Positive locking for sphericals [Archive]

MalcolmG

06-19-2008, 12:15 AM

Staking sphericals works pretty well, it's certainly the lightest and probably easiest method, although you have to make sure you get your staking forces right or you can have them fall out and/or bind up. Apparently some manufacturers don't recommend staking (as we've found with some metric sphericals we've been trying to get), although I can't imagine why since that's surely how they're secured into rod ends.

The down side is that generally once you've staked a spherical into a housing, that housing cannot be reused (unless you're a rough @#$%), so if it's welded to a wishbone then your wishbones become a replacement item

Brett Neale

06-19-2008, 12:27 AM

We've used circlips on our outboard wishbone sphericals for the last couple years, and a small steel cap on the inboards last year. Both worked well and were replaceable, but they're going to staked all round this year because of weight and rigidity. One problem we thought may affect our circlipped sphericals was possible deformation from welding, but it didn't seem to affect any of the housings.

Fil

06-19-2008, 01:33 AM

with the staking, make sure you make your holes are to the manufacturers spec, especially the chamfers that they recommend, i had a spherical unstake itself because the chamfer was too small and didn't seat properly. We used ANC 4TG sphericals from aurora for inboard staked sphericals, the catalogue gives you all the specs you need including the staking tool.

The other way to do it is using a bearing cup with a shoulder on the upper side and a snap ring on the bottom side, to hold the bearing in. This is heavier, but you can replace the bearings if your careful. With welding the cup to the wishbone, it would be best to do post heat treatment machining to get the tollerances correct.

We use bearing cups on the outboard ends of the wishbone and staked bearings on the outboard ends. We stress relieve the wishbones in their jigs and then machine the bores to suit.

Otherwise you can do what WA do on their front upper inboard wishbones and stake your bearing into the mount and use a clevice on the wishbone to pickup the bearing. This is a really nifty way of doing it.

murpia

06-19-2008, 02:16 AM

I am a big fan of the concept of staking sphericals into small machined inboard brackets and the camber / toe bracket outboard.

Wishbones are much simpler, just requiring simple clevices.

Only the lower outboard joints might be better off the 'traditional' way.

Regards, Ian

John Grego

06-19-2008, 09:35 AM

If you get your tolerances right then a good press fit works as well. We staked most of our bearings but we found out that some of the ones we needed had a 6 month lead time! So we got traditional ones and considered making a staking groove in them. We ended up just tryin a press fit since the tolerances were exactly what the bearing manufacturer specified. We had no problems with slop or bearings backing out. However, it did make me a little uneasy...

Austin B

06-19-2008, 10:53 AM

We used tie-rod ends (not in bending) on all of the inners, except the front uppers where we used machined brackets attached to the chassis. All of the outboads were clevises, with the bearing press fit into a part of the upright. This upcoming year I think we are going to go with the chassis-mounted brakets all around, for better adjustability.

http://www.columbia.edu/cu/sae/car/12.JPG

Drew Price

06-19-2008, 11:23 AM

Austin,

Just in case the judges ask, inboard threaded rod ends are in a little bit of bending during braking and acceleration - remember the shear load input at the outboard side.

This load is pretty small compared to the axial loading, and I neglect it during the design phase (for strength considerations anyways), but it's still there.

Best,
Drew

Jon Oneill

06-29-2008, 11:26 PM

Thanks again guys.
We'll be going for staked sphericals as well.
We were looking into surclips but it meant the wishbone ends doubled in size. Thus more weight.
Never even thought of staking them.

Where did you all get your STAKING tools from? We cant find anything in OZ.

Thanks again.

Fil

06-30-2008, 12:16 AM

The staking tool is usually in the bearing catalogue. you have to make it yourself.

http://www.aurorabearing.com/Files/aurora-bearing-technical-data.pdf

on page 12 there is a drawing of the staking tool for aurora bearings. We make it out of silver steel and then anneal it.

JamesCH13

03-03-2009, 01:38 PM

You do not have to make the staking tools yourself, I got a set of staking and finishing dies from High Performance Vehicle Engineering for $170 shipped.

I staked in Aurora HAB-5TGs into a 6061 bearing housing @ 10,000lbf using the HPVE staking and finishing dies. when i tried to press the bearing OUT of the housing the bearing's liner failed a little bit above 3,000lbf but the race was still staked into the housing.

