As someone has already said, I think it was Doug, there are so many ideas, notions, instructions out there about how and when lugs should be thinned o ut - if at all.
I was introduced to the process way back in 1953 at a time when most fra mes were either bronze-welded ie lugless, or built with cast lugs. In those days the cast lugs were cast in sand, and often left the mould complete wi th "flash" around their edges, or with wall thicknesses that were both ugly and heavy. The most commonly used lugs were made by Brampton, Chater-Lea, Ekla and Aerts.
I learned the trade from a frame-builder called Hilton Wrigley, who work ed from small premises In Marsden, nr Huddersfield, just on the edge of the Pennines in the north of England. I think that Hilton was self-taught, hav ing been an engineering draughtsman..
If the lugs were to be used with the pattern as cast, then the lugs were filed to remove all the casting "flash, then the profiles were cleaned up and refined. Then ,depending on the actual brand of lug, as some had thicke r walls than others, the surplus thickness was removed. This was generally removed from all the lug's surface to reduce weight, and then the surfaces were slimmed down from the centre line towards the edges, in what we called "feathering"
As I recall from my early sessions, this often laborious work was carrie d out as a necessity in order to reduce the thickness of the casting so tha t the heat input from the torch would be reduced, thereby ensuring that the tubes themselves would not be overheated and burned. It has to be remember ed that many frame-builders used to use the old compressed air - town gas m ixture torches, The flame was no where near as hot as that of an oxy-acetyl ene torch, but it was much bigger. and softer...known as a "brush" flame. T he heating up period was much longer than for oxy-acetylene, and therefore any process that could be applied to the joint, within the bounds of safety, to reduce that period, was used. The beauty of the brush flame was that it covered the whole of a joint, even a bottom bracket assembly, a nd it was possible to obtain a uniform temperature throughout the joint, th is uniformity ensuring that the brazing spelter flowed quickly throughout t he joint. Because the lugs were accurately reamed inside, there were no int ernal voids at the angles, to be filled with the spelter.
Any post-brazing filing was kept to a minimum and usually consisted of l ight polishing and final profiling with a very fine file and then an emery strop. It has also to be remembered that in those days sand-blasting equipment was not in as common usage as currently. With frames using very e laborate hand-cut lugs, we used to flux up the joints with a borax paste an d then leave the paste to harden. When hard, the delicate operation of remo ving as much superfluous flux as possible was carried out with small toothb rushes and artist's paintbrushes.. By this means we tried to avoid any surp lus spelter from getting into the outlines of the lugs., as it would have b een very tedious task to have tried to remove it by hand.
Recently I have bought three French or Belgian frames made either just b efore WWII or afterwards, They are beautifully elegant, rendered even more so by the extremely skilful execution of the filing down of the cast lugs. The lugs themselves are very small, and very similar to Nervex Serie Legere , but smaller in scale. The profiled edges of the lugs virtually blend  ; and taper into the tubes with such finesse that from a few feet away the joints appear to be lugless. The standard of workmanship is not equalled on any other frame that I have ever seen.
I find it difficult to fully understand how the builder achieved this ef fect. Either he obtained the tapered edge before brazing or he must have us ed jewellers' needle files to carry out the post-brazing finishing, b ut to do this without knicking the tube would have been extremely difficult ., and probably not possible. Depending of just when the frames were made, I think that there is a possibility that they were brazed with a paraffin(k erosene, I think) blow-torch - hence the need for the impeccable reduction in the thickness of the castings.
Apart from not being able to work out how the lugs were prepared, the ot her infuraiting thing is that none of them carries even a single decal or h eadbadge. A couple of other identical frames in the ownership of a Fre nch collector also are devoid of transfers..
Norris Lockley, Settle UK
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