HELP CENTRE NUT

[B.A.]

Greetings,

Does anybody know what is the right thread that i should use to an aluminium centre nut??

Tks in advance,

B.A.

[B.A.]

Greetings,

Does anybody know what is the right thread that i should use to an aluminium centre nut??

Tks in advance,

B.A.

[Fyhr]

A left hand thread on one side and a right hand thread on the other? http://fsae.com/groupee_common/emoticons/icon_confused.gif

[Chris Allbee]

more than happy to help: 1/4 - 28 UNF.

Seriously, the FIND button has a wealth of information behind it....as does your nearest engineering classroom...

[Jersey Tom]

I found a 1/4-80 (no joke) tap in the back of the shop once. That might work.

[JR @ CFS]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Fyhr:
A left hand thread on one side and a right hand thread on the other? http://fsae.com/groupee_common/emoticons/icon_confused.gif </div></BLOCKQUOTE>

Just make sure to get them the right way around http://fsae.com/groupee_common/emoticons/icon_wink.gif The nuts should always be tightened in the direction of the rear of the car. Braking torque is larger than the accelerating torque, therefore if you set them up this way, the torque acts in your favour to tighten the nuts rather than losen them off.

We currently use a centre nut, but are seriously considering moving away from this solution!

[Jersey Tom]

I'll chip in seriously.. we ran 1 1/4-18 UNEF hub threads. 4130 Rc35 hubs, 1144 centerlock nuts. Worked fine other than the hole in the wheel center being too small to use Goodyear's tire mounting machines (1 1/2 to 1 3/4 diameter).

I was considering running RH / LH threads, but went with RH all around instead. If the hub threads got damaged, at least I had a 1 1/4-18 adjustable die I could run on em to clean em up without having to unpress the whole assembly and throw it on a lathe with a threadfile.

Castled the nut, drilled the hub and put a clevis pin through it when torqued. No way its gonna back out.

Bout every other time I torque the wheels I clean the hub threads (and rest of the upright assembly) with brake cleaner to get all the brake dust and grime outta there, then hit the threads with a spurt of Starrett M1 lubricant. Keeps everything happy. Torque to 75 ft-lbs, call it good.

[JR @ CFS]

That's a good point! Cleaning them is essential! Our removal and refitting procedure takes anywhere up to 1 hour after a full test day. Make sure to put a groove in each flat surface of the nut to allow you to inject some lubricating oil about 10minutes prior to removing them. For refitting, just follow the advice given by Jersey Tom. Although I would say, reading that, sounds like an awful lot of hassle over buying some standard parts for a mini cooper and putting them on there.

[Fyhr]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by jonnierice:
We currently use a centre nut, but are seriously considering moving away from this solution! </div></BLOCKQUOTE>

And we're running 4bolt and i'm considering a center nut...

We should talk a bit more when the competition is over http://fsae.com/groupee_common/emoticons/icon_wink.gif

[BenB]

Since the torque is transmitted through the studs not the nut whats the reason for using left-handed threads?

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BenB:
Since the torque is transmitted through the studs not the nut whats the reason for using left-handed threads? </div></BLOCKQUOTE>
Left-hand threads on the left-hand side of the car means the wheel stays on under braking if the pegs (studs) fail. Also the wheels decelerate more under braking than acceleration, so the inertia of the nut will act in the direction to tighten under braking.

Personally though, I think a right-hand thread all round would be fine given the positive locking requirements of the tech regs.

Regards, Ian

[Jersey Tom]

Agreed. RH works just fine, especially if you lock it worth a damn.

The torque is transmitted through the drive studs, yes. But its not a slip or press fit for sure. There's some slop in there, and in theory I suppose you could have enough wheel torque to overcome the grab of the nut until the recesses on the wheel center lock up against the studs. In this case, running the different threads will tighten things up rather than loosen. Thats the theory at least.

[Mike Flitcraft]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by murpia:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BenB:
Since the torque is transmitted through the studs not the nut whats the reason for using left-handed threads? </div></BLOCKQUOTE>
Left-hand threads on the left-hand side of the car means the wheel stays on under braking if the pegs (studs) fail. Also the wheels decelerate more under braking than acceleration, so the inertia of the nut will act in the direction to tighten under braking.

Personally though, I think a right-hand thread all round would be fine given the positive locking requirements of the tech regs.

Regards, Ian </div></BLOCKQUOTE>

If the stud fails, it won't matter if the threads are left hand or right hand, the nut won't be there.

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike Flitcraft:
If the stud fails, it won't matter if the threads are left hand or right hand, the nut won't be there. </div></BLOCKQUOTE>
The scheme we are discussing is a threaded axle with a single centre nut, with a number of unthreaded pegs or studs to transmit torque from the axle to the wheel.

So if all the studs fail the wheel is retained by the centre nut.

(Courtesy of Atlas F1):
http://img101.imageshack.us/img101/2305/gp8gg5.jpg

Regards, Ian

[Fyhr]

Im not certain if this is valid for center nuts, but if you make a quick calculation for a normal 4 bolt pattern you will see that the friction at the contact surface takes up most of the torque. Unless you have a very small contact surface between your wheel and hub it should be the same for centerlock too.

[Mike Flitcraft]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by murpia:
The scheme we are discussing is a threaded axle with a single centre nut, with a number of unthreaded pegs or studs to transmit torque from the axle to the wheel.

So if all the studs fail the wheel is retained by the centre nut. </div></BLOCKQUOTE>

All I said is that if the threads on the stud that holds the wheel on fails, it doesn't matter if it is right handed or left handed threads, the wheel's coming off.