Lathe/ concrete requirments

K

kylec

Guest
What would you guys recommend for the amount of concrete to set a lathe on. grizzly
g0709?

Thanks
Kyle
 
You will doubtless get some answers that would make the concrete company really happy. However, based on my experience, if you have a concrete floor that is reasonably level and not cracked, set it there. Level it, and see how it does over time. If it is stable enough, the floor doesn't crack, and you are able to use the lathe, you are done. You are in SD so I expect any concrete floor in a heated building will have a foundation around it that goes below the frost line, which will help. I've set lathes, not as heavy as yours, on garage floors for decades and they've worked fine. At the moment my lathe is sitting on a 6" poured concrete floor and working fine.

If it isn't satisfactory, depending on why it isn't satisfactory, you can cut out the concrete and pour a new pad that's 2' or 3' bigger than the lathe footprint in every direction. Once the decision is made to do that, it is probably best to dig a footing for the perimeter of the pad to undisturbed earth below the frost line, or bedrock which ever you enounter first and build a foundation wall around the pad. Pour the footing, foundation wall, and top it with a pad 8" to 12" thick. Use rebar in the footing, foundation wall, and the pad.

Fitch
 
4"-8" of concrete that was poured over a well compacted base (like a few inches of gravel) will suffice for these small light lathes. Main thing here is to not tightly fasten the lathe to that base. Concrete poured on the surface of our earth moves constantly.

Set the lathe. get the twist out of the bed and recheck periodically . If it makes you feel better, set concrete anchors where the bolt-down holes are but don't tighten them, just let the lathe "float".

If this is a fresh pour allow at least 28 days or so for the concrete to attain full hardness and stability.
 
I pour concrete for a living. Structural concrete. I'll go along with what's been said but add emphasis to the subgrade situation. I tell clients every day "A job's only as good as its subgrade preparation!" What's UNDER the concrete is 'wayy more important than the 'crete itself. You can pour a whole truckload into a huge concrete BLOCK to set your lathe on but if the subgrade settles all's you've got is a heavy boat teetering in the swamp.

IMO 8-15 days curing is sufficient for shrinkage issues if timing is a problem. The remaining time is for tensile strength and surface hardness.

DEFINITELY you must be set up in such a way that frost can't intrude bottom or sides because freezing water WILL shift it.

al
 
Hey Al,
I notice that no one has mentioned reinforcement. If a slab is cut, and a thicker block is poured within that cut, and that block has an agressively designed rebar cage, wouldn't that tend to keep the block from twisting and bending more than just the concrete itself with minimum code reinforcement?
Boyd
 
Boyd, well actually Free Willy did and I chose not to include any reference to reinforcement in my response because I disagree.

Reinforcement is not only unnecessary but could actually ADD twisting stresses by dint of the fact that it adds a component which has a different expansion coefficient than the base material. A "bimetallic spring effect" as it were. This is how a thermostat or flasher works.

Nothing wrong with concrete, nothing wrong with reinforced concrete but in this application I believe K.I.S.S. rules.

And make your subgrade bulletproof.

al
 
kylec said:
What would you guys recommend for the amount of concrete to set a lathe on. grizzly
g0709?

Thanks
Kyle
Click to expand...

A grizzly lathe is not a heavy weight, so you could get by well with a good and solid 4". Six of course would be much better, but four should work fine. Just be sure that you don't set the lathe over any cracks in the floor, or expansion joint. If your doing a fresh pour, I'd also recommend installing lag bolts. These are more important than the leveling screws. Set the lathe on 1/2" thick 6" x 6" CRS steel pads (3/8th's will work as well)
gary
 
JerrySharrett said:
4"-8" of concrete that was poured over a well compacted base (like a few inches of gravel) will suffice for these small light lathes. Main thing here is to not tightly fasten the lathe to that base. Concrete poured on the surface of our earth moves constantly.

Set the lathe. get the twist out of the bed and recheck periodically . If it makes you feel better, set concrete anchors where the bolt-down holes are but don't tighten them, just let the lathe "float".

If this is a fresh pour allow at least 28 days or so for the concrete to attain full hardness and stability.
Click to expand...

Jerry,
it's much easier to get a lathe bed strait (and keep it strait) with lag bolts working opposite of the leveling screws. The worst leveling jobs I've ever had have always been with non lagged machines
gary
 
alinwa said:
Boyd, well actually Free Willy did and I chose not to include any reference to reinforcement in my response because I disagree.

Reinforcement is not only unnecessary but could actually ADD twisting stresses by dint of the fact that it adds a component which has a different expansion coefficient than the base material. A "bimetallic spring effect" as it were. This is how a thermostat or flasher works.

