Build Diary of an MMB-5

[RalphH]

For those interested; thought I would share how I shaped my nut slots without a set of luthiers nut files...
Wet n' dry abrasive paper (I used 220 and 400G) wrapped around wire of various diameters. Two examples shown here.
To be able to do this properly, you need to drag the back of the paper across the edge of a flat surface in 2 directions 90 degrees to each other. This makes the paper more flexible and able to form curved shapes. If you don't do this, the paper tends to shape a V instead of a O.

[Simon Barden]

I've never used nut files for bass nuts. I'm not actually sure that I've seen any to buy and I have looked around. A small round needle file is all I've ever used (normally the pointy end). I think you'll need to work on the slots with the nut installed (the top E looks a bit higher than the bottom B slot), so you may find a round needle file easier.

[RalphH]

I've never used nut files for bass nuts. I'm not actually sure that I've seen any to buy and I have looked around. A small round needle file is all I've ever used (normally the pointy end). I think you'll need to work on the slots with the nut installed (the top E looks a bit higher than the bottom B slot), so you may find a round needle file easier.

Yep, I found it hard to get quality round files of the appropriate sizes, hence the abrasive paper route.
The best thing about the "wrap the wire" technique is that you can make almost any diameter "file" required, and the finish is quite smooth.
All the slots will probably need a tweak once the nut is installed; I was cautious with depth as did not want to be in the same position as the stock nut placed me in. I left a good 0.8-1mm extra height overall.

[wazkelly]

You could always wrap a bit of grit paper around an old bass string and drag that back and forwards through the groove which is better than what I did on a DB Made Bone nut where I just used a set of old strings on their own and it took forever to file down. No risk of taking too much off on one those bone nuts doing it this way.

[RalphH]

You could always wrap a bit of grit paper around an old bass string and drag that back and forwards through the groove which is better than what I did on a DB Made Bone nut where I just used a set of old strings on their own and it took forever to file down. No risk of taking too much off on one those bone nuts doing it this way.

Hi Waz, Yes that would work, You're a genius. You would need to go one step down for each string however; (E string in the B slot) as the abrasive paper increases the diameter by about 0.5mm, and it would be easy to make the slot sloppy if it was the B string + paper in the B slot.
How's that MMB-4 coming?

[Fretworn]

Having said that, don't want the string slots to be tight either, as this can cause tuning issues.