Molding a concrete slab to use as a base for a bench mill.

verbotenwhisky said:
I might be incorrect in what I thought you were saying as you and DaBear3428 seem to be talking flatness and I am looking at the leveling and concerned about the pads where the mill will be bolted being level in reference to each other to simplify mounting the mill. Personally I would not actually set the mill on the concrete because it will absorb moisture and mold it which isn't good for the metal, I would build a shelf a bit lower, half way down to add mass and lower the center of gravity like I did on my wife's wood lathe. I do not disagree with your contention that stiffness and stability is important, actually adding mass and lowering the CG would play into that 100%. My contention is that what ever you set the mill on would be best if flat and level so there is a known reference surface there to start with.

Some times I note that we tend to disagree to agree from misunderstanding, most everyone here is sharp/smart and trying to get to the same destination, we are all headed to the same place...
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i do not disagree that normal flat (.01") is good but the OP is talking about surface plate flatness.
 
dabear3428 said:
sorry for drooling on the photo

like i said i'm on the fence for what to get after i get my shop air conditioned but i sure like the pm-940V
i did not look at your location, i work in Corpus and live north of there.
i have the same issue with locking my z on the grizzly and i'm mulling over the idea of adding a counterweight to keep tension on the head at all times. how good is the motor/vfd that ships with it? good low speed tq?
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The motor has been very good, its cooling fan is a bit noisy but not bad, I haven't had any reason to move the belt to the low range, the high is perfect for what I do and it'll run a 3" face mill, 6 cutters through aluminum 1/4" deep full width without dropping much RPM, steel such as 1045 and 1018 I haven't attempted anything deeper than .120" with the same results.
 
verbotenwhisky said:
The motor has been very good, its cooling fan is a bit noisy but not bad, I haven't had any reason to move the belt to the low range, the high is perfect for what I do and it'll run a 3" face mill, 6 cutters through aluminum 1/4" deep full width without dropping much RPM, steel such as 1045 and 1018 I haven't attempted anything deeper than .120" with the same results.
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Nice
 
verbotenwhisky said:
The motor has been very good, its cooling fan is a bit noisy but not bad, I haven't had any reason to move the belt to the low range, the high is perfect for what I do and it'll run a 3" face mill, 6 cutters through aluminum 1/4" deep full width without dropping much RPM, steel such as 1045 and 1018 I haven't attempted anything deeper than .120" with the same results.
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Is your shop air conditioned? In my unconditional shop I cannot keep the rust off my equipment
 
dabear3428 said:
Is your shop air conditioned? In my unconditional shop I cannot keep the rust off my equipment
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I installed a 18000 BTU mini-split which has a specific dehumidifying setting and when I want to work in the garage i switch it to cool or warm which ever is appropriate.
 
Provincial said:
If the walls were poured separately from the floor (you can tell if there is a seam around the edge of the floor) then you must consider them as two completely separate structures. Even if there was rebar stubbed to carry through to the next pour, they do not have structural integration.

I've told this before, but a fellow I know took a 1940's Craftsman (Atlas-built) 12" lathe and formed up two pyramids to cast concrete tied into a concrete floor. The pour for the pyramids was carried up high enough the capture the feet of the lathe bed, with long anchor bolts using the existing mount holes in the feet. This set-up was used to make 1" Acme double lead screws for a paving machine. The spindle was modified to a roller chain drive, and the threads were cut in three passes. The pyramids were like adding 1,000 pounds to the weight of the machine, in terms of rigidity.
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I'm new to all this, but one thing I think you need to consider is NOT attaching the mill column to the wall. It's very possible as @Provincial states that the floor and wall are not attached. Code for where I live (Colorado front range) is to build this way to accommodate the inevitable shifting due to expansive soils. Even if integral-cast, I wouldn't count on the floor-wall structure to maintain machining precision. If it's cracking, it's moving...
 
dabear3428 said:
Is your shop air conditioned? In my unconditional shop I cannot keep the rust off my equipment
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Just outa curiousity, what type work are you going in Corpus? We just finished a big project at KOS in Ingleside.....
 
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