16 replies to this topic

[SubSandRail]

I am getting ready to do the 6 lug conversion, and wanted to make sure that I drilled in exactly the right spot. So I made this template that fits over the 4 lug hub, and has the 4 extra holes that are just big enough to put the tip of a pencil in to mark it. It is fiberglass and was made on a milling machine, so it just barely fits over the four lugs with zero slop.

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[Rossta86]

I am not saying it is not a good idea, but when i did mine, i just put a few pieces of masking tape in the right area, bolted the 6 lug wheel to the hub after i had knocked out two adjacent studs, and used a marker and a center punch to mark the correct spot s to drill. Came out great. im sure you are already gonna do this, but i would defiently use a drill press and not a hand held drill. Get a good bit too, the front hubs are some tuff stuff. If you can't find a 13mm or 14 mm tuff bit or whatever the studs are, a 9/16 weill work, u jsut have to weld the studs in from behind, or else they will spin in their bore. Plus with the weld u can fill in the uneven spots since the back on the studs do not sit flush on the front hubs. Maybe more info that u wanted or needed, but i remeber when i did mine i asked some questions but nobody really had any of the answers i wanted.

[SubSandRail]

I have been trying to decide whether to weld them on or not. I did it for my dune buggy, but it is not street legal and never gets up to highway speeds.

If the studs are hardened, welding could make them a little more brittle. I may build up the uneven parts of the back of the hub with weld then grind it flat.
Your method obviously works, but i like the idea of having less than 0.005" error on the stud placement.

I'm still looking for rear disk setup. Does anyone know if the hubs are the same, front '83, '84 to rear disk '85 to '89? It would be great if I only had to carry one spare hub that would work on any location.

[Adam N.D.J.]

The front and rear hubs are not the same. The front axle stub that goes into the hub is bigger than the rear stub.

[Qman]

I did it with the wheel as a pattern and it worked but I definitely like the pattern(template) idea. I think if you have access to machines a steel or aluminum one with steel inserts woulb be better. Reason I say this is the uneven surface on the backside of the hub makes setting up in a press dificult at best. Nice job though. I may have to get with you, I need to do another set.


Ken

[RXTurbo]

35/64's is the hole size.

The back of the hub really should be counterbored or milled flat for the stud to seat on.

[SubSandRail]

Qman,

The milling machine is for circuit board material, it does not handle metal. It is in a RF design lab. I do have a friend with a lathe, and I talked to him about building up the back of the hub with weld, then making it flat on the lathe before drilling the holes. The template is available anytime. The more use it gets, the better. Do you press out the unwanted studs or grind them off? If you press them out, do you fill the hole with weld, or leave it open?

RXturbo,

Thanks for the info on the hole size. I have not purchased the studs yet, but am hoping to find better pricing. So far the tire places want $4 or $5 each, whether they press them in or not. I have not talked to the auto parts stores yet.

[soobme]

My plan is to chuck up the hubs in the lathe and use it to scribe a mark through the center of the holes that are there. Then all I have to do is bolt it to a 6 lug wheel and I have the center of my marks in 1 direction allready all I will need to do is center punch the holes in line with the the holes in the wheel. After I drill them I think I will weld arond them and turn it flat agen in the lathe.

[Qman]

Welding the back is overkill. All you need is a flat surface to allow the studs to sit flat. Drill your holes and spot face the backside of the holes. It will leave you with the same amount of material as the stock holes have. I never even welded the "old" holes closed. I was going to but haven't gotten to it yet and have not had any issues to date. About a year on them now.

[RXTurbo]

You can face off the back of the hub using a 1" end mill held in a drill press... well if you have a press big enough!!!

Before I bought the mill I used to hold stuff in a tool post vice on the lathe and then hold the end mill in the 4 jaw chuck and take very light cuts...

[The Scooby]

if your wories about strength that much just take an acedline torch and heat the whole hib red hot around the studs after you weld them, then toss it into some room temp water, this is an easy way of forging it and it makes it ALOT stronger.

Good Luck,
Shean

[RXTurbo]

Don't do what The Scooby says to do, this will harden the steel around the studs making it brittle. The only way to stress relieve the hub after welding it up is to have the whole thing immersed in a furnace and uniformly heated and then cooled down in a long controlled matter this anneals the steel and makes it the same strength throughout. Problem here is that next time you drive the car the hardened drive shafts will chew the splines out of the hub. So you need to get the splines induction hardened, this is a concentrated heat applied using an electrical coil. This is then hardened by quenching.

The rest of the hub is then again stress relieved. The only place that can do this for you is a professional heat treatment shop. No home use equipment is suitable for doing the above properly.

[oddcomp]

my old highschool shop teacher put out the bucks to set up a cryo-treatment thingy

instad of heating stuff up he cryogenically tempers teh steel with extreme cold
from what i ahve learned when i pop in every now and there at school to say hi

is that it works well on crankshafts and is very popular for gun barrels
for instance i do not recall teh actual rate but but its pretty close
where a normal gunbarrel would stay accurate for say oh 1000 shots <just a example i forget his actual numbers>
before the bore wore down enough to lose the rifling in it and throw off the accuracy
the same .. well identical barrel cryo treated
is good for around 2-3000 shots before a noticeble shift in accuracy

and he has actually tested this
if you can find someone having the hub and such cryo treated may be a bit better if not cheaper?
i do not know how much he charges but if anyone wants i can ask next time i am in the area

i been thinking of getting my suby crank treated

[SubSandRail]

I have experienced the problems of having hardened metal in the wrong application. I think I will grind off the unwanted studs and pull the new studs in with an impact driver. That way there is no bending from pressing or beating the unwanted studs out and the new ones in, and no change in the strength of the metal from heating. Thanks for all the advice.

[RXTurbo]

I beat the studs out on my hubs and then put them on a mandrel I made. There is no change to face run out once mounted. I don't even want to start on how 'out of round' the hubs are from the factory!! It is not uncommon for a hub to be off centre by up to a tenth......

[gonehuntn]

So what is the problem with countersinking the holes on the back side?
You already have it in a drillpress. Why cant ya just flip it over and countersink the holes?

[Qman]

You don't want to countersink them. Spotfacing is the optimum approach. It will maintain a flat surface for the studs to sit into.

On a side note, Gonehuntin, get a hold of me when you have time to talk.

Ken