Arbor material?

[vanhooglesnort]

What would you recommend I make a new wheel arbor out of? I know it should be hard, but I still have to turn it. Something I can anneal and then harden?

[Bob Tascione]

Hi Vanhooglesnort,
Any high carbon round stock should work fine for you. Fortunately many watch/clock supply houses sell packages of blue steel often referred to as staffing or pivot wire. The blued stock is (should be but do file test the metal for hardness) tempered down to a simi-hard and tough level that is easy enough to machine without further annealing and hard enough for many arbors eliminating the need to harden after machined. In some cases a harder arbor or pivot may be called for or desired so hardening can be done after the part is machined. Also ‘piano wire’ is often used.
The following links may be of help: Especially the mile hi clock supply .pdf
https://www.blackforestimports.com/AdvancedWebPage.aspx?cg=648&cd2&FromPage=
http://www.ronellclock.com/Blue-Steel-Staff-Pivot-Wire-PW-51.htm
http://www.milehiclocksupplies.org/66.pdf

Hope this help Vanhooglesnort!
Bob

[david pierce]

Van,
There are essentially three types of drill rod classified in the way they are hardened. These are water hardening, oil hardening and air hardening. The reasons for selecting one over the other have to do to various factors such as material cost, development of cracks during the heat treatment process, sensitivity to distortion, resistance to decarburization and various other factors. The more common types are W1, O1 and A2. W1 is the least expensive but is the most prone to microcracking and dimensional distortion. This is mainly due to the abrupt temperature change during quenching in water. This steel is generally used for low precision applications such as knives, scissors, tweezers etc. O2 is subjected to less shock during quenching due to the fact that it is quenched in oil and changes temperature more slowly. It is therfore less prone to micro cracks and has better dimensional stability than water hardening steels. Oil hardening steels are used for drill bits, end mill cutters, and other precision cutting tools. A2 is by far the most expensive and costs about three times the price of the water hardening steels. The hardening process involves heating the part to a cherry red and simply letting it cool in the air. This minimizes the shock of abrupt temperature changes during quenching. It is used in applications where micro cracks and dimensional instability are unacceptable. A2 is used in products such as stamping dies and other products requiring high stability after heat treating. A 1/4 inch diameter rod that is three feet long costs about $10.00 from MSC and would probably last most watch and clock makers several years of pivoting.
David

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