(For additional strength Schwinn also brazed steel sleeves into the interior of its frame tubes at the joints.)įillet-brazed bicycle frames are strong and have a neat and clean appearance, but they are uncommon because of the additional craftsmanship required. The extra thickness of the fillet also provides strength, and its smooth contour distributes stresses evenly. In this method of bicycle frame construction, "mitering" or cutting the tube ends so that they fit together precisely is critical so that capillary action will draw the molten filler into gaps for a strong joint. Fillet brazing involves building up brass filler metal in a smooth "fillet" around joints. Fillet-brazing is an alternative method of constructing high-quality lightweight bicycle frames without the use of lugs.īrazing is a joining process employing a filler metal, like brass, that melts below the melting temperature of the parent metal workpiece. You will need to pay attention to paint schemes and colors, seat binding posts, drop outs, serial number structure, font, and size, welding construction, and other ‘tells’.Until the recent rise of quality TIG-welded and composite bicycle frames, most high quality lightweight bicycles used lugs (external metal sleeve fittings) to join their frame tubing. This is not as simple as it sounds because nearly all manufacturers made very similar frame styles. While this may seem obvious the first thing to do is to make sure you are looking at a Schwinn frame. After the war all boys 26” tire frames were 18”. In the prewar years Schwinn offered their boys 26” tire models in several different frame sizes (16”, 18”, and the so-called ‘tall frame’ 20”). The juvenile models mimicked the adult models to a large degree. The girls frames were pretty much the same and were differentiated between model lines largely by paint schemes or equipment e.g. This article will not cover either girls or juvenile models. I am not going to try and associate the models to the frames because both straight bar and cantilever frames were used for Autocycle models and trying to explain Motorbike, Cycleplane, Standard, Super Deluxe, etc… gets complicated.
Many different models were built on these frames. Essentially there are three basic styles the straight bar, the DX, and the cantilever frames. This article is not going to cover all the varieties of frames Schwinn built through the years of which there are many.
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