Welte T-100 Test Rolls
By Robbie Rhodes
There were three different types, or "levels", of T-100 rolls created by M. Welte & Soehne in Freiburg for testing the Welte-Mignon: "Skala Rolle", "Monteur Skala" and "Fabrik Skala". Specimens of all types still exist, and their attributes seem to correlate with the titles. I have not myself seen the the rarer styles; this brief report is based on conversations with knowledgable technicians and collectors.
The test rolls entitled "Skala Rolle" (or "Rolla") are not terribly rare. After checking the lock and cancel components the tests on the roll seem to be limited to notefield testing and simple, basic checks concerning the crescendos and mezzo-forte hook operation. Since these rolls were available for purchase from the piano dealer, the tests did not lead the piano owner (or novice technician) toward any complicated or critical adjustment procedures, and of course no specialized equipment was required to perform the tests. These rolls were perforated on the familiar red paper.
The "Monteur Skala" test roll ("Installers" or "Assemblers Scale") was not intended for general use by the public, although it's likely that some made their way into the hands of the master technicians in the field. These rolls were perforated on white lined paper, the same as used for draft rolls during performance editing. I don't know yet exactly how this roll differs from the former, except that it has more and different tests than the "Skala Rolla"
Only two "Fabrik Skala" ("Factory Scale") test rolls are known to exist today, and they both display an obvious difference from the other two types: on Fabrik Skala rolls there are two, and possibily more, different hole diameters which are used in critical tests. For example, one test sequence at minimum expression level strikes the same note twice in succession, but with different hole diameters. All playing notes are tested in this way. A plausible explanation is that this sequence was for testing the friction of the player stack and piano action. The note is supposed to sound with the larger hole, and with the smaller hole the hammer is not supposed to touch the strings.
One important difference between these three types of test rolls is probably in the quality control exercised during production. The Monteur Skala and Fabrik Skala rolls, punched on the same white lined paper as used for master rolls, have a significant amount of pencilled notes added as they were checked for accuracy before being placed in service. One can imagine a German artisan testing the finished hole diameter with calipers or a plug gage, to make sure the perforator alignment and punch and die set was okay. The distance between expression commands and the notes would have been carefully measured and controlled, too. This care simply isn't evident in the commercial production rolls on red paper.
More information is needed about these rolls, and hopefully will be forthcoming from Europe.
-- Robbie Rhodes <rhodes@foxtail.com> 13 July 1995
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(Message sent Fri 14 Jul 1995, 04:57:18 GMT, from time zone GMT-0700.) |
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