Shopsmith Forums

Thought the group might enjoy this...

Nice video on what's involved in repairing cast aluminum by building it up with welding rod then machining:

Part 1: http://youtu.be/LtOBVczZQDM

Part 2: http://youtu.be/GsXifnJUmO4

... then the customer broke it again...

Part 3: http://youtu.be/Mq_6es07Qv4

Part 4: http://youtu.be/g-8KhwXULSI

This guy's videos are great!

enyoc wrote:... then the customer broke it again...

There is a valid reason for that!

frank81 wrote:There is a valid reason for that!

... and that is?

enyoc wrote:... and that is?

Several reasons, the biggest being that once the workpeice cracks you've passed the fatigue point. You can fill the spot in, but if the piece is not comsetic and undergoes normal stress it will break again relatively soon. Even with an expert weld, the orginal crack can spread or new cracks appear next to the weld.

Don't get me wrong, I've filled aluminum with welding rod before but it's not a permanent solution. Aluminum can be fickle.

frank81 wrote:You can fill the spot in, but if the piece is not comsetic and undergoes normal stress it will break again relatively soon.

Watch the videos. It broke elsewhere.

After trying different methods of aluminum and cast iron welding and types of brazing, I found that I could buy another used headstock, joiner part or what ever part that broke for a lot less effort and most times less cost. It takes a lot of time to properly weld aluminum or cast iron if you can even accomplish this task. My efforts left a lot to be desired and did not look that pretty. For my custom and modified jobs, I found a professional aircraft aluminum welder with proper equipment and knowledge who is not cheap and was very hard to find. He still does all my finish welding for me. I tack the parts together in a jig for him and he finishes them nicely but costly.

enyoc wrote:Watch the videos. It broke elsewhere.

Right...that's what I said. If the part breaks the entire workpiece is approaching its fatigue limit and at risk of failing anywhere. It's a problem with aluminum and cast iron, you can get away with filling steel.

frank81 wrote:Right...that's what I said. If the part breaks the entire workpiece is approaching its fatigue limit and at risk of failing anywhere. It's a problem with aluminum and cast iron, you can get away with filling steel.

Yes, many times, once aluminum tears or breaks, you need to get another part. Also the heat from the welding can weaken the area around the weld if you are not really careful. The videos really brought back memories from my younger days. Sure would have been better if I could have had at home the equipment that was shown. I played with this kind of equipment when I was in the Navy. My current machinest does have this kind of equipment in his home shop as he does all my major machining for me. I have much smaller equipment.

In this and many other cases, you cannot make an item or part idlot proof. The driver of the truck, by popping the clutch again, broke the drive shaft again which broke the part off. I would have recommended installing drive shaft retaining loops after the first time. These were required on all drag racing cars to retain a broken drive shaft since the 50s.

Bill, the MythBuster guys kinda disproved the "pole vault" reaction to a broken front u-joint. It took them about 10 (that they showed) tries to get a Plymouth Fury III to drop the front of the driveshaft, and most of the time it just bounced along the ground (Alameda NAS runway.)

They ended up digging what looked like a pole vault hole, in the runway, and it still took 5 more tries to hit that pocket.

And, if popping the clutch did that, that was a POORLY designed setup. My '70 Roadrunner would just smoke the tires. (That car was amazing. The missing rubber patch, caused by the shift from 1 to 2, you could cover with a piece of 8.5X11 paper.) the guy I sold it to, replaced the 383 Magnum with a 440, and it would lift the driver's front wheel on launch. (We won't mention the mileage!)

steve

For all the time Keith spent repairing the part and the money spent by the owner I think they'd just machine a new part with all the equipment and material he had available. Just sayin':rolleyes: . And then engineered safety cages for the driveshaft. And then fire the errant driver - or at least give him a shovel and a wheel barrow or maybe a Tonka-toy dump truck and tell him to haul rock that way for a while.

Maybe the truck that part goes to is so old the part is unavailable? (Not likely, but possible). Probably the trucking company's readiness for the specific type of truck/equipment was critical and he couldn't wait for a part to be delivered.

And now I'm sitting here wondering why I spent so much time pondering the "Paul Harvey" (the rest of the story) about the affair.