Adding weight to SS for stability

[jimh]

Has anyone tried to add some weight to the Shopsmith in order to handle out-of-round wood being turned?

I have read that this is common with full-time lathes. Adding 100-200 pounds of sand to dampen out oscillations.

What would happen if you tried to hang extra weight on the lower tubes? How much can they handle? Would you be able to use 4 hooks to support a board with sand bags or have to spread the weight across more of the tube?

[manvelar]

This is not scientific, but people have buiilt storage cabinets that hang from the near the ends of the lower tubes - one I found out about the other day is made from almost a full sheet of 3/4 plywood and has enough room for all the accessories plus the jointer to be tucked away. I don't know how much all that weighs, but I'd bet it's over 100 pounds. I suspect those lower tubes can support a lot of weight.

I'm getting ready to turn a rather large chunck of Maple (about 18 inches diameter and 6 inches thick) and I'm a little worried about how it will run until I get it round. I never thought about adding weight to the machine - I might give it a try.

The other suggestion might be to invest in a speed reducer if you do a lot of this sort of work. I don't have one but it's on my list.

[dusty]

I haven't done this myself; I do very little turning and haven't had the need. However, if you will browse this forum, as well as the other, you'll find several references to adding weight for stability (while turning).

Most will propose sand bags, concrete bags, etc. You'll find talk about filling the tubes with sand, molten lead and many others.

As you add weight, keep in mind the center of gravity. If the weight is too far off the ground, it will work against your objective and could produce a safety hazard.
___________________
Making Sawdust Safely

[Nick]

It's a common practice among professional turners to sandbag their lathes. Not only does this add weight, but the sand has the usefull physical property of hysteresis which makes it act like a sponge for soaking up vibrations. I once interviewed Rudy Osolinik when he was still alive. Rudy was the former director of the woodworking program at Berea College in KY and a world-reknown turner. In his personal shop, he had several Mark Vs that he used exclusively as lathes, and they were all sandbagged with 200-300 pounds of sand. He told me sandbagging was almost required to successfully turn extremely thin sides of bowls and similar pieces.

With all good wishes,

[edflorence]

Interesting.

I like the idea of a "dedicated" SS that would be used primarily as a lathe. For a long time I have had the idea to take the legs off my old Mark V (after I get my new 520 that is!) and mount it on a sand-filled wooden box. This dedicated machine would remain in one location in the shop, but would be accessible from at least the front and both ends so it could still be used in drill press mode and for SPT's. I wonder if being bolted to a box of sand would have the same damping effect as sandbags?

Ed
Idaho Panhandle
MkV 500

[Nick]

It's a good idea, Ed, but it's not quite as simple mounting the Mark V on a box of sand. To get the maximum effect of the hysteresis, the machine actually has to "float" on top of the sand. In my book Using the Scroll Saw, Jim McCann and I designed a sand base that would suck the vibration out of a benchtop scrollsaw. It worked like gangbusters -- you could balance a nickel on edge on the table of a low-end Delta when we were through. You might build a somewhat larger version of this design for the Shopsmith.

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With all good wishes,

[alaskanexile]

Several times I have stood on the lower tubes with no apparent detrimental effect. Weigh about 150. If the weight is suspended near the ends of the tubes, cannot imagine it would be a problem. Don't know how much dampening effect it may have. Guess it would logically depend at least partially on how out of round the object is. Roger

[fjimp]

Nick,

That is a great looking box. How would you salely mount that to or below the lower tubes?

As always thanks for the education. Jim :)