On the left is the basic Draw Bar. It is used to cinch any MT#3 attachment one may need to lock onto the spindle of the 7x10 lathe or the Minimill.
It is made of Aluminum but could be made from any material one may have on hand.
Most of the material I have in my shop has been found at various scrap yards in my area.
The rod is simply common threaded rod found at any hardware store
To the right you can see the rod and nut as well as the collar that fits inside the lathe outer spindle bore. Diameter is not critical and simply can be made any reasonable size so long as the larger part is at leas 1/2" to 1" bigger than the spindle outer diameter. The washer that you can see is simply epoxied to the collar to prevent marring by the locking nut on the draw rod.
Here we can clearly see the collar's narrow portion. It must fit pretty snug within the spindle inner bore and that is about .800" give or take a few thou. As you can probably see, I beveled the edges not because they needed to be, but for the looks that it imparts. Try to get into the habit of always beveling all possible sharp corners and edges. Not only does it keep the user from enduring needless cuts, it just gives your projects that extra edge of excellence.
On the right you can see the completed unit partially inserted in the lathe spindle. Rod thread sizes will depend on the particular tool you are mounting on the spindle so you may have to make a couple of different sizes to accomodate all of your MT#3 spindle tooling.
Here is the unit fully inserted and ready to be used on the lathe. Projects such as this are very simple and easy to build and if made from readily available materials or scrap will cost pennies to build and save you a lot of money!