Adjusting The Nut Grooves/Slots On My Double Bass

[Stompbox]

[size=5]I recently posed a question on the forum asking about the high bridge and nut grooves/slots on my Zeller double bass & I got some very helpful replies, including this link:-[/size]

[url="http://www.dennishavlena.com/bassetup.htm"]http://www.dennishav...om/bassetup.htm[/url]
In this, the guy writes some every sensible stuff – a section of it is below –

[color=#000000]ADJUSTING THE NUT GROOVES: [/color]
[color=#000000]A badly adjusted (high) nut is very often the main cause of high playing action. [/color]
[color=#000000]The nut should be checked and adjusted first. If a regular business card (slid between the strings and the [/color]
[color=#000000]fingerboard, at the point where the string leaves the nut) just nicely fits, with no play -- not too loosely or tightly, this string's nut groove is most likely ok. [/color]
[color=#000000]To lower a high groove, use hobby-store small files to carefully deepen the groove to "business-card thickness". [/color]
[color=#000000]Go slow and check often. [/color]
[color=#000000]Here's a tip: Even after following the above instructions it's sometimes difficult to really know if the nut grooves are lowered enough. I've found that if you take an elastic-type guitar capo (one with a double strap is best) and affix it upside-down (the elastic fabric side facing the fingerboard) an inch or so from the nut --- and then play the bass --- you can get a better idea if the nut grooves are low enough. [/color]
[color=#000000]If it's noticeably easier to play with this inverted capo on, this is a good sign that the nut [/color]
[color=#000000]grooves need some slight deepening. Go carefully and slow though.[/color]

[color=#000000]Graphite from a sharp #2 pencil when applied liberally to each bridge and nut groove decreases the friction and lengthens string life. [/color]


[color=#000000]I thought long & hard about this and determined to have a go myself – I’ve done a reasonable number of jobs myself – refretted two guitars, cut & fitted a couple of nuts and rewired pickups on basses & six strings, so I thought I’m sure I can do this….[/color]

[color=#000000]I got a piece of very thick card (it measured 0.6mm thick), and I cut the card to about 25mm by 90 mm .[/color][color=#000000]The other items I used were a roll of masking tape, a set of small files (in the red plastic wallet), and a carpenter’s pencil, which has a very soft 6B lead to lubricate the slots (it’s just that I had this pencil so if you have a go there’s no need to rush out & buy one - I’m sure that a 2B would be fine). [/color]

[color=#000000]Also I had a knife to sharpen the pencil a straight edge & the ever handy electronic tuner.[/color]

[color=#000000][attachment=111633:Tools sm.jpg][/color]


[color=#000000]I checked the action, like the man said, and, with a small piece of this very thick card, it just fell out from under the strings.[/color]

[color=#000000]I did one string at a time, and was very conscious of the fact that once it’s filed off, it’s difficult to put it back! [/color]

[color=#000000]I did, however, keep the filed out ebony wood dust – I understand that if you are [b][i]really[/i][/b] stuck (having taken too much out), you can mix the wood dust with a little cyanoacrylate glue (superglue) and use it as a very hard “filler”. Fortunately I didn’t have to do this.[/color]

[color=#000000]I put the card under the strings and up tight against the nut, and folded the excess length back around the neck & held it in place with masking tape. By the time I finished, I just held the card in place with one hand, and filed with the other.[/color]
[attachment=111634:bass b (1) sm.jpg]

[color=#000000]I filed the slots carefully, so as not to make them too big, as the circular file I have is tapered, so I put masking tape around it higher up, where it would make too large a slot for the string, to prevent me using that bit of the file.[/color]

[color=#000000]I started with the G string, and took the slot down a bit at a time, since I didn’t know whether the guy who wrote the article in the link above was right in saying “Business card thickness” .[/color]

[color=#000000]In the event he was right (to my mind anyway) – I may, in fact, get a thinner card than the one [/color]
[color=#000000]I used & re-visit the job to lower them further still.[/color]

[color=#000000]By putting the card across the fingerboard, you can hold it in place whilst you file, and you won’t mark the fingerboard.[/color]

[color=#000000]It is also easy to see when you have reached the thickness of the card, as your file starts to touch it. I took care to make sure that the slot sloped slightly towards the pegbox – in fact I was just following the existing contour of the slot.[/color]

[color=#000000]The tricky one was the low E string – my bass has a Romberg Bevel to allow more movement of the string – what it meant to me as regards deepening the slot was that I had to take care to go deeper at right angles to the face of the flat part of the board, rather than going down toward the back of the neck, if you see what I mean?[/color]

[attachment=111635:E slot sm.jpg]
[color=#000000]The picture is, unfortunately, a little blurred, but I think you’ll get the idea.[/color]

[color=#000000]I filed the slots, as I said, a bit at a time at first, then restrung, put up to pitch & played, then did it again. [/color]

[color=#000000]Having done the G and the D, I was happier to go to the card thickness with the A straight away, which was fine, and then with the E – as I say, taking care to make sure that the slot was in the right sense to the fingerboard.[/color]

[color=#000000]Having cut the slots deeper, and restrung it, I checked to see that the strings are not too tight in the slots, and that the strings are not “buried” deep in the nut - the G is in to a depth so that the top of the string is below the surface of the nut, but the others are on or above the surface and they all run smoothly, so that’s fine with me[/color]

[color=#000000]The last thing was to lubricate the slots – I used my ultra soft 6B carpenter’s pencil - see the next picture – I’m so pleased that I have finally found a use for it since buying it at a tool stall in the market ages ago thinking “Hey that’ll be useful”. [/color]
[color=#000000][attachment=111636:E graph sm.jpg][/color]

[color=#000000]I am very pleased with the result, and feel that I know my bass a little better now.[/color]

[color=#000000]I’m confident enough to go ahead, and am now in the process of lowering the string height/action by working on the bridge as well, so when I’ve done it, I will put it together in an article with photos like this.[/color]

[color=#000000]I hope that you fellow bassists will find this of interest.[/color]

[color=#000000]All the best,[/color]

[color=#000000]Geoff.[/color]

[color=#000000]28[sup]th[/sup] June 2012.[/color]

[Silvia Bluejay]

Very, very useful. Thank you.

[sarah thomas]

Very useful, thanks. I would regularly lower the nut height on ukuleles but tackling such a big and expensive instrument brings a new fear. Glad to hear it all went well and you've given me confidence about trying this myself.

[Stompbox]

[sub][sub][size=4]Hi - just put a post on about the adjustment of my bass bridge :-[/size][/sub][/sub]

[sub][sub][size=4][url="http://basschat.co.uk/topic/180451-adjusting-re-cutting-bridge-on-double-bass/"]http://basschat.co.uk/topic/180451-adjusting-re-cutting-bridge-on-double-bass/[/url][/size][/sub][/sub]

[Stompbox]

I've just posted a new topic about making a disatnce piece for your bass to position the bridge correctly - a very useful,simple item - this is the link to it:-

[url="http://basschat.co.uk/topic/180540-make-one-of-these-for-your-bass-bridge-distance-piece/"]http://basschat.co.uk/topic/180540-make-one-of-these-for-your-bass-bridge-distance-piece/[/url]