I needed a machine that would give me the ability to make a specialized part for my motorized bike project. The part connects a 5/16" x 24 thread output stud to a 3/8" dia. driveshaft. It couldn't be found anywhere, so I needed to make it. I just happened to have an old craftsman tool with the right configuration to solve my problem, with some alterations and a mini lathe chuck I was able to build what I needed. The lathe chuck was the perfect addition to this machine because of it's ability to hold round stock or flat bar stock in perfect 90 deg. alignment with the drill chuck. This machine can now be used for boring, tapping inside threads and with threading dies for male threads. It can be powered by any drill for boring operations or operated manually for tapping and threading.
The first step for this retrofit was to build and secure a mounting plate with a large pass through hole for long stock and four position holes that mate with long set screws attached to the back of the chuck. The lathe chuck simply drops into the position holes. I also flipped the beam over and where the original drill head attached, the top end of the shaft has been squared to accept a 1/4" socket extension.
Here we can see the pass through hole and the ends of the upright rods that have been extended down 1/2" to mate with holes in my workbench plank. This adjustment holds the machine in place when force is applied.
In this picture we can see the machine completely assembled and setup for a drilling operation. The round stock mounted in the chuck is going to be center bored and threaded. When completed it will become a specialized coupler.
After twice boring the stock first with a 21/64" drill bit half the length and then using 17/64" to complete the bore hole it is ready to be tapped. When finished it will have 1/2" of 3/8"x16 threads and 1/2" of 5/16"x24 threads.
I can use a regular tap handle with a 1/4" short socket extension to spin taps.
So far I have shown boring and tapping operations. This step shows that threading dies can also be placed in the jaws of the lathe chuck. Stock up to 3/8" dia. can be held in the original drill chuck. Dies that are to small can be installed by first placing them in a die handle and then clamping the handle in the lathe chuck jaws.
In the following steps I am going to demonstrate the real versatility of this retrofited drill guide. Here I am adjusting the newly added work rest.
In this step I am showing that flat bar stock can also be drilled by clamping the stock in the chuck between the step ledges.
I also made the mounting plate supports with flush pegs so that the mounting plate can easily be removed. Here I am using it to hold the lathe chuck in my drill press.
I think this tool would be great for any hobbyist or small shop with limited space. As you can see I built this in a limited space, my wife's kitchen table.