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How to Measure For and Make a Barrel Cover

From Horology magazine, December, 1937

How to Measure For and Make a Barrel Cover

ALTHOUGH this job is not an everyday occurrence, the man at the bench will, however, find it necessary from time to time to make a barrel cover. How often does he, after having supposedly made all necessary repairs and cleaned a watch, find upon reassembling same, that the cover on the barrel will not hold tight? True enough a barrel contractor often does the trick.  In many instances though, results are obtained that are not satisfactory and the only alternative is a new cover.

Before work on this cover is started, inspect the recess in the barrel to make sure it is in good condition. Most likely you will find it rough or worn, which, of course, must be corrected first. This can be done by cementing the barrel with the recess for the cover out, on a cement chuck. Care must be exercised to get same to run true in the round end flat.  Good results can be obtained for this operation by holding a pointed peg wood in the hole for the arbor and on the tee rest, and with the lathe running at a fairly good rate of speed. With a graver then it is an easy matter to recut the old recess, slightly on a taper inward to insure a snap fit. The cover then is made to fit this new recess.

In measuring for this cover as is shown in the drawing, the first dimension that is needed is the total outside thickness of the barrel or the A measurement. Now we must have the thickness of the lower boss and the barrel arbor, or B plus C respectively. A then minus B plus C will give us D, or the upper bearing. The depth of the recess is then measured for the E dimension, and this subtracted from D will give us F, or the height of the boss. To give the barrel arbor endshake, deduct about .03 millimeter from the height of the boss.

Now that these calculations have been made, we can proceed with the work.  Rough out a brass disk large enough for the cover and slightly thicker than is the cover plus the boss. This is then cemented on a cement chuck and faced off flat. The stock is then cut back the F measurement, leaving the boss slightly smaller than is the diameter of the arbor. 

If care is not taken and this diameter is left larger than the diameter of the arbor, the cover will not stay on when the main spring is wound up. The cover is then cut to size to fit the recess. As a snap fit is desired, the edge should be on a slight taper (about one and one half degrees. This will leave a rather sharp edge and it is a good policy to round off same as is shown in the drawing. A slot must now be cut on the edge of the cover for the main spring end, also a notch so that same may be easily removed. The cover is then ready to be faced off to its thickness. This is done with the barrel cemented on a cement chuck. Make sure as before in the cementing up of the barrel and the recutting of the recess, that it runs true in the round end flat. The cover is then snapped on, with the slot for the main spring end directly opposite the one in the barrel, and turned down flush with the barrel. With a graver then sink a center and drill a hole slightly smaller than is the diameter of the arbor; with a boring tool now bore hole to fit same. As a precaution, if it is a Swiss watch and the main spring end does not project through the cover, it is a good practice to mark cover and barrel so that it can be taken off and replaced in the same position, eliminating any possibility for it to run out of true. 

Although this seems like a long way around to do this job, with a little care good results can be obtained and the barrel complete will be as good as new.

Depression Story Gives New Idea

Here is perhaps one of the last of the depression stories.

A merchant is reported to have told his clerk: 
"Tom, because of your good work, I am going to make you a partner, giving you a share of the profits." "Thanks, sir, but I really believe I am too young for such responsibility and besides I have a family to support. I believe I would rather keep my present job and salary." "No back talk, young man," replied the merchant. "Business is business and we've got to cut expenses."

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