Oahu Acoustic Square Neck Tuning and String Tension

[Mike Gobbi]

Recently obtained a Vintage Oahu Acoustic square neck with an overall scale length of 24 inches and would like to tune it to open D. Have been perusing some posts that say that that the Oahu should be able to handle 160 lbs. of string tension. Before installing strings just want some opinions about the independent research done so far.

Using the String joy string tension calculator for acoustic 80/20 bronze strings relative to a standard acoustic guitar come up with the following results below, a total of 135.7 lbs. string tension using a standard acoustic guitar string gauges.

Have the following questions:

Would the relative tuning D4 A3 F#3 D3 A2 D2 work.

Would you recommend 80/20 Bronze or Phosphor Bronze Strings?

What do you think of the string gauges?

Please advise.

[D Schubert]

I have an old Oahu student model square neck, the one with the . It works well with light gage acoustic strings tuned to D or lo-bass G. Medium gage strings and/or hi-bass tuning have caused the top to belly up and create a hairline crack in the top. Not very loud but sounds great with a Fishman soundhole pickup.

[Mark Eaton]

Phosphor bronze vs. 80/20 comes down to personal preference, how it sounds to your ear. I generally go with phosphor bronze on any lap style acoustic though I'm mainly referring to dobro.

I think your string gauges are too light for Open D. Especially the .012 first string. I believe you would be dissapointed with that one in particular - too wimpy.

Check out the 15-60 set from John Pearse in the link below. This is intended for a Weissenborn style guitar, a considerably more delicate instrument than the typical Oahu. I didn't find an overall string tension on the site, but I didn't look very hard either. There are even heavier gauge sets for Weissenborn from Pearse that are suitable for Open D.

I started out on steel taking lessons as a 10 year old in 1964, and before I went electric, for the first several monts at the music studio we played loaner flattop squareneck guitars guitars like Oahu, Kay, etc. They were the guitar equivalent of a Sherman tank. They had to be since they needed to be able withstand a lot of abuse dished out by young students.

https://www.juststrings.com/jps-3160l.html

[Mark Eaton]

I have an old Oahu student model square neck, the one with the . It works well with light gage acoustic strings tuned to D or lo-bass G. Medium gage strings and/or hi-bass tuning have caused the top to belly up and create a hairline crack in the top. Not very loud but sounds great with a Fishman soundhole pickup.

Interesting that the top bellied up and there was a hairline crack. But then it was likely a very old instrument and quality control wasn't exactly top notch to begin with in those days.

[D Schubert]

I use much heavier strings on my Dobro. But if it’s the same student model Oahu that I’m familiar with, it’s very lightly constructed and won’t tolerate heavier strings. Not built as sturdy as a Dobro or even a higher-end Oahu.

Mark, I agree with your "wimpy-sounding" assessment of those string gages but my own experiments with heavier strings were almost a structural disaster.

[Glenn Wilde]

It would help to know what model Oahu you have. I think the birch student models, basically Stella square necks are more robust than, say, a 66k. I run acoustic mediums down around C# on the 66k. I put a bridge Doctor in the 65k and it worked wonders with it's bellying, that one can take a bit more tension. I've had a few of the student ones and never had one come apart on me.

[D Schubert]

There is an Oahu squareneck for sale on the forum, like the one I've been describing.

https://bb.steelguitarforum.com/viewtop ... highlight=

[Michael Butler]

i have what seems to be pretty much the same oahu. i use open D and i'm using 12/54 strings but i don't remember the brand i used. no problem with the tension and playability.

play music!
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[Brian Cheetham]

I put Asher Acoustic Hawaiian lap steel strings on mine .014-.058