More Details About My DIY Homemade Wood Lathe

Awhile back I wrote a post about a Homemade Wood Lathe that I designed and built and HERE is the original post if you want to see what I am talking about. I decided to write a new post because I have been getting a few emails about some of the construction details. Specifically folks have been asking about the DIY Lathe Headstock and how the Motor Speed Control works.

  

Homemade Wood  Lathe

 

I'm going to assume that if you are reading this post you have probably read (or might want to read) the original post to get an idea of what I am talking about. I'm not going to go into the details of the lathe itself as I covered those in the first post. Without going on with more and more introduction I'll jump right in to the details!

First off, below is a closeup picture of the headstock that I built. The main components are of course the bearings and the 3" square wood head post that supports them. The spindle is a piece of Chrome-Moly Pipe that runs through the entire headstock so I have access to each end. On one end is a pulley that has a belt going down to the motor and on the other end the pipe just sticks out toward the work area. I have a video explaining how this lathe works HERE on my YouTube channel.

 

DIY Lathe Headstock

 

There is a spring between the pulley and the headstock that keeps the bearings in tension or under a thrust load. The bearings are actually heavy duty furniture bearings that are intended to carry a heavy thrust load. and they work pretty good considering. The spring is trying to push the pulley away from the headstock post and they pulley is attached to the Chrome-Moly Pipe with a set screw. The pipe is prevented from coming through the bearings by a snap-ring set in a groove on the work end of the pipe. Below is a sketch of the cross-section of what is going on.

 

DIY Lathe Headstock Cross Section

  

In the sketch above you can see the Chrome-Moly Pipe running through the center with the bearings on each end. The bearings are seated in what amount to wood nut bearing seats (green in the sketch) that screw into the wood headstock post and are designed to secure the bearings. I had to get these 'bearing seats' from a big hardware store that specializes in furniture. The snap ring is in red on the right hand side of the sketch and as mentioned sits in a groove that I cut in the chrome-moly pipe with a hacksaw blade. There is a flat washer on the left side to give the spring something to press against and finally the pulley.

  

All of this together allows the chrome-moly pipe and pulley to spin together when the belt is driven by the motor. Checkout the original post HERE again to see how this all works in the lathe. That post also explains why I am spinning a pipe in the headstock and how I use that to attach various mandrels and spindles.

  

The lathe motor speed controller is pretty straight forward and is really a variable DC power supply. The most important part of it is the Variac variable autotransformer that gives the high current voltage control. Below is a schematic of what I built.

 

DIY Lathe Motor Speed Controller

Click on the above picture for a bigger and clearer view. or email me at ottobelden@yahoo.com if you want a clearer picture. Comments below this post are great too! Anyway on the left side of the schematic there is a double pole switch that turns the power off and on. Of course I put a fuse in there to protect the electrical stuff and a AC lamp so I can see when it's on. Next is the Variac transformer that takes the input voltage and steps it down based on where the wiper on the transformer is set (with a knob on the outside). Next after the transformer is a full bridge rectifier to convert the AC to a DC voltage. AC goes in on the left in the schematic and DC comer out the right.

 

Homemade Lathe Motor Speed Controller

 

After the rectifier I put in a DC volt meter that has a high power low ohm  (0.1 Ohms) resistor in parallel with it (wired in parallel). The resistor is a small value so that most of the power flowing to the motor goes through the resistor and the meter just reads a small voltage drop across the resistor. The voltage is proportional to the amount of current in the circuit so the short explanation is that the meter and resistor are working together as an ammeter. I put this in so I could have some idea how hard the motor is working while the lathe is running but in practice the needle hardly moves.

  

Next in the circuit is a capacitor that is just there to smooth out the voltage and help reduce spikes due to the brushes in the motor sparking. It isn't all the necessary but I had it so I put it in there. The last neat thing is another double pole switch that I use to change the direction of the motor. Being able to go in reverse is handy for sanding. Lastly there is yet another fast blow fuse just in case something in the wiring or the motor itself shorts. Hopefully that fuse will protect the Variac autotransformer.

  

I built this lathe 9 years ago and it is still running and turning out cool wood projects like the Bamboo Wood TopsMulti-Center Turned Statue Experiment I did. HERE once again is the original post about this DIY Lathe that I built. If you have any questions or would like more details please leave a comment or email me!!
  
Be sure to have a look at the Site Index of Posts link HERE to see some of the other wood projects and lathe related things I have built.