This link should give you new threads today, but when the page is full, it will not continue into other forums.

That beats writing code in a pinch.  If you want a link to search specific forums over a specific number of days, post back.

It appears that the New Threads button is intended to give you the posts since your last log in.  I've logged off/on without causing a change.  There may be a problem with the code.  (The code appears to be okay, the problem was still the huge Machinery Talk display.)  At any rate, the very active Machinery Talk forum hogs the search results page.

I suggest that you use the SEARCH button on the upper left to search which ever forum you wish to search over the time period you wish to search?  You can add other criteria there also.