UDS smoker newbie

Hello everyone,
I am slowly getting my UDS smoker built and will post pics when I can. I wonder if I could ask for advice?
I have drilled holes for my ball lever valves for the airflow but I can't source any lockable washers or anything else to keep them securely attached. I am thinking of giving up and using magnests over the holes instead.
Can anyone tell me what they use to secure the ball lever valves to the drum and where they get them from?
Thanks
I am slowly getting my UDS smoker built and will post pics when I can. I wonder if I could ask for advice?
I have drilled holes for my ball lever valves for the airflow but I can't source any lockable washers or anything else to keep them securely attached. I am thinking of giving up and using magnests over the holes instead.
Can anyone tell me what they use to secure the ball lever valves to the drum and where they get them from?
Thanks