Ken, the purpose in my previous post was not to belittle you, much less foment an argument. But since, in so many words, you clearly implied that I don't have a clue I find myself pretty much forced to revisit what I said and see if we can maybe end up on the same page.
Firstly, I am in no way confused about the nickle and dime set-up method - not in the slightest. I, in fact, understand it well enough to see an issue with using a dime as described; although I acknowledge that in most cases it will work - especially with vintage instruments built in an era when fret profile options were probably more limited. But there are exceptions to most every rule and I'd hate to see you blamed, after the fact, for giving bad advice.
When setting a dime on the fret board adjacent to the first fret the actual "gauge" in effect is the thickness of the dime minus the peak height (or more properly: the crown height) of the fret. That's the rub: there is no universal crown height. Using StewMac as an example reference, their fret wire recommendation for a modern dulcimer would be the following profile: width=0.080", crown=0.040", tang=0.062". However, who knows what fret convention (if any) was in effect over 30 years ago, and builders of any era are in many cases going to use what is readily available and/or go with their own personal preference - even staples. Again, using StewMac as a readily available reference, their fret wire crown height options range from 0.036" to 0.074". While the more extreme heights are recommended for electric guitar and bass, if rules can be broken then certainly recommendations can (and will) be ignored.
Now, bear with me, the thickness of a dime is 0.053". Therefore, using 0.040" as a "standard" dulcimer fret wire crown height, the effective "gauge" of a dime-on-a-fret board is 0.053"-0.040"=0.013". In the "it won't work" example that I provided in my prior post, the crown height slightly exceeds 0.053" (thickness of a dime), and yes - the fret is properly set. Clearly, in this particular case the nickle and dime method would be inappropriate for a nut adjustment. Were I the newbie you portray me as, and blindly followed your advice, I would be screwed! I will credit you as now being able to understand that.
Lastly, please pardon me for answering your "chest thumping", but I've been into a variety of stringed instruments for over 60 years, know a bit about "set-up" - up to and including complete fret jobs on guitars. In the final 21 years of my career I was a metrologist (that really IS a word meaning, briefly, "one who measures"), a legislative liaison and was responsible for state petroleum law enforcement - so I do know a bit about measuring things and rules and adversarial relationships. My intent here, and in my prior post, was in no way meant to belittle you. I'm truly sorry you took it that way. However, my concerns about the nickle and dime method stand - they are justified. I must say that your rebuttal was beneficial inspiration for additional research yielding such things as the thickness of a dime, information about fret wire profiles, and the availability of suitable feeler gauges to use between the string and first fret. I found that a 17 blade feeler gauge set covering a range of 0.010" to 0.035" is available for $3.99 at an auto parts store within a mile of my home. Your effective target gauge of 0.013" is in that set and overall will be a valuable tool in determining the string-to-fret-gap in dulcimers that have what I perceive as good action as opposed to those that do not. Until now I've been squeamish about messing with nut adjustments on my more prized dulcimers but your kick-in-the-butt has, though somewhat inadvertently, given me considerably more confidence. For that I thank you!
UPDATE: I caught an error in my previous post which the forum daemon will not allow me to edit (I gather because it is too dated), so I will acknowledge it here. The symptom described in the second sentence following the quote is related to improper fret setting - not a low action adjustment at the nut. An action set too low would be characterized by open string fret buzzing (duh!). No excuse for the misinformation other than a mind that drifted off while trying to meaningfully organize a plethora of intonation symptoms and causes. Note to self: Don't multitask whilst writing technical material.
updated by @jim-hedman: 04/01/18 01:14:03AM