Mill sitting on a ledge, build up with concrete, steel, something else?

Been away from things for a while, finally getting back to rebuilding my VN #12 and it has a new home it needs to move to. The location is half over an existing ledge (large garage) about 3 1/2" above the floor. I'm not worried about the slab, but this means that I have 18x27" of Van Norman base that needs something under it, as thin air won't support it.

In trying to determine the best direction, a few thoughts came up including modified taller feet/levelers, building a heavy steel box (I have a bunch of 3x3x1/4 angle sitting around) under each corner or across the front, or what seems easiest on first look, concrete.

Talked to a friend who appeared to know a thing or two, but 'a quick form and a couple bags of quickrete' seemed a bit lacking. I'd think I would need to drill in some rebar, scarify the existing (have bonding agent on hand from another project) and perhaps the crack resistant fiber reinforced pre-mix? How far past the base would I need to go?

Top heavy 200lbs of equipment on something I'm unsure of kind of bothers me, thoughts on the best approach and material to bring support under the front half of this machine?

Trip

200 lbs? You wouldn't even need to take the concrete mix out of the bag for that, set it on the floor and sprinkle some water, it'll hold.

If its 2000lbs you still shouldn't have a problem. Form it up, mix up 3 bags of quickcrete and away you go. I suppose you could scarify and use a bonding agent with drilled rebar as long as you don't want to remove it again.

If this is a removable in the future slab I'd pour it with some visqueen on top of the floor with some steel mesh in it, if you've got fiber why not, then pull it up and mix up some hydracal/hydrastone to grout it to the floor. If you need to remove it, get at it with a pry bar, pull it off the floor then chip the hydrastone away and be back to where you were before. For easier removal cast a piece of PVC pipe through it so you have a place to throw a bar in it to pick with a hoist.

4x4s cut to fit would do it for me.

A SackCrete pad cast in a basic wood form is the real deal in these situations.

Chances are you'll wish to put the mill somewhere else so don't do anything permanent to the floor. Pour your mix over a single ply of 2 mil poly which will act as a separation barrier. The poly is thin enough to conform to the keyed indentations under the weight of the pour. Indent the floor in a few places so the pour will key and not shift.

Your VN mill is a light weight as such things go. Knee mills are intrinsically stiff and almost insensitive to out of level condition. I've seen knee mills sit crooked on an old carpet laying on a dirt floor and stiil perform accurately.

The only time out of level is a PITA on a knee mill is when you need the coolant to drain back to the sump (not off the table onto the floor) or you want to quickly align a work surface parallel to the table and a precision level is the handiest way to do it.

Forrest Addy said:

A SackCrete pad cast in a basic wood form is the real deal in these situations.

Chances are you'll wish to put the mill somewhere else so don't do anything permanent to the floor. Pour your mix over a single ply of 2 mil poly which will act as a separation barrier. The poly is thin enough to conform to the keyed indentations under the weight of the pour. Indent the floor in a few places so the pour will key and not shift.

Your VN mill is a light weight as such things go. Knee mills are intrinsically stiff and almost insensitive to out of level condition. I've seen knee mills sit crooked on an old carpet laying on a dirt floor and stiil perform accurately.

The only time out of level is a PITA on a knee mill is when you need the coolant to drain back to the sump (not off the table onto the floor) or you want to quickly align a work surface parallel to the table and a precision level is the handiest way to do it.

Click to expand...

Ok, I'll admit, I overthink and overbuild damn near everything. Sounds like a few votes for a simpler approach. How far out from the base would the pad need to be? Asked a master electrician friend of mine who said their standard for 1-2klb equipment is 4" past the base.

And yes, I forgot a 0, 2000lbs, not 200...

Appreciate the info folks! It'll be a while before it's running, but it's been sitting with the knee only for a year, I'm excited to think the table and head may be sitting on it again before the new year starts!

Trip

Most mills are leveled by placing shims under the corners until level and no rocking is evident. Just think of your front shims as being a little thicker; the 2000 pound weight should be enough to hold the shims down, especially if you start with a 3" thick piece of aluminum bar spanning the front of the machine, then add shims for level.

Exactly as Forrest Addy said. If you don't want to key it to the floor just cast it in place and install a couple of angle iron braces with tapcon screws after removing the form and trimming the plastic sheet.

If you decide to remove it later just unscrew the braces and pry up the slab. A few small screw holes are easy to fill with Rockite.