Slide rule workshop X
Chris' mystery slide rule Nr. 8
Slide rule made of thin layers of timber, pressed and glued together.
During the last 10 years of the slide rule era a further refinement in materials was introduced at Faber-Castell,
i.e. laminated wood (Preß-Schichtholz). This involved paper-thin layers of wood that were pressed and then glued together.
Data copied from “Rechenschieber - eine Dokumentation” by Dieter von Jezierski, p.27:
- In this book it is mentioned that slide rules were also made of thin layers of timber. In my view a kind of veneer.
Questions:
- Has anybody an example of such a Faber Castell or another brand which used the same technique?
All the Tavernier-Gravet slide rules of 36, 40, 50 cm are made with 5 layers of timber:
3 are boxwood, 2 pearwood (b,p,b,p,b).
The picture is a T.-G. 50cm Soho slide rule with address “39 rue de Babylone”,
so dating about 1860.
Marc Thomas
- Does somebody know the FC number of this type of slide rule?
- A slide rule is about say 5 mm thick. Veneer is about 1 mm thick.
So what problem solves the several layers of thin timber?
I think that this method permits to make the rule much rigid, and avoid the deformation due to its length. Pearwood was used (for instance by Morin) to make ordinary rules or squares with no graduation because of its colour, brown. Boxwood is more clear, almost yellow and the graduations appear very clearly. Internet says that boxwood is “appropriate to very thin work” Marc Thomas - Is this a cheaper method of production?
- Any idea what the advantages are?
- Any idea in what year this type of construction was used / was started?