I had been wondering about a more detailed pic of fork crown and then it appears! Although hard to know how relevant fork is to ID of bike as a different number than frame albeit similar suggesting same builder. I agree looks like a Fischer track fork crown (Swiss) that was used by Italian builders as Masi and used by British builders as Raleigh and Mercian at a time when Italian style Prugnat lugs were coming to the fore. Difficult to tell from a similar looking Davis track crown.
http://bulgier.net/pics/bike/FrameParts ... index.html
As Dave says, it could be a Holdsworth shop frame as number fits with the post 1965 shop sequence of numbering. Also in the 1967 shop catalogue there was indeed the option of Nervex Pro lugs. Your frame's serial number is not placed on BB edge as most of shop examples Dave has collected during the '65 to '67 period. Interestingly the only 1967 example of similar placement of serial number across the BB as yours is the alleged first Pro built by Reg collard for Addy. Explanation could be either your frame is a Collard special or an outside contractor/trade build. However lack of a metal head badge (unless evidence holes have been filled?) does throw a wrench into things! Although one or two of Dave's examples of shop builds also apparently have no metal badge, it makes it difficult to commit to Holdsworth without a metal head badge or signature "shop" features. See Dave's Excel file.
Wonder if you've researched Mercian of which I know little about? Quick look on website as well as Mercian Flickr Registry shows a similar numbering system to shop Holdsworth ie 2 digit date and the number of build for that year. Flickr has a track frame with a Fischer fork crown and added reinforcing tangs on inside surface. https://www.flickr.com/photos/mercianre ... ateposted/
Appears around '65 to '67 2 digit year could be either at beginning or after build number and serial also placed on BB, altho unclear to me re position. Mercian certainly used lots of Nervex lugs - apparently persisting into the 90's! Also at this time they used a straight rear brake bridge as yours has. Interesting, Mercian used a transfer and not a metal head badge. Although.. the big feature perhaps making Mercian a stretch is your semi wrap over seat stays, as mid and later 60's Mercians seem to have full wrap over seat stays. Although in a 66 catalogue on Mercian history site it states specs of track model Super Vigorelli could be altered to customer requests. If you haven't already gone down the Mercian route might be worthwhile contacting them. Apparently they will research serial for a small fee, although sounds like their serial records pre 1970 are lacking. Perhaps someone with more Mercian knowledge might comment.
Sorry re rambling. Hopefully there will be an Eureka moment!
Doug
http://bulgier.net/pics/bike/FrameParts ... index.html
As Dave says, it could be a Holdsworth shop frame as number fits with the post 1965 shop sequence of numbering. Also in the 1967 shop catalogue there was indeed the option of Nervex Pro lugs. Your frame's serial number is not placed on BB edge as most of shop examples Dave has collected during the '65 to '67 period. Interestingly the only 1967 example of similar placement of serial number across the BB as yours is the alleged first Pro built by Reg collard for Addy. Explanation could be either your frame is a Collard special or an outside contractor/trade build. However lack of a metal head badge (unless evidence holes have been filled?) does throw a wrench into things! Although one or two of Dave's examples of shop builds also apparently have no metal badge, it makes it difficult to commit to Holdsworth without a metal head badge or signature "shop" features. See Dave's Excel file.
Wonder if you've researched Mercian of which I know little about? Quick look on website as well as Mercian Flickr Registry shows a similar numbering system to shop Holdsworth ie 2 digit date and the number of build for that year. Flickr has a track frame with a Fischer fork crown and added reinforcing tangs on inside surface. https://www.flickr.com/photos/mercianre ... ateposted/
Appears around '65 to '67 2 digit year could be either at beginning or after build number and serial also placed on BB, altho unclear to me re position. Mercian certainly used lots of Nervex lugs - apparently persisting into the 90's! Also at this time they used a straight rear brake bridge as yours has. Interesting, Mercian used a transfer and not a metal head badge. Although.. the big feature perhaps making Mercian a stretch is your semi wrap over seat stays, as mid and later 60's Mercians seem to have full wrap over seat stays. Although in a 66 catalogue on Mercian history site it states specs of track model Super Vigorelli could be altered to customer requests. If you haven't already gone down the Mercian route might be worthwhile contacting them. Apparently they will research serial for a small fee, although sounds like their serial records pre 1970 are lacking. Perhaps someone with more Mercian knowledge might comment.
Sorry re rambling. Hopefully there will be an Eureka moment!
Doug