You have to think a bit about what happens to the bed when you are cutting
something on the lathe. Is the load downwards deflecting the beam in the
manner that an I-Beam was designed or is the load on the bed different?
I'd suggest that the tool bit, when 3" off centerline, mounted to the
carriage which in turn transfers the cutting load two load points. The
top of the back side of the ways and the bottom of the front side of the
ways. In other words, it twists.
Tubes, especially round ones, are the best a resisting twist but it's hard
to mount a flat ways to it. Rectangular tubes or box structures resist
twist far more. The Gingery design is an open box but the bracing is
cross wise so it doesn't resist twist as well as x bracing.
Before you decide to change the design, do a couple of Mechanical
Engineering Statics courses at University. After that you will understand
the type of load bearing members that are needed.
So often someone slams the higher education aspects of learning. The
reality, if correctly applied can save hours of time and materials. Not
that Engineers can't make mistakes. Tacoma Narrows bridge is an example
of that. But all in all we owe what we have to the research that they do.
It's just that some of them aren't as good as others and we tend to focus
on the few that aren't as good as examples to generalize a negative
attitude.
Look at every possible lathe you can find. Photos etc. Look at the beds.
Look a the ways. Look at the new High Speed CNC turning centers. When
all is said and done, you'll see a common approach to solving the
problems. Not because they are lazy but because the other ways don't work
in an (and this is key) economical fashion.
John
Automation Artisans Inc.
http://www.autoartisans.com/ELS/
Ph. 1 250 544 4950
> -----Original Message-----
> From: gingery_machines@yahoogroups.com
> [mailto:gingery_machines@yahoogroups.com] On Behalf Of james122964
> Sent: Saturday, March 05, 2011 5:28 AM
> To: gingery_machines@yahoogroups.com
> Subject: [gingery_machines] Re: Building a lathe
>
>
> Glad I asked about the I beam, seems everyone experience
> counters my intuition because I thaught I beams were very
> ridged and strong. I have some square 2 inch 250 wall maybe
> I will try and fit that in instead.
>
> To all, I realize that I do not know what I am doing, I just
> have the basic skills to accomplish it. I have been making
> things from metal for quite some time and casting repair
> parts, although not on the scale needed for these machines.
>
> I really appreciate the advice and frankness.
>
> thanks
> Jim
>
> --- In gingery_machines@yahoogroups.com, "Chris (CB)"
> <boyercl@...> wrote:
> >
> > I can not dispute your design for your project as I have not
> > seen it. :)
> >
> > I will say this. :) If I beams or the design of an I
> > beam were a "good" idea for a lathe bed I would think some
> > one would have used it to produce a commercial machine some
> > time in the last 200 years during the modern lathe design
> > process.
> >
> > Wood lathes while sharing many similarities with metal
> > lathes do have quite a few differences.
> >
> >
> >
> >
> > On 3/4/2011 11:31 PM, keith gutshall wrote:
> > > Hello Chris
> > > You know I work on some unorthodox machines.
> > >  I have been working on a pedestal wood lathe, the arm
> for it is
> > > Â two heavy flatbars with a spacer in between them. It has a
> > > Â pivot point at one end.
> > > Â It is 18in long and there is no give to it at all.
> > > Â It looks like a good idea for a lathe bed with some
> wider spacers
> > > Â it would be stiff and no viberation on it.
> > > Â
> > > Â Keith
> > >
> > > Deep Run Portage
> > > Back Shop
> > > " The Lizard Works"
> > >
> > > --- On Fri, 3/4/11, Chris (CB)<boyercl@...> wrote:
> > >
> > >
> > > From: Chris (CB)<boyercl@...>
> > > Subject: Re: [gingery_machines] Building a lathe
> > > To: gingery_machines@yahoogroups.com
> > > Date: Friday, March 4, 2011, 7:30 PM
> > >
> > >
> > > Â
> > >
> > >
> > >
> > > Jim
> > >
> > > This idea has come up MANY times over the years.
> > >
> > > In short NO... :)
> > >
> > > If you are goint to make the bed from some stock material
> > > the best solution is some form of box tub.
> > >
> > > Which form thickness, filler is always a fun debate. :) LOL
> > >
> > > But tubing will produce a more stable lathe with less
> > > vibration...
> > >
> > > Yes scrapping whatever ends up being your bed "ways" will
> > > need done.
> > > It does not need done before making patterns..
> > >
> > > On 3/4/2011 6:45 PM, james wrote:
> > >> I am starting the gingery lathe, but, think that I would
> want to do a
> > >> deviation. I am thinking of using a I beam for the bed
> and wanted to know do I need to have the bed and ways scraped
> beore making the patterns for head stock and carriage? seems
> to me the casting would be needing so much work that I could
> just fit everthing up, then do the casting and scraping.
> > >>
> > >> any and all advice is needed and appreciated.
> > >>
> > >> thanks
> > >> jim
> > >>
> > >>
> > >>
> > >>
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > >
> > >
> > >
> > >
> >
>
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>
>
http://groups.yahoo.com/group/gingery_machines/app/peoplemap/view/map
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