Determining approx year for Stanley Electric Tool Co drill + Black and Decker

[Watchmaker]

Hello everyone. For the past few years I have been trying to put together a collection of usable tools that are pre-1940, as in pre-WW2. I have found it to be quite difficult to find tools this old in my area. 99% of the ones I find are 1950s thru 1980s, which I am not interested in. I suppose that's because manufacturing really took off after the war, and thus regular people were able to amass a collection of tools, but I digress. 
 
Here I have this Stanley Electric Tool Co drill. It is 14" in length. It's in very nice working condition with plenty of power. The serial number is DE8469J on a big brass information placard. Also on it is a US patent number of 1821436. According to this source, the patent was granted in 1931: http://www.datamp.org/patents/displayPatent.php?id=15852. Also the screws for the motor brushes as well as the internal trigger switch casing are made out of Bakelite plastic which was used extensively in the 1930s. Jacobs chuck. I strongly believe this drill to be pre-1940, but I wanted to get some other opinions! I won this in a local auction for $3, and it's one of my favorite tools. 
 



 
 
Next is this Black and Decker drill. The information placard is missing, but it looks like it used to be a sticker. This one is 10.5" long. It has a big motor and wooden handle which has 3 positions it can screw in. The brush screws are Bakelite plastic. I'm a bit unsure on the year of this one. It's all held together with phillips head screws, which leads me to believe it's from the 1950s or 1960s, but that's only a complete guess. It works well and has a good bit of torque. Jacobs chuck. Any ideas? 
 



 
Last is this other smaller drill. It's 11" long, but the motor is fairly small as well as the chuck. The information placard is riveted on, but the printing has worn away. It runs and has power, but not as much as the larger drills. The chuck is an HIA Chicago type.


 
 
Thanks everyone for checking out my post, and for any information you may have!

[john k]

The big Stanley, I would peg the age as the late 30s, has to be some Stanley info on it somewhere.  The B&D, the late 50s, early 60s, remember my dad had one very similar.  The last one Chicago type, definitely from the 60s, just from the space age styling of it.  Before WWII electric drills were heavy, and expensive, compared to the labor rate at the time.   The tens of thousands of people working in defense plants got used to them which increased their worth post WWII.  I'd be sure to use cords with a good ground with tools this old.  You don't want people to call you Sparky!   

[mikeswrenches]

This much from the "Vintage Machinery" site.

Originally known as "The Stanley Works, R. L. Carter Division", it was created when The Stanley Works bought out Ray L. Carter's line of portable routers during the 1930s.

Not much help...but a start.

Mike

[Watchmaker]

Thanks for the replies gentlemen. I had read that exact excerpt from the Vintage Machinery website. The Stanley drill I have no question that it's from the 1930s, which I'm happy about since I have so much trouble finding tools from the 30s. The other two I questioned the most.