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Topic Closed178 axle support
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StephenH View Drop Down
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Joined: 29 Nov 2015
Location: Wake Forest, NC
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Posts: 6428 		Direct Link To This Post Topic: 178 axle support
    Posted: 05 Mar 2019 at 8:51am
Toyanvil: I guess I figured out how you came up with your user name. Thumbs Up Nice work on those parts. They look really nice and so does the completed trailer. Now that leads to the question of what is that car on the trailer?

Offgrid: Thank you for that additional information. It is good to have someone who knows the engineering end of things.
StephenH
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ouR escaPOD mods
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offgrid View Drop Down
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Posts: 5290 		Direct Link To This Post Posted: 05 Mar 2019 at 4:32am
I looked up the axial force and torque specs for 3/8 in grade 8 bolts and got a torque of about 25-30 ft-lbs (asuming lubricated threads) and an axial force of about 8000 lbs (per bolt).

The coefficient of friction (cof) of steel on steel is about 0.7 so that clamp should develop a sliding resistance of 4 * 8000 * 0.7 = 22000 lbs. The max lateral force on it from a 3g bump load on the axle is going to be something like 5000 lbs if the new support took all the load and the axle tube took none. So you'll have at least a 4x safety factor against sliding. In less technical terms I don't think its going to go anywhere. 

With 11000 lbs on each side of the clamp I do believe you are correct about needing the gussets.Thumbs Up I wouldn't recommend putting rubber in between the parts, I doubt the rubber will take that much compression and the cof of steel on rubber is about the same as steel on steel anyway, so it won't really improve things. 

Here's a couple useful links if you want to look at the numbers:
1994 Chinook Concourse
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Toyanvil View Drop Down
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Joined: 15 Feb 2019
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Posts: 157 		Direct Link To This Post Posted: 04 Mar 2019 at 11:09pm
We must be typing at the same time. I have a Miller 211 and an old MillerMatic 35. I love the 211, best welder I have ever had. I am thinking about something between the mounts and axle, not sure what. My friend owns a machine shop and powder coats, I powder coat everything I can. We even powder coated every part of my car trailer when I was done modify it



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Posts: 157 		Direct Link To This Post Posted: 04 Mar 2019 at 10:48pm
I am doing the welding. I hope to have time after work tomorrow to build some gussets for the sides of the wings, I don't want the wings bending down when I tighten the bolts. Then I just need to drill holes for the bolts and a drain hole. I will be using 2 grade 8 .375" x 1.25" bolts per side, so a total of 8 bolts.
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StephenH View Drop Down
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Posts: 6428 		Direct Link To This Post Posted: 04 Mar 2019 at 10:30pm
I re-read the posts and realized that you are doing the welding yourself. Nice work! I have a wire-feed welder that I got at Harbor Freight. I'm not sure if it would handle a job like this. I think so, but I will need much more practice before I can do a weld as nice as yours are.

Do you do your own powder coating? Once everything is done, are you going to put some sort of sheet rubber between them and the axle to both pad them and to increase the gripping strength so they would be even less likely to slide and to help keep moisture out?
StephenH
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Posts: 157 		Direct Link To This Post Posted: 04 Mar 2019 at 9:29pm
Getting closer, just need to make some more gussets.

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Posts: 5290 		Direct Link To This Post Posted: 04 Mar 2019 at 4:32pm
StevenH, not having seen the finished product I was visualizing the connection between the frame bracket and the axle attachment as a moment connection (one that can handle a torque), not a pin joint.  

Since Toyanvil is planning a pin joint I agree with you, it will want to rotate and the axle attachment needs to be tightly clamped so there is enough friction that it doesn't want to creep outward over time. So there should be a gap between the clamps and the bolts should be torqued pretty tightly. 

In the angle reinforcement approach, I think the u bolts work fine. The u bolts themselves are not in direct contact with the axle and the nut plates are really thick material and a bit over an inch wide. All the forces are vertical so there isn't any tendency for things to creep or move laterally. You are only clamping the parts together, not trying to develop friction to resist a sliding force.
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Joined: 29 Nov 2015
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Posts: 6428 		Direct Link To This Post Posted: 04 Mar 2019 at 2:39pm
Originally posted by Toyanvil

That's a good guess,  as that is the plan.  LOL I hope to have them welded up tonight after work. My axle has lost it's camber, it is now almost flat with less then an 1/8 inch of arch with no load.

I look forward to seeing how they look after you get them finished. Even if I take the other tactic of using angle iron, I think that welding some tabs for bolting to the axle tube would be a good method to attach the angle to the axle.
StephenH
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ouR escaPOD mods
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Posts: 157 		Direct Link To This Post Posted: 04 Mar 2019 at 11:44am
That's a good guess,  as that is the plan.  LOL I hope to have them welded up tonight after work. My axle has lost it's camber, it is now almost flat with less then an 1/8 inch of arch with no load.
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Posts: 6428 		Direct Link To This Post Posted: 04 Mar 2019 at 10:01am
Originally posted by offgrid

StephenH, it doesn’t need to be attached to the axle, it will be pressing down from above.
The reinforcement I did has to be u bolted because it’s on the bottom. 2 different ways to skin the same cat.

Toyanvil, just for comparison, my axle crown is only 1/4 inch and I don’t have any noticeable negative camber. StephenH’s brand new axle only has 3/8 inch crown. Those are with the trailers on their wheels. So just from looking at how much negative camber you had, I’m wondering if your axle tube ends were bent at the attachment points while you still have a little arch left in the center?

I disagree. From what I can see, the bracket on the frame has a bolt and the axle bracket has a bolt and there is going to be some sort of jack screw between them. This is not rigid, but will be able to swivel on the hinge bolts. That means that the axle bracket will slide along the axle since it would not be fixed to the axle Toyanvil mentioned bolting to the axle. That is why I offered my suggestion and just edited my prior post to suggest a solution to the problem of how to attach it to the axle so it won't slide.
StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS
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