I think it was Bob Reid who referred to the fact that a frame made of Accles and Pollock Kromo tubing would seem to weigh less than a similar sized frame made from Reynolds 531DB. From my limited experience of working Kromo..I have never actually made a frame from a raw set of these tubes, but I have reworked and worked on a fair number of Kromo frames, I would agree whol- heartedly with Bob.
My learning-curve with Kromo from a point of view of working the steel as opposed to riding it - somewhere I have an Accles and Pollock Hetchins - really began in the mid-70s. At that time it seemed as though folks were wanting to get back on their bikes..and to embrace a healthier life-style. However whatever the sociological reasons..old frames stared coming out of attics, garages, garden sheds and barns and thier owners who had last ridden the their machines some twenty five years previously were more accustomed to the running gear of those days. Discovering that the ultimate-spec bike of the 50s would no longer cut the ice in the 70s, most of the owners decided to go for drastic " make-overs" and sometimes surgery, to bring their pride an joy up- to -date.
Within the "makeover" department the frames usually were stripped of all existing braze-ons such as Simples D/T gear bossses, the double-rollers on the bracket, often the Simplex boss on the rear drop-out was removed and replaced with one to take threeded hanger etc. In addition to these replacements, there was a growing demand for the "new" b/o pieces such as bottle bosses. It was in that context that I remember I discovered some of the more exotic metalurgical properties of Kromo tubing.
Whether or not there had been a very successful retailer of Dawes bicycles in the area in the 50s, I do not know, but in the mid-70s dozens of Dawes lightweight frames appeared at my workshop as if a container load had just been unloaded at Liverpool docks. It should be remembered that in those days and earlier the Dawes company had an envious reputation for building high class touring bikes...My mother had even spent her honeymoon pedalling one around the Yorkshire coast.
One model of Dawes seemed more popular than any other. It was built with semi-fancy lugs, whose pattern could best be described as a "looser" Nervex Pro; it had "D" section fork blades..and the rear drop-outs resembled a bigger version of the standard Stallard pattern. Its other very noticeable feature was its lack of weight. There must be experts out there on the LIst, I hope, who are going to tell me just what this model was...I hope so because I still have a couple. The name "Feather" or "plume" comes to mind.
Any way..there I was with one of these frames in the jaws of my vice, in the process of adding a set of bottle bosse to the down-tube... a very simple job...could almost do it blind-fold..no measuring involved..just a little pre-drilled jig to help me mark out for the holes..or the on-tube location points. Bingo..a dab of the J-M Easy-Flo No2..job's a good one.
However on that particular occasion I recall observing the incredible phenomenon of the whole tube arching inwards as I applied the gentle heat on the lower end of the tube where the bosses were being silver-soldered.. The job completed, I remember wondering whether the slight curve would gradually disappear as the frame cooled. I began to recall all that advice I had received years earlier about building frames in jigs, about building- in stresses and distortions etc. I don't think that that tube..a length of Accles and Pollock Kromo ever did return to its original straight length. Subsequent jobs on similar frames were always carried out with a less cavalier attitude and very gentle pre-heating of the whole tube with a soft brush flame was necessary to avoid producing a shallow arch along the down-tube.
I assumed from this salutary experience that Kromo was a more sophisticated alloy than other steels such as 531..possibly it had received some form of heat-treatment, as did several Vitus tubes in their day. One lesson I did draw was that from that day..I have sinc ealways endeavoured to add all braze-ons to the three main frame tubes..before brazing these into the frame itself, hoping in this way to not build-in any unnecessary stresses. This method requires more care possibly, more time..put just possibly..and there could be my first PhD thesis in it..it might just avoid more broken tubes
Norris Lockley...Settle Uk..where it's very damp and miserable.