A Machine Shop Project

A few nights ago, I worked on a machine shop project after working hours.  I am thankful my employer allows me to use the shop for personal projects.  It is even encouraged, for I seem to learn alot when doing these types of projects.

Here, I am making an aluminum adaptor hub for a lawnmower project.  This hub will adapt a new engine to the existing drive shaft.

I started with a 4 inch diameter by 6 inch chunk of aluminum.  I started in the mill, and squared up the rough-cut end.  I had to make sure it was also perpindicular.

By doing that, I was able to mount it easier in the lathe.  Indicating in the Z axis shows runout within just 0.001 or 0.002.  It took a long while to get it centered.  A 4 jaw chuck can be challenging and frustrating.

I managed to face off the opposite rough end, and take the outside diameter to just 0.002 under 4 inches.  I also put in a hole for locating purposes later on.  Aluminum always leaves a real nice finish.

Over to my recently-restored monster bandsaw.  I chopped through this chunk like it was butter.

Back to the mill to square up my bandsaw cut, and take it down to specified thickness of 1.500.  I also indicated in and zeroed at the center for a radial hole pattern.

I started all my holes with a center drill.

Here's an example of my digital readout.  The X and Y axis were zeroed at the center of the workpiece, and now I can just move to the proper coordinates for each hole.  Pictured would be the 6 o'clock hole location.

Drilling holes generates alot of chips!  I have 4 through holes, and 4 blind holes.  I drill through into a planar piece of wood.

I started the blind tapped hole by hand.  I just use the chuck as a guide, and put the mill transmission in neutral.  This way the threads are started straight and don't veer off halfway through the hole.

The other 4 holes were counterbored for socket head cap screws.

Out of the vice, and onto the rotary table to make a big hole.  Since I don't have drill bits that are 1.5 inches in diameter for the center through hole, I use the rotary table, and mill it out with a smaller end mill.  First, I have to indicate in the center of the table for my zero point.

Then I clamp my part down.  Center of the part is directly over the center of the rotary table.

Then I simply move one axis to enlarge the hole.  Here I made a 1.500 through hole with a 0.500 end mill.  To do so, I simply move the X axis to the right 0.500 inch.

Also notice I made a ring of 1.875 inside diameter by 0.500 deep.  To make 1.875 inside diameter, I move my end mill to 0.6875.  Mill math is fun.  Lathe math is more fun.

And here's my final part.  This will get bolted to the flywheel of the engine with the counterbored cap screw holes, and then the drive shaft gets mounted to this hub with the tapped holes.

The 1.500 inch through hole and related larger groove is simply clearance for a big nut on the flywheel.

It was a fun project to work through for an evening.