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Okay Gibson has used the term 24 3/4" scale length to describe multiple scale lengths. So what is the actual scale length of 57 J-45 as based on Michael Collins J-45 plans? It does say its 24 3/4" on the plans. Is it actually 24.750"? Want to be sure before I buy a fret template. Mike

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Another day, another dollar.

Mike, I've measured a number of J45s from that general era and there doesn't appear to be a "standard". Very often the nut-to-1st-fret is shortened and some of the other frets are also in odd places. I worked out the scale lengths on the ones that passed through my shop by measuring all the fret spacings (forgetting the nut to first) and then doing a least squares fit to get the best fitting scale length. They appear to be metric rather than inch sizes, with close to 630mm (~24.8") and close to 625mm (~24.6") being the two most common. I think the Ibex fret rule has 24 27/32" (631mm). A lot of this arises, I think, from Gibson doing approximate conversions from round metric numbers into nearest fractional inch numbers. However, also see this.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

1957 J-45 scale length is 24.625". 1954 and earlier J-45 scale length is 24.75". This is double the measurement at the 12th fret, not the compensated string length.

James

I'm not sure how "fixture wear and general variability in Gibson process control" give fret spacings entirely consistent with different scale lengths. Not that Gibson's process control was ever real good in those days, mind!

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

The difference between the scales you mentioned is nominal. Just use whichever one you have a template for and go with it.

I've got a '56 J-50, and if I remember correctly, it's a 24.5" scale(12 1/4" nut to 12th fret). Seems like I remember it being called a 24 9/16" compensated scale.
It may even be "rule of 18", I'll have to check it again when I get home. I've printed out several different scales lengths, and none of them line up all the way up the neck, but they were all 12th root of 2.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

To everyone thanks for the info. Trevor I know what you mean. I have owned and worked on a few Les Paul's and SG's and have seen variations here particularly the SG's scale being slightly longer then the Les Pauls. James the plan gives some variation choices between a 57 and the 54 but doesn't really give any details on the different scale lengths of the two. As for the plans I am not looking to follow them strictly but use them as a guidance. Todd I have seen the variation you have mentioned about Martins and I believe I have read where Martin itself described these variations as fixture wear. And to David who PMed me thanks for taking your time. I have checked out the links you sent me and will search for more of your post. Thanks...Mike

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Another day, another dollar.

The Gibson scale I have used since the late-1970's measures 12 3/8" from the nut to the 12th.

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John