Nothing wrong with concrete, nothing wrong with reinforced concrete but in this application I believe K.I.S.S. rules.


And make your subgrade bulletproof.

al
Click to expand...

with the weight is looking at I doubt you'd need much wire or rebar. Concrete will move all over the place if it's not done right, and I've had to learn this the hard way more than once. I always used the densest form of concrete they sell, and never had a lot of problems with it. But if the lathe or machine center was heavy, I used a lot of rebar in it that was welded in place. I did a 13.5 foot thick isolation pad once for a G&L boring mill that had three flat bed truck loads of rebar in it (built to OEM specs!), and the pad still shifted all over the place.
gary
 
squeakie said:
. I did a 13.5 foot thick isolation pad once for a G&L boring mill that had three flat bed truck loads of rebar in it (built to OEM specs!), and the pad still shifted all over the place.
gary
Click to expand...
Mine didn't and it was for a floor-type 6" bar G&L, 20' X and 12' Y. 125 yards of concrete. Our Civil Engineers know how to do big foundations like the above and hugh steam turbines for our power houses. We didn't use Giddings '& Lewis specs, we used Eastman's specs.
 
The rule of thumb for rotating machinery foundations is that the foundation weigh at least 3 times as much as the machine. If you have a pad over 6 inches thick, you should but rebar in the top and bottom to prevent shrinkage and temperature cracking. These days, the best anchor bolt option is to set the machine, mark the bolt locations and install chemical anchors (threaded rod with a plastic container of epoxy, like Hilti).
 
FWIW, I used my light 1300lb lathe for years 'floating' on the levelers and not bolted down to the slab.
The difference in it's performance after being actualy bolted down was nothing short of amazing.
Plus getting and keeping it level became a much, much easier job.

I always found it very curious that the old-time machine shops and manufacturing facilities usually stayed away from using any concrete floors.
Most pic's from the industrial revolution show wood floors, usually built with blocks of oak or maple and stacked end-grain up, as in a butcher block table.
I understand some of these block floors were 4' or more thick and suported vast weights.
Can you imagine what a floor like that would cost to duplicate today :eek:
 
JerrySharrett said:
Mine didn't and it was for a floor-type 6" bar G&L, 20' X and 12' Y. 125 yards of concrete. Our Civil Engineers know how to do big foundations like the above and hugh steam turbines for our power houses. We didn't use Giddings '& Lewis specs, we used Eastman's specs.
Click to expand...

Just guessing off the top of my head, I would say that boring mill had a 9" quill. It had 72" x+ & 72"x- with about 72" in y. Originally we bought a new K model Devlieg with all the latest CNC drives, but no tool changer. The place went belly up with the machine about 90% finished. Their creditors would not let us have the machine unfinished (all finished except for paint and final wiring). The Devlieg made that G&L like a clunker!

The isolation pad was actually inside a two foot thick case of concrete with walls of anti vibration material between the outter pour and the slab. The concrete was so think (and plain stupid) that I doubt it was cured in six months! We set Devliegs and K&T's on three foot thick pads setup in similar fashion without a hitch. I've yet to ever see a machine center from anybody run with a Devlieg when tooling was of equale quality and design.
gary
 
Mountain Mike said:
The rule of thumb for rotating machinery foundations is that the foundation weigh at least 3 times as much as the machine. If you have a pad over 6 inches thick, you should but rebar in the top and bottom to prevent shrinkage and temperature cracking. These days, the best anchor bolt option is to set the machine, mark the bolt locations and install chemical anchors (threaded rod with a plastic container of epoxy, like Hilti).
Click to expand...

That's similar to what we did. But we placed the lag screws while the concrete was still soft. Had the others pull loose on occassion. Then the machines were rough leveled with double wedge jacks under them (bolted to the machine frame). After the machines were leveled to within .003" in 12', we either filled the void with an epoxy mixture or used a special grout. A week later we leveled the machines with an electronic level (.000020" in 12' max with .0001" vertical error off a calibrated cylinder square).
 
Being in the Machine Shop Business, I can say that nothing beats a good solid foundation on any machine larger than some little bench lathe.

We have all of our larger machines on an independent pad, for instance, our 52 inch x 40 ft NR Leplond Lathe, (about 120,000 LBS), sits on five feet of reinforced concrete, with pillars. And guess what, we still have to check the level and alignment periodically. Of course, the fact that Houston is essentially a reclaimed swamp has a lot to do with that. Non of our larger machines are bolted, the weight keeps them in place. They include the Leblond, a 32 ft Lehmann Hydrotrol, a 28 inch x 26 ft Leblond, and a new 30 inch x 28 ft Kingston. The Big Leblond and the Lehmann are duel carriage machines.

