One time I weighed the Samsonite rolling carry-on with Judy's pins at an airport and it was 35 pounds. It had about 600 pins in it.
We never checked the pins but always used carry-on. The first time we flew after 9/11 was for the Columbus Day weekend less than a month later. When the case went through X-Ray the screener panicked. We asked (at Dulles) to be examined out of public sight. The screeners would remove the plastic bags and also open the pin books and leaf through the pages; then I would do the repacking.
Actually we travelled through Dulles often enough that at least one of the TSA supervisors got to know us. However, we learned to warn the person on the X-Ray in advance, and then for the back room screening Judy and I would talk to this supervisor about Disney while one of the screeners would go through the bag.
And of course at Orlando they are very used to pin collectors.
If you use a small airport you might call in advance and talk to (and get the name of) the TSA manager to make sure staff at that location are aware of policy. Then if you have any problem with a screener or first-line supervisor you can give the name of the manager you talked to and ask that they confirm what you said. Note that you should be polite but firm, and do not yell.