Milwaukee Electric Tool is a subsidiary of Techtronic Industries Co. Founded in 1985, TTI is a leading marketer, manufacturer and supplier of home improvement and floor care products, employing more than 20,000 people worldwide. Stanley Black & Decker is the owner of Dewalt and Techtronic Industries (TTI) is the owner of Milwaukee Tool. There are no notable cross-over, partnership, or cooperation efforts between these companies.
Brands such as Ryobi, Dirt Devil, Oreck, Milwaukee Electric and Hoover, for example, are owned by Techtronic Industries, based in Hong Kong. Stanley Black & Decker, based in Connecticut, owns many brands beyond its name, including Lenox, Craftsman, Irwin Tools, DeWalt and CribMaster. Somewhere I saw an interesting article about MKE's leadership, coming from DeWalt and the use of the same marketing techniques that put DeWalt on the map in the mid-90s. When other companies were doing the same in the cordless tool market, DeWalt began creating new tools and listening to pros.
TTI (licensed by Emersson or sublicensed through Home Depot) produces the Ridgid line of small power tools (many of them looking like those of the AEG brand in Europe). In an interesting turn of events, Ridgid table tools (miter saws, planers, table sanders and table saws) are now manufactured by Chang Type Industrial Co. Shane Moll (President of Power Tools) Tim Albrecht (President of Hand Tools & Storage) Paul Fry (Vice President of Wireless Technology).
Milwaukee Toolgrew steadily during the 1960s and 1970s and the company expanded its product lines.
Part of that agreement appears to have consisted of Emerson supplying some tools, such as vacuum cleaners to Home Depot under the Ridgid brand, and possibly other stationary and desktop tools similar to those they had been manufacturing for Sears. As you said, Milwaukee has been beating the crap out of Dewalt in terms of 12V tools, especially mechanical tools. The Group also manufactures garden irrigation products, as well as cutting equipment and diamond tools for the construction and stone industries. However, at least between Milwaukee and Ryobi, there has been at least one “internal patent dispute” involving Ridgid.
Who makes Harbor Freight Power Tools remains a mystery, possibly because they may have changed suppliers in the past. And while Dewalt and Milwaukee have sister tool brands, Makita has no relationship with any other tool brand. After crediting God and his excellent staff for the success of what is now the industry's largest power tool review publication, Clint DeBoer expects to see continued growth for the company as it rapidly expands its reach. Not to be left behind, others have suggested Powerplus as the manufacturer behind the Drill Master, Warrior, Bauer and Hercules lines of tools.
This is a valid opinion, but I must point out that Milwaukee Tool has also invested heavily in new factories and in the expansion of existing facilities, which means more jobs.