Mondial Rear wheel bearings, axle groove nut

Hello Guido

Can you post a pic
I do not understand what the exact problem is
The mondial is not in my garage so I cannot have a look on the car
Have send a pm to you some time ago
You must have missed that

Frank

 

Guido
contact me, i've got the right tool (meaning in this case: other manufacturer and very recently proven to work with a job on my gtb)

 

Hi Guido, I tackled this job as part of my winter project on the 328 last year. Before starting the project I looked at the Baum ring nut tool and was worried that it wasn't tapered enough to fit in the flange and grab the nut as you describe. With the help of my father (who happens to be a talented gunsmith) we made our own socket with a slight taper at the end which worked great. You'll notice in the photo below that the taper is very subtle. You have to be careful because the nut calls for 158.5 ft/lbs of torque (at least on a 328) so if you taper the tool too much, the end may be too thin with resultant failure with that torque load. I suspect that the Baum tool has been treated/hardened so any modifications as far as grinding a taper may be difficult. You might try taking the tool to a machine shop and see if they'll throw it on a lathe and taper it for you but again this may be challenging if the steel has been hardened. Best of luck.
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Nice work!

 

Guido, what made you want to change the bearings? Was she wobbling at speed or something?

 

Great looking tool you guys made there. Do that with a rotary table and a milling machine?

What did you start with? A large socket or ?

 

Guido, Ettore is right - the Baum tool is probably hardened, so, lathing a slight taper on it will take good carbide tooling and a good quality lathe. If you don't happen to do such things yourself, and want to try a less elegant means you could try grinding a slight taper on it with your bench grinder. It'll be slow work, but you'll get there OK if you're careful. Like Ettore said, don't take off any more material than you absolutely need to!

 

Thanks Cliff. We started with a hunk of cylindrical steel that my father had lying around the shop (a remnant of a blank used originally to make a long range rifle barrel). The outer diameter of the blank was close to spec but needed to be turned down a small amount using a lathe. The taper was also achieved using a lathe. A milling machine was used to achieve the inner configuration. Before handing it over to me, my Father "hot blued" the socket to give it the dark appearance you see in the photo. While completely unecessary given the tool's application, bluing is a process of "electrochemical conversion coating" that oxidizes surface steel thus providing corrosion protection. He was bluing a batch of rifle parts and thought the socket would look cool black. http://en.wikipedia.org/wiki/Bluing_(steel)

 

You dont necessarily have to use a lathe tool when turning something down. You can cheat and make a clamp for a 4" angle grinder to be bolted into the tool post .

Turn the lathe on AND turn the grinder on and use the grinder to machine away what high speed steel ( and many tip tools ) will not handle.

Like a lathe tool basic rules apply , keep the wheel at centre height etc etc ...

A good practice is to either cover the lathes bedways during machining or clean them thoroughly after you finish the job .............. or both.

 

"I have the right tool from Baum tools
http://www.baumtools.com/pdf/FERRARI_CAT_2008.pdf number FR 106
but this tool not engaging the nut...I'm afraid there is no washer under this nut, so tool FR106 cannot go deep enough to turn this groove nut."

How can this be "the right tool" if it doesn't fit??? What the hell is wrong with the designers at Baum??? "There 'otta be a law".

 

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Oh.......I withdraw my comment. Still, for the cost of Baums tools, they could have added the chamfe,r in anticipation of a missing washer. But, none the less, I was wrong. Mea culpa.

 

Somebody used the proper tool to put that nut on and torque it down in place in the first place....and, without a washer underneath it. So, there's a tool out that fits, and that will adequately bear the torque spec, even without a washer under the nut. That tool may be in Maranello however.

Personally, I'd just take the baum tool and put a very small taper on it with some good tooling and my lathe. Another way I could do it is with the rotary table and the head on my milling machine inclined a couple of degrees. In either case, if only a modest amount of material is taken off then it should be fine and fit.

Any decent machine shop could do this in about 10 minutes too.