Plans for a lathe.
In Dec. 2012 Mary got me a lathe for my birthday and I have been turning out various things. From the beginning she hinted that it would be interesting to make a period style lathe. Most pictures are of spring pole lathes that work on a reciprocating action. The work piece is rotated back and forth by a string that moves up and down aided by a foot pedal and a spring pole that keeps the string tight and pulls it up after you release the foot pedal. This means that the wood is cut only half the time.
Then we found a drawing done by Leonardo da Vinci in approximately 1480 of a rotational treadle lathe with a wooden flywheel to keep the wood rotating at a constant rate even during pauses in treadling. After some encouragement by members of some Facebook A&S groups I decided to go for it.
The biggest design challenge was to make it both portable and sturdy. The frame is going to be made in two pieces. One piece will hold the flywheel assembly and the other will be the work area with the treadle footman in between.
The axle will be made from a 48” long 1” diameter piece of 1018 steel. Master Damales has offered to help me with the forge work for this. One end of the axle will be ground to be the drive center.
In order to avoid having to transport and deal with the huge wheel, I am going to use two 24” hardwood tabletops commonly available at hardwood stores screwed together. For additional mass I am going to use 1.5”x17” flat stakes designed for concrete forms screwed between the table tops. The stakes were donated by Baron Giles. Ok, I claimed them when he was cleaning out his garage.
The frame will be made from dimensional lumber. 2x12s for the base with holes drilled to be able to drive spikes into the ground for stability. The verticals will be 2x6 or 2x8 with 2x4s for the bracing members. I will use triangle blocks or stringers to add additional rigidity to the joint between the base and the vertical members. The other braces will be notched into the vertical members both for a cleaner look and a larger glue surface area. A more period form of joinery would be peg and glue but I will probably use screws that are counter sunk and covered by pegs, and of course glue. Since they won’t be seen I will drive lag screws, probably 3/8”x3’ with fender washers up through the bottom of the base plate into the vertical members, most likely 2 per member set 1-1/2” in from the edge.
The dead center will be a piece of all thread with a point ground to one end. There will be a coupling nut to guide the all thread. Another coupling nut will be attached to the back end with a set screw to tension the work piece. The set screw on the center coupling nut will be tightened to hold the tension.
The tool rest will be a sleeve that slides over the upper spreader braces. The top edge will cut to an edge for minimal friction. I may cut a groove into the top of the rest and insert a strip of bar stock.