+- MetalworkingFun Forum (http://www.metalworkingfun.com)
+-- Forum: Machinery (http://www.metalworkingfun.com/forum-10.html)
+--- Forum: Milling Machines (http://www.metalworkingfun.com/forum-12.html)
+--- Thread: Setting Up My PM935 Mill (/thread-2981.html)
RE: Setting Up My PM935 Mill - Mayhem - 01-03-2016
Personally I wouldn't bother. I would bet money on the base being plenty stable as it is. Put it back together, stick the leveling feet under it as per Willie's picture and make some chips already
RE: Setting Up My PM935 Mill - DaveH - 01-03-2016
(01-02-2016, 10:23 PM)EdK Wrote: Any mechanical engineers out there?
Ed
I was one, I'm not allowed to call myself an engineer anymore, I can call myself a Retired Engineer - does that count
DaveH
RE: Setting Up My PM935 Mill - f350ca - 01-03-2016
Join the club Dave
RE: Setting Up My PM935 Mill - f350ca - 01-03-2016
Depends on how far out your going to cantilever the feet Ed.
RE: Setting Up My PM935 Mill - DaveH - 01-03-2016
(01-02-2016, 10:23 PM)EdK Wrote: My question is do you think the 1/2" 1018 is strong enough to hold the mill? I sure hope so since I really don't want to buy some thicker steel.
Ed
No
DaveH
RE: Setting Up My PM935 Mill - DaveH - 01-03-2016
And now I suppose you will want me to explain my answer to your question
DaveH
RE: Setting Up My PM935 Mill - DaveH - 01-03-2016
On first sight increasing the base size is a good idea to increase the stabilization and it always is.
However it is how the base size is increased that can cause problems and how the base fits in with the overall structure.
With the same size of object - the heavier one is more stable than a light one, coupled to this is where the majority of the weight is (at the top, middle or bottom)
eg. An empty 3'x3'x3' cardboard box is easy to tip over, fill it with sand ..............
Weight is important.Coupled to the weight of the object is the strength of the material the object is made from eg the cardboard box will 'rip' before it is tipped (pulled) over.
The strength of the material of your mill can be visualized by having a 1/2" thick lip around the base of the machine - say 2" wide and a hole at each corner for the support pads. This would be easy for the manufacturer to cast and the extra width will increase the stability. On a light weight machine all is fine not too sure on a mill your weight.
Cast iron is great in compression nearly in destructible, in tension quite bad - tends to crack and break.
This is my thoughts regards your mill.
The 1/2" steel needs to be a whole plate (or at least behave as) and solidily fixed to the underside of the mill base. The 4 bolts holes I feel are not enough 8 would be better, but it must be fixed solidly. The steel base could be 4" larger than the mill base 2" all round.
There we have it - with a feet pad at each corner. The machine is switched on and the vibration goes down to floor via the steel plate which vibrates like a drum.
Just bluudy great. 
We need to increase the thickness of the steel plate - more mass = more damping, go for 2" thick plate. Now with the 2" thick plate should be better than the 1/2" plate except it is only going to be fixed at 4 points - that is just not sufficient.
That's my 2cents
DaveH
RE: Setting Up My PM935 Mill - DaveH - 01-03-2016
Ed, Unfortunately it is not quite so straight forward as it seems at first sight. If it were all the manufacturers would narrow the bases and have an add on.
It's good to think outside the box
now get back in your box DaveH
RE: Setting Up My PM935 Mill - Mayhem - 01-03-2016
Gee Dave - four posts to get to the exact same answer as me...
RE: Setting Up My PM935 Mill - Sunset Machine - 01-03-2016
My non-engineer impression was that it would be like mounting the mill on leaf springs. Even some leveling devices strike me that way - why put a mill on stilts? Normally you would shim, bolt and grout for stability. Makes housekeeping easier too.