Vintage Workshop
Services for Brough Superior motorcycles and their contemporaries

Castle forks top clamps last update: 12/2003


The Castle fork uses top clamp lug that keeps the rear legs and the stem together at the top.

The Brough Superior Club provides a casting to make this clamp.

Now, first of all, you want the sides to be flat and to measure.

I am aware this is not the best clamping practice, but have you got a better idea?

Now, after carefully aligning the castings, the bores for the rear legs and the stem can be roughed out.

Next these have to be bored out to the exact size required.

And same for the stem hole (but different diameter!)

Next (thanks to having clamped the work to the rotary table of the dividing head) the lugs can be tilted and flats for the clamp bolt heads machined.

Oh, by the way, mind picture in the background, how else can you keep yourself motivated along this long long way!

Then, centre bore the bolt centres ...

... bore the the core diameter right through and, in the front half, bore the through hole diameter.

Then you still need to cut he bolt threads.

(Well, this is debatable, as some Castle forks use through bolts and nuts, but the vintage forks that are fitted to my MX80 have these threads)

Now, the next operation is a bit critical.

We need a slitting saw of just the right size and a bit of courage.

And that was that!


Any kind of feedback to is appreciated
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