rear knuckle upper spherical discussion
 

since bob has convinced me not to go poly(that discussion can be found here https://www.miataturbo.net/race-prep...ushings-81552/ ), im going to start with sphericals in the rear upper. i was just going to get the ISC kit, but i dont like the idea of welding the retainer rings in. its really not a big deal, so i will if i have to, but is there a better way?

i was thinking of drilling through the knuckle perpendicular to the bore, and threading the keeper rings and then threading 2 screws through the knuckle into each ring to hold them in. something small like an M4 or 5. the same idea behind the grease zerks holding delrin bushings in place. i was even thinking of maybe threading the ID of the knucle and making collars threaded on the outside to clamp the bearing in. kind of the inverse of a shock body and its adjustable perches. i need to see if i have access to the right size tap before i could do that though, as buying a tap that size is prohibitively expensive for just this little project. yet another thought if the wall thickness of the bushing bore is enough, would be to drill and tap around the circumference and parallel to the bore, and make a cover plate, using spacers to hold the bearing in. you could ad a sealing element to the plate to keep water and junk out. its hard to describe and i cant think of an example.

got a better idea? i have a mill, lathe and welder, and 2 spare knuckle to experiment with, so just about any option is open.

my other question is what type of spherical is best for this application? standard PTFE lined? nylon lined? unobtanium lined? and since i can chose my own, would it be worth the effort to get one with a grease groove, and setup a zerk to keep it alive longer? those of you running sphericals, how long do they last you and under what conditions?

my rear upper knuckle bushings are so shot, i get a least 0.5 degree of camber change, and figured why go replacement rubber when i can be a baller.

discuss:

im bored out of my mind, so i made a highlighter cad drawing to help you guys understand what im talking about:
https://www.miataturbo.net/attachmen...ine=1417304871

and having thought about it, you would obviously only have to do this on one retainer, the other can be permanently welded in.
i think itrs pretty self explanatory but
pink is miata knucle
blue is the bearing
green is the retainers
screws are orange in the fist, yellow in the last pic (and they would be countersunk to avoid conflicts between them and the ruca)
retainer plate on the last one is orange

I would be tempted to use green loctite (bearing mount). That stuff is pretty strong but with heat can be removed.

I agree. Make a sleeve with a step on one end for the bearing to sit against and a groove for an internal snap ring on the other end. Press in sleeve with green loctite retaining compound and call it a day.

--Ferdi

i thought about retaining compound, i have 609 and 638 in the garage. i just didnt want to rely on that by itself to hold the bearing in. the static numbers look fine, im just not sure how it will hold up to repetitive shock loads. the sleeve idea is fantastic, much more surface area for the retaining compound and i can control the interference fit, snap rings make it easy. i could even pin one end of it for insurance. i was trying to think of how i could mount the upright in a 4 jaw and machine a groove into it as the snap ring idea occurred to me. using a sleeve didnt :rofl: . the only issue i can see, is with only a 1.5" bore, by the time the sleeve thickness is accounted for, your left with a smaller bearing. i need to run the numbers to see, but i think 1/8" wall would be plenty with a 0.060" ring groove, leaving me with 1.250" bearing. im sure that would be fine.

i got a chance to measure everything today. i was going to go with idea 3 (retainer plate on the end), but there is only 0.360" difference between the width of the upright and the width of the ruca. adding an 1/8" plate would reduce the amount of permissible misalignment. not sure by how much, or how much is needed, but i think that would be difficult. the thinest section of the bushing housing is also only 0.220", which doesnt leave room for a very big fastener.

638 is some good shit
https://tds.us.henkel.com/NA/UT/HNAU...ile/638-EN.pdf

4,200 psi shear strength and oil/hydrocarbon proof. i used it in the past to fix a wallowed out steering stem on my kawasaki.

i dont know why i have the 609, shear strength is lower at 2,290 psi

anyone have advice on which series of spherical to use?
http://www.qa1.net/rod-ends-and-rela...rical-bearings

I really think that the retaining compound would hold the sleeve in just fine. Though you could have the sleeve flanged on one end and use an external snap ring on the other.

If I remember correctly, 1.25" spherical bearings are not a common size. It will most likely be 1.1875", which would leave you with plenty of wall thickness for the snap rings. Plus, I think the bore is 39mm = 1.535", which gives you even more.

