A microtome
is needed for cutting samples for microscopy. The samples have to be suitably thin,
so the cells and structures in general are in only one layer, unoccluded. Multiple techniques are used here,
with handheld microtome being one of the oldest and simplest.
Off the shelf microtomes are however somewhat large and unwieldy. A small one was made on a whim.
The microtome has a few basic parts. The top table, where the cutting action happens; this has to be flat. The hole in which the sample is held, whether in wax cast or in e.g. a cut piece of carrot. And the piston, usually screw-actuated, which controllably pushes the sample out.
A M16x40 hex-head bolt was used as a starting point, for the table and the body of the device. The piston was chosen to be made from a piece of 10mm steel rod (part of a shank of a M10 bolt that gave the rest of itself to another project). The screw was chosen to be an unmodified M12 bolt randomly laying around.
A hole was predrilled to the bolt head on a lathe, then continued through all its length on a drill press.
 M16 40mm bolt |  bolt head predrilled |  drilled through |  drilled through, head side |
The hole was then drilled to 10mm from the head side and 10.2mm from the shank side. A standard M12 thread was cut in the shank side, to about half the length.
 M12 bolt, M16 bolt drilled and threaded, 10mm rod |  M12 bolt, M16 bolt drilled and threaded, 10mm rod |
The head was faced on a lathe to be flat.
 Head side, drilled and faced |  Bolt, drilled and faced |
The piston rod was faced as well.
 Rod, faced |  Rod, faced |  Rod, faced |
The rod was placed into the hole in the bolt and its fit was tested if it can move freely.
 Bolt with rod in place |  Bolt with rod in place |  Bolt with rod in place |  Bolt with rod in place |
The assembly was put together and briefly tested, so far without the sample. The nut plays no structural role, is there only to make the assembly easier to hold in hand.
 Full assembly |  Full assembly |  Full assembly |  Full assembly |
 Full assembly |