How much floor do I need under a 3520B ?

[Drew Marold]

Hi folks, first time posting here. There is a 3520B with my name on it being loaded on a truck that should be here Friday. My workshop is in the basement of my 1889 Victorian house, with a cement floor poured some time in the 50's. My dad advised me to drill a hole in the floor to check the thickness of the concrete, as back then sometimes they just put down a thin coat to cover the dirt.
I was wondering if anyone knew the ground pressure of one of these beasts, and has anyone ever had issues with the floor under it ? I am ridiculously excited for this thing, I'm moving up from a no-name $200 mini that has stated to fail, and can't wait to do some serious turnings.

[Harvey M. Taylor]

NOT A BAD IDEA AT ALL TO DRILL A HOLE OUT AWAY FROM THE WALLS.Max

[Fred Belknap]

I have my 3520B on concrete and no problems and I doubt you will have any either as concrete has a long life. It is probably as hard now as when poured. If it isn't crumbly I wouldn't worry about it. It probably isn't level and you will need to level the lathe, it has adjustable feet. If you have to take it down a stairs be sure to get help as it is heavy. Congratulations, it is a great lathe.

[Jerry Marcantel]

If you are concerned, and the concrete turns out to be thin, go to a metal fabricater, and have them make up some 1/4"? or 1/2" plates x 8-12" square to take the load at the feet. Problem solved......... Jerry (in Tucson)

[Paul Williams]

It is obvious in the old basements I have seen with a thin layer over dirt. Tends to flake or crack. I suspect you will be OK. I like Jerry's solution if you are concerned. However, I don't like standing on concrete, so I would lay down some 3/4 inch plywood. Perhaps use thinset to level the concrete under the plywood if required.

[Dennis Nagle]

There is compacted dirt under whatever thickness concrete you have down there. Be gentail, set it down without impact and you should be fine.

[Drew Marold]

Thanks for all the input guys. I'm thinking I'm probably ok since in the ~13 years we've been there the floor has never flaked or cracked.

[Matt Mackinnon]

Jerry and Paul have the point. It really doesn't matter how thick the concrete is, it's more a concern about a point load. if you put a sheet of 3/4" plywood, then that distributes the load over a much wider area, and it won't crack.

Think of it like a pin and a balloon. it doesn't take much force to pop a balloon with a pin, but it takes a whole lot to pop it with an open hand.

[Reed Gray]

Well, as an old concrete finisher, you will most likely be fine. They quit using 'dry pack' (mix of aggregate and cement loosely put down and then capped with 3/4 inch or so of grout) shortly after the turn of the century. You most likely have 2500 psi concrete on the floor. As long as the concrete is 3 or more inches thick, no problem. Drilling a hole might give you an indicator as to how thick it is. My only worry would be if there was a vapor barrier under the slab, but that wasn't a common practice way back then. Having extra metal on the feet might not hurt, but they need to be attached to the lathe feet some how or the lathe will vibrate off because there is always a little wobble when you turn.

robo hippy

[Thomas Canfield]

There is an adjustment screw at each leg. I made a wooden saucer with a washer in the middle to set the screw on. The washer spread the load of the screw head, and the wooden saucer (about 4" D x 1"T oak) spreads the weight. I have recommended to others on a wood plywood floor to use a 2 x 6 flat across at least 2 joists to spread the load across the plywood to avoid the spring of the floor. Get a good/level support, because you are likely to put it to the test in the future.

[Drew Marold]

Well it got delivered Wednesday of last week, and I wound up just assembling and using the leveling feet, no extra pads. Seems to be fine. Here's the new toy, with the lathe it replaced for comparison. It's just a teeny step up from the old one...
263395

[Dennis Nagle]

Big difference Drew. Welcome to the Mustard club.

[Justin Hemphill]

Hehe, I find it very amusing that you have a pic of your (I'm assuming! :)) baby thrown in there in your "Stuff I've made" pictures. :)

You've got some beautiful work there! That curved box with the drawers is fascinating.

[Drew Marold]

Thanks Justin. I did make the baby (though I had some help with that one). I had forgotten about those shots, they were showing the brackets I made to attach the co-sleeper to our bed.
The curved box is my interpretation of the "Pisces" box from "Building Beautiful Boxes with Your Band Saw" by Lois Ventura. I'm definitely going to try those again, that was a fun project.

[Dennis Nagle]

That's a real step up Drew. Congrats.