Hi Hoony , its for a prototype cartridge , I am limited with room , so I cant use 28 . I have 25, 26 and 28 x 1 , but not 27 . They are very expensive to buy as a special order . If we dont go ahead with the project or change it to another pitch , it will be another pricey item lying around forever . DC Swiss could make a die +tap for $1850 , so I am trying my luck here first .I am not getting any younger , therefore much of those special tools will go to scrap one day , unfortunately .