A virtual magazine for a true passion!

Editor: Jaap Horst

Volume 23, Issue 2

Dismantling an unknown Bugatti part

Jaap Horst

You may remember that I put a question on the appropriately named questions page on my BugattiPage.com website several years ago, see here, and scroll down to 31-8-2011. . Recently, I repeated the question on Facebook (the Bugatti Trust page), but with no reactions giving some insight into what it may be.

Of course I though about this a lot, obviously it is a worm, intended to drive a worm wheel, but detachable from that worm wheel housing. Both ends of the shaft can be fitted with a wheel, so as to move the worm. My best guess is that it must be a part for Ettore's sailing yacht, of which we know he had several parts made. Though many of those are of bronze, which would be much more appropriate in a marine environment, where the aluminium used here would rapidly corrode.

Well, I recently acquired the part, I'm not 100% certain, but it seems to be the same one, at an auction in the USA. As mentioned in the article on BugattiPage.com. there is a second identical part, but more finished: there are holes in the flanges on both ends of the housing, there are grease nipples fitted, and the ends of the axle has bored holes. The one I have does not turn at all, but then, the grease is in there for a lot longer than I live!

The dimensions:

Calculating from the curvature of the section where the wormwheel should fit, the diameter of the wormwheel is calculated at 250 mm.

Some overall photographs.

A series of details, showing on the one hand the workmanship, on the other hand the fact that the worm has never touched a worm wheel.

Some details of how the center part is fixed using 8 bolts. Definitely of the Bugatti type.

The "rear" of the housing, showing some corrosion that has taken place over the 70 years or so. Shows directly that this part and a marine environment would not be compatible.

Markings on the rear, where 0-0 and 1-1 should fit. Next to that, the entire part dismantled.

Some of the bolts, and the nuts. The bolts, M5 x 85, have been constructed by turning a blind nut on a very short thread on the shaft. Not the easiest way to make a bolt, though the dimensions are far from usual.

Details of shaft and worm after dismantling. There are 4 bearing surfaces, two on either side of the worm, and two on the ends of the housing-"trumpets".

Center part of the housing, some of the 8 long holes bored through it are open on the inside....

The worm (including bearing surfaces) is fixed on the hollow shaft using two pins going through it, here barely visible. The worm fits very snugly into the housing.

Surprisingly, after putting everything back together again, having cleaned all bearing surfaces and greased them lightly, the axle can be turned relatively easy. Meanwhile, there is absolutely zero axial play. Both are proof of the brilliant workmanship, on such a long axle, with four bearings so wide apart, the alignment must be perfect, if not the axle would turn more heavily.

But now, I still do not know what it is for.....

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