM_EDM_DRO] Z Axis Mechanical Layout Options - Bridgeport
M Head


> Hi Mark ,
> I bought a clone mill (FIRST with 50 x 10 table) a couple of years ago.
It
> had been retrofitted with SERVO Products controller and 3 axis drives.
> When I bought it it wasn't fully working. Had a couple of electronic
> problems which the folk at SERVO gave me wonderful help with and I was
able
> to fix.
> However the Z axis had been adapted locally with a mixture of tooth belts
> and gears ( they had done a frightening amount of work to produce a crappy
> result) to drive the quill pinion and it was not working and the previous
> owner seemed to have had continuing problems with it.
> From bits and pieces I had learned from this group and elsewhere I decided
> this approach was not for me, so I started from scratch and built a quill
> drive using a screw positioned where the depth stop screw was fitted .
> There was a retrofitted mill at my place of work so I was able to have a
> good look at it , though I did not copy it exactly. I had room to fit a
> double tooth belt drive to the screw which enabled me to mount the motor
> vertically at the side and with a second short belt turn the drive at
right
> angles and drive the screw. This enabled me to keep the block mounted on
> the front of the quill short and consequently reduce the cantilever
effect.
> I used a piece of acme screw material (good quality stuff) and a matching
> bronze nut. I cut the nut in half and built an adjustable anti backlash
nut
> assy. At the time this cost $96 NZ which was about 1/6 of the cost of a
ball
> screw and I wanted to be sure things worked.
> Of course , guess what I found in a second hand machinery dealers shop 6
> weeks later .... a brand new 16mm ballscrew with nut the right length ,
for
> $160NZ !!! So I now have that stowed away for insurance .
> However that was nearly 2 years ago and the Z-axis has been working fine .
> About 1.5 thou of backlash last time I checked, but I can live with that
for
> the work I have been doing.
> I did manage to stuff up one particular time and drove a cutter straight
> down into a block of plastic when the motor was still switched to manual
and
> didnt run.
> Broke the belt and gave me a heck (I'm trying to be polite) of a fright .
> However a new belt fixed it and didnt do any other damage.
> I can email you some photos if you like . Perhaps I should tune myself in
to
> how to put pics on the group files . It is much easier to follow on a
> picture.
> I definitely would not consider driving the quill rack and pinion though.
> Backlash can be a major pain and the rack has not been designed for
> measurement accuracy, that comment comes from guys way back on the list
and
> others ,not just me.
> If I can help lets know
> Regards
> Graeme
>
>
>
> ----- Original Message -----
> From: "natchamp_87" <mark@...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Tuesday, November 19, 2002 12:31 PM
> Subject: [CAD_CAM_EDM_DRO] Z Axis Mechanical Layout Options - Bridgeport M
> Head
>
>
> > Well, I got my new (to me!) BP M head mill. I have already started
> > taking it apart for the clean up, ball screws, etc. One of the
> > things I have not resolved is the best way to accomodate the Z axis
> > travel. I am hoping someone can shed some light on the best way to
> > accomplish this.
> >
> > If I move the quil, it appears there are a couple ways to do this.
> > 1) mount a motor to turn the same shaft as the hand lever. This to
> > me has a problem of very long travel for a given rotational travel of
> > the motor, unless I severly under drive the pulley which still might
> > not be enough?
> > 2) mount a motor to turn the fine feed shaft and worm gear. This
> > would fix the long travel per motor rotaion in 1 but the worm gear
> > isn't fixed to the shaft, it works on friction. I could key-way the
> > worm gear onto the shaft? This, to me, seems like the best approach
> > for moving the quil.
> >
> > If I move the knee I would need a bigger motor and could still under
> > drive to address the higher torque required. However, there doesn't
> > appear to be any good mounting locations for this method.
> >
> > Can anybody shed some light on this? I know people have done this
> > many times and would love to hear some insight. Thanks a bunch.
> >
> > Mark
> > mark@...
> > www.mark.hargett.com
> >
> >
> >
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> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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