Drilling and tapping hubs/discs
 

Hey people,

Would like to ask some opinions again please. I am considering drilling and tapping my own hubs, as I cant find a place close to me that is willing to do it (there might be this one more shop that might do it, but I am not counting on it). Problem is that I can not find any taps in 14mm diameter. sizes, let alone the right pitch.

Now, the DIY shop close to me has got a kit, these:
http://i13.ebayimg.com/03/i/06/25/19/a3_1_b.JPG

They come as a 'start, tap and finish' set. Problem is that they are 12mm diameter only. I would like to go to a 5 stud pattern.

So my thinking is this... If the Super Beetle/Fastback came with 4x14mm lug nuts, would it be a bad thing to go to 5x12mm lug nuts? I would prefer if I can get hold of 'press in studs' but again, to find them here and then to get somone to press them in with a hydraulic press .....?

So, I give the floor to you....:agree:

don't use 12mm nuts unless the wheel was designed for them!

I'd go with press in studs, you can even hammer them in to start wiht and then wind the nut up to pull it in straight..

Rich

Ricola,

Thanks for the tip. Yeah, I wouldnt have used a 12mm stud/lug nut if the hole in the wheel was 14mm for example. Just if I had the option to use 12mm studs/lug nuts, I would've made sure that I had a wheel to suit. But thanks anyway for reminding me.

As you say about the press studs. someone else also said that they dont need to be press fitted. "Just fit them and bolt them down" I was told. I would need to know the hole size(Down to the Micro reading) to make sure the holes arent drilled too big. I would've thought that 13.5mm or so would be the right size?

Thanks for posting.

BTW, fantastic progress that you made/are making on the Phantom!!

Thanks :D

13.5mm would be way too small, it would take a massive amount of force to press the stud in. A good guess would be to measure the diameter of the bottom of the 'teeth' on the stud and add a bit, it should only be fractions of a mm smaller than the max stud diameter. You should be able to look up press fit tables for exact numbers..

Rich

nice one! I am going to try and get my hands on some studs first before any drilling is going to take place.

So, If I understand correctly, you are redrilling stock 4-130 drums/disks to Porsche pattern? There isn't enough meat in the new holes to tap for the 14mm wheel bolts. I spotface the back and then press in the studs. It's the only way I do 'redrills', helps me sleep at night.:)

Lanner

I didnt understand the term "Spotface" so I did a Google and found this. As I understand another word for it is "Countersink", correct? From what I can see on the net regarding spotface tools, is that instead of using a normal drill and do the countersink, one uses a 'flat' drill (like in the pic below) to do a nice and flat 'countersink', correct?
http://www.lomas.co.uk/gifs/bit4.gif

Thanks!

You got it :agree: . They also make counter bores w/pilot. The pilot goes in the hole as a centering tool so, the tool doesn't "walk" on you.

Wheyhey, at last I am learnign something! :laugh:

So....This is what I think the order of drillinig should be, please correct me if I am wrong.
1. Drill pilot holes according to new stud layout. Use the appropriate size drill, same as the pilot drill on the Spotface tool.
2. After drilling, spotface the holes making use of the pilot drill.
3. Drill final holes, 14mm.

:confused: This method seems the most logical to me. The way I see it is that if the pilot drill is much smaller as the drilled hole, the spotface bit can still 'walk' a little?

Cheers!

In the aircraft business the term counter sink and spot face are totally different . A spot face is a flat seat , and a countersink is a beveled hole for a flush fastener .
See ya , Steve

zeroaxe,

Yeah, you've got the procedure correct.

Brad_gt,
You're right. Spotface is when the machining is perpendicular to the hole. Countersink is for flat head screws or rivets, so that the fastener is not above the surface. The holes on rotors for the disk-retaining screws on most cars are countesunk holes.

spotfacing is just used to get a flat surface, normally involves skimming the top off a cast surface..
Rich

Flat,

Thank for the ocnfirmation. I will note this down in my 'tech book' ;)

Brad_gt,

Yes, sorry, I should've clarified myself. Countersink is done with a normal 45° drill bit.

It has been confirmed by Flat, and elsewhere with a picture about the webbing problem at the back of the hub/disc. So the tapping idea will probably be scrapped. I guess I would just have to make up my mind and stick with Porsche pattern :( No wheel swapping here anymore...

I appreciate the input from everyone. Anyone know where a jig can be had from?

Thanks!

Any good machine shop can make a jig. Give them a drum, or rotor, and have them make the jig bolt to the current bolt pattern. Then tell them the hole size, and the dia. circle, and number of holes. The mill I have here at work has a DRO(digital read out) that has a program on it that figures the hole spacing by just giving it the circle dia. and hole size, and number of holes :D . I know this doesn't help you, but it gives you an idea to find someone across the pond to do it... even if their mill doesn't have DRO.

Hmmm, I will take over a drum (lug it on my motorcycle there) and ask some questions. What are the popular CNC files it can read? CAD?

And no, your fancy-shmancy DRO machine at work doesnt help me!!! Lol:laugh: