Vintage flashlight trouble

Bought this 1920's something Yale light recently. Fits 3 D cells, and a e10 bulb.
I simply cannot get it to work.
Tube is seemingly completely free of battery damage, and it is overall in rather good shape.
Contacts look clean and good, switch feels fine, yet apparently, there is a issue somewhere.
Am I overlooking something?

Pictures:
https://imgur.com/a/gDEfL

Get a digital volt meter out, set it to ohms with sound. Hold the plus (or minus it don't matter) to a spot on the light body. Poke various places with the other probe. Beep means flow. Silence means a block is there. Try various places on the spring, the switch, the bulb assembly, reflector etc.

My experience has been in more cases than not unseen oxidation in rivets that hold the switch to the light are the culprit. Q-tips soaked with a de-oxidizer like de-oxit or tarn-x and applied to rivets etc get it going again.

And crazy as it sounds sometimes a good looking bulb fails to light.

Try that and report back please.

By the way, welcome to the site.

Did you try bypassing the tail cap with a piece of wire?

Well, you were right.
Rivet attaching the switch contact to the tailcap is oxidized. No current flow.
Everywhere else is fine, and conducts current just fine.
Going to clean it off, and see if it fixes it.
Thanks.

Rivet;
https://imgur.com/a/Yr5VH

Good photo.

Showed me your conduit to the bulb. If your findings had differed I was going to ask you to provide that very type of photo to explain other possible interuptions.

Now one thing I found once you get it going, is if you clean even longer the light will quite possibly burn even brighter due to a more efficient circuit path. The lower the number on the ohm meter the less resistance is occuring. And you may start out at a reading of say... 17 as an example and be able to get it to read a 10 or less.