"I bought a clasp on eBay for US 4.99. I then tried using it on a Seiko bracelet, but...."
The Seiko bracelet only has two length adjuster holes for the clasp, and often receive mails about how it can't be finely adjusted.
So I tried buying a three hike clasp on eBay.
Double Button Stainless Steel Fold over Buckle Clasp on eBay
The folding part isn't solid, and the push button construction is shoddy in comparison to Seiko.
1. I tried changing just the head.
It was easy to replace.
There is a subtle size difference between the parts, making it a pain to be taken off and on.
So much so that the finger used to press the push button will begin to hurt.
It can be used if it comes down to it, but it wasn't at a level that I could recommend.
2. I tried changing out the entire clasp.
I removed the end of the bracelet piece, and connected it.
The pin that goes into the link is fine, and would not fit into the clasp.
I think it can be used if I is glued in place.
I think it's fun to try out various things for just UD 4:99. Although I don't recommend it.