1/16 Bucyrus Erie 25B

[Rvjimd]

Jared,

Couple of questions for you.

On the spring tension tag line, does it have any difficulty with changes in boom angle? I have done mine with a counter weight and I look at the spring version thinking it would hide the counter weight. But, I see LOT of movement in the counter weight when I boom up or down as the bucket moves further or closer to the boom.

And, I don't know how I missed the sand box clamshell video... That clam works GREAT! Did it work that good right off the bench? Did you have adjustments to make to it? I may take a second look at mine, maybe create another. I tend to use my drag bucket just because it works so much better than my clam. Hope you can find time to get back on the new crane project.

Thanks,

Jim

[Jared]

Wrong thread, Jim, but that's ok. The tagline is led out through the front of the machine down near the boom pins and then up to a sheave so nothing really changes with the boom angle. I had to monkey with the spring geometry trying different tension and pivot points on the lever. I'm still not completely satisfied with it but it's good enough.

It's been long enough that I can't remember for sure, but I think the bucket required adding weight to it. I had to use thicker material for the bottoms and add weight to the center bar to get it to open reliably. That sand is pretty fine so pretty much anything works in it. It's volcanic ash from Mt St Helens when it erupted in 1980. The same stuff the gift shops sell a 1/2 oz vial for 10 bucks and the sand pits sell for 2 bucks a yard.

[Rvjimd]

Jared,

As a newbie machinist I have to ask. How or why did you decide to make the side frames from a single chunk of aluminum instead of starting with to pieces of bar stock and then bolting them together with spacers? It looks like a lot of milling to remove all that material in the middle? I have the same question about the center part? I was going to try an make the center from a 1/4" plate and then add "side skirts" to make the upside down box.

I made some of the sides using channel, but I think I'm going to redo them using two part of bar stock and spacers and then I can do rollers as you did.

Thanks again for the thread! I refer to it as I am working on mine.



Jim

[Jared]

Jim, the main reason I did it this way is because I have a mill and I wanted to play with it. Another reason is because it's easier to 3D model one part instead of having to draw and assemble multiple parts on the computer. With a built-up design, it could be a little harder to keep the inside and outside pieces aligned with each other if a bolt hole is just a little off. Although I suppose you could bolt the pieces together and then do all the machine work on them after. I would design a little fudge factor into the overall dimensions of the rough parts so they could be squared up with the mill after they were assembled if need be.

Actually, milling out the center was the easiest part. The outsides took the longest.

[Rvjimd]

Jared,

Thanks, that all makes sense to me now!

Jim

[Rvjimd]

Jared,

One more question for you. Was there any specific reason for using brass and steel for the lower rollers? I am about to start making those parts and not sure what to use or why. In think I can see using steel for the shafts but I was going to use aluminum for the rollers as well as the drivers and big rollers. I think the aluminum is cheaper than brass but I'm not sure, I do know I have more aluminum stock on hand than I do brass.

If I get a but more done here I guess I could start a build thread of my own?

I sure would like to see you get back on yours!

Thanks

Jim

[Jared]

I used stainless rod that was somewhat polished to have a smooth shaft that wouldn't corrode in our humid winter climate and brass because I hadn't turned it much and wanted to play with it. I think next time I would use acetal (Delrin) for the rollers because it's self-lubricating and real easy to machine. Aluminum is certainly cheaper than brass and I think it would work just fine. It will wear out sooner since it's softer but unless you're planning on putting a serious amount of hours on it there shouldn't be much trouble. The main thing is to use a shaft material that is harder than the bearing material so you don't wear out the shaft since generally speaking bearings (or bushings) are cheaper and easier to replace. Using the same material for both isn't a good idea. Looking forward to seeing yours and don't be afraid to start a thread.

[Rvjimd]

Jared,

Thanks for all the answers! And, thanks to Steve as well for the pictues of the BE, I have been using the drawings in my build. I have a pretty good start and made some design decisions yesterday so I think I am ready to start producing track pads.

Jim

[Rvjimd]

Jared,

When you made the axels for the rollers did how did you insure the second end was in the same plane as the first when you milled the second end? Same question I guess when you drilled them?

Thanks,

Jim

[Jared]

Have a look on the second page at post #27. You can see the fixture I made to hold them so I could mill and drill both sides. I milled the flats on all the parts first and then drilled the holes so I wouldn't have to be swapping endmills and drill bits twice every part. This way all you have to do is remember your settings on your dials to come back to for repeatability. When you mill the flats lock the Z-axis and don't move it so each shaft is at the same height when you bolt them to the side frame.

[Rvjimd]

Jared,

Thanks! I am learning how important it can be to recognize how the order you do things impacts the production of parts.

Jim