The photo shows a cup washer & a spacer, all the spacer does is give clearance between the blade & the blade guard.
That is all that is really important along with the secure holding of the blade.
Thanks doug let me try and explain what I'm thinking.
On the Dw125 the parts should look like the image below:
Thanks to Doug i now know it consisted of three parts one arbour/spacer and 2 cup type washers that make contact with the blade.
The problems with the original set-up as Doug said are
They are cup washers that are useless if your blade has reducing rings
What i want to do is look into instead of buying the original parts buying the parts form the dw1251 which allow you to use the standard 30mm bore blades available almost everywhere.
The dw1251 parts look like the images below:
What i need to find out is if the parts will fit without the blade cutting into the blade guard? to know this i need to find out the dimensions of a couple of parts on the dw125 i need the width of the cup washer and the total width of the spacer/arbour.
The required dimension!
The other dimension is of the part from the dw1251 inner collar/arbour seen here on the right this is the part that allows fitting of the 30mm bore blades.
Thats probably as clear as custard but i hope someone understands and can help with dimensions!