MIMF

Hi.

I would like to improve the playability of my Martin D28

Currently the relief is > 0.63mm and the action at the 12th fret is ~ 3mm

I can't find any numbers from Martin themselves. I'm guessing there will be more relief and a higher action on this instrument than on a solid body electric...but I don't have any ballpark numbers. Can someone offer some tried & tested advice please?ps

3mm ~ 0.118"

0.63mm ~ 0.025"

Thanks,
Rob.

Typical relief is .010" and typical action is .060". Adjust the truss rod first to set the proper relief and see how far that brings down the action.

Depending on the age of the D 28 it may incorporate a non adjustable trussrod. Adjustments to relief may be limited to fretwork or leveling the fretboard and be somewhat problematic. Stewmac lists the typical bass string action (12th fret) at .090" so yours is not too far out.

Barry may be a little high on the relief and a little low on the action, but definitely ballpark. You have to do very good fretwork to get the action that low.
I'm guessing that your D28 isn't old enough to have a non adjustable rod, there is an adjustment accessed through the soundhole.
I generally use the truss rod to get the neck dead straight with no string tension as a starting point. String tension usually pulls pretty close to the correct relief into the neck. Don't try adjusting the truss rod with string tension, it's strong enough to hold it where it needs to be with string tension, but it may NOT be strong enough to pull it to where it needs to be under string tension.
How much saddle is there above the bridge? You need to lower the saddle by twice as much as you want to lower the action at the 12th fret, after you get the relief set correctly.

I'd want relief to be around a quarter of what you have now 0.15mm or 0.006 inches
Set the relief to this then check nut slot height and then 12th fret action.
You may find that adjusting the relief down to this brings the 12th fret action down to 2.5mm or even lower. you may even have to RAISE the saddle

Thanks guys.

It's a 2004 model D28 so I guess the truss rod is adjustable. Thanks again.

The 'set up' should be tailored to your playing style, generally less relief and lower action if you play lightly, and more relief and higher action if you are more aggressive. Not all D-28s can be set to the same specs, as some tend to buzz more easily than others in spite of 'perfect' frets.

If this guitar is under warranty I suggest you take it to an authorized Martin Service center, as the playability is part of what the warranty covers. It's not rocket science but you can seriously damage the rod if not done properly, and in that case your warranty would be out the window. I would let the Martin tech make the adjustments.

As you can see you are getting all sorts of suggestions for adjustment specs, they can't all be right. If you want to learn the ins and outs of set up then I suggest you get some inexpensive instruments to use as study material, read some books and websites covering the process, and go for it with your 'school work' before working on expensive instruments. It's not difficult but you do need some specific knowledge, especially if things don't go the way you want.

The best website I know for setup information is
http://www.bryankimsey.com/
He is firmly of the belief that low relief is the way to go even for aggressive playing and my experience backs that up.
With excess relief, you may play cleaner in the "cowboy chord" area, but get past the 6th fret and you end up climbing out of a hole and next fret to string clearance is reduced.
Lower the relief, don't be put off if initially that causes buzzing, that just means you need to raise the saddle.