Wed Sep 27, 2006 5:11 am
The anchoring may perhaps vary with the maker. Mine are sewn on, about 1.5 inches forward of the back split in the waistband (the tunnel is pieced at the split on mine). I suspect this is intended to permit later alterations. An unsewn elastic could easily be altered, but in that construction the tunnel would have to be completely removed and reattached after the trousers were altered.
With modern materials it should be possible to get an elastic that will last a long time--decades, at least (it's pretty densely woven on mine). I haven't had any long enought to wear out the elastic, but if it happened, I'd think it could be replaced--open the tunnel at the waistband edge, rip the old stitching anchoring the elastic, remove the finish-cloth tip with the button hole, reattach it to the new elastic, stitch down the anchor, re-close the tunnel.
Haven't ever seen an internally mounted version. I'd thnk you'd want the elastic to go outside the interlining of the waistband at least, so that it compressed the waistband to your waist when you bend, rather than pulling it to you via the finish cloth tunnel only, which would risk gapping and possible tearing. That construction would require a wide enough waistband to accommodate vertical slits for the elastic to emerge to the interior (kind of like the tabs on Gurkha shorts). Presumably you'd want the tips covered in a waistband lining cloth rather than the finish cloth, and discus-shaped brace buttons to attach to, for comfort. One drawback of this version, of course, would be that you'd have to open your trousers when you wanted to adjust the tension to a different button. Depending on your needs, that might not be a serious drawback, given the cleaner exterior finish. Does this sound feasible, tailors?