(there were plenty of downtube shifters that ran outer cable up to the downtube shifter - all the way past BB and on to the mech, cable clipped all the way along - mainly on older and cheaper bikes as it was way quicker and easier to build them up - and with less braze ons for frame builder
brake cable outer is normally fine for the friction if you've no gear cable- but might not fit in ferrules - although often stripping a bit of the outer plastic will allow it in)
a dedicated stem shifter will have the right band-on size and the stops and normally have longer arms for ease of pull plus clearance over top of stem (this one is WELL over priced):
you need to fit ferrules like this :
http://www.ebay.com/itm/VINTAGE-SUNTOUR-ALLOY-BICYCLE-QUILL-STEM-POWER-SHIFTERS-/160850491085?pt=Cycling_Parts_Accessories&hash=item25736fb6cd#ht_1593wt_905
(there were plenty of downtube shifters that ran outer cable up to the downtube shifter - all the way past BB and on to the mech, cable clipped all the way along - mainly on older and cheaper bikes as it was way quicker and easier to build them up - and with less braze ons for frame builder
brake cable outer is normally fine for the friction if you've no gear cable- but might not fit in ferrules - although often stripping a bit of the outer plastic will allow it in)
a dedicated stem shifter will have the right band-on size and the stops and normally have longer arms for ease of pull plus clearance over top of stem (this one is WELL over priced):
http://www.ebay.com/itm/ViNTAGE-Suntour-Power-Shift-PowerShift-Stem-Shifters-Deraileur-Gear-JAPAN-MAEDA-/221097906166?pt=LH_DefaultDomain_0&hash=item337a764ff6#ht_477wt_1160