... what is with this Nagasawa love ? Nagasawa and nearly all other certified japanese keirin frame builders have used cut-and-plug fork dropouts for a number of years now. no framebuilding "mystic" there (recall treks from the 80"s). as for filing "shorelines" on lugs ... are you crazy !
... these frames are just worhorses that can be taken out on the first ride ... any little bump/dent in the frame (usually on the side of a top tube, from the bar hitting it) on a crash will disqualify it. why do you think all the ebay used keirin frames these days come with an installed headset (usually hatta swan) and bb (without the bolts). they move on quickly ... and move on.
... anyway, there seems to be more than the usual keirin frames on ebay these days ... that have the older (classic) construction methods. good bargains i say ... talk about thinning the heard over there). i just got an "older" 56 cm Stratos that is as mint as it can be. soft white paint, gold sparkle, lug/support cutouts like american builders used to do before they got dementia and went crazy on excess.
... your mileage may vary (who said that on the list by the way :)
robert clair
alexandria, va
usa