Dragline Crawler Build

[Wiskybilt]

Looking great Jim! I like the progress and constant updates. Keeps the interest up!

[Rvjimd]

Parting off one of the spacers for the pairs of side frame rails.




I changed my side rail design a bit, should have one set finished tonight...

Jim

[Rvjimd]

Got enough finished to do a first check of the "scale" of my undercarriage to the crane.










Jim

[Rvjimd]

How would you make these idler rollers?







I need to make 12 of them. I am starting with 3/4" round aluminum stock. They have a taper to help clear the drive dog tabs on the pads. This is one of those things that I look at and think " that shouldn't be too hard", and then when I start making them I end up with two or three and NONE of them are the same. I had been trying to make the taper using the side angle on my right hand turning tool bit, but that is problematic when it comes to doing the second (or left hand side if the part stays chucked up for the entire process, which I think it should). So, now it finally dawned on me, use the compound to make the taper.

My problems are:

Keeping concentricity. (I think I solved this by NOT over drilling the center hole, so that when I pull the stock out, I don't start off on the next part with an off center hole.)

Getting the same length on the shoulders on each side.

Getting the center rib in the center.

I am using my dial indicator on a mag base to move the carriage in as I turn the shoulder.

Should I be doing this with the part chucked once for the entire part? If so, should I be using a left hand turning tool for the left hand shoulder and Turing away from the chuck?

I think this all comes back to one of my very first questions when I got started with the lathe, "how do you know what steps and what order and how to decide what tool or procedure"?

Thanks for any tips or suggestions.

Jim

[9W Monighan]

Keep the bar chucked through the whole process. Leave enough bar sticking out of the chuck so your tools can do what is needed for say,2 or 4 rollers. Turn the OD , do the step and taper using LH and RH tools, center drill, rough drill, ream to size you need, part off the finished roller making sure the left and right are equal so rib is centered. Now this process will keep everything concentric but don't drill too far because when you have to pull the bar out of the chuck to machine more you will have to face the bar off so it's clean to start another center drill.

[Rvjimd]

And now, for something completely different...

Here is my first prototype drive tumbler! Still working out the details.



Don't even have the second side formed because I didn't leave enough center hub to hold onto. Back to the lathe...

Jim

[Rvjimd]

Finally got one tumbler done both sides. I am waiting on hardware so I can assemble an entire unit. Need to have it nearly complete so I can tell what I need to do to the drive dog ears on the pads and the tumbler flanges.

I am pretty sure I am going to need to put a bevel on both, just not sure how much on each. I sure it will be more trial and lots of errors.



Jim