Building a driveshaft is different than building a pump shaft. They can't machine you one. If they tell you they can, don't believe it. It won't work. The entire shaft is hardened, especially where the bearing rides. It's not just a piece of cold rolled steel. Besides that, you won't want to pay them to cut all the splines. Sorry bud. You can't make one.
20 years ago, had a John Deere grader that an input shaft went out of the trans on. Original shaft was NLA from Deere. Known problems with that trans, so they redesigned it and started over. Options were all new trans (machine not worth it), good used (if you could find one), or have one made. Went with the last option. Just like any input shaft, it was hardened. One machine shop laughed. We just thought they didn't want to do it. Found one willing to either try to make new splines on the old, or build new. I can't recall. Either way, had it made and put it in. Now, we are talking days of work here..... grader made it, oh.... 60 feet. Ate the splines right off the shaft. Turns out....they have to be pretty hard to last very long.
Before you go saying this is smaller.... it doesn't matter. Same laws apply.
Can't make them. Better find a hydro.
