Watts Did you say? Pivot loading. ??

[LowBuckX]

Im using 1.25 IDx 2 inch needle bearings and a 1.25 x 2inch Axle with 3/4 grade 9 axle bolt. Should I make a bracket to put the Axle bolt in double shear or will I be OK in single with the 3/4 grade 9. This is a frame mounted Watts...

Also are 5/8 chromemoly 14,485 PSI teflon lined Heims with grade 9 bolts OK for the links. ...


Thanks guys I did search with no results did find one post about the same with no answers. .

[JRouche]

Im using 1.25 IDx 2 inch needle bearings and a 1.25 x 2inch Axle with 3/4 grade 9 axle bolt. Should I make a bracket to put the Axle bolt in double shear or will I be OK in single with the 3/4 grade 9. This is a frame mounted Watts...

Also are 5/8 chromemoly 14,485 PSI teflon lined Heims with grade 9 bolts OK for the links. ...


Thanks guys I did search with no results did find one post about the same with no answers. .

Sorry, I didnt quite get it. Are you talking about the center pivot bolt or the axle side of the link end bolt. Ummm, either way, hell, 3/4" bolt is gonna be strong enough. Sounds like a tank. What kinda gun are you gonna mount??

The 5/8 rod ends sounds a lil weak for the size. Check out some QA1 ends. For example, the 5/8-3/4 is 31,680 Lbs for static load. The smaller 5/8x5/8 end is 17,955 Lbs. I like QA1 rod ends, hard to beat them for the price. JR

[LowBuckX]

center pivot bolt. I call the part that the needle bearings ride on a axle. On the QA1 rod ends. I was at Summit racing today and ordered the QA1 5/8 5/8 and the Competition Engineering Rod ends and they are exact matches side by side every measurement tool mark ETC ETC twins sept for the price.
This is just rough machined right now. 2 inch thick for refferance.


The bolt is just a stunt double

[JRouche]

Thats a SOLID looking center pivot... Did you make it?? Care to email the code ))

Thanks for the heads up on some cheaper rod ends. Sounds like they are made by the same folks with a price cut for non-disclosure of the manufacture.

You see that alot. And without insider info, like you just provided its hard to find out. You know, like refrigerators. One company makes the same unit but tagged under diff labels, and prices.

How much were the CE ends?? Ballistic sells the QA1 XM-10 5/8x5/8" for 17 bucks (16.99) each. Sounds like the same ends but you got a better price.

Man, cant wait to see the build up pics. Looking good.. JR

[LowBuckX]

The propeller is just free hand on a Brigeport. The steel center pivot (axle) was made on the cnc with simple g code in MDA.

On the rod ends they are $17 for the CE but Summit wanted $24 for the QA1 XM and $22 for the XMR....

[JRouche]

The propeller is just free hand on a Brigeport. The steel center pivot (axle) was made on the cnc with simple g code in MDA.

On the rod ends they are $17 for the CE but Summit wanted $24 for the QA1 XM and $22 for the XMR....

Nice work on the prop. I should have realized it was done on the manual machine, lay out blue. Duh!!

And the ends are about the same price. Surprised summit doesn't have a competitive price on the QA1s, they are usually pretty close. I have bought a few items from ballistic, great prices and solid products. Umm, no affiliation at all. JR http://www.ballisticfabrication.com

[silver69camaro]

5/8" is way more than needed, should be OK there. The pivot bolt will be fine too.

The only thing I would keep my eye on is the roller bearing. Keep that well greased, loads on those bearings isn't too high when static (shaft must be spinning at reasonable speeds for peak load capacity). The rollers can get beat out pretty easy if they aren't greased, which would then make it very sloppy.

[Apogee]

Just curious, but are you planning on running seals with your needle bearing? What is the inner bearing race made out of and what hardness is it?

Tobin
KORE3

[JRouche]

I was gonna comment on the bearing too but wanted to see what you had in mind first, cant ever tell till the finished piece is out there.

What I was wondering was how will you have the bearing take the side loads. And not so much the suspension side load but just the bolting up side load. I used angular contact bearings and they act well for both rotational load and the side load.

I cant see how you will keep it from jamming up when you crank down the bolt. Are the two sections of the race you made long enough that there will be a slight slip fit, front to back, thats what I figured you did.

But then the sides of the roller bearing will be acting as a bearing surface even if your arms are completely parallel with the pivot. They will still be in contact on the outside edge. And with a play designed in the race you made there will either be sliding on the aluminum and race or with the bearings and race at the edge of the bearing.