RacingManiac

03-03-2009, 02:05 PM

we staked the inboard bearing into welded post machined housing on the a-arms, with a bit of green loctite to give it some insurance. Staking tool was really just the closest sized sockets with a manual press. Outboard we have machined housing(again post-machined after welding) with smalley spiral retaining ring..

Drew Price

03-03-2009, 02:46 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Staking tool was really just the closest sized sockets with a manual press. </div></BLOCKQUOTE>

!!!! http://fsae.com/groupee_common/emoticons/icon_redface.gif http://fsae.com/groupee_common/emoticons/icon_redface.gif http://fsae.com/groupee_common/emoticons/icon_redface.gif !!!!

Best,
Drew

Pennyman

03-03-2009, 10:50 PM

We're using snap rings this year to retain our sphericals. So far they work well and the bearing cups that weld to the a arms weren't too hard to make. Hardest part was cutting the snap ring groove.

RacingManiac

03-04-2009, 06:57 AM

@Drew:

7 cars that I've seen and 4 that I've done myself and it worked for all 8 a-arms every time....http://fsae.com/groupee_common/emoticons/icon_wink.gif

Never had a single bearing poped out on me neither....

Drew Price

03-04-2009, 12:52 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RacingManiac:
@Drew:

7 cars that I've seen and 4 that I've done myself and it worked for all 8 a-arms every time....http://fsae.com/groupee_common/emoticons/icon_wink.gif

Never had a single bearing poped out on me neither.... </div></BLOCKQUOTE>

Cool. Sure beats shelling out the $170 or whatever for the tools, or spending 3 hours on the lathe making up a set.

I may try something quick like this, I'm a lot more comfortable pressing against a retaining shoulder to take axial loads from push / pull rods, but they are a royal pain to machine.

I have thought about making up a reamer with most of the guide chamfer removed so it could go right up against the shoulder, but like everyone knows, time is always the problem.

Best,
Drew

harshitr2

02-01-2016, 01:35 PM

Bumped into this really old thread, but got to ask this question. We've been machining a grove for a snap ring on one side and a shoulder on other side of the housing for sphericals for both our Baja and formula cars, and we've used bearing sizes right from 1/2" to 8mm bores. But we've always faced this problem of our snap rings rubbing the bearing balls (see the image). We've used the high misalignment series from Aurora. Has anyone faced this issue? The interference has been really small, and grinding the snap ring just a little (near the circled zone) has been a quick fix. I have always thought of staking the bearings in future, but since many teams are taking the snap ring route, I thought it was worth asking!
989

Adam Farabaugh

02-01-2016, 02:12 PM

This is not a solution to your problem, but for all the teams that use snap rings: how do you avoid slop in these joints? Do you shim each and every one of the bearings against the snap rings into the housings? I guess slop here may not be the worst thing (doesn't affect control arm length that much really) but just seems very sketchy.

Grinding away that part of the snap ring very likely makes it difficult to remove the snap ring right? Is the snap ring method easier for you to manufacture? Or do you do it so you can remove the bearings and re-use?

jd74914

02-01-2016, 02:13 PM

We had the same issue with similar circlips and would also grind off the innermost region of the tab to prevent interference.

Our final solution was moving to staking. Staking is really easier once you make the staking tool since you no longer need to machine inner groves, use snap rings, and can reduce the flange thickness (biggest advantage for us).

jd74914

02-01-2016, 02:15 PM

harshitr2

02-02-2016, 12:37 AM

Grinding away that part of the snap ring very likely makes it difficult to remove the snap ring right? Is the snap ring method easier for you to manufacture? Or do you do it so you can remove the bearings and re-use?

Yes, it makes installation and removal of the bearing a little messy, because the snap ring interferes with the ball on removal and installation. And yes, snap ring method seems easier for us. There are a few members in our team who have become very proficient in machining snap ring grooves! Also, as others have said, the control arm becomes a replacement part once bearings are staked. Non availability and non familiarity with staking tools is also a reason.

