Hi. We have an antique bed -- a 3/4, 1880s, Eastland style bed. I have a custom made mattress for it, in the 3/4 size.

We currently are storing the bed, but want to use the mattress for our son's bed. (He is still to little to not destroy an antique bed ).

I have a convertible crib, that converts to a full-size bed (you have to buy a metal frame, but it comes with the headboard and footboard).

Is there a way to use the 3/4-size mattress on this full-size frame? Does a steel bedframe adjust to that small? And is there a way to attach it to the headboard/footboard, since it will be an off size?

I don't mind if the head and footboard are too wide -- but I don't want dangerous metal gaps on the frame itself.

Thank you so much for your help!