One More Word on Type Studies, (This old horse ain't dead yet)
I recently received an email from a fellow who was questioning the accuracy of the type study listed on my website and had some observations of his own that he thought should be included. Now, any email that has the words "YOU OUGHT TO..." included automatically lowers the credibility of the author 10 fold but yet, I read on. The full text of the email is not relevant for this article save to say the fellow had apparently figured out a way to determine exact production dates of the hundreds of thousands of planes, over the course of 125 or more years that Stanley made planes in New Britain. In my considered response I thought it wise to logically address his assertion and help him obtain a better understanding of his Bailey Bench Plane Type Study (BBPTS) reality. Below is the text of my response, slightly edited for this article. Take it for what it's worth as just one guy's opinion, but intended to help others get their own grasp on BBPTS reality.
DISCLAIMER: Now, for those of you BBPTS purists who have studied the study ad nauseum and know every nuance, contributor and/or BBPTS researcher, I have probably made a few errors in some of the facts presented about the origins of the BBPTS. My historic assumptions are based on what I've read in PTAMPIA and learned from folks with whom I've spoken at length about the subject (and what I recall from those conversations). I've also taken some literary license to emphasize points I was trying to make. My memory isn't what it used to be so if I "misrecalled" something or violated the terms of my literary license, gimme a break, cut me some slack and get over it. That's not what this is all about anyway.
Dear Mr. Asshole (No, I didn't actually say that)
Thanks for the note and the input. It seems that you've done some study on the matter and you've made some keen observations. Understand first that I did not write the type study you refer to. I referenced a number of sources and have used other's work. I merely placed it on my page as a reference for folks looking for one.
The official Bailey type study that we generally refer to first appeared (as we now know it) in Roger Smith's book, Patented Transitional and Metallic Planes in America, 1827-1927 Volume I. (Smith credits Al Sellens for doing original research which was published in his book THE STANLEY PLANE) It was based on a Number 4 Bailey plane because it, along with the Number 5 were the most common planes produced by Stanley. In addition, they both shared overall characteristics so generally the changes that Stanley made to their planes, for purposes of modern type studies, applies to both. These two sizes accounted for well over 50 percent of Stanley's plane output so they would indeed be the logical choice for a type study that was compiled over 100 years from the date of the type 1. Smith's rendition has been slightly modified by various researchers over the years but the basic structure has remained the same since the book was published in the early 1980s. It's interesting to note however, that while the study focus is on #4/5s and is specific to them, it also generally can apply to the other Bailey bench plane sizes, but with exception. The following is based on my own observations while restoring over 1000 bench planes, the vast majority being Stanley Bailey.
Of course we all know that the Number 1 did not change very much over it's history, perhaps only cosmetically as the iron logos changed and perhaps the frog base (though I've never observed a type 1 No 1). They never had a lateral lever so there's no identifying data to support a production date based on that. The depth knobs were always solid. No patent information appears on any of them that I've observed. The knobs were always short, the earliest with a beaded base. I have an example from around 1876 more or less and the only difference between that one and one produced around 1930 is the logo on the iron and lever cap and the beaded knob.
Number 2 Bailey planes are similarly typed as with the 4 and 5 but with many fewer changes over the years. The frog receiver and base changed from the early H shaped type 1-2 to the later straight front no grooves, then arched front with grooves and remained in that configuration until the type 20 came out in the 1950s. There were other subtle changes as with the 4 and 5s but not as frequent nor as significant.
My observations of the large planes number 6-8 is similar to that of the number 2. They changed on a timeline completely different than the 4/5. Significant changes to the structure of the main casting and frog took place during similar production periods but not as frequent and in different sequences. I have noted frequently that many of the larger planes with "B" castings marks on the frog and body will have frog adjusting screws. As you know from your own research, "B" casting marks are a characteristic of type 8 planes ca1900ish. Frog adjusting screws didn't appear on Bailey planes #4/5 until type 10, at least 7 years later. In fact, on 4s and 5s the type study indicates that the frog base was not even capable of receiving a frog screw because of it's lack of depth until type 9-10 so it would have been impossible to retrofit one with a frog screw. It is however believed but not verified, that some or even many type 10 planes were indeed retrofitted to accept a frog screw, or perhaps they were the early rendition of the main casting prior to the frog screw being introduced to the line. It had been a standard on Bedrock planes since 1898 or so and Stanley was transitioning Bailey planes as the patent ran out on the Bedrock. This proves that the larger planes followed a different path of evolution This would also provide an explanation of your observed "anomaly" on your number 6.