J-rob68

02-02-2016, 08:41 AM

You can always use spirolox retaining rings as an alternative to snap rings if you are having clearance issues. Check the link below for more info. We use these in our production control arms and camber plates.

http://www.smalley.com/retaining-rings/spirolox

harshitr2

02-03-2016, 12:19 AM

Those might be the way to go, Jason, spiral retaining rings. Thanks for your inputs!

darges

02-03-2016, 12:26 PM

I'll just add that we have used those spiral retaining rings for years on our chassis side bearings. They're a little difficult to get in, but using a thin razor blade usually makes the affair simple. They can be found pretty easily from suppliers like Grainger too.

02-03-2016, 06:50 PM

Why you students always over-complicate things?

http://www.chinafastener.com/ImgStd/DIN/StdPic/7993-2.gif
(Obviously, they also work in internal grooves.)

"Round-wire circlips (or snap-rings)" are so simple you can make them yourself. Just some stiff (= high-ish tensile) wire wrapped around a round bar of appropriate diameter.

Or you can use softer wire (eg. galv. med-tensile fencing wire) and press it into the groove in such a way that it gets riveted in there for a semi-permanent fit (use small drill and "pick" to undo). This also removes any play of the spherical in the housing. A drop of Loctite also helps.

Z

J-rob68

02-03-2016, 09:57 PM

Yes lets manufacture parts for simplicity rather than purchasing readily available, engineered and tested parts with shear data already provided ;). All good infor here though and certainly could be an interesting piece to work with for some of the freshmen engineering students to apply some basic hand calcs and make parts for the car. But when time and rescources are extremely scarce in the fsae world I think its a bit silly to waste time on those sorts of things.

I think its great so many different options have been shown here, I always made a huge point to take as many pictures of different applications at competition so that I could brainstorm and utilize the best of each design as I saw fit. Personally Im a fan of staked bearings if you have the machining capability to knock those out quick enough and with the proper tolerances. This saves you quite a bit in overall part count and surprisingly a chunk of weight too. cool ideas guys.

Swiftus

02-04-2016, 01:14 AM

...staked bearings if you have the machining capability to knock those out quick enough and with the proper tolerances...

If the car needs to get back out on track ASAP, a screwdriver and a hammer do a mighty fine job of staking a bearing for a day.

MCoach

02-04-2016, 11:08 AM

...staked bearings if you have the machining capability to knock those out quick enough and with the proper tolerances...

You mean this isn't a freshman project at other schools? This is usually one of the first things that team members were introduced to. We never have had a staked bearing assembly fail. However, from several cars that were around from before my time, I have had sphericals fall out of the buckets into my hand while working on them due to improperly machined or worn out circlips, grooves, and/or buckets. As JD pointed out, they're supposed to be press fit in the first place. What are you trying to save my recycling sphericals or control arms?

acedeuce802

02-04-2016, 12:16 PM

You mean this isn't a freshman project at other schools? This is usually one of the first things that team members were introduced to. We never have had a staked bearing assembly fail. However, from several cars that were around from before my time, I have had sphericals fall out of the buckets into my hand while working on them due to improperly machined or worn out circlips, grooves, and/or buckets. As JD pointed out, they're supposed to be press fit in the first place. What are you trying to save my recycling sphericals or control arms?

This. Buy stock at the proper OD, get a good carbide drill that's slightly undersized, and a good reamer to make a 0.000" press, but ream after welding. Then a countersink bit and some kind of depth gauge to double check. Be conscious that reaming will make the countersink smaller. Once we got the proper tooling, the operation took 5 minutes per part. The only axial spherical failures I've seen were the ball popping out of the race before the stake let go.

02-04-2016, 06:34 PM

Yes lets manufacture parts for simplicity rather than purchasing readily available, engineered and tested parts with shear data already provided.
...
But when time and rescources are extremely scarce in the fsae world I think its a bit silly to waste time on those sorts of things.

Jason,

Do you honestly think it is quicker to order circlips, ... and then wait ? weeks for delivery ... rather than just wrap some wire around a round bar? No wonder progress in FSAE-land is so glacially slow. (Methinks too many students think a hundred hours spent in front of the computer screen is better use of "scarce time and resources" than one hour spent in the workshop!)