--Ferdi

:dunno:

https://www.miataturbo.net/attachmen...ine=1417485978

theyre actally 38mm, as this is the largest reading i get, its measures closer to 1.496 in other positions. ill look into sizes and hopefully order some bearings tonight. thanks for the idea ferdi. you are the winner.

Ah, I am sure your measurement is right. I had an ES bushing sitting on the table and it measured a tad over 39mm.

What are your plans for the other bushings? My plan was to use delrin or nyloil for all the others. I was being lazy and initially planned to use the ES bushing in the rear upper, but I do have access to a machine shop and could easily make sphericals happen.

--Ferdi

delrin, AF blend, or nyloil. i need to tackle this and some offset front uppers asap so i can get a decent alignment. i just got a new set of rivals and dont want to camber wear them like i did to my last set of tires. after that, ill think about the rest, but more than likely just delrin as AF bend is expensive and i havnt seen any feedback on nyloil. the lower control arms will probably stay rubber as i dont want to deal with binding, unless i get out of hand and try to stuff bearings in those too.

the ES bushings are always a little big so they press fit a little.

the installed diameter of the snap ring is what will determine everything. a 1-5/16" snap ring has an installed diameter of 1.396", so that leaves exactly 0.050" wall at the snap ring, which is fine if i make it a slight press fit.

i decided on that size based on this:
Internal Retaining Rings | Arcon Ring

they are 0.050" thick and i happen to have a 0.059" internal cutter.

1.3125" bearing. SS, PTFE lined, its supposed to be their best wearing bearing that isnt nylon based, we will see.
http://www.summitracing.com/parts/hal-sib10t/overview/

another thought is to make the sleeves 2 separate pieces, no snap ring groove machined at all. now make the snap ring 1.5" installed into the bore itself, probably using a 1-7/16", and using a 1.375" bearing. then press the 2nd sleeve in against the snap ring (maybe 0.002" short so its not stuck tight and impossible to remove) so the 2 separate pieces comprise the snap ring groove.

the 1-5/16" snap ring has a thrust load rating of 9,300lbs, which ironically enough is less than what i calculated to be 9,732lbs if i were to use just 638 on a 1.3125"x0.562" bearing race, let a lone a 1.5"x whatever"

Nice find on that bearing, if I decide to go this route, I'll most likely get the same ones.

--Ferdi

decent options in 1.375 for idea #2 as well
http://www.summitracing.com/search/p...SortOrder=Desc

Skip that bearing, unless you want to have to replace them all the time. Wait I take that back, looks like thats just QA1 re-selling the Auora SIB series bearing. I like the AIB because of the anti-corrosion stuff on the inside, couple dollars more money.

Here's what you do. You make a sleeve that is the width of the knuckle, one end is 1.125" diameter and set so the bearing is in the middle, then the width of the bearing is 1.3125, snap ring groove, and then 1.3125 to the end. Press that into the knuckle and drill some holes in the knuckle to spot weld the press fit sleeve to the knuckle. You'll also need to make aluminum spacers which fit inside of the 0.75" diameter of the spherical and have the ID of the control arm bolt (10mm?) and also have a taper cut on them.

Use Aurora AIB-10T.

Another option thats a billion times easier and cheaper but makes adjusting toe a HUGE pain in the dick. Put a solid aluminum bushing in there with a 10mm ID bore, and make 1 tie rods to replace the upper control arm with. This gives up camber adjustment at the top of the upright but also requires you to adjust the lengths of the arms when you change toe at the bottom of the car, and it should only fit with 60mmID springs at a max. You'll want to use AM-10T rod ends for this, and aluminum hex rod. If you really want to go this way I'll run the numbers and make sure you dont have to go to the AM-12T just to get the larger hex rods.

the AIBs are about half the price, and the sales literature indicates the SIBs to be "top of the line"...? it would make sense that a chromoly race would wear better though.

im not sure i want to go through all the hassle of tie rod control arms, but feel free to run the numbers for science.

Wonder if there is enough meat in the knuckle to just cut the top hoop off the knuckle and drill and tap for a threaded rod end screwed into whats left of the knuckle to replace the upper pivot point.