Almost think it will self destruct at some point. Curious. Im sure you worked it all out, I just cant see the design. JR

[LowBuckX]

I was thinking of changing it up and adding some spindle tapper bearings and races. Right now the needle bearings press in. Pivot is 2 inch exact -bearings measure 1.990 wide and my inner race is 2.005. so its a .005 clearance. the race is A2 that will be hardened if I deside to stay with this idea.. Im going to investigate the tapers and race design should be a simple changeover... This is a project for the up comming winter... just starting the pile-o-parts..

This is why I ask to get this good feed back to make changes... Thanks

[silver69camaro]

Personally, I think any sort of roller or needle bearings is unnecessary in that area. The only thing it will do is add weight and complexity. What's wrong with an oillite or a urethane bushing?

On that note, if you do use urethane, it can really dampen the gear noise than can transmit from that area.

[JRouche]

Personally, I think any sort of roller or needle bearings is unnecessary in that area. The only thing it will do is add weight and complexity. What's wrong with an oillite or a urethane bushing?

On that note, if you do use urethane, it can really dampen the gear noise than can transmit from that area.

I think urethane would be a bad choice. Too much friction. And the loads encountered at that bearing are tremendous. And if the pivot is frame mounted like mine the weight of two ball bearings doesn't matter. JR

[Damn True]

Nice work on the machining. Better still on the thread title.

My suggestions:
sealed roller bearings supporting the prop
SS teflon lined rod ends

[LowBuckX]

Im going to exsplore the tapper and oilite and urethane bushings further. The bearings will be only $10 for both so no big exspense...

[Norm Peterson]

Properly detailed, I wouldn't be particularly concerned about friction with poly. As long as you aren't trying to axially compress the poly, the moment about the pivot axis due friction should be negligible. Even if you can develop 50 ft-lbs, that's only ±10 lbs wheel load.


Norm

[silver69camaro]

I think urethane would be a bad choice. Too much friction. And the loads encountered at that bearing are tremendous. JR

Why do you say that? Worst case you have about half the vehicle's weight applying a load to that pin in a 1G corner, so you're only looking at about 1600-2000lbs there. That's not much at all.

When designing the watts linkage for our three link, we used poly for a number of reasons and the safety factor I used in that allows the assembly to withstand any forces that could ever be applied to it, short of a major wreck. The sizing still allows a common oillite to be substituted, but all my testing and experience shows that it's just not needed.

Friction is pretty much zero. You can turn it by hand then the links are removed.

[CRead01]

poly doesn't sound too bad to me but what about delrin as an option?

[modular93fox]

check out this kit, pricey but looks super clean and extremly strong:

http://www.totallypolished.com/watt's_link_kits.shtml

clint

[JRouche]

Why do you say that? Worst case you have about half the vehicle's weight applying a load to that pin in a 1G corner, so you're only looking at about 1600-2000lbs there. That's not much at all.

When designing the watts linkage for our three link, we used poly for a number of reasons and the safety factor I used in that allows the assembly to withstand any forces that could ever be applied to it, short of a major wreck. The sizing still allows a common oillite to be substituted, but all my testing and experience shows that it's just not needed.

Friction is pretty much zero. You can turn it by hand then the links are removed.

I was under the impression there was a whole lot more load than that. And really, Im just working off of memory and some reading, not any real data of my own. Ok, well cool, guess poly will work. Some delrin AF might be just as nice. For sure I know the bearings I have will work and they are just as inexpensive as poly. But like I always say, there are many ways to get a suspension to work. All great ideas here.

I have dealt with poly on control arms and noticed there is a break away friction while under load. Once its in motion then the friction seems to diminish. But the "stiction" factor seems to be there. If it will cause a jerky motion during driving, I dont know. All sounds good.. JR

[JRouche]

check out this kit, pricey but looks super clean and extremly strong:

http://www.totallypolished.com/watt's_link_kits.shtml

clint

That is a good looking watts link. Only thing is its a rear end mounted pivot. Rear roll center is moving with the ground. Changing RC. With a frame mounted pivot the RC stays consistent to the center of gravity of the car, not ground level. So now you only have the front RC moving slightly in relation to the CG instead of both ends. Rear end mounted pivots are more common than frame mounted, maybe due to packaging issues. They do have a good looking product though huh... JR