On Sat, 5 Dec 2020 02:01:25 +0000, Cokesfloat
wrote:

Where can I get a chuck for my 9” older ras with 5/8” 18 left handed thread mount chuck

Are you sure it's not 5/8" x 16? 18tpi would be really strange. If
it is 5/8" x 16 you can try:

https://www.amazon.com/Superior-Electric-J3113HH-48-66-1381-48-66-1380/dp/B002UOGDJ6/ref=sr_1_1?dchild=1&keywords=5%2F8-16+Drill+Chucks&qid=1607139714&sr=8-1