Threads in bending bob, dont do that. The press fit and tack with a spherical isnt all that difficult. I guess you could just press fit with green locktite, but you're really relying on mazda having held a decent tolerance on something they only ever intended a piece of rubber to press into.

its a machined hole, its within 0.001, not including the wear from 23 years on the road and years of autocross.

also:
"LOCTITE®
638™ is designed for the bonding of cylindrical
fitting parts, particularly where bond gaps can approach 0.25
mm "

agreed about the threads in bending mode, and it necks down substantially after the "hoop", so i dont think there is enough meat anyway.

I know that green loctite can do that. Do you want to try it? I realize the bonding strength, The wheel bearings on my FSAE car were held into the uprights with just a press fit and green loctite, no snap ring because lazy. It probably would be fine, and really even if the press fit + loctite failed its fully encapsulated in the control arm so you're not going to crash.

that was my thinking. i dont want to weld it only because it will be hard to reverse, especially if i plug weld it.

so i want to order the bearings asap. i haz snap rings and steel and lathe.

AIB it is? im not concerned with cost,(within reason) i want what will last.

Yeah wait, I got the different aurora levels mixed up. AIB and SIB are more or less the same but AIB has a alloy steel inner race and SIB has stainless. They're rated for the same so the weaker stainless doesnt have a down side besides price. Its up to you then. Just dont forget to get the one with T added to the end to get teflon liners.Dont forget to snag some 1" do 6061 round stock so you can make he spacers that slip over the bolt and inside the spherical.

I believe Leafy is also specifically talking about getting Aurora branded bearings. I've used them in the past and they are very good. I don't know how the QA1 bearings from Summit compare.

--Ferdi

i think leafy is right, they are just rebranding them. their part numbering system and engineering data are identical. where are you guys buying auroras from?

Yes. The QA1, based on the part number and specs could very well just be a re-badged Aurora. But for like $10 more is impossible to beat the ABWT series for NHBB, especially if you're going to be experiencing axial loads.

Have you guys seen the Maruha spherical bearing set? You can see how they install them in the arms, basically looks like they are just pressed in. They mention alignment issues and a jig they have to verify correct positioning of the bearing.

Full bearing ball bush/ Mazda MX-5 Miata

https://www.miataturbo.net/attachmen...ine=1417594642

http://i408.photobucket.com/albums/p...psc74414c1.jpg

This is the rear upright on my car, making a control arm change, but these work really well.

QA1's are definitely not Aurora. They're alright for the price, but just seem kind of cheap to me. I don't have personal experience running them, but our Baja team does without issue. I believe their spherical sizes are way over-designed, though. If your budget allows Aurora, I would stick with those. I believe it's the McMaster sphericals we tried also on our FSAE car, and they had a much much lower push-out force than the Aurora of the same size.

no american retailers that i could find. those do look great though. i dont have time to wait on an engrish email and shipping from japan.

where are you guys getting your auroras? i found some auroras on aircraft spruce, but not the AIB or SIB series.

Google says a company called motion industries sells them. I know I can get them through Kingpin Machine too.

I wouldnt drop the $1200 on the murahahas, thats more or less what it would cost you to have Kingpin Machine make you a set using auroras.

We get them directly from a PO through Aurora. Though, we get a student discount through them, and that may not be the best price at full cost.

bitchin
https://www.motionindustries.com/pro...p?sku=02056567

yea the mahuras are really pricey, but i figure i could afford 2, if i could find them.

Don't you know you're perpetuating a Miata stereotype by using PINK marker?! :rofl:

pink was intentionally used to illustrate the miata :party: im glad someone picked up on that :rofl:

now can anyone figure out why i used blue on the sphericals?


i called motionindustries, they drop ship from auroroa, ill have them wed or thursday next week. ill knock the sleeves out sometime between now and then, and hopefully slap it all together the following weekend.

hail sagan! but no

bearing are ordered, you know youre getting good shit when they ask if you need certifications.

You get the same stuff, but they can charge you more. :)

i know, all i meant was the product is probably of high quality if certs are offered for it. theyre for things that fly. $7 ebay sphericals do not offer certs.

someone at work specified certs for a 1/4 turn fastener on accident. so now we pay $12, instead of $1.50. im still trying to get that reversed as i just ordered $1200 in fasteners that should have only cost $150 :(

Yep, no reason to get certs on anything unless its required.

