Mall Tool Co. vintage lock mortiser

I have about 40 doors in my house, which is an 1890s victorian two family, about 325 m^2 (3500 ft^2). You know how those victorians loved their zillions of little rooms with doors separating them! These doors all have nice old mortise locks in them. I'm replacing some of the doors, and want to reuse the locks, but its a bit of a chore to install them in a new door slab.

Porter Cable and Virutex make door mortising machines, but they cost upwards of $1200. I did two doors for the downstairs apartment using a jig I made for the drill press and a forstner bit to clear most of the wood, followed up by a chisel to finish the mortise. This worked fine, but was time consuming and rather awkward. If I only had one door to do, I would just live with that since it wasn't all that bad. However, I have at least 15 more doors to do so I wanted to think about a more efficient method.

I found this vintage machine on ebay for something like $200 and thought I would give it a try. It came in an enormous rusty tool box with no instructions, and the box is almost as heavy as a person. State of the art in "portable" tools 75 years ago. Very solid though, and apparently still functional. I'd be surprised if my router still works in 75 years.


Most apartments of 1890s vintage are chock full of lead paint, and ours is probably no exception. All the doors have like 20 layers of paint on them, and all bind badly in the jambs. Beyond the fact that it's highly annoying that the doors don't work properly, dust created by impact or friction in doors with lead paint is a top cause of lead poisoning in children.

If I didn't have lead paint to worry about, I would go to town with the power planer and solve the binding problem in a shower of wood chips. But with lead in the picture, there are a few concerns with this approach. First would be that the work itself would create a lot of lead dust. Renovation is the #2 cause of lead poisoning (old windows with lead paint, and the dust they create with impact and friction is #1), and planing woodwork with lead paint would be considered very high risk. Even with the edges planed, there is still an impact hazard presented by the door edge when it contacts the jamb.

Another approach would be to send the doors out for tank stripping to get all the paint off. I did this on one door long before we had kids (it cost $100/door at our local stripper), but the process is very hard on the woodwork, and it comes back with the grain fuzzed up and drastically changed in color. To get a finishable surface, I had to do a lot of sanding. This door was done about 9 years ago, and it has been in our third floor bathroom since then. One bad effect of tank stripping is that the chemicals used in the process permeate the wood, and even though I sanded quite a bit before finishing the door, the moisture in the bathroom has allowed the residual chemistry to react with the finish. Now the door looks kind of yellow and splotchy, worst at the top, least bad at the bottom, presumably from shower steam which is more concentrated toward the top of the room. I also read an article about how tank stripping actually drives lead bearing compounds into the wood matrix, so even though the door doesn't have paint on it, it is still full of lead waiting to get released by sanding. The article referenced a case where a kid got high lead levels, the most likely suspect being the sanding of dip stripped woodwork in the house.

The option we chose was to replace the doors. This is kind of painful because the old doors are nice, thick, 5 panel doors, match the house, are sound mechanically, and we own them already. But all things considered putting in new doors seemed like the best solution. Simpson makes a reasonable 5 panel door that is pretty close in looks to our old ones, and almost as thick, with attractive beefy vertical grain fir veneer on the rails and stiles.

This mortiser is from the Mall Tool Co. of Chicago, model P9000. I couldn't find anything on the web about it, though I did find some information on the Mall Tool Company. From VintageMachinery.org:

The Mall Tool Co. was founded in 1921 by Arthur W. Mall, in Milwaukee, Wisconsin. A year later he relocated the business to Chicago. The company became very successful, employing over 2,000 people making power drills, circular saws, chainsaws, and other handheld products. 

In 1956, Mall Tool Co. was acquired by Remington Arms Corp. and renamed the Remington Power Tool Division. In 1969, some entrepreneurs purchased this Division and named the it DESA Industries. They were acquired by AMCA (Master Consolidated) in 1975. Parts and service for Mall Tool products are no longer available.

So this machine was made sometime between 1921 and 1956; I'd say it has a 1940's kind of look to it but I don't actually know how old it is.

It took me a while to figure out how the parts all fit together and how it is supposed to work. Some of the actions were frozen with hardened grease or rust. But after a bit of kerosene, wire brushing, lube, and exercise, it appeared freshened up enough to perhaps be functional.

