Making A More Solid Mini Mill Base

[fabguy]

Here's the story: I purchased a PM25mv mill with base. My garage floor is not level, sloped for drainage should I hose off the floor. I grouted the welded sheet metal base to the floor (measuring on two of four edges) to be within a couple of thous and bolted it down. The top is way not flat (thin welded sheet metal). There was no way to get even close to flat just bolting the mill to the base. I leveled the mill using washers and shim stock (the welded top is all over the place measurement wise). Got it within an couple of thous. The cast iron base of the mill is set on roughly 2 square inch of support at the corners.
My buddy programs Mazaks and is lecturing me on the need to come up with a more solid contact with the base to dampen vibrations. My argument is that no mater how this mill is mounted on the current base, the thin sheet metal base will resonate at certain speeds/cutters no mater what I do. I could make a 3/8" machined top plate welded to 3/8" stand to solid it up. I'm not sold that this is necessary (but obviously preferred). I searched for an aftermarket stand built tougher, but found none. Your thoughts? I can make a bull base for this thing...Should I? I intend to eventually convert to CNC.

 

[woodchucker]

My thoughts are to get rid of the grout and sheet metal, then take the base that you are using , install neoprene levelers in the bottom. and level using them. Leave the floor as it originally was. But that's just my opinion.

 

[Bob Korves]

The PM25 is a fairly light mill. If you are looking for rigidity, you are not going to get it, at least compared with machines weighing a couple tons or more. Level is not a bad thing, it allows you to be able to use a level to assist in setting up work and keeping round things from rolling off the table, nothing more. Grouting the base to the floor achieves little more than constraining your mill to one location only. I have moved my mill mill several times since I got it for shop reorganizing. The previous mill was also moved. Machines are not part of the building in my eyes, and might even be moved for a specific job to make room for the oversized work and then returned. I think you are chasing rigidity on a machine that simply does not have it. That does not mean you cannot do very nice work, just that you have to approach it differently, allowing and compensating for the machine you have.

 

[T Bredehoft]

My PM25 is secured to an old Formica kitchen counter top. I glued and screwed a piece of another counter top under the machine so it's 1 1/2 inches thick. The counter top is hung on the wall and supported by 2x4 legs every two feet. .I encountered my first problem with vibration the other day, cutting a 1/4 " slot in a piece of 1/4" steel with a 3/16 two flute end mill. I have a plastic damping materiel tight between the base and the Formica. I traced the vibration and found the whole counter top was quivering.
I'm not sure that 3/8 would be thick enough steel to damp your machine.