Visit the website for Long Island Indicator Repair. They have an incredible amount of information on many manufacturers, brands, or "labels" of dial indicators, mikes, and dial calipers. They even have information as to whether parts or service are available, either thru some branch of the OEM or seller, or thru their own shop.
Craftsman, as is well known, never made anything on their own. The parent company, Sears, Roebuck & Co, wrote up specs for what they wanted or found companies who already made it as a stock item, and simply ordered it in large lots for inventory. It used to be a "secret" as to who Craftsman used for making the various tools. Some years, their power tools were good quality, maybe Millers Falls, maybe Black & Decker (back in the 50's, B & D made good tools) , then they went down a few notches and used Wen (or some firm making similarly low-end power tools). Wrenches used to come from a drop forge shop in Springfield, MA, but not any more. They now come from other plants and the quality really has come downhill. Back "in the day", Sears/Craftsman specified good quality tools and went to reputable US vendors. Nowadays, it is another story, unfortunately.
It would not surprise me to learn that Craftsman machinist tools of the 40's-50's were made by Lufkin. Back in the day, Lufkin made as good machinist tools as Starrett or Brown & Sharpe. Lufkin, not being so big as Starrett or B &S, might have been the more likely firm to have made machinist tools under Craftsman's label. Another firm might have been Union Tool, in Orange, MA. Their combination squares are pretty much what Starrett made. Dial indicators may have been made by Gem, out in Ohio. Gem either made indicators for Lufkin, or took over that portion of Lufkin's business when Lufkin got out of making machinist tools. Federal Gauge, in Providence, RI, is another likely maker of Craftsman dial indicators. I have a Federal dial indicator that is remarkably similar to a Starrett "Last Word" dial indicator.
I think nowdays, Sears may be using Chinese imports for most of their machinist tools, sold to the lowest bidder, let loyalty, quality and reputation be damned.