Project "Snow Drift"

[8ntruck 6,369]

7 hours ago, Handy Don said:

Spoiler alert: This is a bit technical by a one-time mechanical engineer.

 

I tried setting this up as a "sum of forces" model, just to see scale and direction, with the joint at different positions in its rotation.

Came away realizing that it all comes down to:

- strength of the castings holding the pivot bearings -- probably adequate since they are already supporting similar or greater loads to transmit power

- strength of the bearings and races -- longitudinal -- again, seem to already be strong enough to transmit power, the longitudinal forces are new but are in the same planes as the rotational forces and seem to be well within the symmetric bearings' capabilities, 

- strength of the bearings and races

   -- lateral with inner "T" at horizontal/vertical -- the added "supporting" forces for the horizontal shaft of the joint's inner "T" resolve into the same directions on the bearings and races as do the rotational forces in the "standard" use; depending on the amount of "play" in the bearings, there may be some force pushing "sideways" on the vertical shaft's bearings

  -- lateral with inner "T" at 45º angle -- the added supporting forces are shared by all four arms of the "T" and at each bearing the force is split between being in the plane of the bearing (all good) and at 45º to that plane (i.e. tending to push the bearing's inner race sideways, kinda like a WH PTO on an engine crankshaft).

 

So that incremental load of each joint's share of the machine weight + operator + "bumps" varies from being borne by fully and "in plane" by the two bearings at the horizontal "T" to being 50-50 and angularly on all four bearings when the "T" is at 45º

 

So, to me, it is the strength and capacity of the bearings to handle the 45º loading over time that is the key to the machine's durability. I'm going with it working fine for what @Oldskool has in mind.

 

 

 

Just throwing an opinion in here from another retired mechanical engineer.  While I have not gone as far as setting up an analysis, I agree with the @Handy Don conclusion and reasoning to get there.  I don't think the side load on the u joint in this application will be a big issue - assuming that operation will be on "reaonable" terrain.

 

Shock loads could be a problem for the u joints.  But you would need some pretty big ones to break something - maybe something on the order of dropping it off the trailer onto concrete.  Rock crawling would also supply impact loading opportunities as you crawl off of a rock and drop down to the next level.  Traversing logs would also provide the same sort of loading.

 

I like the idea of modifying the tank caps for use as a shroud around the u joints.  As somebody observed, it will keep the support struts off of the ground in the event that the u joint gives up.

[Oldskool 6,582]

I did happen to get the hood and grille done yesterday.

Edited January 25, 2021 by Oldskool

[Oldskool 6,582]

Here is what I came up with to disperse the load on the C-clips. I will be using grade 8 bolts when fully assembled. 

Edited January 25, 2021 by Oldskool

[DennisThornton 4,769]

I've replaced a few u-joints and they all gave lots of warning and none broke.  I think I remember one having lost all the bearings in one cap...  Not sure.  I suspect these will work just think they will wear prematurely. 

I really don't see a screw suddenly falling off but I think the production units will need additional bearings.

[Handy Don 10,595]

26 minutes ago, Oldskool said:

Here is what I came up with to disperse the load on the C-clips. I will be using grade 8 bolts when fully assembled. 

Very clever! I like this a lot. It'll keep the bearing race in in case of failure--maybe even give you a "limp home" capability in the worst case. I doubt it compromises the yoke integrity in any serious way.  Since it'll be essentially permanent, I suggest red loctite on assembly as well.

 

I took a close look at a U-joint I have on hand and noticed that its "cross" arms butt directly up to its yoke arms. As long as it's "axles" don't fall out any side force is well-handled. I'm not sure how this was assembled since there is no clip! This is from a 3-point hitch drive.

In the "Drift" example, if your tank is to the left and your rear arm to the right, then the force (blue arrow) from the machine's weight is upward via the lower arm of the left yoke and carried by the horizontal axles of the cross to both arms of the right yoke. Your joint looks very similar but the cross isn't quite as "chunky".

 

This video below of how a u-joint goes together was pretty helpful (could have speeded up parts of it!) I'd have used a vise to squeeze the needle bearing sleeves onto the axles. And you do have to pay attention to the yoke symmetry to accommodate the grease fitting!
It does show how side force would push against the clip--it is the opposite of the assembly force!

 

[Oldskool 6,582]

8 minutes ago, Handy Don said:

Very clever! I like this a lot. It'll keep the bearing race in in case of failure--maybe even give you a "limp home" capability in the worst case. I doubt it compromises the yoke integrity in any serious way.  Since it'll be essentially permanent, I suggest red loctite on assembly as well.

