Wow!  Every forum submissison I enter becomes a gigantic learning experience for me.  I'm trying my best to follow your strumming discussion.  Thanks for expanding the topic... I need the instruction!   But, back to the original question about adding a fret:  I think I have the answer:  I'll just get another dulcimer that was built with the extra fret(s).  After all, aren't two dulcimers better than one?  Now, if I can just figure out a way to convince my wife that the banjo equation also applies to dulcimers...

Thank you both, Ken & Greg/Banjimer.  I, too, find dulcimer ideally suited to syllable playing unlike guitar which tend to be closer to "incessantly repeating a pattern."  I was fairly sure this 1/4 vs. 1/8 notes was what was happening, but thought it deserves clarification.  Our Ditties are never Bum!

Think of the "Bum" strum as a quarter note.  The "Ditty" strum is two eighth notes.  So when Ken says he's a syllable strummer, he is using the "Bum" strum for a single syllable of a quarter note duration and the "Ditty" strum for two syllables of an eighth note duration each.  

To play two eighth notes (double syllable) in the same amount of time as one quarter note the strings are strummed on both the outward and inward movement of the pick.  For the quarter note (single syllable), the strings need only be strummed on the outward motion of the pick.

Like Ken has stated, strumming well is not a matter of incessantly repeating a pattern, but rather matching a tool box of strums to the melody as reflected in the way the syllables fall in relation to each other.  Further complicating the matter are "fill notes", which can be used to extend the duration of notes longer than quarter notes.

Lois, I'm not really a bum ditty player. I'm more like Don Pedi describes as syllable player fitting the strums to the words of songs. As I understand bum ditty it is a single strum followed by a double strum. You can also do ditty bum which is the opposite; a double strum followed by a single strum. Hope that helps you.

Ken

"The dulcimer sings a sweet song."

This discussion is split between "Fret Addition" & talking about strums.  I noticed Banjimmer (@greg-gunner"> @greg-gunner ) gave the common strum using "Bum - Ditty."  I suddenly realized I've had a problem with this common strum that maybe can be clarified here. 

My question is "Does 'Ditty' imply 2 strums just as the word 'ditty' is 2 syllables with probable emphasis on the first half?"  On guitar the strums were highly clarified, but it looks less obvious for dulcimer.  I do strum in both directions unless the song seems to require repeated strokes in one direction to stress the gravity of the melody.  If I'm doing Bum-Ditty is it something like "In - Out" (or vice-versa) or is it "In - Out - In" or even "In - Out - Out" with the part after "In" occurring in the same amount of time as a "Bum"?  To put it another way: Whole - Half/Half?  Because of the time signature I'm presuming the latter as opposed to Whole Note in one direction, then Whole Note in the opposite.

Hope this makes sense and all you Bum-Ditty-ers don't mind clarifying this.

Not much to add that hasn't already been said. Like, Dan, I hope you are not planning to add a fret to a hundred year old dulcimer or one from on of the historic traditional builders. Keep in in mind that adding the 6 1/2 fret is not just putting a fret midway between the sixth and seventh frets. You need to calculate the proper placement for the 6 1/2 fret either by doing the math yourself or using a fret calculator. If you already have the equipment to do the job yourself, go ahead. If not you may find it less expensive to have it done by a professional.

Ken

"The dulcimer sings a sweet song."

There are some things to think about for fret installation; 

1. tools; fret saw with depth control, square, hammer/press, measuring device and file[s] for leveling and finishing the ends.

2. where to put the slot

3. the correct size of fret wire

The 6+ is far enough from the nut-0 fret to be rather difficult to place, the 1+ is easy.

It's probably more efficient to pay for a single installation unless you think you may do more of them.

As KenH has already told you, strumming in both directions is not mandatory.  However, being able to strum in either direction is a great skill to have in your toolbox.  Your strumming hand creates the rhythm, and strumming is a combination of out and in strums.  Begin slowly strumming in one direction only (Bum Strum).  When you can do this without difficulty, strum out and in and strike the strings on both the out and in strum (Ditty Strum).  Then alternate the two strums (Bum-Ditty Strum).  Finally, try different combinations of the Bum and Ditty strums to match the rhythm of the time signature.

4/4 Time

Bum - Ditty - Bum - Ditty etc.

Bum - Bum - Ditty - Ditty etc.

Bum - Ditty - Ditty - Bum etc.

and so forth

3/4 Time

Bum - Bum - Bum etc.

Bum - Ditty - Ditty etc.

Bum - Ditty - Bum etc.

and so forth

The key is to not keep repeating the same pattern over and over, but rather to freely change the pattern within the song to create variety and interest.

The key to playing in both directions is to practice very slowly and often. You'll get it! Sit yourself down and practice slowly and stick with it. In the end you'll be glad to have the skill. Your hand has to go in both directions anyway, so why not make good use of it?

Once you get comfortable with it you'll find your playing gets more fluid and pleasant sounding. When I hear an audio clip of someone playing and if right off the bat sounds unpleasantly choppy to me and with awkward timing, it usually turns out they are strumming or picking only in one direction.
Think of it like walking with both legs as opposed to hopping along on one leg. One leg will get you from point A to point B, but it'll won't feel very smooth and pleasant.

If you play in chording style (fretting across all strings) then yes a 6+ fret is going to make things waaaaay easier for you. (And you won't have to learn all the different chord fingerings for each tuning.)
If you are only going to be fretting melodies on the melody string then learning to retune to different modes will be all you need to do. (and in most cases you'll be only retuning one string.)
If it were me I would get a pro to install that fret since you don't want to mess up the fretboard and you'll want it to not come out later and to look matched. I once went to a music store/guitar store and they did a nice job for a small fee.

First of all, you do not need to "strum in both directions".  I spent some 25 or 30 years being an 'outie only' strummer before one day accidentally strumming both ways and making it work.  I still strum 90% out-only.   You're just starting -- give it time.

Secondly, you do not need a 6+ fret, because you can retune (usually only 1 string) in just a few seconds, to change between the most common tunings to get notes you don't have in your base tuning.

I  think you should first spent some time (a week or two) daily practicing and learning how to re-tune quickly between DAd, DAA, DAC and DAG (the 4 most common Modal tunings).  Play a song in one Mode, retune the melody string, play a song in another Mode, re-tune the melody string... rinse and repeat.  After a couple of days you'll become a wizz at changing that one melody string in just a few seconds.

I think if you're dead set on having a 6+ fret you should, if possible, first borrow a 6+ fretted dulcimer for a few weeks to see if it really is your cuppa tea before possibly irrevocably changing a dulcimer which was intentionally built without the modern non-diatonic 6+ fret. If you can't borrow a ^+ dulcimer, make a temporary 6+ fret with some tape and a piece of paperclip.

To fret or not to fret, that is the question...yes it will make contemporary play much easier. I am a traditionalist and simply retune, but I realize retuning aint' for most folks and the 6+ is the way to go. IMHO

P.S. Please tell me it aint' a hundred year old piece you're fittin' to add a fret to?

I got my 3 string dulcimer and am enjoying the learning process.  (However, I'm finding that strumming in BOTH directions while fretting is like rubbing my stomach and patting my head at the same time.)  Anyway, I got an instrument that does not have a 6+ fret.  I'm starting to think that a 6+ fret would give me more playing options.  So, my question...  What do you think of me installing a 6+ fret?  I've never actually installed frets before but I have replaced some missing frets during a banjo restoration.  Any input greatly appreciated.