Grade of Materials

[nograss]

In some books on Waltham "Numbers and Descriptions" of Waltham Watch Movements along with serial numbers, size,etc.; there is a "Grade of material" letter shown. The letters most often used are "P", "A" and "U". Could someone please tell me what these letters signify? Thanks.

[nograss]

In some books on Waltham "Numbers and Descriptions" of Waltham Watch Movements along with serial numbers, size,etc.; there is a "Grade of material" letter shown. The letters most often used are "P", "A" and "U". Could someone please tell me what these letters signify? Thanks.

[Tom McIntyre]

Position, Adjusted, Unadjusted.

You might take a look at this glossary (http://www.nawcc-info.org/WalthamDB/Glossary.htm) on Waltham terms.

[Steven Mercer]

From the Glossary (http://www.nawcc-info.org/WalthamDB/Glossary.htm):

U - "U" stands for "Unadjusted." These include most 7-15 jewel watches. These are usually not adjusted for positions or temperature (other than that provided by the bi-metallic compensation balance). Timing screws are brass and there are usually no mean-time screws. A "U"-grade balance staff has no oil grooves and the coarsest pivots. Wheel pivots are the coarsest used in the model.

A "A" stands for "Adjusted." These watches, usually with 15-17 jewels, are usually adjusted to temperature and perhaps 3 positions. They may have a gold center wheel. The balance wheel may have one pair of gold mean-time screws, but the other balance screws are usually still brass. An "A"-grade balance staff may have one oil groove and intermediate pivots. Wheel pivots are intermediate in size.

P "P" stands for "Positions." These are usually 17-23 jewel watches adjusted to 5 or 6 positions. They almost always have a gold center wheel and the highest grades have an entirely gold train. Usually they also have gold jewel settings. The balance wheel usually has gold balance screws, and often has two pair of gold mean-time screws. A "P"-grade balance staff may have two oil grooves and has the finest pivots. The wheel pivots are the finest used on the model.


Steve

[Kent]

As Steve says, these the usual meanings and are only guidelines. For example, the earlier model `83, grade No. 35 is described as being a 15-jewel movement, adjusted to six positions. As such, its material is indicated as 'P'.

Kent

[Spike]

Among physical factors characterizing watches of various levels of adjustment Steve mentions gold timing screws, gold mean-time screws, gold jewel settings, gold center wheel or entire train.

What advantages are associated with using gold in these applications? Might the relative softness of gold confer any disadvantages?

[Tom McIntyre]

The perceived advantage (apart from marketing cachet) was that gold had better lubricity than brass. If you make a gear train out of hard metals acting on hard metals, you need to polish it well to avoid losses. If there is any hard material that gets caught in the train, it can cause scoring and other damage. The material that cause the trouble can be microscopic in size. With soft metal interfacing with hard metal, you get a natural lubrication due to the soft metal absorbing the very small particles.

At least that is what I have been told. When designing gear trains for our robots, we used highly polished high performance steel gears for the entire train. However these were high load gear trains. In a watch the loads are very light.

[Corrected typo in "cachet." Us professor types have to be careful or the students get out of line. :biggrin:)

[Jon Hanson]

How about rust and corrosion which can cause less perfection in adjustment?

[Spike]

Is it generally observed in studying watch movements that gold’s perceived lubricity and anti-rust/corrosion advantages have “stood the test of time” compared to contemporaneous alternatives?

[Tom McIntyre]

It hasn't been long enough yet. The brass-steel trains should be good for about 500 years while the gold-steel ones should last about 1500 years. The newer phosphor bronze alloys are probably an order of magnitude better than those numbers.

The reason for the high performance is in the design of the wheels and the essential absence of contact friction in horological wheel works.

Fred McIntyre adapted the horological wheel design to gear pumps with great success in the 1930's. http://www.awco.org/MWCo/Presentation/fredafter.htm

[nograss]

Thanks everyone. I really get an education when I ask a question. I really enjoy it and learn a lot.

[Spike]

Kent Singer says (http://www.pockethorology.org/Railroad/Railroad.htm) that “a near universal inclusion of two features occurred over the course of only a year or two around 1906-1908. One was that the marking "Adjusted" gave way to "Adjusted 5 Positions".

