Instead of the threaded inserts that are normally used for takedowns, I'd like to use the inserts with threading only on the inside and a button head on one end to push in from the belly of the riser. I know South Cox of stalker stickbows uses these, but I'm pretty sure he gets them custom milled. Anyone have a source for these push in inserts? McMaster Carr only has rivet nuts and t nuts that are 1/2" or so in length and I'm trying to find something closer to 2".

https://www.boltdepot.com/Product-Details.aspx?product=14345
Perhaps these sex bolts can be used
https://www.craftmasterhardware.com/shop-by-category/door-accessories/pk611-s-parker-611-sex-bolts

Or these,
https://www.mcmaster.com/sex-bolts