Heavy duty 10,000lb (5 ton) low profile machine moving dollies, with solid steel rollers. These will move your Bridgeport milling machine, lathe, CNC machine, or any other type of heavy equipment that you need to move around your shop with ease. You can also mount these skates to your machine permanently if you wish, making it convenient to slide your machine out when necessary to access the back side for clean up, routine maintenance, chip clean out etc. I hand make each and every one of these skates in my own shop, using all locally sourced steel, and all the hardware is grade 8 for maximum strength. I make all of the rollers by hand on my 1942 vintage Monarch lathe from solid bar stock. I turn each one for concentricity and to ensure smooth rolling, and then they get center drilled and bored before reaming them for a perfect fit onto the axles. A light coating of grease is all that is needed for smooth operation. This creates a very strong and reliable design known as a "plain bearing" which is much stronger and more reliable than a ball bearing. In high load applications such as moving heavy equipment around, ball bearings can fail due to point loading, which is the last thing you want during a heavy move. Plain bearings can handle much more weight than ball bearings, because the load is spread evenly over the entire surface area of the bearing. The 2.250” inch wide solid steel rollers are fully contained within the undercarriage of the skate. This not only makes them compact for storage, but since all of the weight is straight down straddling the axles, it prevents any flexing of the axles, which can be a problem on designs with outboard wheels. The skates are very low profile, and only stand 1.75” high, which is much lower than any of the competing models, making them much easier to get under a heavy load, without having to jack the load too high up off the ground. And unlike the cheaper models that don't come with an attachment point, mine come with a mounting bolt to securely attach the skates to the bottom of any machine to keep them from sliding out when moving a heavy load across uneven floors. I machine each and every one of these skates by hand, using all manual machines in my small home machine shop in Ohio. This listing is for two (2) skates. Thanks for looking!