Bolting Lathe to Floor

[Neil Bosdet]

Thanks for posting this Kevin. It's a good safety point and worth noting but I still think I'll bolt it down.

[Bill Howatt]

My 20" General is bolted down and I disagree that you won't notice out-of-balance vibration when rotating too fast. It still is very obvious.

I agree that wood will fail if it isn't sound and this is the cause of very serious, even fatal, turning injuries. When turning possibly suspect wood like burls, keep the speed down.

Twisting the bed is possible since apparently cast-iron and perhaps other metal will "flow" over time.

[Cameron Wood]

I'm not a turner, but I would think about letting 6x6 end grain blocks into the floor, cut flush with the surface and drilled.

Then install threaded rod & epoxy in the holes drilled in the concrete, the epoxy applied through tubing to avoid a mess.

This eliminates the pounding, allows some adjustment of the rod, and is strong in cracked concrete. Just cut the rods flush if the machine is moved later.

Any shimming would be between the blocks and the machine legs.

[Edward Weber]

From the Robust website:

Q? Is it OK to bolt the lathe to the floor?

• Yes, so long as you don’t twist the bed, there’s certainly no technical reason not too. Please keep in mind that when an unbolted lathe starts to move or dance across the floor, that’s nature’s way of telling you to slow down and balance your work. You’ll lose this feedback if you are bolted to the floor. Also keep in mind the wood will fail before the lathe will, and flying wood can cause serious injury or death.

One slight change I would suggest to the fine folks at Robust.
You don't lose the feedback, it just presents itself in a different way.
If you can't tell when you're turning unbalanced wood, stop turning and learn how.

[Neil Bosdet]

Good comments. I thought the same.

[Edward Weber]

You lathe doesn't just suddenly start walking on it's own, there's plenty of indication before hand that it's getting ready to move.
Being able to "feel" and hear, as well as see what the machine and tools are doing, is an important part of turning.
Bolting the machine down just changes what feedback you get but it's still there.

[David M Peters]

I also have an AB with a similar shop floor setup. 2x4 sleepers with a 1-1/8" subfloor above.

I've lag-bolted my AB down to the floor but it'll still thrum the floor and jiggle if I spin something large too fast. So while bolting the machine down has reduced some vibration it certainly doesn't eliminate it. My solution has been to better learn to respect the wood & machine and to work around it.

While planning this shop my idea was to install concrete piers below the legs if vibration proved to be a problem but it hasn't yet proven to be a big enough one.

[Omer Klee]

I used a wedge anchor like these https://www.hilti.com/c/CLS_FASTENER..._7135/r8863215, hole the same as the nominal size, as I recall. One on each leg. I don't know how these come out, if at all if you want to move the lathe.

Attachment 521283

When you drill the hole for the anchor drill completely through the floor. Set the anchor as you normally would, to anchor the machine.
When you are ready to move the machine you can lift it over the anchors and leave them or take off the nut and washer and drive the anchor down below the surface of the floor. Then fill the hole with quick patch cement.

[Neil Bosdet]

When you drill the hole for the anchor drill completely through the floor. Set the anchor as you normally would, to anchor the machine.
When you are ready to move the machine you can lift it over the anchors and leave them or take off the nut and washer and drive the anchor down below the surface of the floor. Then fill the hole with quick patch cement.

Great suggestion!

[Jeffrey J Smith]

I designed and built my shop to house the Robust AB when we moved to the small island we retired to 9 years ago. I had an architect friend design specifically to support my turning addiction. The turning area is at the front part of the shop and is 23’ x 12’. The whole shop main floor is 23’ x 24’.It is built on foundation footings with the floor in the turning area on 2x12 joists on 12” centers, 12’ long. The subfloor is 1-1/2” plywood. The joists run perpendicular to the lathe bed. The crawlspace below is about 2’ at the tailstock end and 4’ at the headstock end. I poured square footings under each leg (approximately) and used jacks to support two 4” x 10” beams under the joists where the legs hit the floor. The result is a foot-friendly wood floor that has minimal vibration - no need to bolt it down.

[Randy Heinemann]

I would avoid bolting it if you can at all help it. I've used the American Beauty at Trent Bosch's shop for classes I've attended and they just don't move. The floor in his teaching area is wood also. The only time I ever saw a lathe in his shop move was when one of the students who was doing a very large off-center turning turned the speed up instead down. Other than that, none moved. People in the last 2 classes I took were more advanced and tried a lot of different things including off-center axis turning and the lathes just stayed in place. My guess would be that you might not have the lathe leveled so that all 4 feet are perfectly solid on the floor. The best idea would be to call Robust and give them the details. I'm sure they would provide good, solid suggestions about leveling and/or anchoring if that is necessary.

[Kevin Jenness]

Twisting the bed is possible since apparently cast-iron and perhaps other metal will "flow" over time.

It's not due to the metal flowing over time, it's just that most castings are not that torsionally stiff and their alignment can be affected by uneven support. Lathes based on enclosed tubes or box sections like the Oneway and Robust are inherently more difficult to twist.

You can dial in the supports by levelling the lathe on three feet and adjusting the fourth one until you get the least amount of vibration with a running unbalanced load. Check that the head and tailstock centers are aligned.

I'm not against bolting lathes down. I used to have my General 260 bolted and I may or may not do it to the Oneway when (if) I get it permanently located, Wide stance bases need it less than narrow pedestals like the General.

[Patrick Morris IV]

Have you tried "settling" the lathe.
Loosen the bolts at the top of the legs (all eight) until the washers are loose, attempt to shake lathe ind directions across bed. Tighten bolts.
Procedure is described in your manual to be done when setting up or when moved.

[Neil Bosdet]

Have you tried "settling" the lathe.
Loosen the bolts at the top of the legs (all eight) until the washers are loose, attempt to shake lathe ind directions across bed. Tighten bolts.
Procedure is described in your manual to be done when setting up or when moved.

I did do an extensive leg adjustment when I located the lathe. I got the lathe very solid (i thought). I have not done this "settling" process yet. I don't understand what it will accomplish, but I'll do it and report back.

[Neil Bosdet]

Thanks again to everyone for their input. I thought I should update you all. I have not bolted the lathe to the floor yet but I have been carefully observing my speeds and seem to be doing OK. I'm used to turning very fast with smaller projects. Turning large, green bowls is new and I'm getting used to it now. I think I'll still bolt it down but I'm no longer in a rush to do so. Cheers, Neil