But most amusing in the above quote is "... engineered and tested parts with shear data already provided". I would love to see the utterly useless calculation that used such "shear data". Or the justification for spending the time to do such a calculation. And with said calculation probably done to at least 5 significant digits! Grooaaann.....

Z

https://s-media-cache-ak0.pinimg.com/736x/19/67/2e/19672e6ca01a96ab2cd53d5277545020.jpg

JT A.

02-04-2016, 08:29 PM

Z, you're on the wrong forums if you want to groan about kids not spending enough time in the workshop.

And the logical thing to do would be to order some circlips before you need them, then work on other things in the meantime. If you planned ahead, they'll be there when you need them with no time wasted. That is obviously faster and more productive than making your own hardware/fasteners when they are cheap and widely available, then STILL having to make all the other parts. You know that, but you like arguing for the sake of arguing. So keep beating up your dumbed-down strawman arguments. Nobody is claiming that waiting until the day they need parts, ordering them in the mail, and then sitting around doing nothing until they get there is an efficient use of time

Kevin Hayward

02-05-2016, 01:57 AM

Machined steel key rings work well as retainers. They come in a variety of convenient sizes and it is a quick job to modify them on the lathe.

Living in Perth (the most isolated major city in the world) there is often no chance that a part can be quickly sourced, or sometimes even sourced in any sort of decent time. One year we had no retaining clips for the diff stub shafts, making the incorrect assumption that we could source one within a few days. We came up blank after contacting/calling/visiting just about every place in Perth that would sell them. As best as we could tell the nearest one was overseas and would take much longer than we could wait.

In the workshop there was a large box full of University key rings that were about the right size. Car ran for years without any problems from our key chain machining job. It was such a quick job on the lathe that we ended up making a few more retaining clips that way as it would literally take longer to pickup the part or organise it to be delivered.

Interestingly we had a similar problem sourcing CV boots that year, and since then have made our own which has saved massive amounts of time and made for better designs.

...

Living in the US for a while was an eye opener. Just about everything could be had at any time for almost nothing. Not everyone lives in an environment like that.

Kev

J-rob68

02-05-2016, 11:34 AM

Interesting perspective on lead times for each location Kevin! I think we Americans are spoiled. Most fsae teams can get parts within 2 days from McMaster. Everyone has different resource levels and hurdles. I will say that tolerances are pretty important in these systems if you want to avoid compliance. Luckily even long lead times can be accounted for if you have all your deadlines and purchase times in order. It's nice when everything shows up exactly when you need to for quick build times.

BillCobb

02-05-2016, 05:30 PM

There are 2 Tractor Supplys, a Grainger, 2 John Deere Ag-Line dealerships and a Kubota dealership nearby me that stock all of these parts in bin boxes and bags. Look for non-traditional sources other than 'racing supply' shops. You'll save some money, too. For the same matter, a decent auto junk yard with ATV, UTV, snowmobile, lawn tractor, CUT, SCUT and UFO scrap is a handy source, too.

Isn't that what "Junk Yard Wars" was all about ?

Kevin Hayward

02-06-2016, 08:40 AM

Bill,

We have one decent 'racing supply' shop in the city, which would be considered very small by American standards. Most of the decent suppliers in West Oz cater for mining or agricultural. Most commonly held sizes tend to suit much bigger machinery and there has been a worrying trend of companies holding less stock and counting on flying it in from Melbourne. We had a fairly long running mining boom that had some interesting effects on related and even non-related industries in our state. Basically if it wasn't needed to dig dirt it wasn't stocked anymore, and non related industries experienced a skills and knowledge drain as it was siphoned by FIFO (Fly-In Fly-Out).

Difficulty in sourcing parts and materials has developed a bad habit where I tend to drop in on any interesting supplier I might see on random trips, much to the consternation of my wife and kids! Nobody told me before becoming a father that children were more interested in ice-cream than checking our a new brand of molydenum disulphide grease. Kids these days ...

