Hub question.

[Sentara]

So everyone.

How hard do you all think it would be to make wheel hubs which would make mk2's run 5 lug sawblade offset?

I actually know the answers, just wondering what you all think.

[dogstar]

depends on what type of equipment you have, and how much time youve got.

to make hubs, a lot of material and quite a bit of machining time, to make spacers, not much of either.
difficulty is just a matter of how well the design is done, could be very easy or very hard.

[Supra_devil]

i've seen pics of people that remachined mk3 hubs to fit a mk2, not sure of the work required for the rears, but the front was probably "fairly" straight forward. part of the pita is making brakes fit afterwards.

adapters can be made but that has its own problems.

[Sentara]

What kind of material?

[dogstar]

good shit... stainless if you can afford it.
dont remember codes, but tool steel might be a good idea too.

[Sentara]

Hey dogstar, do you actually know what you are talking about? No offense man bad from what I gatherd both of your choices would be dangerous, in my opinion that is. What did you get this info from?

A good friend of mine thought it would be a great idea to machine several driveline components using 17-4ph stainless. It's a precipitation hardening stainless of higher quality than 300 series stainless which is most common. The result, it was fine in the summer but come winter, the components started to crack!

Tool steel is ductile and soft, but gummy, before heat treating that is. That's what you do with tool steel most of the time, heat treat it to achieve it's positive qualites. After heat treating it is damn hard, not something you would want for a hub.

Stock hubs are made of a low carbon shit steel, soft, very soft. I tried to get a hardness reading from one and the damn thing would not even register, under 15 rockwell.

So, after talking to people like Jody at pat's driveline, my boss, other co-workers, the end decision [one that is an uprade in every respect over stock] is to use a molybdenum chromium steel, such as 4140. Not to exspensive, nice to machine...

Of course this could all be bs, but I think I'm right? ha.

[dogstar]

well, most of my information i got from my boss, who is old and english is not his first language...there may have been a miscommunication, or i explained what i was asking poorly.

stainless shouldnt crack in winter, if that was common i dont think it would be so widely used in the aircraft industry.
i actually spoke to some gents at acorn welding recently on a different topic and they said stainless is used in their applications because of the heat extremes it needs to be able to handle.
granted the material they use does contain small amounts of titanium, i would imagine that has something to do with its properties. (it was 321 iirc)
i would suggest that your friend chose the wrong grade of material for the purpose, rather than saying that "stainless steel" was the problem.

and yes, tool steel does need heat treating, so why not treat it to the hardness thats required?????
im not sure i understand the problem, lol.

as for whether your right or wrong, machine the hubs and find out.
if you already know, why bother asking

[Sentara]

[quote="dogstar"]well, most of my information i got from my boss, who is old and english is not his first language...there may have been a miscommunication, or i explained what i was asking poorly.

Perhaps.

stainless shouldnt crack in winter, if that was common i dont think it would be so widely used in the aircraft industry.

Yes you are right, I should not make such blanket statements. But stainless comes in many different conditions, The kind he used was actually 17-4 1100..Very brittle when it get's cold. NOT the right stainless to use [ it is also a good **** stainless]


i actually spoke to some gents at acorn welding recently on a different topic and they said stainless is used in their applications because of the heat extremes it needs to be able to handle.
granted the material they use does contain small amounts of titanium, i would imagine that has something to do with its properties. (it was 321 iirc)

Makes sense.


i would suggest that your friend chose the wrong grade of material for the purpose, rather than saying that "stainless steel" was the problem.

Again you are right. I know feel foolish.

and yes, tool steel does need heat treating, so why not treat it to the hardness thats required?????
im not sure i understand the problem, lol.

I think you mis-read Barry, It ISN'T hard, hence no heat treating needed.

as for whether your right or wrong, machine the hubs and find out.
if you already know, why bother asking

Ouch, that hurts. I've turned the blanks, the other tricky part is hitting the .0003 tolorance in the bore. Why bother asking? To get replies, and to learn. Seems to have worked :lol:

[dogstar]

didnt mean to sound quite so harsh, but im blunt like that :)

and meeting the tolerance shouldnt be too hard ;) cmon, get that cnc machine tuned up
if my 13 year old laser can hit 1 thou tolerances, a mill/lathe should be able to do better :)

[Sentara]

No problem man.

Curious. What sort of application's are you hitting these .001 tol's on. I am laser ignorant.

Just so you know, I'll hit the size on the manual. It would be kinda silly to do on an cnc in my opinion, unless your making a hundred or something like that. Just creep up on it.

[Supra_devil]

i can't speak for him but i do remember him mentioning headgaskets, and i've seen some of his works that were very precise and required tight tolerances.

Also, you have the kind of facilities that others don't. is this a project for you only or is this something that you can do for others once the project has been figured out?

the mk3 sawblades are 37mm offset
by using z31 300zx front hubs with stock mk2 supra bearings and the 300zx dust seal you can run 5-bolts in the front. the offset needs to be increased(which the mk3 is more than the mk2, stock mk2 rims being 8mm iirc).

The rears you can order toyota crown (iirc) hubs from aus. i know of a guy with some available. they bolt in using stock hardware.

To increase the offsert for the rear without looking funny you can use a spacer or adapter to push the wheel out.

Now i just mentioned yet another way to do this. An adapter plate can be made very easily with your facilities, a 4x114.3 to 5x114.3 adapter. this will also push the contact face out and thus require higher offset wheels, again mk3s run higher offset. a 30mm adapter would do the job nicely.

http://groups.msn.com/_Secure/0QgANAyQTT3q6bIc89VsAe8iyaUzNazhV1!0YO07NBZygjHCMs X89H*HZt9TpaRG!PIGmsEVVTBTd!Bb8wsLJbuPFZDnH5ayn2Sl tPjj0Dgo/offset.bmp?dc=4675531776909180109

these numbers are not exact but it gives you an idea of the offset differences between stock and mk3.

[dogstar]

tolerances that tight.... mostly just for fun, and cause we can.

we made some signs/logos for Triple S performance, the leg of the letter N was about 7 thou thick, i decided to shave it to 5 thou on the next piece. :)

CNC being silly!!! grrr.. lol
my opinion is that if you can make the computer do the hard work, then why not :)
at least that way you know that once your programming is done, then you set it and let it go, should be able to duplicate 2 perfect hubs with no problems.
and yes, you can do it manually, but i dont like working that hard.