I'll have to see what an Ohio broider is.
Edit: here's a guide
https://www.backyardchickens.com/articles/ohio-brooder-with-temperature-controls-and-a-collapsible-brooder-for-storage.75918/
I wouldn't do a hole in a board but the heat bulb housing that feed store sell. The clamps are sturdy and if there's any question, wire is a good binder
I use ceramic reptile bulbs or a red bulb. There's no use worrying about fire hazard if used properly.
https://www.amazon.com/gp/aw/d/B0C2CLRDWZ?psc=1&ref=ppx_pop_mob_b_asin_title