As you are aware, Stanley produced millions of planes over the years, especially during the latter part of the 19th and early 20th centuries. My understanding is that the foundries would tool up to produce parts and pieces in bulk, sometimes producing more frogs than bodies or lever caps. Same with the rest of the components like the lateral lever, frog screws (to a lesser degree as they fit all size planes), and brass depth adjusting knobs If Stanley had parts left over from an earlier run they sat in storage for months, years, perhaps decades in the case of the lower sales volume sizes like 1s and 2s, even the jointers, until there was a call for them. Left over parts were used over whatever period of time they lasted so, (using the modern type study as a guide), if Stanley produced a large run of brass depth adjusting knobs with patent data stamped inside around the time that the patents were running out, any surplus would go on whatever plane needed one as it was being assembled, not necessarily in any order. If the need was for a left handed threaded style the threading was applied to the need, not to the specific plane. My guess is that Stanley combined the threaded studs and knobs and they were installed already assembled, the frog being threaded to receive the stud at the time of assembly. For Stanley, maximizing profits was THE priority, not model consistency. In other words, if the part fit, the part was used, even if the part had been sitting in storage for months, years or decades. Most were indeed interchangeable or could be slightly modified to fit. Newly patented parts were introduced over long periods of time, not on a specific date that could be identified in a type study.
I don't think the type study is wrong, nor do I think it should be changed, modified or rewritten. Nearly every documented type study I've seen, including Roger Smith's original rendering and Leach's interpretation, will suggest that a type study is not an exact document. It is a general guide to provide a time period reference to production. As most type study authors will tell you, there are far too many variations, anomalies and unverifiable aberrations to make them exact. The timelines are sometimes decades long and planes could have evolved to some degree even within that shorter period. Production methods changed, machinery improved, assembly became more efficient through mechanization vs. manual human assembly. Stanley didn't care about model consistency and if you could go back in time and ask them about type study consistency, you'd be hospitalized for mental derangement.
Finally, take into account the fact that your plane is well over 100 years old. Unless it's been in your family history since it was new it's probably been owned by several, if not dozens of owners, some of which probably, or at least potentially could have made changes or modifications to it, repaired it or replaced parts on it. I do it all the time. Most of the time I try to be type consistent but that's because I'm restoring it correctly for resale or more importantly, for my collection. 100 years ago, a fellow making a living as a carpenter or working in a factory didn't give a hoot about his plane except to make sure that it was clean, functional and did what it was made for. These people didn't go out and buy a new plane because the lateral adjuster fell off. They'd order a new lateral lever from Stanley or their local hardware store and install the new one themselves. Same with any component that broke so long as the parts worked for the application. They were not collectors and didn't care if the plane was "correct", just that it worked. We can assume that Stanley produced replacement parts at some rate consistent with the parts used on the regular bench planes so that might mean a replacement depth adjusting knob ordered by someone in 1920 may have been produced in 1910 or even earlier.
If you've read to this point you are probably asking yourself, "Why did he take up so many electrons writing this?" Well, it's because I believe that sometimes folks rely too heavily on what some study tells them and not on their own personal observations and suppositions. A type study is a reference, not the Holy Grail. It will give you a general idea not a specific date of production. It was never intended to do that. Regarding his type study, Roger Smith is reported to have, to some degree, lamented his authoring the document because so many question it's accuracy and believe it should be modified or updated. I was contributing editor to Don Wilwol's book on Sargent planes in which there is a chapter on dating several models that Sargent produced. While he doesn't regret the effort, he always told me that he was dubious about it because he knew that people would take it for more than it was intended. I believed then and do now that Don was correct and though I really appreciate Roger's immense contribution to the project, the same would apply to his lamentation.
I wish you the greatest of luck in your endeavor to accurately date your plane.