The worst case I have seen at work was with a certain PLT fastener. This fastener is identical in every specification to a NAS counterpart. The PLT's have a much more involved certification process though, and get the letters "PLT" engraved into them instead of "NAS". The NAS fastener is $3.90 each. The PLT is $64.50 each with a quantity discount when you order 10000 of them. Think of the money saved if our company would have gone with the NAS fastener, considering there are over 800 of these fasteners on one wing, and the company plans on making many, many wings over time.

And that phrase makes all the difference in the world.

but see, at least you work somewhere that has airplanes, so that mistake would be easy(relatively) to make. i work at the post office :giggle: our supply people are morons.

Haha, nevermind then. Unfortunately, it was not a "mistake" on our company's part. It was a situation where in a meeting they asked everyone to look for ways to reduce cost, so I did.

I found the PLT fastener price and said WTF, and began searching and found a direct NAS counterpart. When I presented the idea during another cost reduction meeting, a couple stress guys were opposed because "We have always used the PLT in this area", and therefore this idea was ruled out. We are literally throwing like $50k away every time we build a wing, because "That's what we have always done" :bowrofl:

Anyways, I just used this for an example of how certifications will drive an insane amount of cost into parts.

/Rant

Cert = you're basically guaranteed it's not Chinese shit knock off material...

I'll take my aeroplanes assembled with certified fasteners thank you very much!

Unless you're buying a part with a cert from china or india, forging a cert aint no thang there.

That is incorrect. You can get quality products from China and India. You just have to find a place with tight quality control. Generally that means you have to have someone on the ground there though to keep tabs on them.

i made a sleeve today, but forgot to snap a pic.

using MSP CAD, i made a drawing for those wanting to reproduce my efforts.

https://www.miataturbo.net/attachmen...ine=1417834812

That was kind of my point, you can get good stuff from china and india but you can also get parts that a crap with good paperwork.

That might not be a press fit. When I measured all my bushing holes before I sized my control arms they were all more or less 1.56 depending on how much the control arms had ovaled. I didnt measure the knuckle but I know the bushings are the same diameter, but its totally possible the control arms are larger or I've managed to stretch the shit out of mine. But before you cut the stock please double check the bore and make sure you're not catching a lip or something.

i measured at atleast 8 spots with a snap gauge. all within 0.002" of 1.496". but yes others should check theirs first an adjust accordingly.

May I ask, why a taper on one side? Will you not just press the bearing into the open end and use a snap ring to secure it? Is the taper necessary?

its just for aesthetics, it could just be a simple shoulder too as long as its cut back enough to clear the bolt and spacer under articulation.

That was what I was interested in. I wanted to see if you did it for the articulation. I am excited to see how this works for you, but I am also interested in your metric of improvement. Will you just be going by a "seat-of-the-pants" gauge or do you have data points that you will be comparing?

i made a pair of sleeves the other week, but i had a snap ring snafu and encountered dimensional inaccuracies from aurora. this cause a gap of about 0.012" between the bearing and snap ring. i was also using a small boring bar and things were chattering a little, wasnt happy with ID surface finishes. neither likely would have caused any issues, but im ----.

the bearing race width measures 0.560", aurora indicates 0.562". if you use the drawing above take note of that change.

made another pair recently that are picture worthy. i ended up going to 1.495" on the OD, as i didnt want a press fit into the knuckle. i find these spherical bearings to be sensitive to bore diameters, and 2 compounding press fits would have just been too difficult to control with any accuracy. especially when aurora install specs give a bore range of 0.0006". i made the ID 1.311", and its a nice tight fit.


this shows the one concern i had about the snap ring ears not clearing the ball. the drawing indicates a snap ring groove depth of 0.042 +/- 0.002. i went to 0.048" to help with clearance. there is 0.016" clearance between the ears and the ball as measured with a feeler gauge.
https://www.miataturbo.net/attachmen...ine=1419302795

https://www.miataturbo.net/attachmen...ine=1419302795

i love good rigid tooling. this was after a 0.050" depth of cut with a roughing insert, but finishing feed rates.
https://www.miataturbo.net/attachmen...ine=1419302795

at 1.495" its a perfect slip fit, went in by hand after sanding the bore clean.
https://www.miataturbo.net/attachmen...ine=1419302795

https://www.miataturbo.net/attachmen...ine=1419302795



this will be part of my suspension package as a whole. i dont think this one mod will make any appreciable difference in performance or feel compared to a bushing in good shape (maybe lewis hamilton would notice, im a mere mortal). currently i can grab my rear wheels at 6 and 12 o'clock while the car is jacked up and change the camber a degree or so with hand pressure; i pushed my bushings out with my thumbs. a new stock replacement bushing would have fixed that too, but i dont like the idea of a bushing cut to a taper (or crowned) to deal with articulation. this seemed like a more proper fix to me, and because race car.




