The portable mills can cut lumber with speed and accuracy, though the subsequent steps of planing and drying must still be performed to produce finished lumber. There are portable mills with rails on the ground allowing a log to be positioned easily without hydraulics. Raising heavy logs without hydraulics can be a problem. Most trailered mills position the log on top of the trailer some models have hydraulic log loading arms and some do not. Purchasing bandsaw blades and having them sharpened is more expensive than circular saw blades such as those used on a swingblade sawmill. Some businesses transport their mill to harvest urban timber where moving the logs would be impractical. Portable mills can be trailered and set up on site, next to the trees being cut. These cut faster and can handle larger logs but do require additional set up.
Larger mills have recently come on the market which are portable only in sections. Many companies now manufacture and sell personal and portable sawmills, and Norwood Sawmills in North America has registered the most portable sawmill patents. This is in contrast to traditional mills where the log moves on a trolley while the blade remains fixed. Use of band blades also allowed for a different design where the head, consisting of the blade and a power source, moves back and forth while the log remains stationary. The smaller kerf on these blades dramatically increased the yield from a given log. Unlike traditional mills, they used a thin-kerf blade of the type used on a band saw rather than a circular blade, which reduced weight and cost, and reduced the size and weight of the bearings and support blocks. More recently, with the invention of the Wood-Mizer in 1982, portable bandsaw mills represented a dramatic shift in design. This was, and remains, a traditional occupation for Amish men unlike most mechanical systems, small sawmills typically do not use electricity. Prior to the advent of the portable mill, small-scale sawmills were generally cobbled-together affairs constructed and operated by (almost always) two men with a penchant for tinkering. Many early sawmills were designed to be belt-driven from a steam traction engine (which could also be used to transport the saw). Another company that built such mills was the American Sawmill Machinery Company. These mail-order examples were "private label" machines manufactured by the Belsaw Company. The first dedicated portable sawmills were typified by the "One Man Farmer's Sawmills" that featured large circular blades and were marketed during the early twentieth century by companies like Sears, Montgomery Ward and JC Penney. It was used to winch and haul log booms across lakes and water, then winch itself across land or water to its next site, and finally it would be reconfigured to run a saw to mill the timber. Arguably, as once used in early Canadian forest logging, the donkey engine was one of the earliest portable sawmills.
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