Need some advice on material selection

[sanddan]

astroracer,

What software are you using to design with? Just curious.

Dan

[JohnUlaszek]

If the crush sleeve and thrust washers are sized properly the bolt can not rotate. I would be more worried about potential binding issues. I am assuming you will make a welding fixture or post-weld machine your LCA bolt holes?

I use Pro/E every day so I know how much work you have tied up into those models, and I also know what a tremendous tool the solid models are, nice work.

John

[astroracer]

Thanks for your comments everyone. I really appreciate the help.

Dan,
I am using Unigraphics V18. I run this program at work 10 hours a day...

JP,
I think I will run with the 1018. I may redesign the width of the brackets to incorporate some hardened washers on the inside as bearing plates for the sleeves and bushings.

John U.,
Does that sound feasible? I could tack weld the washers to the inside of the brackets. I could possibly get away with 10ga for the bracket material if I did this.
I will be fixturing everything before it is welded and I haven't decided if I will post bore the bolt holes or not. Probably not because I can fixture it up easier and cleaner then it would be to try and drill the holes after the welding and keep everything square.
Thanks for the complement too....
Mark

[JohnUlaszek]

Astro
The key with poly is to use the crush sleeve OD as the bearing sufraces for the ID of the poly bushing, this means your sleeve should have an overall length slightly longer than the bushing stackup.

The thrust load is where the problem comes in, you want to handle thrust without creating bind under braking which creates a non-linear rate of change in bump travel. This may not be a signifigant issue for most, but if you are going for an idealized setup, you will want to at least think about this.

Your right about the fixture, post weld machining does not make any sense.

John Or Paul, you want to correct or add to this???

John

[ruggles]

astroracer

your setup looks pretty good. I have had some experience with poly bushings on jeep suspension(both leaf and 4 link). From what I have seen, poly is good as long as you have a way of purging out the old grease and adding new somehow. Alot of offroad poly bushings are fluted(grease grooves) and use a bolt with a zerk fitting on it. This works nice, but I am not sure how much weaker the greasable bolt is than a regular one. I am sure there are alot of people that will disagree with me (about poly being worth a crap) but I think it is good if you use it how you are intending. Good luck.

Paul

[astroracer]

Okay guys, sounds like I have a plan.
John U.,
The stackup over the inner sleeve is exactly as you mentioned. I have yet to check it with torqued fasteners in an installed position but I'll do that as soon as I have some brackets made. I will then build my welding fixture to suit.
I think I will use hardened washers on the inside of the brackets and plug weld them from the outside through holes drilled in the bracket. I can then finish off the welds to make them disappear. 7ga 1018 will be used for the brackets.
Ruggles,
The bushings have grease grooves and I will be adding grease zerks to all of the bushings after they are welded up.
Thanks to everyone who has jumped in to help. If anyone see's any problems with this plan please let me know your concerns.
Mark