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Greetings,

I have two project cars, a 33 16V in build and a 'sud tarmac/race car awaiting a full built from scratch. (Check out my 16V rebuild thread in the boxer section for progress). I have a set of Brembo 4 pot calipers from a late model GTV - unfortunately they will not bolt straight on to the original hub carrier and it doesn't look like custom adaptors will work either - I need to construct a hub carrier from scratch with the correct caliper offset to suit the disc.

I've spoken to an auto compliancing engineer about doing this, and there is no problem as long as the material used is strong enough and machined correctly. I don't have access to CNC gear but I'm considering using emachineshop.com or Autocad and simply providing the DXF file to a local machine shop. I have the skills to accurately measure the stock hub carriers and calculate the correct offsets, caliper bolt pattern etc.

So here's hoping there are some machinists on the BB that can provide me some advice on this:

- What material should I use? Aluminium or steel?

- What grade of aluminium or steel should I use?

- What tolerances do I need to take into account to allow for the correct fitment of the stock wheel bearings?

- Anything else I need to consider?

As both the 33 and the sud are using the same suspension set up I'll have 2 sets of carrier hubs made.

Any comments appreciated!

~Benjamin
 

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- What material should I use? Aluminium or steel?

- What grade of aluminium or steel should I use?
I'm looking at doing something very similar. If I do do it, I'll be using K1040. 4130 Chromolly would also be very capable.

- What tolerances do I need to take into account to allow for the correct fitment of the stock wheel bearings?
Measure the hubs accurately down to 0.02mm and replicate those dimensions.

- Anything else I need to consider?
Radius perpendicular intersections :p. When going from the area that contains the bearings to the flange that the wheel will bolt onto, make sure that you use generous radii to keep stress at bay. It also make assembly easier if there are decent chamfers for the bearing race bores.
 

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Do you have a picture of what you're trying to replicate? You'll want something better than Verniers to measure the bearing bores. I'd guess you'd want about .0005" / .013mm interference on the bearing diameter.

Duk, is K1040 anything like K1045? If so, I didn't think it was all that great? What are your thoughts about bearing race interference?

Scott
 

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Duk, is K1040 anything like K1045? If so, I didn't think it was all that great? What are your thoughts about bearing race interference?

Scott
I believe that they are related, but I don't know much about materials. I ask my boss if he's ever around about that stuff.
I suggest K1040 because it gets used to make large drive shafts for rolling mill roll lines, it's nice to machine and I trip over pieces every now and then from 'retired' shafts.
It's heat treatable, too.

As for bearing race interference, I'd just accurately measure the original and replicate those dimensions. Without some reference material to help me determine what sort of fit (probably a heavy transition/light interference fit), I think that'd be the wisest choice.
 
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