First Week in the Shop

During our first week in the shop we focused on completing our wheel assemblies because we were in the process of slightly modifying most of our other parts in order to accept modifications made to the "gate."



To start, we cut and faced our wheel shafts to be 2.25" in length. Then we used the lathe to drill a hole in the center of two of them to accept the output shaft of the double gearbox. After making a slot for an E-clip and milling/tapping a 4-40 cross hole in the shaft we were ready to complete the assemblies. First, we pressed the custom bushings into the wheels. Then we used a quarter inch reamer to make the hole the correct size for press fitting.







Next, is where we ran into some problems. When pressing our machined shafts into our wheel/bushing assemblies the shafts failed under the compressive force of the arbor press. At first, we thought it was because of the cross hole, as that is where it failed, but upon machining two new shafts with the exception of this hole, we tried again with one. It failed again.

We seemed to have been the first group to try pressing anything, so we talked with Bob, John, Mike, and Toby to see what we could do. After measuring the machined shafts with a micrometer it was found that small imperfections brought on by holding them in the lathe or in a vice caused too much friction.

To solve this problem we used sand paper and a file to smooth out the part of the shaft that would go into the bushing. It worked great. So we decided to do this to our spare shaft that still had the cross hole which also worked. We were left with only one thing to do. Mill this hole out of the shaft that already had a wheel on it. We did this and now have four completely assembled wheels.