(edit due to MT.net censorship: ---- = butthole-ish)

Very awesome piece. I look forward to your other components. I have a dedicated autocross car that I just put a full poly bushing kit into and am very unpleased with the binding. Even with zerk fittings and a very liberal amount of grease it is very difficult (almost impossible) to move the upper/lower control arms by hand when torqued.

How much to make a set? I would probably just weld the sleeve into the upright.

im so glad i took bobs advice regarding poly, thats exactly what i didnt want to find out the hard way.

im not sure ill have time to make another nice set, but ill see what i can do. do you want my "prototypes"? these do take quite some time on the lathe, so probably at least $80 for a pair, shipped. that includes the "good advice" discount. :party:

Do you do the inner spacer sleeve as well? I have been looking at just getting the ISC ones but I think yours look better engineered.

Miata Suspension

years ago I built some custom top hats for Koni shocks and used a very similar setup to convert NB top hats to sperical ball tops instead of rubber bushings. They worked very well till I upgraded to XIDA doubles amd sold them.

yes, i will be making my spacers this weekend or next week when i go to install the bearings. so if you want those too, let me know before i start so i can make 2 sets at once. adding those will be more $ of course. i plan on making them as simple as possible so tapers and such shouldn't be needed.

The ISC ones were $100 for the set both sides including bearings. I suspect ISC uses cheap bearings however and the way they did theirs is more cheaply done no snap ring groove etc.

ISC uses 4 simple rings, that dont need to be held to a precise tolerance. i could make those in 15 minutes and they would be $20 at most. if i was selling them as a retailer in large quantities, i would buy some 1.5" pipe, turn the OD with 1 pass, and knock them out for less than a dollar(at my cost).

my doohickeys requires 2 precision cuts, many features, and takes me about 3 hours to do a pair. send my drawing to a local machine shop(actually dont, theyd laugh at it), it will be much more than $80 for a small qty.

i talked to my friend whos an estimator and cad guy(he laughed at my drawing) for an aerospace machine shop. if i could get enough interest/group buy to justify writing a cnc program, the cost could come down considerably. im told ill probably need at least 15 people.

ISC is fairly permanent and difficult to R&R, the snapring way isnt, but is much more expensive if you dont have your own lathe.

pros and cons, you get what you pay for.

im sure ISC uses a 38mm bearing, which i suspect is a snug fit into the spindle but not quite interference. i cant comment on manufacturer or country of manufacture, but they are the steel on steel variety which is cheaper. you can see the grease groove in the pic on their site. the 2 PTFE lined aurora brand bearings i got were $84 to my door. you can get a steel on steel qa1 for like $11.

Your drawing's not that bad, I've seen worse. Theres no dimensional or geometric tolerances or surface finish callouts and the dimensioning itself is sloppy as fuck but at least its got all the dimensions you'd need to make it and the machinist wont have to do math.:sad2:

Ill take a set.

I've had first hand experience with ISC's Engineering and fabrication skills. not that impressed. I have their Swaybars the bar arms and front brackets are which are good, a bit heavy but the pillow ball bearings are way better than urethane and I hand to correct the bend the arms a bit to get fit as intended. the end links were cheap garbage and I could do a better job on the rear swaybar mounting brackets with a dull hacksaw. I think they freehanded them with a cutting torch and an angle grinder. I made my own end links with aluminum rod ends and aluminum hex bar stock. also re made the rear swaybar chassis mounts using 5/8" aluminum rod ends and re-made the brackets out of 1/4" aluminum dropping about a pond of weight.

Not trying to derail the thread but do you have a build thread or anything on this? That sounds interesting and I would love to draw from your ideas.