I understand that surviving records seldom tell us how many positions were implied by the term “Adjusted” on early watches.

Question: Is it reasonable to suppose that the characteristics enumerated by Steve above correlate well with the number of positions implied by the term “Adjusted” on early watches?

[Kent]

Spike:

The term "Adjusted" meant whatever the movement manufacturer specified it to mean for any given grade at any point in time. In 1901, both the Waltham model `92 Appleton Tracy & Co. and the Vanguard were marked adjusted. The AT&Co was specificed at that time as being adjusted to three positions, while the Vanguard was spec'd as being adjusted to five positions.

Just a few years earlier, the U.S. Watch Co. at Waltham specified its grade No. 52 to be adjusted, seemingly only to temperature (having a compensation balance but adjustment to position not mentioned). At the same time the firm's "The President" grade, also only marked adjusted, was specified as being adjusted to all positions (probably six).

Kent

[Spike]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Both the Waltham model `92 Appleton Tracy & Co. and the Vanguard were marked adjusted. The AT&Co was specificed at that time as being adjusted to three positions, while the Vanguard was spec'd as being adjusted to five positions…the U.S. Watch Co. at Waltham specified its grade No. 52 to be adjusted, seemingly only to temperature (having a compensation balance but adjustment to position not mentioned). At the same time the firm's "The President" grade, also only marked adjusted, was specified as being adjusted to all positions (probably six). <HR></BLOCKQUOTE>If a guy had examples of those four watches in hand it would be interesting to see whether their levels of adjustment are consistent with constellations of characteristics like those Steve lists in this thread.

[Barry J. Fish]

Gentlemen,

I have a question about 5 position adjustments: what about those watches signed adjusted made prior to the Vanguards or possibly the United States Walthams? To what number of adjustments are these?

Thank you.

Barry

[Kent]

Spike:

Steve's stated characteristics, reasonably good descriptions though they may be, are still generalizations. They'll give a good indication, but not good enough to be certain for many watches. It may be useful to look at the 15-jewel Waltham model `83s described in an 1887 distributor catalog:
<span class="ev_code_brown">www.elginwatches.org/scans/sales_catalogs/1887_S_F_Myers/l_waltham_watches.html</span>
(you should copy this address and paste it in your browser address bar - <span class="ev_code_blue">if this doesn't work the first time, try opening a new window for your browser, one without a previous visit to the NAWCC website</span>)

The grades No. 25 and No.35 clearly state the number of position adjustements and Steve's guide is consistent. However, in looking at the AT&Co and Crescent St. grades, you're still left wondering about it, although the Crescent St. seems to be a superior watch to the AT&Co.


Barry:

The ambiguous use of the word "Adjusted" on American movements goes back at least as far as the early 1870's and possibly earlier. "Adjusted" could mean adjustment to temperature, or to temperature, isochronism and positions (number unstated). I just picked those watches as examples

Kent

[Spike]

A movement Kent cited, the Waltham M83 No. 35, would be in the Glossary’s “P” group with regard to number of adjustment positions and in the “A” (or even the “U”) group with regard to number of jewels.

When it comes to the reliability of rules of thumb, woe is (apparently) us!

[Tom McIntyre]

We are in danger of confusing correlation with cause and effect.

If a watch was adjusted to precise timekeeping, the cost of the adjustments overwhelmed the cost of the materials. In particular the finish on the pivots and other parts was expensive as well as the adjustment operations themselves. The finish was necessary to allow the watch to be regular enough to be adjusted.

Jeweling is not really relevant. There is no good evidence that center jeweling improves the performance of the watch or improves its ability to be adjusted. English watches were often highly adjusted and had as many as 19 jewels without center jeweling. Center jeweling in the pillar plate was often omitted because of the likelihood of broken jewels with the large hole and relatively thin walls of the jewel.

So the thing to remember is that jewels do not really count above 15 and certainly do not count above 17 in terms of adjustability and therefore the grade of the material. Remember the U, A, P refer to material grades, they only correlate with watch grades.

[Spike]

Thanks for the clarification Tom.

I’ve even read that more jewels than eleven are irrelevant with regard to performance. Doggone it, I can’t find the reference.