Big Complicated Machines

BCMs #5 – Another Craven Brothers Tool

A typical metal planer

Greetings, everyone.

Today we’re going to look at another overly large machine tool made by the Craven Brothers, a metal planer.

Metal planers are a nearly obsolete metalworking tool for making flat surfaces on cast or forged metal objects. The picture above shows a typical metal planer. In operation, the workpiece is secured to the long table, then the cutter is lowered from the cutting head to the desired depth, and then table and workpiece move back and forth against the cutter by means of a leadscrew, geared or hydraulic mechanism, and making longitudinal cuts. Metal planers have largely been replaced by milling machines and grinders which are more accurate, but they are still used in certain applications, one of which being working on extremely large pieces. That is where the machine below would come into play.

These pictures are of a Craven Brothers metal planer with a 10 foot 6 inch by 45 foot bed with a 15 foot vertical capacity. By contrast, our typical planer looks to be about 2 foot by 8 foot by 3 foot, according to my calibrated eyeball.

I couldn’t find out much about the Craven machine, other than it was made primarily for factories that made large engines, such as maritime engines and large power fixtures for factories. The one in the picture is probably still in use somewhere, even today.


A Craven Bros. 10'6" x 45' x 15' planer

Another view.


Craven pictures courtesy of

  • P161911

    Speaking of old machine tools, when I was at Georgia Tech in the early 1990s several of the lathes and mills available to mechanical engineering students still had property tags on them from the US War Department. When the ME department went to move into a new building and the psychology department was moving into the old ME building it just wasn't worth it to move the old tools. I'm not even sure they remembered how they got them in the building and had no idea how to get them out. As far as I know those machines are still there.

    • The Professor

      I imagine that they are still there, unless someone managed to sell them. These behemoths must have been a true bastard to install back when they were made. In a later post I have a couple of video clips of a very big Craven brothers lathe that was disassembled and moved to it's current location, still all in pieces and waiting to be re-assembled or maybe sold. It's fairly educational.

  • OA5599

    I used to work for a company that purchased some WWII-era forging machines. They had been in place for a decade after the prior owner shut down. I think we paid half of the scrap metal value (which was still a five-figure sum–these things were heavy) for the machinery. We spent WAY more than that to move them 30 miles to their new home: A couple of moderate-sized cranes to pull the roof off the old building and put it back, a heavy-duty crane to lift it onto the trailer (17 axles, if I remember correctly), the same heavy-duty crane to unload and to spin the truck around (too many articulations to back it around the corner), and a bunch of guys in hardhats to wait for the other guys in hardhats.

    With used big machines, the purchase price is just the tip of the iceberg.

    • The Professor

      Interesting story. That pretty much confirms something I've been thinking about since I've been researching these things. If you wanted to acquire one of these beasts because you had a use for them, it would cost a small fortune (or maybe even a large fortune) to move and set them them up, even if you bought them for scrap value. Still, I imagine that it would be cheaper than buying the modern equivalent that had the same capacity. I wonder if the trade-offs are worth it? Probably to the right person.
      I'd like to have seen the move that you guys did.

      • OA5599

        When the machines were unloaded, they were temporarily placed near where they needed to go. It turned out that one of them was a little too close to where the slab needed to be poured. To have the big crane come back out, lift the machine and set it down 20 feet away cost four grand, cash only, for a job that was 45 minutes on site.

        I know somebody who was given, for free, one of those gigantic too-big-for-public-roads dump trucks used in quarries. It was broken in some non-economically-repairable manner, and the scrap metal was worth less than the trucking companies wanted to charge to haul it (due to the required specialized equipment and oversize load permits). My friend was able to make it happen only because he happened to know somebody looking for an engine core and had a brother-in-law with the right truck who agreed to haul what was left for whatever they paid at the scales.

  • B72

    I used a small version of something very similar. On ours the tool oscillated rather than the workpiece. We called it a "shaper". The machine had an electric motor, and a 4 speed manual gearbox. Once I put it in 4th, and the arm moved fast enough to make the machine vibrate across the floor. It was supposed to be bolted down, but ours wasn't. To avoid getting in trouble for messing with the gearbox, I had to figure out how to get the machine back to the place on the floor where it started. I ended up putting it in fourth again, turning it on, pushing it so that it vibrated back towards the right spot, and shutting it off at the precise moment when alignment had been achieved. Pushing a heavy vibrating tool is a bit unnerving.

  • craigsu

    Why is there a twist in the outer drive belt in the first photo? Does it double back on itself (like a figure 8)? Maybe it's just taking up slack to provide proper grip.

    • The Professor

      It's for reversing direction.

    • I've been told that for some applications the belt is twisted and joined as a Möbius strip in order to distribute the wear evenly.

      • The Professor

        That's quite possible. Back in the old days, factories and machine shops used a device called a lineshaft to supply power to various machines via belts. Here's a link that has lots of pictures and doe a bit of explaining:

      • The Professor

        Here's another site with lots more info. Warning: it will play some old-timey music when the page loads, but it stops eventually. I just muted my speakers.

      • The Professor

        This is off topic, but at least you'll see it. I downloaded a batch of hires pictures of things that might be of interest to you. There are a bunch of very good pictures of various crystals, none of which I can identify other than iron pyrites and (non crystalline)gold. There are also a few pictures of some interesting geography that you might like. With luck, these will all be new to you. Here is the link to the Flickr set –

        You can do what you like with them.

        • Hey, thanks! I recognize most of those minerals and can make some educated guesses on the others, if you like. I don't recognize the geographic settings, but it is a big planet and, as a mineralogist, I don't get out much.

          I may have to borrow some of those for my class on minerals and gems.

          • The Professor

            Oh, I don't need them identified. I just grabbed them because they were of very good quality and weren't your typical crystal photos. I'll never forgive the New Agers and the disservice they've done to crystals. I was really hoping that they would be something you could use in your classes. Use anything and everything you can. Consider it my attempt at influencing your students. To study, with any luck.
            There was zero information about the photos where I downloaded them, it was just some guy dumping a load of pictures. Of the landscapes, I don't recognize any of them, but I think that the ropeway picture might be from Italy, possibly in the Dolomites. It doesn't really matter, they're all interesting on their own.

    • The Professor

      I replied to mdharrell instead of you the first time, but check out this link. It plays music, be warned.

  • Raymondo62

    I was an apprentice fitter at Craven Brothers in 1962 and was in awe of the machines that were being manufactured in the factory in those days. The company manufactured some of the largest machine tools that the world has seen, from the idea inception in the drawing office to the to the actual manufacture of the nuts ,bolts wiring, and casting of the huge lathe beds that were transferred from the foundry, which was situated across the road from the main workshops by train. The lathe beds were left to harden outside for two years before the fitters were allowed to startlevelling the beds by scraping. I remember standing beside one of the motors made in the factory to power the machines and being dwarfed by its size. There was a problem of operating some of the lathes due to the size and complexity and as a result the company kept on asking a man known as 'The Dane' to come out of retirement to operate one machine.I mentioned that I was a fitter and my cousin was a planer operator on another huge machine. Unfortunately, no one could sustain the type of work that Craven did without sub contracting and that subsequently caused the demise of the company in 1966.A sad end to an amazing manufacturing company.