Turning Solid Wood Drums
Woodworkers discuss the problem of turning and hollowing out large logs. March 3, 2006
Question
I have been making small solid shell drums on a Shop Smith lathe and would like to be able to turn logs about 28" in diameter. Any recommendations on proper machinery? This is a small scale operation, so no need for massive machinery.
Forum Responses
(Solid Wood Machining Forum)
From contributor J:
I have turned djembe shells up to 16" in diameter and 26" tall on a Oneway lathe. I wouldn't recommend any lighter duty lathe for such operations - the rotating mass of a green log is significant, and never in balance.
I recently built my own lathe, but it is limited to about a 24" swing. Anything larger than that calls for real heavy duty construction and expensive bearings. I have made stave built drums up to 36" in diameter, but I have shaped the outside by hand. The problem with large drums is you can't get them through standard size door openings.
From contributor R:
You could rig up a couple of center supports and use a router for the exterior. The inside could be handled in a similar fashion with some creative thinking. You might also look up Steven Hogbin's book on turning in which he made a large lathe using a differential from a car. Full sized turning will require massive machinery, no matter how small scale an operation. There's been a few articles on making lathes in early Fine Woodworking, so expect to spend some money unless you find an old patternmaker's lathe. It's doable, but it will take some research and machine shop help. I once owned a patternmaker's lathe that would swing 24" and cost me $500. Do you know how to move such tools affordably? Another challenge, and they are typically three phase, so learning all you can about converters is a must.
From contributor K:
I built mine from parts salvaged from a railroad shop lathe. It has a 4.5" diameter arbor, and weighs 3000# with a 5 hp 3 ph motor with VF drive. I can swing about 7' on it, but I have not yet. If I were to build another, I would pour a concrete base full of steel to bolt it to.
From the original questioner:
Thanks for all the input. I came across the VB36 Master Bowlturner Lathe from VB Manufacturing and feel it is the perfect rig for what I am trying to accomplish. The problem I anticipate is its price tag. Worth it, I am sure, but I like having options. I wonder if there are plans out there that show how to build a lathe of similar character.
From contributor B:
I have a project that requires turning sections of logs for stools. My client has requested I hollow them out to lighten them up. How is this done?
From contributor J:
I have turned djembes (West African goblet shaped drums) up to 16" in diameter, and needless to say, they have to be completely hollow. Starting with a section of a log (I have used SYP, oak and maple), the outside is turned round, and then the goblet shape is turned. The center of the drum was drilled out using a 4" diameter Forsner bit, then with one end of the drum glued and screwed to a piece of plywood which was attached to the lathe faceplace, one end of the drum was turned hollow, parallel to the exterior shape and about 3/4" thick. Then the drum was demounted, swapped end for end. The same glue/screw method was used to secure the now hollow end to the faceplate, and the other half of the drum was turned.
Essentially, the hollow turning was done with the drum cantilevered off the drive end, and when necessary, a steady rest was used to stabilize the rotating mass. It is important to cut side grain, not end grain, thus the drilling out of the center of the piece. A hook or eye tool can be helpful, and turning green wood is probably better than dry. As a side note, the SYP log was so wet that when a tool was applied to it, water would shoot out of the drum, soaking the shop from floor to ceiling. Great fun...
From contributor B:
I am curious: did you clamp the drums in a press when you wasted out with the Forstner? I've found that unless the bit is supported all round with material, it tends to side slip. I am always left with something to chisel out, which, needless to say, is tough inside an 18" deep drum.
From contributor J:
The bit was chucked into the tailstock and the work turned at a very low rpm. Doing it this way kept the hole coaxial with the drum. The bit could be advanced using the leadscrew in the tailstock, up to the limit of its 4" travel. Then an extension would be added, and ultimately, the bit would bore half way through the drum - roughly 12-13 inches. As with the turning process, it was necessary to swap ends to complete the drilling.
I have also hand carved drums out of logs using a custom made in-cannel gouge with a long handle - that facilitated carving out the inside of a drum. Such a tool is almost a necessity when attempting to hand carve the inside of a deep hollow form.
From contributor B:
Is there no way to hollow out drums on the lathe? My current project requires the top of the drum to remain intact, as it will eventually be a stool. M idea: waste as much as possible using a forstener, bolt the green log to a large lathe using a ply face-plate, slowly turn the inside of the drum, cut the drum away from face-plate, slightly deeper than the lag bolts used to affix it to plate. Dangerous?
From contributor J:
I have been doing woodworking all my life without serious harm, so part of the deal is to assess risk and work accordingly.
There are as many ways to approach this project as there are wood turners. If you lag screw the top to the faceplate, you will end up with holes on the top of the finished piece. If you leave the end of the log in place, it will most likely crack as it dries, using the screw holes as stress risers.
Using glue to affix the top of the piece to a piece of waste wood which is then screwed to the faceplate might work. Once again, you have to figure out the best way to make a positive but reversible mechanical connection to the lathe. A chuck with large jaws might be another thing to consider. At 28" in diameter, the jaws would probably have to be custom made, but if the order is large enough, it might justify the expense.
The end product can be made but it will require a lot of careful planning, and maybe some trips down blind alleys. I have brainstormed djembe production with a professional turner, and we have come up with interesting ideas, but the economics are usually a stumbling block. Whatever you decide to do, use care and caution and think about all the pitfalls before something jams, breaks, bites, grabs or flies off the lathe. Wood is not a uniform material and surprises lurk within every piece.
