Spokes too short to build?
 

This is useless question but I'll ask it for the fun of it. I have an old hub and old rusted spokes from a wheel that had a damaged rim. In any case, I bought a rim thinking I was going to rebuild the wheel. Then I realized the Alex x202 rim I bought is slightly larger. (I'm thinking of buying a new hub, spokes and nipples just to sell a complete wheel to avoid wasting the rim.)

Anyway, I measured the old hub and calculated I need 262 & 264mm spokes for the Alex rim. However, the old rusted spokes are 259 & 261mm. So, am I correct in assuming I may just as well go ahead and build a new wheel instead?

the threads of the spoke have to fill the nipple * or the nip head will break off after a while..

* flush to the bottom of the screwdriver slot, ideally,

At a minimum...when a wheel is done:

1. Ends of the spokes must penetrate the thickness of the inner wall of the rim.
2. Come up to about 1.5mm below the screwdriver slot of the nipple.

That's what gives the fastener arrange the minimum support it needs.

Anything less usually means you haven't penetrated the thickness of the rim . . .

. . . which means cheaper nipples will snap in half sooner - quality nipples will snap later.

Nipples are nipples, not spoke extenders.

=8-)

OK, it's cool to have clear explanations of what's going on.

Stream of unconsciousness.

Your old spokes may measure xxx, but did you observe how far they threaded into the nipple?
If the ends were poking through the rim strip, you should have enough.
If they were short of the screwdriver slot already, no go.
Possibly the 261 could be used in place of the 262, but do you want to use 1/2 rusty spokes?
Wheel building with rusty parts sucks. Get new inexpensive spokes & nipples if you aren't going to keep the wheel.
Do you know what you can ACTUALLY sell that new/used wheel for? Your's is NOT an economic undertaking I would pursue.

If you have a bunch of old junk and just want to see if it'll make a wheel, why not. The calculation could be off, who knows? :)