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View Full Version : Heavier Lathe Cabinet is Better, Right?



gzig5
10-05-2011, 04:26 PM
I'm mulling over how, and from what material to make the bench/cabinet that my 4' SB 10L will be mounted to. The machine did not come with a cabinet so it is up to me. My thought is that I want the bench to be as massive as possible to better absorb vibration and inertia transients (plug reversing spindle). But, it has to be modular or portable enough to get it into my basement.

The structure will be from 1 1/2" square tube and incorporate some drawers and cabinet for storage. For the top, I have available 2 pieces of 3' x 6' x 1/2" steel and/or a 42" x 8' long section of Maple bowling alley 2 1/2" thick. If I made the top 21" deep x 60" long, I could rip the maple and double it up and then cut the steel to size and double it up. Rough calculations tell me the wood would weigh 85 lbs each, and the steel plates would be 175 lbs each. If I make a wood and metal sandwich, the 6" thick top would weigh 520 lbs and could be carried individually down the steps. Once together and probably laminated together with epoxy of some type, they may never again come back up, but that isn't my problem. The whole stand would weigh about 800 lbs, maybe more if I pack the hollow tubes with sand to dampen vibrations.

So, is this overkill for a 4' bed Heavy 10 or would it be worth the effort? How much is enough and when is it too much? Obviously a thick top reduces storage, but not that much. Any other downsides that I'm missing other than the potential chiropractor bill?

macona
10-05-2011, 05:42 PM
Considering that the base of my 10EE is one monolithic cast iron structure you really are not at heavy yet.

There is an article over on PM from WWII about how to build a cast concrete lathe stand for doing precision work.

daryl bane
10-05-2011, 05:52 PM
I was very impressed in the bench The Artful Bodger did.
http://bbs.homeshopmachinist.net/showthread.php?t=49462&highlight=concrete+bench

jkilroy
10-05-2011, 06:32 PM
Same with my Rivett, one big iron casting, about 4500 lbs worth for a 13x20 sized lathe. Wider at the bottom is a good thing, low center of gravity.

Spin Doctor
10-05-2011, 06:40 PM
Its not just how heavy the structure is. You have to have some way of determining just how reisitant to vibration the structure is. What if you build a suitable base using the idea yo have and then top it with a piece of granite about 2 inches thick. And put vibration absorbsion mounts in between tne base and the granite

Bill736
10-05-2011, 10:00 PM
An interesting topic, since we've all seen so many different types of lathe benches. I've always wondered about wooden benches, since it moves so much during wet/dry weather. Perhaps inside, the humidity and temperature can be better controlled. In my own house, however, the effects of wood movement are demonstrated by my half louvered closet doors. The panels move in and out , revealing a strip where there is no paint. Yet, some lathe manufacturers sold wooden lathe benches. If your lathe has a 3 point mounting, I suppose it would lessen the problem. Steel will certainly move with temperature changes, which can be significant in unheated shops.
Concrete is certainly a solid base, although I don't recall how much temperature changes affect it.

darryl
10-06-2011, 02:08 AM
Seems you're willing to do a bit of work to build this stand. I would probably use one layer of maple and one of the steel plate. I would bed the steel plate to the maple with an epoxy like coffee table resin. There won't be much gap anywhere so it won't take all that much. You might build a temporary dam around the maple to contain a low-level 'lake' of epoxy, which the steel plate sinks into. The end result would be a sandwich with a fair bit of weight, but very non-resonant. As far as mounting the lathe to it, you might lay out, drill, and tap the holes for mounting bolts, then later once the epoxy has cured you can drill the pilot holes further into the wood and run the tap again. You can brush some epoxy around in those holes to seal them. The mounting bolts would go into the maple a short way, but not enough to bottom out in the wood.

If you didn't want to tap holes, but just drill them to pass the bolts through, you can always temporarily mount the bolts from the underside, then drill some recesses in the maple to accept the bolt heads. The bolts would be epoxied in place as the steel plate is being bedded into the maple. You'll end up with studs sticking up to mount the lathe bed onto.

It might be good if you could turn this maple and steel sandwich upside down and lay it on three points, then use that to align the structural members as you fasten them together. This should mean that the top and the structure are not stressing each other. With adjustable feet, you mate the stand to the floor so that each foot carries its share of the weight. Now the floor also doesn't apply any stresses to the stand.

The lathe would be placed and bolted, using shims etc to either keep the bed in alignment or apply slight forces to align the bed. I won't go into details of that- it's been bantered about lots on other threads.

I don't think that you'd need to go more than those two layers for the top. More than that would be a waste, IMHO, and the law of diminishing returns would rule. You would probably want to acclimatize the maple in the room in which it will be used, and do the epoxy sandwiching in the same room. The temperature should be kept stable and at a normal setting. The steel plate should be in there also so everything is at the same normal temperature. You would probably 'paint' the bottom and sides of the maple to seal it, prior to laying the steel top. It would be good to pour the layer of epoxy, then let it soak into the wood for at least ten minutes to monitor the diffusion of any air bubbles that might rise out of the maple.

