3: Third attempt at self-reproducing machine tool


The third and current as of 2018 attempt to instantiate a self-reproducing machine tool is a suite.

A suite of standard specialized machine tools, for example: table saw, band saw, vertical and horizontal mills, drill press, and lathe.

Each can make a part of itself and some parts of the others.

Together they can make all parts of each.

Together they are co-reproducing.

Individually they are partially self-reproducing and partially other-reproducing.

By adding a redundant X axis slide to the heads of the mills and powering the X slides,

out-of-range duplication of that X slide becomes possible, in addition to

duplication of all smaller parts.

With clever design, I believe all parts of all the other machines can be made "smaller", that is,

within the limited work envelope of the mills and the other machines.

It is necessary to prove two things:

One, that every feature on every part can be made, and,

Two, that every part will fit into the work envelope of its featuring machine.

If this is done, the proof is complete.

We may remember that part overhang is permitted as long as

features located with a machine are within the work envelope.

Some features are not located to such precise tolerance.

Jig overhang is also permitted.


I intend to start with

a board foot of material per machine.

Initially I'll use a 1/4 inch slab of virgin HMWPE and a 3/4 inch slab, each

12 x 12 inches.

Later, I'll use a 3/8 inch slab of MIC-6 aluminum tooling plate, and

a 5/8 inch slab, each 12 x 12 inches.

The table saw can grind aluminum to a bearing surface.

HMWPE is a low friction material suitable for a model.

The third attempt will *not* involve a foundry.

The third attempt will *probably* not involve CNC.

The third attempt *must* use opposing motor driven redundant X axes on

the milling machine heads and ways to reproduce

those X axes to a non-trivial degree of precision.

The dovetail ways will initially be built up from

slab segments cut with a table saw at bevel angles,

clamped and permanently screwed together with

permanent washer and removable paper shims

to establish the needed working clearances,

including a gib strip.

It seems likely that a doubled Y axis will be necessary

to support

the long X axis

during reproduction.

Such doubled Y axes would be

timing belt synchronized

to avoid jamming.

In a final version these ways *might* be


with brass bearing faces.


Robert A. Freitas Jr., Ralph C. Merkle, Kinematic Self-Replicating Machines, Landes Bioscience, Georgetown, TX, 2004. 3.12 Bradley Self-Replicating Teleoperated Machine Shop (1980) http://www.molecularassembler.com/KSRM/3.12.htm