Anschutz 54 receivers
Hey buddy.
I have some experience with these little guys.
Get out your Ouja board, rabbits foot, and oil of newt before you go tapping an Anschutz 54 action. The front guard screw won't be that big a deal cause the material is dead soft, however the rear one does get some heat treat (closer to the bolt's recoil lug surfaces) and it can be tough as nails.
This is also dependent upon when your receiver was made. Not all 54's are the same and the older ones were heat treated from one end to the other. This always makes it interesting when threading the receiver rings.
If you call Neal Johnson's Gunsmithing, Inc. in Colorado Springs he'll whip you up a set of screws. Just order them a touch long and grind to fit if you don't know your exact length.
The cap screws will use a larger wrench which is a good thing cause the factory ones are kinda prone to stripping out. (shooters using wore out allen wrenches don't help the cause much either)
If you still want to make your own, MSC industrial supply sells the die for cutting the threads. I use a moly based cutting fluid for this as grade 5/8 cap screws tend to be a little "crunchy" on the outside.
Good luck.