4-to-5 lug drilling template?

[farleyd]

Is someone as a template on how to position the 5-lug pattern over a 4-lug rotor/hub?

A printed one would do it. Or a jpeg file?

Or a mathematical representation?

Thanks.

[mike mueller]

This is not something you want to trust with a template, too much room for error. Take it to a shop and tell them it's a 5 on 130 bolt circle and use one of the exsisting holes. It's as simple as that. They'll put it on an indexing/rotary table or mill. Using a drill press will not give you the accuracy you want unless you have a fixture which would cost you more money to have made. Best best is to have a shop that has done it before.

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Mike Mueller
Antioch, CA
1970 1.8
http://www.pelicanparts.com/MotorCity/mmueller/personal.html

[sammyg2]

Mike is right. The hub needs to be dialed in with dial indicators on a rotary table/mill.
Once is is centered exactly on the rotarty table, it is turned until one of the holes is lined up exactly. The table is set to zero degrees. Drill the first hole (about 9/16" depending on the studs). Then rotate the table one fifth of a circle or 72 degrees, then drill the second circle. Keep going until you run out of holes.
Trying to do this in a drill press is just asking for trouble.

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Gerald Gore II (Sam)
73 914 350 small block

[rich]

Okey.. here goes. You CAN do this at home but you will need the following things. (This will sound like a receipe card lol) You will need a drill press with a (CIRCULAR!!) table, You will need a drill index tool, (this tool is usually stamped from tin. It is used to aid in determining what size bit to use when drilling the wheel studs)You will need a digital caliper,(Eletronic) You will need a round five hole wheel spacer,(Pelican parts can probably sell you a set of 4)You will need 4 NEW rotors.

Heres the method I used: Place your rotor and hub assembly on the drill press table. Use the stalk end with the slide point to center your rotor on the table. (I can't explain this any clearer without using drawings and stuff and I don't have time for that)
After you get the rotor centered and clamped to the round drill press table, bolt one of the five hole wheel spacers to the hub assembly using the stock lug bolt. center the round wheel spacer using the same method as discribed above. After all the round things are centered, select a drill bit just slides through the wheel spacer. (This is the complicated part) Insert this bit in the chuck. Swivel the drill press table right to left, so as you spin the table the drill bit slides into the wheel spacer. If you do this right you will not need to reset the right to left setting between holes. Use the big drill bit to make a centering mark for the next step. Do not try to punch the big drill bit straight thru!! IT'S THE WRONG SIZE FOR THE STUDS!! After you have a center mark from the big bit, you will need to change to a small bit to thru drill the assembly. After you have drilled the thru holes, slide the threaded end of your wheel stud into your drill index to select the proper size drill bit for your final boring. After you have finished the four new holes, remove the stock lug bolt from the wheel spacer. If things are all centered properly, you should only have to spin the drill table and drill the threads out of the last hole. Their is a tool that makes the knurled slots for the base of the new stud, but if you use hardened studs you should be able to USE A PRESS and install them. This is a lot of work and if not properly done will end in disasterious results. Think things through carefully. And good luck.

[farleyd]

Hey thanks for the tip! But it looks like i miss most of the tools. Ill go to a machine shop.

I still need to know what lenght of studs should i use? I know that longer is better and that i could use open nuts, but i already bought some 911 lugnuts, and i just cant install larger Fuchs under my fenders. So the need for longer studs doenst apply to my 914.

So, what lenght should i buy? IS is the lenght described in the Pelican catalog is for overall lenght? effective out-from-the-Fuch threaded lenght? or all-threaded part only? Excuse my english terms, not my main language.

[sammyg2]

The technique that Rich describes can be pulled off corectly by a competent amatuer machinist, but the average Joe might not be able to. Of course the average Joe would not have all the equipment to do it, so there ya go.
I also wonder about the spot facing on the back of the hubs. I used an end mill the last time I did one. I guess the same could be done on a drill press.

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Gerald Gore II (Sam)
73 914 350 small block

[rich]

Sam is too correct in saying that this COULD be done at home. But this kind of thing is most often reserved for a competent machinist. As I said, Improperly done, this procedure could yield disasterious results. BTW I had to bring my front hubs into a machinist to have the spotfacing done on the backside. My hubs were 1972 models with the reinforcement webs. So I guess I didn't do the whole job myself. But I had the sence to call a pro before I ruined something. If you've never done anything like this before get an expert to do it for you. You'll be money ahead. MHO

[Conrad W Peden]

As far as the spot face goes. An end mill is not flat on the bottom unless it is ground to be so or you are using circular interpolation(fancy for moving the cutter around in a circle as is done on CNC machinery). An endmill cuts deeper around the edge than in the center only by a couple thou. but enough to affect the concentrations of the stresses on the hub. So what happens is the stud is only seated on a small ring at the edge of the hole and not the whole 'flat' spot-face.

A proper spot-facing tool would serve you better. This is something a machinist would have.

Conrad Peden
72 L20E in rusto.
73 L20E in resto.



[This message has been edited by Conrad W Peden (edited 11-19-2000).]

[farleyd]

In another topic i posted, someone suggested that i could use pre-1974 911 rear hubs/studs DIRECTLY into my 914 rear stock splines and bearings? Eliminating the need of redrilling my 914/4 rear hubs?

Have i got this wrong or is this right?

Thanks.