Many times throughout the thread, I’ve mentioned that Stanley, and some other fairly well known manufacturers, made some well designed, useful hand planes. Amazingly, the plane that I’ll feature today was made by a little known entity, R. M. Rumbold, Co., in Thornton, Illinois. More often than not, Stanley was the innovator when it came to designing job specific, specialty planes. Sargent had their share of good ones too, like the #507 block plane that was featured earlier in the thread. It was not unusual for Stanley to “buy out” smaller manufacturers, thus allowing Stanley to continue manufacturing the smaller company’s products under the Stanley name. The plane depicted below seems to have escaped Stanley’s notice. Either Stanley didn’t believe in its design, or perhaps it didn’t fit into Stanley’s product line. I’ll talk more about that a little later.
R. M. Rumbold Butt Mortise Plane (BMP):
The BMP was specifically designed to cut shallow mortises that would mostly accommodate hinges, lock sets, strike plates, etc. At first glance, it could very easily be mistaken for a “contraption” or gimmick item, and therefore dismissed as such. On the contrary, its simple, well thought out design makes it one of the most useful specialty planes that a wood worker could own. The BMP functions much like a traditional router plane, flattening the bottom of a shallow mortise with ease. What makes it so handy, and separates it from other router planes are its dimensions. A traditional router plane is wide across its handles and short going front to back. Consequently it’s more prone to rock/wobble as it’s pushed and/or pulled along the edge of a work piece. The BMP on the other hand is long and narrow (9 5/8” long and 1 9/16” wide) making it stable for working on the edges with less tendency for rocking/wobbling. The BMP can be pushed or pulled in either direction, thus allowing a user the ability to work into the very corners of the mortise being cut, without having to rotate or adjust the work piece itself. The large window/throat (2 ¾” long and 1 1/16” wide) in the sole provides a clear view of the cut. The cutting iron is ¾” wide and set into the plane with the bevel side down. The BMP has very few parts. Its pressure cap is cast in such a way that it’s captive on a steel rod that runs from one side of the plane to the other. The cutting iron ramp is part of the main body casting of the plane. The BMP appears to be fragile, but never leaves me feeling like it’s not capable of making the cuts for which it was designed. If abused, misused, or dropped, it will crack just like any other plane. If used appropriately to make cuts for various window, cabinet, and door hardware, then I believe that it’s more than up to the task at hand without any disappointments or apologies.
Using the BMP could not be easier, and good results can be had with just a little bit of practice. To cut a shallow mortise, the work piece needs to be marked, and the waste to be removed, outlined with a knife. I like to further clarify the lines with a sharp chisel and a rap or two from a mallet. Using the chisel and mallet, flake up the surface of the cut as shown below. Stay inside the lines and don’t cut too deep. I like to set the iron on the BMP to about half the depth of the final cut. Carefully remove the flakes created with the chisel. Starting in the middle of the mortise, carefully push the BMP to the end of the mortise. Now, turn the plane around and pull it toward you and the other end of the mortise. Once the flakes have been removed, set the iron, using one leaf of the hinge, to the final cutting depth. Again, starting at the middle of the cut, push the BMP to the end of the mortise. Turn the plane around and pull it to the other end of the mortise. If the cutting iron is sharp and care is taken to stay inside the lines, you’ll end up with a flat bottomed, square cornered mortise, that’s cut to the perfect depth. Care while using the plane is a must because there are no fences or depth stops to aid the user. The mortise is the result (good or bad) of freehand operation. Still, this plane is really a pleasure to use and I’d recommend it to anyone who wants to try something a little different when it comes to making hardware mortises. There are most certainly other ways to cut shallow mortises, but using a BMP is my favorite method.
The Rumbold BMP was patented in December, 1951. If you would like to do a little more research, its patent number is 2,579,911 and was invented by Wilbert Dohmeyer. I’m not entirely sure how long the plane was manufactured, but my guess is that by the mid 1960s it was out of production. In my opinion, the BMP was well designed, and easy to use. So why didn’t Stanley make something with a similar design, or better yet, why didn’t Stanley just buy out Rumbold? My guess is that the BMP was too late for the party. By 1951, Stanley’s hand plane offerings were decreasing. Most of the specialty hand planes once produced by Stanley were long gone nearly a decade earlier. The BMP just didn’t fit into Stanley’s plans. Today, I occasionally see old Rumbold BMPs in online auctions, or at tool shows. They don’t seem to show up too often at neighborhood garage sales or at flea markets. They’re available, but you’ll have to look a little harder for them. Lie-Nielsen currently makes a BMP modeled after the old Rumbold. Generally speaking, original Rumbold’s cost a little bit less than the Lie-Nielsen version. If Stanley had in fact made a BMP for a few years, say during the 1920s to 1940s, today it would probably be very collectible and cost prohibitive, like so many of its other specialty planes that are now long gone. By virtue of the fact that the original BMP was manufactured by an unknown company, it’s still relatively affordable, and worth owning. If you come across one at a reasonable price, buy it and use it. It’s a great tool. In a later post, I’ll show you Stanley’s answer to cutting shallow hardware mortises. Without giving too much away, I’d opt for the Rumbold BMP, and I think you’ll agree.
Jim C.
(See the Rumbold BMP in use on the next page of this thread.)