Kev

harshitr2

02-06-2016, 12:01 PM

Agreed with Bill and Kev. When Racing shops are in discussion, i'd like to put in some thoughts. I'm from Kanpur (India). We have NO racing supply shops not just in our city, but in the whole country! We don't get decent quality spherical bearings, ball joints (FS/Baja size), rod ends, flaring parts, etc in India. We order our yearly stock of such things from USA. I have seen team members drooling on parts offered by stores like Summit Racing and McMaster. But yes, people have learnt to source most of the things from local stores, which stock things for agricultural and industrial machinery. We had an incident when we were searching for aerospace safety lockwire, they haven't heard of anything like that before. Then when we told them the SS grade and gauge of wire, they got us the wire! Same happened when we searched for stainless steel brake line tubing in our city, no luck. We gave them dimension and material and tubing type, and they sourced us the tubing locally!

02-06-2016, 08:08 PM

...the logical thing to do would be to order some circlips before you need them,...
If you planned ahead, they'll be there when you need them with no time wasted.
... obviously faster and more productive than making your own hardware/fasteners ...

... dumbed-down strawman arguments.

JTA,

"Strawman arguments" huh? Reread this thread, and see that Harshitr2 followed your advice above, and it FAILED!

"... we've always faced this problem of our snap rings rubbing the bearing balls...
... grinding the snap ring just a little ... has been a quick fix.
... it makes installation and removal of the bearing a little messy, because the snap ring interferes with the ball on removal and installation."

I repeat that when you students (yes, all of you who have "been nowhere, done nothing"!) realise that Engineering is NOT about sitting in front of a computer screen ordering trinkets from the McMaster's catalogue, but rather that it is about the NEVER ENDING quest to find new ways of making things that actually work better than the old junk, then maybe we might start seeing some interesting engineering getting done.

Who knows, maybe even some faster FSAE cars in 2016?
~o0o~

Harshitr2,

Every half-decent workshop should have a box of "miscellaneous small springs". A quick rummage through that box should find you a suitable sized spring to make "round wire snap-rings".

But my currently prefered solution is still this one (from earlier post).

"Or you can use softer wire (eg. galv. med-tensile fencing wire) and press it into the groove in such a way that it gets riveted in there for a semi-permanent fit (use small drill and "pick" to undo). This also removes any play of the spherical in the housing. A drop of Loctite also helps."

None of the "circlip/snap-ring" methods eliminates the play of a spherical in a slightly oversized housing (although Loctite helps). The "mild-steel wire" approach above eliminates ALL play, as well as providing very positive retention. It requires a small workshop press (10 ton at most) and a home-made tool to do the pressing. And some engineering ingenuity to figure out the little details...

Z

PS. And if, when you students eventually become "Engineers", you are not continuously improving the prior-art, then...

http://i1095.photobucket.com/albums/i478/jicorrila/hoser_zpse571164c.jpg

:)

BillCobb

02-06-2016, 08:42 PM

Mentioning molydenum disulphide grease just brought back a distasteful memory from the past. Girlfriend brought me home some strawberry jelly filled donuts and offered me one while I was out servicing the hay equipment before mowing. Seeing a blob of bright red stuff on my nice & clean white T-shirt, I swiped it into my mouth expecting it to be the fresh drippage from a Marv's freshly sugar powdered jelly filled deep fried still warm donut. But instead, it was zerk drippage.

It's blueberry or else nothing for me from now on.

BillCobb

02-06-2016, 08:50 PM

What about eBay ? I buy a lot of rod ends, springs, swivels, stainless tube, welding rod, saw blades, ag and windmill parts from various suppliers. How's your, UPS, FED-EX, postoffice connection? You are closer to Hong Kong and China than I am.

harshitr2

02-07-2016, 12:26 AM

Ebay India has poor automotive stock. Although they have all kinds of stuff for ricers! Rodends from china, umm... may raise concerns on quality. SKF rod ends are available locally, but we've never used them because of inferior quality. UPS, FedEx have really good service, but it's the customs department which gives us the pain. About anything can be sourced from any corner of the world within a week till it reaches the custom office, then it takes another week for them to clear it up! Anyways, as I said earlier, people have learnt to source things locally. We know shops at a distance of around 15 km from our workshop, which can fabricate ANY kind of springs in few hours. Hardware is super easy to source, fasteners, saw blades, welding equipment, pneumatics, hydraulics, etc., again from heavy machinery and agricultural stores. It's the racing equipment that isn't available, only OEM parts are available. This year, we ordered a 3/16" flaring dies from summit racing, worth $1.2 each, and paid $120 for shipping!