I just picked up a really nice 10" octagon .357 barrel for my Thompson Center contender. It came with the original wooden forearm but no attachment screw; I've looked online for replacements but have had no luck.

Any suggestions on what to try? Anyone have a spare forend attachment screw?

I had the same problem with a 10 inch octagon in .221. My solution was the cheap way out. I went to Lowes and bought a 3-pack of stainless (that's all they had in the correct thread size) screws. Then I chucked one of them in drill and ran the edge of the screw head against coarse sandpaper until it was reduced in diameter enough to fit into the forearm recess. Lastly, I had to use a Dremel with a cutoff disc to take two threads off, since the screw was bottoming out before getting the forearm snug. It works fine and wasn't a big bother to do.

...sometimes you also need the 'tophat' that seats the head of the screw in the forend. Some of the octagon forends really had a bored hole! I hat to recommend the 'bay' but they often times have scalpers posting these accoutrements. Clever metal shop skills often payoff in such circumstances. I salute you Leon!

The forend I have has a 1/2" diameter straight bored hole, no attachment hardware or anything for the screw that attaches to the barrel to bite into. Looking like I'll have to rig something up out in the shop.

Nothing to it. I am retired and have more time than money, I just kept thinking until I got the idea. By the way, that early Contender was a pawn shop deal that had a stainless 10 inch .22 LR barrel and a two screw forearm even though the barrel had only one lug. Since I got the whole rig for $300 out the door, I had some room to tinker. I ordered a single screw forearm from Midway and then found a .221 Fireball barrel for $70 plus tax, so I had to figure if a round barrel forearm would work on an octagon barrel. It looks a little different, but everything works well.