 

I took a close look at a U-joint I have on hand and noticed that its "cross" arms butt directly up to its yoke arms. As long as it's "axles" don't fall out any side force is well-handled. I'm not sure how this was assembled since there is no clip! This is from a 3-point hitch drive.

In the "Drift" example, if your tank is to the left and your rear arm to the right, then the force (blue arrow) from the machine's weight is upward via the lower arm of the left yoke and carried by the horizontal axles of the cross to both arms of the right yoke. Your joint looks very similar but the cross isn't quite as "chunky".

 

This video below of how a u-joint goes together was pretty helpful (could have speeded up parts of it!) I'd have used a vise to squeeze the needle bearing sleeves onto the axles. And you do have to pay attention to the yoke symmetry to accommodate the grease fitting!
It does show how side force would push against the clip--it is the opposite of the assembly force!

 

Thanks. This will be my last upgrade until I have a failure. Until then all is good. I may have an unexpected failure elsewhere. We all will see soon.

[Oldskool 6,582]

I just dropped the hood off to get the finishing touches. It will be back in a couple of days.

[Pullstart 59,694]

Pinstriping?  Bomber pinup?  Fillet O Fish?

[DennisThornton 4,769]

17 minutes ago, pullstart said:

Pinstriping?  Bomber pinup?  Fillet O Fish?

Plating, airbrushing and gold leaf.

[Oldskool 6,582]

@pullstart @DennisThornton nothing quite like that. Keeping in mind I went military. WWII to be exact. My father and his 4 brothers and my grandfather were in WWII. My father was in the Third Army at the Battle of the Bulge and my grandfather was in the Azores and Okinawa. And that is why I picked WWII

[Oldskool 6,582]

Slow but sure.

[ebinmaine 63,116]

7 hours ago, Oldskool said:

@pullstart @DennisThornton nothing quite like that. Keeping in mind I went military. WWII to be exact. My father and his 4 brothers and my grandfather were in WWII. My father was in the Third Army at the Battle of the Bulge and my grandfather was in the Azores and Okinawa. And that is why I picked WWII

With that in mind I'd love it if you and our hiking buddy could shoot the breeze....

[Oldskool 6,582]

14 minutes ago, ebinmaine said:

With that in mind I'd love it if you and our hiking buddy could shoot the breeze....

Oh really?

[ebinmaine 63,116]

1 hour ago, Oldskool said:

Oh really?

Trina's best friend is a nut for anything WWII. 

 

[Oldskool 6,582]

5 minutes ago, ebinmaine said:

Trina's best friend is a nut for anything WWII. 

 

That would be cool

[71_Bronco 1,072]

Id love to see the screws matte black or a matte silver. I think the 2 tone would look really sharp.

 

But its ultimately your choice. Either way, its looking phenomenal and I look forward to the final product. 

[Oldskool 6,582]

Just now, 71_Bronco said:

Id love to see the screws matte black or a matte silver. I think the 2 tone would look really sharp.

 

But its ultimately your choice. Either way, its looking phenomenal and I look forward to the final product. 

Actually they are going to be Rustoleum flat black. All flat colors and the Rustoleum is easy to touch up

[DennisThornton 4,769]

Barber stripes?  Screws?  Wouldn't be that hard.

[Pullstart 59,694]

11 hours ago, Oldskool said:

Actually they are going to be Rustoleum flat black. All flat colors and the Rustoleum is easy to touch up

I’d imagine if the drums were gloss, they would wear better on the terrain?  

[Oldskool 6,582]

11 minutes ago, pullstart said:

I’d imagine if the drums were gloss, they would wear better on the terrain?  

I expect the paint to get worn off rather quickly 

[Pullstart 59,694]

6 minutes ago, Oldskool said:

I expect the paint to get worn off rather quickly 

true, true.  Maybe after perfection, you could find a powdercoater that would sponsor them?

[Oldskool 6,582]

3 minutes ago, pullstart said:

true, true.  Maybe after perfection, you could find a powdercoater that would sponsor them?

Possibly. I'm not even sure where the closest powder coated is to me. I'm assuming 60 to 80 miles one way

[Oldskool 6,582]

I have to say I'm quite pleased with the hood.

[Pullstart 59,694]

22 minutes ago, Oldskool said:

I have to say I'm quite pleased with the hood.

how bout some  so we can all be pleased with the hood?    

[ebinmaine 63,116]

1 hour ago, pullstart said:

how bout some  so we can all be pleased with the hood?    

 

C'MON Man. 

 

You know the rules......