"Electromagnetic Drilling"and The answers to a few of Jeff's Questions

During this last week in class I was given the task of using an electromagnetic drill to drill a precise hole in a mock frame set up in the shop. Since I had never used an electromagnetic drill I went straight too YouTube and started looking for a video of the same drill we have in the shop being used, I couldn't find one. I found many others but not of this particular drill. The next step was to try and find the owners manual online, I found a pdf. and looked over the operating instructions.

 

This hole I was supposed to drill was to be drilled exactly at 1/16 of any inch anywhere length and width wise within the field. I put my hole at 38 1/16" length and 8 7/16" width.

The drill we have in the shop is a Slugger FHM 101 USA.


Here it is during the assembly


The bit I was using was a 9/16" by 2"

Here is the drill completely assembled and attached to the frame rail and ready to start drilling.


Now as I began to drill things seamed to be going good at first, the teeth of the drill bit started to dig in and then they just simply stopped biting. I tried drilling for some 20 minutes, I went through a full tank of lubricant and popped the drill off the frame several times. Making no progress I took a step back.

This is the hole I attempted to cut. Confused and frustrated I asked my instructor a few days later what I might have been doing wrong and was happy to find out that it wasn't me and it was the bit. For some unknown reason this particular bit was in great shape but just wouldn't cut. Re-leaved I sent out to cut a new hole with a different bit. It went smooth as butter.






 Another interesting thing that happened this week was a peer of mine brought in a catastrophic failure in a truck drive axle. All the spider gears were missing at least half there teeth and when my instructor started leading us through the failure analysis it was very interesting to watch him point out where the failure started and what most likely caused it.

After a class discussion my instructor ask us to identify the style of ring gear this was and which side was the drive side and which was the reverse side of the ring gear and why.

After doing some research I came to the conclusion that this was a Hypoid gear set. After turning a couple of tandem Meritor axles we have in the shop and watching the gears turn when the wheel ends were moved forward and reverse. I came to the conclusion that the concave side is the drive side and convex side is the  reverse side. It also helped to reading chapter 23 in Heavy Duty Truck Systems 5th edition.

Another task was to figure out how many speeds this transmission has.

I came to the conclusion right away from the look that it was a 6 speed but I did have my doubts. After doing some hands on shifting of the gears because it is a manual transmission and researching the model number. I came up with the conclusion that this is a Fuller FS 6306X  mid range 6 speed manual transmission.

"Wheel Alignment"

Before the Thanksgiving break I was given the assignment of checking the wheel alignment on a Freightliner truck in our shop. After being previously shown by our instructor, watching some videos and going over "A Common Man's Guide" Me and another student teamed up and began to the Alignment Mastery sheet we had printed out.

The first step was to set the Toe-in on the truck.

After measuring the to see how much we needed to adjust the Toe-in, which turned out to be 1.25 inches





We were then able to adjust the tie rods and get our Toe-in to the proper specification.

We adjusted the tie rods on both sides 5/8 of an inch bring us to what should be a zero angle in the Toe-in.







After getting the steering axle adjusted we then moved on to checking and setting the thrust angle on both the forward drive axle and the rear drive axle.

Once realizing that the thrust angle was off about half an inch, we were able to get underneath and adjust the angle back to zero.

This assignment was pretty simple, however before the lesson in the shop and the discussions with my peers about wheel alignments. It would have been much more time consuming and frustrating to do this assignment. This was my first wheel adjustment on a heavy duty truck and most of what I learned was fairly new, especially getting down and turning the wrenches and making the adjustment. This was an awesome little assignment and has taught me that without to much difficulty I can perform or help perform a wheel alignment and know what a thrustline is and how to tell if it is true along with a lot more I wasn't to sure about before.

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