Jim
You are correct in that I beams are strong. At least for
carrying heavy static loads.
Lathes dont do this though. :)
When a machine is running it will develop its own harmonics
, vibration or song if you will.
The open design of an I beam will allow the outer edges of
the beam to vibrate more as these harmonics increase.
Since your carriage will be contacting these parts of the
beam the carriage will want to follow the vibrations of the
bed.
This will create quite a bit of chatter.
In the Gingery design the headstock is also connected at the
outer edge of the bed.
So now we have a headstock singing at one end, a tail stock
singing at the other and the carriage singing in the middle.
Each part will tend to sing at its own frequency. Or you
end up with a realy bad out of tune song. :)
All of this will end up appearing on the part you want to
machine.
Now on a wood lathe this may not be as big an issue since
you are not expecting to cut to the same tolerance as on a
metal lathe.
On 3/5/2011 8:28 AM, james122964 wrote:
> 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
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
> d
http://groups.yahoo.com/group/gingery_machines/app/peoplemap/view/map
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