ok this is a WERY simple english wheel that i have made a bunch of now,there are no interchangeble dies,instead the dies are standard bearings (SKF) and the frame are standard box tubing,i'm a simple man with simple tools so have some tolerance ;D
all measurments are in millimeter (1inch=25,4mm) so you'll have to get your calculators to change the numbers
1= 490mm cut 45'
1= 530mm cut 45'
1= 400mm 90' both ends
weld the 45' bits together to form an L at 90',then weld the 400mm pice on the 530mm at 260mm from underneath the 490mm piece,now you have the base frame
cut a piece of 40X40X4 tubing to 250mm, i choose to do the ends in my lathe to make sure they are perfect,
,drill a 5mm hole 80mm from one end to tap 6mm tread and one 12mm hole 30mm from the other end countersink the edge on the 12mm
cut a piece of 32X32 solid bar to 170mm,
again do the ends on the lathe,
as you can see i have rounded the edges of the solid bar,this in tha lathe to make it fit inside the 40X40,drill one end with a 6mm drill 10mm rom the end and 7mm from the edge,after that drill one 18mm hole in the end of the bar,this for the up and down control of the lower die,
cut a treaded 20mm bar to 230mm and do one end like shown in the pic,outer diameter 18mm ,match the groove to the 6mm hole in the solid 32X32,
from a 90mm long M20 nut cut a a 30mm bit of then drill 3 holes to tread 8mm,
cut 3 pieces of 8mm bar and tread both ends to 8mm,10mm and 15mm long,
fit a 8mm nut to the 15mm end and a plastic knob to the 10mm,you now have 3 of these,
mount them to the 30mm M20 nut to create this,it's the handle for adjusting the lower die