With the roughly 200 lbs of steel top, you'll probably need to manage it with an engine hoist or something. When it's set into the epoxy, there will be some excess epoxy needing to go somewhere, so you will have to estimate the quantity to use- conversely you would let the excess run off the sides of the maple, onto layers of newspaper or whatever, and use a brush to touch up the dripping.

This would give you a pretty nice lathe stand.

The Artful Bodger
10-06-2011, 02:14 AM
Concrete bench, you will not regret it.;)

J Tiers
10-06-2011, 09:03 AM
has yours made a big difference? last I saw you were still re-arranging the mount for the lathe.

gzig5
10-06-2011, 10:58 AM
Concrete bench, you will not regret it.;)

I'd love to BUT, the major design constraint here is that the individual parts will have to be maneuvered down a standard width set of carpeted stairs that has a 90 degree turn and a fairly short landing area. The 175 lb steel sections will push that envelope from a weight perspective. The tube frame of the base may have to come down in sections and be assembled and final welding in place. The lathe is coming down in its basic components.

I'm aware of the various lathes like the 10ee with massive bases, but struggle to understand what degree or their overall rigidity and performance come from a heavy base or superior bed design. I you take the head and bed of a 10ee and mount it on a well designed (rigid) table that weighs 400 lbs, how much does the performance suffer?

I guess the question I should have asked is this...Is it advantageous from an accuracy and surface finish standpoint to mount a 600 pound lathe on a stand that weighs 700 pounds versus 250 pounds? It would have to be accepted that the lighter stand would be considers appropriately rigid (at least equivalent of SB sheet metal stand). The heavier stand could be made some degree more rigid, but the big difference would be the mass available to absorb vibration. Basically, is it worth the work? I already have the materials.

Rosco-P
10-06-2011, 11:02 AM
Too bad. :( Guess that means that utilizing two of these as legs to suport the top would be out of the question as well. http://www.procastproducts.com/k-rail-concrete-barriers.html

gzig5
10-06-2011, 11:37 AM
Too bad. :( Guess that means that utilizing two of these as legs to suport the top would be out of the question as well. http://www.procastproducts.com/k-rail-concrete-barriers.html

Not at this house. If I ever move, the ease of moving heavy equipment in and out will be a priority.

Gary Paine
10-06-2011, 01:12 PM
... The structure will be from 1 1/2" square tube and incorporate some drawers and cabinet for storage. For the top, I have available 2 pieces of 3' x 6' x 1/2" steel and/or a 42" x 8' long section of Maple bowling alley 2 1/2" thick. If I made the top 21" deep x 60" long, I could rip the maple and double it up and then cut the steel to size and double it up. ....

I personally think the weight is only advantageous from the perspective of spinning badly out of balance workpieces to keep the lathe from moving around. Most important is a secure and well leveled flat base to mount to. If the mounting surface is sufficiently rigid such that it will not flex mounting points out of this alignment, then how much it weighs IMHO should be of no significance.

What I do have experience with is the bowling alley sections. I am guessing your section is like mine - comes with metal cross braces every few feet on the underside. When disassembled, these bases will be found with a crown in the middle, designed so that the weight of the wood will straighten the crown out flat when they support it. The wood section is tongue and grooved and not glued, but nailed - heavily. When the braces are removed, it will flex easily in the width direction and is not at all rigid as would be a plywood or solid wood. It is very hard and durable maple, though, and makes a great bench top.

That said, if you do the sandwich construction as you consider, do not try to rigidly fasten the wood to the steel. You must let the wood float independently. If you fasten the steel rigidly to the wood, when the humidity changes move the wood, the steel will flex accordingly - like a bimetal strip. As strong as steel is, it cannot resist the wood movement and something will have to give.

I would use one of two approaches. Either use both plates in a sandwich as you are thinking with wood in the middle only with clearance holes through the wood and connection between the plates that allow for a bit of expansion in the thickness of the top (schnorr washers, heavy springs or something)...........
OR: I think my choice would be to use the steel and square tubing for the top and design plenty of rigidity in the bench structure. Use the alley section for a good workbench.

Boucher
10-06-2011, 01:22 PM
I built this shooting bench to replace an old heavy wooden bench. It turned out to be substantially lighter and much more rigid. It is all welded construction but could be done in bolted together sub assemblies.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0032.jpg
This has the potential to be easily movable and very rigid for its weight. Just some food for thought.

The Artful Bodger
10-06-2011, 07:32 PM
One advantage of a concrete bench is that if necessary you can carry it down to the basement in a bucket.

My bench weighs 800kgs and takes my 12x36 lathe, a cold cut saw and my little shaper with room to spare.

At this time the headstock of the lathe is secured with 4 bolts via a 1/4" plate on about 25mm (1 inch) of grout, the tail stock end is still just standing on two bolts while I let the bench mature a little more. Even at this stage of mounting the difference is dramatic, rigidity is dramatically improved, there is no vibration and I dare to venture that parting is less dramatic.:D


The concrete construction has other advantages too and one I like is the cast in gutter to catch all the coolant etc.

I put a two part epoxy paint on the top. There are no dings in it yet!

Once again, I fully recommend a concrete machine bench.:D