Building a lathe from scratch

I already have a lathe and I almost never use it, but I have been asked about building a lathe so many times, I figured I should give it a shot. I also figured it would be a good opportunity to make a machine with wooden bearings.

I started by drawing up a rough SketchUp model, and printing a 1:1 view looking at the end.

For much of the material, I used some used high quality 20 mm thick plywood made of hardwood throughout. Above left, I'm cutting the notches in the bottom of the trapezoidal pieces that will form the headstock and tailstock.

Rather than glue the template to the wood, I'm transferring the measurements with a ruler and pencil.

Jigged up for cutting the sloped sides of the trapezoidal pieces, cutting them on my small table saw sled.

Longer pieces of hardwood will form the bed of the lathe. I'm cutting this out of some wood that came from some good quality palettes.

I glued two of the trapezoidal pieces together for the front of the headstock before assembling the rest. Here checking how things fit together.

The tailstock is almost the same construction as the headstock.

Because I'm using used plywood, I have to scrape the varnish off where the glue surfaces are. Then applying lots of glue and clamping it together.

After the glue dried, I drilled pilot holes and added screws, in case the glue fails.

I made three of these brackets that fit between the bed rail on the bottom. A hole in the bottom allows a carriage bolt to sit flush without protruding out the bottom.

I'm using a knife to square part of the hole for the carriage bolt.

Placing the headstock over the bracket in the lathe's bed...

... then bolting it down with a carriage bolt and the bracket I just made.

I might end up just screwing the headstock straight onto the rails, but that can wait for later.

Wooden bearings

Next making the wooden bearing blocks. I'm using a piece of maple, first drilling the mounting holes through it.

After adding countersinks to the mounting holes, I cut it in half on the table saw and firmly clamp the two halves back together.

I then drill a hole just a bit larger than the shaft I will use. The center of the hole is right where the two clamped together parts meet.

Some rounding of the edges on my strip sander, so I don't scrape my knuckles on the rough edges later.

With the bearing block placed on the headstock, I tap the screws to mark where the screw holes need to go.

Then drill pilot holes in the headstock.

The drive shaft needs to have a point on the end. I'm grinding this point on a bench grinder.

Drive shaft pulleys

I drilled a hole slightly smaller than the drive shaft in a disk of Baltic birch plywood.

One disk of plywood would not have a stable enough base on the shaft, so I made two disks to glue together for more stability.

Even though the pulley is a tight fit on the shaft, it needs to be fixed on to prevent it from slipping when using the lathe. I ground a key way into the side of the shaft with an angle grinder and cut a corresponding key in the pulley disks with a jigsaw.

Inserting the shaft. It's deliberately a tight fit. I needed to drive it in with a mallet.

After that, I drive a nail in the space provided by the key ways on the shaft and pulleys. The nail will act as the key.

Then I realized I forgot to glue the two disks together. So I pried them apart a little, added glue, and clamped them back together.

I needed some spacer sleeves to keep the pulley centered on the headstock. I made these by drilling some holes in from the end grain in a piece of hardwood, then cutting out some cylinders around them. These weren't terribly accurate, but good enough to do the job.

I had to cut some notches in the spacers to let them fit around the ends of the nail I used as a key. I also put a washer between the spacers and bearing blocks.

Then screwing the bearing blocks together.

I put the V-belt on the smaller of the two disks, with the motor positioned so the belt rubs up against the larger disk to keep it aligned.

Now that I'm spinning the shaft with a motor, it's time to add some oil to the wooden bearings.

I want to turning a V-groove into the pulleys using turning chisels. For that, I need a tool rest. I made one out of a piece of hardwood. It has a notch cut out towards the bottom so it tilts towards the pulleys.

Then turning the V-groove in the larger disk. The chisel often got caught, stopping the pulley, so it wasn't an optimal arrangement.

With the V-groove turned into the larger pulley, I moved the belt onto that, and then turned the V-groove in the small pulley.

Continue to part 2