No Herman- the Bugatti front axle is more clever than that. The axle is not a casting, it is a machined piece of steel that is bored through, the spring eyes are forged and then punched out, the ends are then forged solid and then fully polished. The clever (and expensive part) is that it is not made from a casting, which due to the chrystaline structure would be inferiour.

Today it is not a problem to cast this axel .Modern cars have the crankshaft , camshaft and conrod cast . Turbine blades are cast and so on .I cast many conrods for aircraft engines .

Hallo,
that the way of thinking which is close to mine. We live in XXI century so it's more safety to use nawadays technilogists esspecialy that we are not sure how it was in the past. I think that the way which Greg presents is closer to the technology od Iwan Dutton Ltd. I have seen some phothos in internet. That what Herman said interested me. I have following questions:

1. First stage of work with axel was the cast hollow or full?
2. Did Bugatti make full axels in models 35-51?
3. How was made the axels in models 54-59, what do you think?
4. Is there somebody who knows something about axels in T36?
5. Can you clearly tell what kind of material was used for axels (T35-59) and how can we named now?

I'm so sorry that I ask so many questions but for me you are authority. I'm going to established some facts not olny dissciss all the time.
I think that the axle can be made in different technologists but we have to remember how it was done oryginaly. Esspecialy that nowadays technologists gives more possibilities.
I'm sorry one more question:
Is there somemody who made the axel themselfs for his Bugatti?
The end of questions.
I wish everybody Happy New Year!

Do you happen to have the book "Grand Prix Bugatti" by Conway (latest edition, with the blue Bugatti on the front)

On page 192 and 194 is some info:

There was a solid axle for the type 35A and type 37. Diameter 36mm, with 37mm wrist diameter.

A hollow axle for the type 35, diameter 40mm, hole 30mm, wrist diameter 38mm, later axles 3 or 4mm larger, to account for greater brake torques.

In all cases kingpins were 18mm.

Material was nickel chrome case-hardening steel, but not case hardened.

Page 50 also has a diagram.

Indeed the base structure was turned on a lathe, holes for the springs punched out, then the thing is bent and the ends forged close. Conway is not clear about the sring holes, whether machined or forged.

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Vive la Marque !!

first ends are closed -forged .After bend , after machine spring holes

The bugatti axle, at least on the Royale was made of AD3- modern equivalent EN36. The Type 54 had the familiar one piece job like the previous Bugattis and only the prototype 57, 57s and 59 had the two piece axle with the collar in the centre to allow a degree of rotational movement.
I have an original Type 44 axle which is a solid forging and not polished, rough as a badgers arse to be honest.
None of the axles from the factory were cast steel.
If you were to cast a steel Bugatti axle today I cannot see why it has to be made in two pieces and then welded up. The internal sand core could be held in place through the spring eyes

if you like to build a high quality axel today , use 4140 in German 42crmo4 . Cast in a heated ceramic mould , and you have the best bugatti axel you can get .

Of course a Bugatti axle is only a Bugatti axle when it is forged.

It may be that some cast materials now come close to the specifications of the forged material, but why compromise?

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Of course a Bugatti axle is only a Bugatti axle when it is forged.

In this case , we should allow for the next Bugatti Festival only cars with real Bugatti axels .foregd ones . It would be the first one with no cars .

It may be that some cast materials now come close to the specifications of the forged material, but why compromise?
Forging is used for cheap producktion , not to make parts better . And with forging you get this dangeres forging pockets . The highest quality you get to cast in to a heated ( about 1200 celsius )ceramic mould . But it cost more money , much more . Look in to aircraft industry production .

Hallo everybody in New Year!
Thanks Herman a lot for informations. Plesae, undrstand me good, I don't want to lever Conway but looking on oryginal draw 12.07.1924 it's difficult not have impresion that first draw showing first stage is the casted element. There are big differences between diameters on the whole long. The places for mounting springs are very precise modeled. Only on the next stage it's machined to the exact dimentions.
In the next stage the ends of axel are forged mounting of springs are bent in 22 engle. The machining of mounting springs concerns only making the wholes. In sum the mounting of spring changed only their location but their outside shape have granted in the first stage of work. Those are my observations.
Greg, can I ask you to show as your rough axel, I mean phothos? I have seen on BOC website in catalog of parts named by symbol C-36 that it's forged axel for T37.
I have expiriences that casting seel is not so easy especialy with those diameters we are talking about. Steel is very lazy in casting and it is not the same that casting aluminum, bronze or iron. And the is no difference is it cast with loosing wax or in sand. I'm deffinetly follower of casting axel in one piece. I think the best is to check it. So I propose to open new subject "Axel front creating".
Apropo's sields of T37 - have you got any news about it?

I use sand and lost wax steel castings all the time for engines . This are 3 engine crankcases 4140 , sand castings , heat treated to 120kg/mm². This engines have over 15 Liters .