Crawler Crane Undercarriage Project

[12bolts]

Excellent work and attention to detail Jim. I love it

Cheers Phil

 

[RVJimD]

I am reworking the frame rails for my crawler, but, it has a twist in it. Here is a short video that should explain what I mean.

Part of the reason I wanted to rebuild these parts was the same twist in the old parts.

I tried to carefully drill the two sides while clamped together in the mill vise.

I tried to carefully turn the spacers in the lathe. The order was...

Chuck the stock in the 3 jaw, center drill, drill center clearance hole to size.
Turn outside diameter down just enough T to make it round and concentric to the center hole.
Part off. I faced one of them to match the length of the first.

I DIDNT machine the inside mating surfaces of the bar stock.

If I loosen the clamping screws a bit and tweak it as I tighten it is better but I want to try and figure
out what I might be doing wrong.

Jim

 

[12bolts]

Jim,
It may be that the spacers are twisting the opposing ends up, What happens if you independently clamp the 2 bars lightly to a flat surface and then fit the spacers. Gently tighten the spacers and also gently tighten the clamps on the bars. Just so they can slide together as the spacers are tightened but not able to get cocked up

Cheers Phil

 

[RVJimD]

Phil,

That helped. I put the assembly in the drill press vise and lightly tightened the vise, then tightend up the screws on the frame rails.

I guess there could be two unrelated issues. The spacers not faced parallel AND OR the two sides simply move up or down as I tighten the screws.

Am I thinking correctly about facing the spacers to get them parallel?

I face the first end, then turn the diameter, then part off, flip it around and face the second end. Is that proper? Do I need to indicate it befoer the second face step?

Thanks for the assistance!

Jim

 

[12bolts]

Jim, If you can work with the "stickout" and still achieve the finish you want, no chatter, problems etc, then I would turn, face and part off without removing the part from the chuck. Then everything would be parallel and perpendicular after parting. No need to turn and face the end you parted unless you are adjusting for length. Are you working with bought tube or are you drilling it? Perhaps your drill is coming out the other end off centre. If so you could drill it through and then turn between centres to ensure the OD and ID are parallel. Bit of fiddling because then you would need to indicate the part to get it true for facing.
How many of these spacers do you need to make?

Cheers Phil

 

[RVJimD]

Phil,

I'm using solid round stock and drilling it. I only need four, but I think my twist was coming from the rotation and clamping action as I tightened the screws. Using the drill press vise has controlled the problem well enough.

Here is a video of the first test. The first side in the video is the new drive tumbler and associated parts. About halfway thru I rotate around to the original side. I'm already working on that side now.

Jim

 

[RVJimD]

Got my undercarriage upgrade finished and it works really well. The new drive tumblers are much easier to make now that I have learned how to make an octagon using the vise and a v block I even made my own v block so it would nest the stock and fit my vise perfect . It got some dirt on it during testing, here are some photos...

Oh, and it anyone has a thought on it, I would like a better way to finish the tensioner. The way they are now, the brass rod rotates and the tension holds it against the tensioner bolt. Not ideal. I would like to put a collar around the end of the shaft but it can't be threaded, otherwise it would screw into the rod and seize it. I need to see this, guess I'll start searching the inter web...







Jim

 

[kvt]

Jim, How about this, Take the ends of the threads off the SHCS and make a yoke to go over the axle the end of the screw would seat in the yoke and push it axle to tension without seizing
Or at least that is what I am thinking. For that mater if you put a bearing in the yoke for the axle then it would even reduce friction on the axle yoke interface.

 

[RVJimD]

I think I understand what you are saying, that sounds like it would work. A round collar around the axel, drill a short blind hole in the radius of that, take the thread off the end of the bolt. I'll try it and post my results.

Thanks!

Jim

 

[RVJimD]

Here is a short video I made on using my Grizzly G0759 mill w/DRO to put a bolt circle of five holes in a pulley for the crane boom on the NyLint dragline.

Jim