5 string neck graft or not?

[Mike Weems]

Ok sorry for the lack of info. I asked this question last night after a long day. I should have let you know that I am a professional luthier. I have been so for 29 years. I have made violins, violas, and guitars in addition to fretted and bowed instrument restoration. The extent of double bass repair that I have done has been mostly school basses and lost of Kay basses for the area blue grass people. I purchased this bass and an old flat back from friend a month ago. The top was off and there were no fittings aside from the tuners. The bass in question is fairly healthy overall.
1. The bass bar was a monolithic type.
2. The conversion date is not known
3. All the maple has air brushed enhanced figure
4. The bass bar will of course have to be replaced
5. The top grads are 9mm at the post area to 5.5mm at most of the flanks.
6. The back is roughly the same 9mm along the center joint to 5.5-6mm at flanks.
7. The neck width measures 42mm at the nut to 68mm at the end.
8. The neck is a dove tail type joint.
9. A low “B” is what has been suggested.
I am doing this to perform repairs that I do not feel comfortable doning for customers but mainly for the love of the trade. I will try to post some pics but this is new to me so bear with me.
Questions
1. Should I leave the top and back thickness as is?
2. Should I go thru a scroll graft to increase width and change to mortis type neck joint?
I should also say that I have done cello scroll grafts so I am not afraid to do this.

[Ken Smith]

5-string?

From looking at the few pictures you are showing me and without any actual measurements of the bass other than the 3/4 size, I can't see why you would pursue this as a 5-string when the neck is a 4-string size.

With comfortable measurements for playing, the strings at the Nut should be spaced from 9-10 mm on average center to center. I have seen basses at 11 and 12mm as well but that is what I called wide. I think 42 mm across is about average without actually measuring anything. I will however measure MY 5-string Hofner that was made AS a 5-string with a wide neck and fingerboard.

Now, bass wise, in USA 5s are rare, very rare. The vast majority of players going low use a C-extension of one type or another. In Europe, 5s are more popular but to the up and coming players, the C-extension is becoming more and more accepted over the 5-string bass.

So, why take a 3/4 bass or minimal construction and re-work it into a 5 string that might not be big enough to carry that low string.

Can we see the Top inside and outside as well as all the other angles of the bass in and out?

[Arnold Schnitzer]

I'm in agreement with Ken, plus this: your bass appears to have inadequate overstand for modern playing. If you do decide to make it a 5-string, you may want to do so in a reversible way. Installing a wide fingerboard would be my first choice (after re-setting the neck).

[Mike Weems]

Wow thank you for all the great suggestions. I really appreciate you helping me think through this problem. After reading the last 2 posts it sounds like I should restore this bass to its original four string status. As I said in my last post I acquired this instrument in its current state. I am not wedded to the 5 string status. Your idea to install a “C” extension sounds quite good. Here are some dimensions that may be helpful.


1. Nominal body length 1103mm
2. The string length is roughly 41.5inchs(1054.10mm)
3. Width of upper bout 508mm
4. Width @ C bout 363mm
5. Width @ lower bout 637mm
6. Rib depth @ end block 197mm
7. Rib depth @ back cut 187mm
8. Rib depth @ neck block 157mm
9. F-stop 585mm
10. Chin of neck to heel 370mm
11. Neck length from frnt edge of nut to end 442mm

[Ken Smith]

Originally Posted by Mike Weems

Wow thank you for all the great suggestions. I really appreciate you helping me think through this problem. After reading the last 2 posts it sounds like I should restore this bass to its original four string status. As I said in my last post I acquired this instrument in its current state. I am not wedded to the 5 string status. Your idea to install a “C” extension sounds quite good. Here are some dimensions that may be helpful.


1. Nominal body length 1103mm
2. The string length is roughly 41.5inchs(1054.10mm)
3. Width of upper bout 508mm
4. Width @ C bout 363mm
5. Width @ lower bout 637mm
6. Rib depth @ end block 197mm
7. Rib depth @ back cut 187mm
8. Rib depth @ neck block 157mm
9. F-stop 585mm
10. Chin of neck to heel 370mm
11. Neck length from frnt edge of nut to end 442mm

Please, inches, Very few people use metric in USA. Of those that do, divide by 2.54 to have a handle on it. 41.5", that is one we all understand. The rest require a calculator for me.

[Mike Weems]

1. Nominal body length 43.5“
2. The string length is roughly 41.5inchs(1054.10mm)
3. Width of upper bout 19 7/8”
4. Width @ C bout 14 ¾”
5. Width @ lower bout 25”
6. Rib depth @ end block 7 5/8”
7. Rib depth @ back cut 7 3/8”
8. Rib depth @ neck block 6 ¼”
9. F-stop 23”
10. Chin of neck to heel 14.5”
11. Neck length from frnt edge of nut to end 17 3/8”
Sorry about that.

[Ken Smith]

Originally Posted by Mike Weems

1. Nominal body length 43.5“
2. The string length is roughly 41.5inchs(1054.10mm)
3. Width of upper bout 19 7/8”
4. Width @ C bout 14 ¾”
5. Width @ lower bout 25”
6. Rib depth @ end block 7 5/8”
7. Rib depth @ back cut 7 3/8”
8. Rib depth @ neck block 6 ¼”
9. F-stop 23”
10. Chin of neck to heel 14.5”
11. Neck length from frnt edge of nut to end 17 3/8”
Sorry about that.

This is more then the basics but, it is a 3/4 and sound is an issue for 5s. I have a 3/4 (maybe) that is a 5er from birth and it is quite a boomer but, born as such. Compare the numbers to your measurements. http://www.kensmithbasses.com/doublebasses/5string/

Still, if this was a 4-string and I wanted or needed to convert a bass to a 5er, this would NOT be the one to convert.

I have a huge English bass, born as a 4 and recently converted to a 5er and then not long after back to a 4. It's an organ and stands up to any bass. This would be the size you want for a 5er. http://www.kensmithbasses.com/doublebasses/tarr/

For reference, here's a bass we converted from a 4; http://www.kensmithbasses.com/doublebasses/mystery2/

And here's one that came in as a 5 and sounded even better with the B lifted off; http://www.kensmithbasses.com/doublebasses/euro5/

Both were fairly new basses antiqued to look older. The sound was there. If your bass is a commercial sized 3/4 and made and intended to be a 4-string, keep it as a 4-string. Not all basses do well as 5s. Many of the old 4s were born as 3s and I have and have had many of those as well. 4-strings is the norm' so stay with that and play it safe.