What we have done with our new smaller lathes, (24 x 80 range), is to take a piece of 2 inch plate, fabricate 6 inch pipe legs, (one each corner and in the middle), on it about 4 feet long, and place this into a 3 ft thick slab. We then weld blocks that the bolt down feet and the jacking bolts of the lathe can sit on that are tapped. We can set the lathe up to where it is cutting as it should, bolt it down, and it stays there. Works pretty good.

All of these newer lathes have jacking bolts with the center cut out so you can use a pull down bolt in the middle of it..........jackie
 
squeakie said:
Just guessing off the top of my head, I would say that boring mill had a 9" quill. It had 72" x+ & 72"x- with about 72" in y. Originally we bought a new K model DeVleig with all the latest CNC drives, but no tool changer. The place went belly up with the machine about 90% finished. Their creditors would not let us have the machine unfinished (all finished except for paint and final wiring). The DeVleig made that G&L like a clunker!

gary
Click to expand...

The DeVleig Jigmils we had were 3J40's and didn't require much foundation. About 42" of reinforced concrete on an isolated base.

A short story about DeVleig, I was there on a buying trip when our illustrious leaders in Washington decided to tax inventory, annually. The guys at Royal Oak were throwing new 25-50 HP motors in the dumpster since it would be cheaper to buy a new one than store one for 5 years. No wonder we are in deep crap and sinking fast!!

Back to the little gunsmith/bench style/tool room lathes, they just don't need much foundation. Look at Bill calfee's shop, his lathe sits on a dirt floor and no rimfire gunsmith has made more winners than him and that lathe.
 
YOOO VINNY said:
FWIW, I used my light 1300lb lathe for years 'floating' on the levelers and not bolted down to the slab.
The difference in it's performance after being actualy bolted down was nothing short of amazing.
Plus getting and keeping it level became a much, much easier job.

I always found it very curious that the old-time machine shops and manufacturing facilities usually stayed away from using any concrete floors.
Most pic's from the industrial revolution show wood floors, usually built with blocks of oak or maple and stacked end-grain up, as in a butcher block table.
I understand some of these block floors were 4' or more thick and suported vast weights.
Can you imagine what a floor like that would cost to duplicate today :eek:
Click to expand...

That's not a regular wood floor, but usually oak blocks standing vertically ontop a concrete slab. First shop I worked in used them. But if you really checked them out, anything critical was placed on concrete
gary
 
JerrySharrett said:
The DeVleig Jigmils we had were 3J40's and didn't require much foundation. About 42" of reinforced concrete on an isolated base.

A short story about DeVleig, I was there on a buying trip when our illustrious leaders in Washington decided to tax inventory, annually. The guys at Royal Oak were throwing new 25-50 HP motors in the dumpster since it would be cheaper to buy a new one than store one for 5 years. No wonder we are in deep crap and sinking fast!!

Back to the little gunsmith/bench style/tool room lathes, they just don't need much foundation. Look at Bill calfee's shop, his lathe sits on a dirt floor and no rimfire gunsmith has made more winners than him and that lathe.
Click to expand...

I remember that event very well! The Fed made out like a bandit buy spare parts for the price of scrap iron! I bought 30+ ball screws from them as well as four or five new quills and bearing sleeves. They were complete with the ceramic bearings and Hydro-Rib bearing packs. I was buying Devlieg 4360 parts.

Calfee has said more than once his shop has a dirt floor, but the machines are on slabs. Never been in his shop (I'm about 90 minutes north of him), but heard about his setup fifteen years prior from the folks who sold him some equipment. Best setup I ever saw was up in Traverse City, MI. This guy built a shop that was on a single pour of vibration absorbing concrete (the stuff with the Styrofoam beads in it). The concrete was over 12" thick and was the same all thru the offices as well. As he expanded his equipment, he'd knock down a wall and make room. This guy does nothing but ball screw work, and is about as good as it gets
gary
 
It's bad DeVlieg isn't in busness anymore

Talked to several fellas who worked down in Royal Oak. They all said that Ol' man DeVlieg new everyone. He would remember that you had a couple kids and your wife's name. So on and so on. All gone now. Those machines are going to the scrappers left and right. Soon to including our 4J96 Jigmill.Just a note, we have four feet of concert under her.

My thought on concert, for a lite lathe. Four inches is plenty.
 
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