When I tried to work inside the smokebox, it was
pretty tight. If I ever needed to work on the throttle valve, I would
have to take the smokebox off which would be a major undertaking. I
decided to cut a hole in the smokebox to make things easier. Then I
made the covering/door. The smokebox is 3/8" thick and does not cut or
form easily. I made the cut on top where it will be hidden by the
skyline casing. I used a single bolt to hold it in place. You can see
how it latches in the second photo.
And here is it installed. Makes
it a ton easier to get to the plumbing and valve in the smokebox.