Joined: Jan 2010
Posts: 9,778
Likes: 1,746
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
VX taper size is indeed the normal, super-precise JIS size, which is 12.90mm, measured 3.2mm (1/8") from the end of the spindle.
There is a lot of offset with some of these Suntour BB's, so a Shimano UN5X in 127mm is what I'd normally use with an AT triple.
But in this case, I have the needed Suntour tool, which perhaps can be found on Ebay?