I was a little apprehensive to power it up the first time, since it had a look about it that it might be hungry for a finger or two, or perhaps it might go in for a violent bout of self destruction. But beyond smelling of old motor and making a racket, it turned the spindle without incident.

The main body of the tool can travel on two linear rails extending parallel to the door edge. There are self centering clamps on each end of the rail set to clamp the tool to the door, and stop screws extending in from the clamps toward to main body. These stop screws are set to arrest the travel of the tool body along the rails, thus defining the length of the mortise. The back and forth travel along the rails is effected by a hand crank extending out in front of the tool, the other end of which has a pinion gear to engage a rack cut into one of the linear rails.

The spindle itself is a hollow tube with a key feature in it. A central rod with the cutter threaded onto the end extends up through the hollow spindle and is terminated by a red wood knob with a bearing in it. The cutter rod has a keyway such that it may be driven by the spindle.

The cutters themselves are in different diameters, to accomodate different locksets. They are not particularly sharp and appear to be die cast, so I'm a bit surprised they actually work as well as they do. The RPMs of the spindle are not too high either. Certainly a different model for wood machining than a 6000 RPM router with a super sharp carbide bit.

I'm a little mystified about how the vertical height of the cutter is supposed to be set and advanced. There is a more widespread vintage mortiser out there made by Stanley, which has a mechanism for auto advancing the spindle after every sweep through the lengthwise travel. The P9000 cutter rod has some coarse acme looking threads for a few inches down toward the cutter end, but I'm not sure what they are supposed to do. There is also a collar on the cutter rod up near the top handle, which is engaged with a fork mounted to a rod. The fork can go in and out based on some metal pieces near the rails. But I think maybe its missing some essential part, or I just am not figuring out how it is supposed to work. In any case the cutter rod moves freely up and down in the spindle even when it is turning.

Not knowing how to work the vertical drive mechanism, or indeed if one is even present, I decided to try just pushing the cutter into the wood manually a bit using the big red knob at the top. After all, why would there be a big red knob there unless it was designed for someone to grab onto? This worked fine actually. After some experimenting, what worked best was to push in the cutter rod by ~2mm, then leave it level and take a sweep back and forth across the whole lengthwise travel using the handcrank. Advancing the cutter on either end of the travel worked, but it seemed to get hung up on chips more easily and ran smoother if it had a chance to do a full sweep per advance. The top of the rod is marked in graduations of around 1/2" so you can see how deep the cutter is.

So after I got the machine working and figured out how to use it, it took ~5 minutes to to cut the mortise.

Kind of rough in the fir veneer part of the cut, but its ok since its going to be well covered by the faceplate anyway.

Awesome! Nice work P9000! I've got a pile of doors I'd like to introduce you to...

I took the machine off the door and started working on the mortise for the brass faceplate. Quickly I realized that I had cut the lock mortise deep enough for the lock body, but hadn't also accounted for the faceplate, so I had to get the machine out and set up again to cut another 5mm down.

Cutting the faceplate mortise took way longer than the lock mortise. I used a marking knife to score around the faceplate, then a trim router to get close to the marked lines, and a chisel to finish up.

My colleague Peter Kane has a dado plane that I can borrow, which might help in cleaning up the faceplate mortise, but maybe I should also make up a router template. One problem is that these faceplates are not completely square or straight, but I guess I could make the template slightly smaller and make final adjustments with a chisel. Then there is the mortising of the strike into the jamb.

Phew, mortise locks are a fair bit of work, but I do love how they look and how they work.

One book I highly recommend if you have a lot of door work to do is The Doorhanger's Handbook, by Gary Katz. I saw this book mentioned in an online forum in a discussion about mortise locks and ordered it to check out from my library. I think I'll buy a copy though since its very instructive and even on the doors I am not replacing there is a fair bit of troubleshooting to do. The book has a lot that is not relevant to renovation of old doors, but its still pretty darn good and has loads of pertinent stuff.

UPDATE - 3/26/2013
A discussion of this post on Old Wood Working Machines forum, with some additional information on door stripping, lock mortising, and Mall Tool Co. products.