Mini Lathe To Wood Lathe Tailstock Adapter

While working on building a travel mug, I found that I needed to drill into the end of a wood piece. The piece was too long to mount into my mini lathe and still fit the tailstock on and the tailstock on my wood lathe couldn't hold a drill chuck. And so I needed to find a way to mount the Grizzly mini metal lathe tailstock onto the wood lathe.

For plans for this project see the Tailstock Adapter Plans page

Here is a picture of the tailstock mounted on the wood lathe.

Mini Lathe Tailstock On Wood LatheMini Lathe Tailstock On Wood LatheTailstock Adapter Side ViewTailstock Adapter Side View

The tailstock adapter is built up using an aluminum plate, a piece of steel half inch l-beam, an 1/8 inch thick flat steel strip and a couple of pieces of 1/2 inch aluminum square.

Fortunately, the metal lathe tailstock is shorter than the the wood lathe. This means I was able to add structure under the tailstock to facilitate the mounting. It is trivial to raise the tailstock by adding shims, but difficult to lower the tailstock since that would require removing metal.

The base of the design uses a 1/2 inch steel L-beam to match the shape of the bottom of the tailstock. Since this raises the tailstock on the left side it is necessary to add a riser under the right side of the tailstock.

These two piece mount on top of a 1/4" aluminum plate. The aluminum plate bears against the lathe ways. The plate is cut from a piece of plate using a hacksaw. A bandsaw or jigsaw with a metal cutting blade would make this step easier.
Hacksawing Base PlateHacksawing Base Plate
To cut this piece with my hacksaw it was necessary to reverse the blade of the hacksaw to cut backwards.
Using hacksaw backwards to finish cutUsing hacksaw backwards to finish cut

Once cut the edges can be clean up by filing. Then the holes must be marked. I picked the two clean factory edges of the piece to make all measurements from. I then marked the distances to the holes from the two edges and center punched at the crosses. I found that circling the crosses with a Sharpie(R) marker helped keep track of them. I then center drilled and drilled the holes to size based off the drawing I created.
Base Plate Marked for DrillingBase Plate Marked for Drilling

Here is a picture of the plate part way through drilling.
Base Plate Partially DrilledBase Plate Partially Drilled

The L beam and flat beam are drilled to match the holes in the base plate. You can see them installed in the images below (a second set of flat beams was added underneath the L beam and flat beam to bring the tailstock up to the center of the lathe).
Tailstock Adapter End ViewTailstock Adapter End View

To align the tailstock to the ways of the bed there are two square beams under the plate that provide bearing surfaces. The bearing rails are not quite spaced the same as the ways of the lathe. This allows screws to be used to provide micro-alignment.

The tailstock adapter is locked to the ways using 2 square beams. The beams are pulled up to clamp against the ways at the front and back by a 1/4-20 bolt. The lock bars have holes for two bolts. I usually only tighten one of the bolts, using the other bolt merely to keep the alignment. Below is a picture of the rear lock bar installed.
Lock RailLock Rail