Agreed. The most difficult part of the whole thing would be material selection and heat treat spec.

The shims pictured were cut off as disks and then the groove in the bottom was cut in with an end mill, not ground. You can see the tool swirl marks and the line near the middle from the two pass process to remove the bulk material.

My assumption is... Cut off raw material to rough length. Mill groove. Heat treat. Grind flat side to final thickness. Laser etch the thickness marking. Coat if necessary.

Direct Link To L Series Shims http://www.precisionshims.com.au/products/slotted