Bob the time traveler has a problem. He went to 75,000,000 BC to get some dinosaur eggs (don't ask) and his time machine re-combobulator broke and a big chunk is missing.

Fortunately he can still make one jump forward in time, but he can't go as far as the XXIV century (his home era). Mostly he could land somewhere before the XX century.

He needs grade 5 titanium alloy to repair the re-combobulator. He just needs to smelt the alloy and his time machine nanites will do the rest.

The further forward he jumps, the biggest the risk of vanishing in the timestream, so he wants to jump the least possible

Consulting his encyclopedia of technology, he tried to figure out when is the earliest in history he can jump to where Titanium alloy grade 5 could be made with the technology available.

He can set his arrival anywhere on Earth. He also has no diplomatic or monetary problems. He can mine the resources or has the raw ores in storage.

P.S.: The story is just to illustrate the case in point. The question's title is all that matters. That is why there is no time-travel in this question.

There's some ambiguity in the question - the title says "has the feedstock" but doesn't indicate whether that's ore, refined metals, or "can get to places where the ore can be found". Assuming it's the first option, ore:

Probably Around 1900

AlexP's comment is valid, but if your time traveller has Future Wikipedia downloaded into his phone-analogue, all of the necessary precursor chemicals and tools should be available at the turn of the last century - their application would just not have been discovered, so you'd have to Scotty it up a bit.

The biggest hurdle would be vanadium. You'd need the pure metal to get proper grade 5 titanium, and the process for its purification wasn't developed until 1927. The chemicals and lab equipment involved did exist, though, so making a small quantity of the material, given all the necessary discoveries being known ahead of time, should be possible. Aluminum would be available (though expensive), and furnaces would be hot enough to make the alloy.

Edit, Addendum:

I don't know how much a few extra decades matters in a multi-million-year jump, but 1950 would be a much better bet which would make his job near-trivial. I suppose you can make the risk of being lost in the timestream asymptotic as he approaches, say, 2200, if you want to limit him, but assuming that's not the case, there'd be a lot less "explaining metallurgists' jobs to them" by just aiming a half-century further upstream.

Depends on how good of a chemist your time traveler is. While the purification methods on many of the needed materials were not discovered until the 1900s a good chemist, craftsman, and historian could go back further to the discovery of the ores he needs.

To make the alloy you will need Iron, Titanium, Vanadium, and Aluminum:

Iron has been around for ~5000 years; so, this is the easy one.

Titanium ore was first discovered in 1791 and could be purified via the Hunter process using chemicals that would be available by 1808 when Sir Humphry Davy learned to isolate pure calcium.

Vanadinite, discovered in 1801 could also be purified by 1808 due to Sir Humphry Davy's discovery.

Bauxite was discovered in 1821. All of the materials you would need for the Bayer process required to turn it into alumina already existed. The Hall-Héroult process required to turn alumina into aluminum could would have taken a lot more work since electrical generators would not begin be discovered for another 10 years; but if your traveler is also a good craftsman, he could fashion a hand-made generator to a steam engine (which had already been around for awhile) to produce the electricity he needs for this final process.

So, if you time traveler is a real McGuyver sort of guy, he could go with as early as 1821, but if you are looking to only start off with fully refined base materials, then early 1900s as jdunlop's answer suggests would be better.