You can get brass blanks. Get some 1″ round stock of brass c36000. Take it to a machinist but don’t tell him what it is for. Tell him you need 100 pieces machined to a 0.954″ OD (+/- 0.002″) by 0.067″ Thick (+/- 0.002″). Order more when needed.
I have a machinist that makes them in batches of 100 or 500 for me. If I get 100 they are $1.53 a piece, but if I get 500 they are just $0.97:-)
Sill checking on the cost of just using quarters……………..
The above plastic blanks make your self.
For nine years in the end anywayif you to work around slot machine that tilt the machine if the slug coins highly unlikly and believe they.