Acoustic Build - J-45ish

Very nice! And my last favorite Gibson. I'll be watching

Dave

 

You've got some great looking wood there. Are you going to make a go bar deck for the bracing? Haven't gotten up the nerve to try a flattop yet, watching this thread.

 

I admire your work ethic and energy ... !!!:

 

I've had a set of J-45 plans in a drawer for years, just never got around to putting one together. I'll enjoy watching yours, there was a pretty good article on them in American Lutherie not to long ago. Lots of different variations thru the years, particularly just before and after the war.

If you are going to build many acoustics a go-bar deck is definitely the way to go but you can get by with curved cauls and some deep clamps. I made my deck so it disassembles and I can put it away in the attic when I don't need it.

When you say Vancouver, is that BC or WA (since you were talking decimal inches I assume WA)?

 

My plans are by Michael Collin of a 1957 J45. They were purchased from LMII and I'm guessing are pretty accurate. Kerry Char, who wrote the article for American Lutherie also did some plans of a 1947 J45 that are available thru the Guild, plan #78. I would be very safe is assuming these are accurate.

It would be worth you reading the Char article (American Lutherie 139, Spring 2020). He talks about the various years of J45's and the changes - he feels that the best years were 42 to 49, good from 50 to 55 but now with the reverse belly bridge and that changes in bracing after 55 have a negative effect on sound. He says that necks did change is shape and width during these times and during the war many of them did not have metal truss rods.

He also makes an interesting comment about how Gibson did their braces that might be worth considering. Char says that as far as he can tell, Gibson never notched the X braces - they simply glued one down, cut the other in half and butted it up against the first one. He also notes that they did not let the ends of braces into the linings but merely feathered them down to nothing. If you want to build a historically correct J45 you can follow Gibson's lead but most contemporary builders would notch the X and let it into the linings.

My question about location was that I have family in Vancouver WA and get there fairly often, plus there is a thriving lutherie community in the Portland area. Many great builders on your side of the line too.

Good luck with the build, let me know if I can help.

Edit to add, you do know also that during the pre and post war years Gibson changed their scale lengths at least 3 times. There have been several reasons given for this - recalculating the scale going from the "rule of 18" to 12th root of 2, possibly changes in a gang saw that they used to cut fretboards, several other explanations. It doesn't matter of course, but be sure to stay true to the one you choose. Also, Ghar shows a J45 where the bridge had been moved to better intonate it - don't just trust your plans for its location.

 

I build acoustic guitars that are heavily influenced by various models, mostly Martins, but I also make changes for various reasons. For example, even tho I've build dovetail neck joints (and I will in the future when they are needed), all of my necks now are bolted M&T's. I can't see any reason to use a compression truss rod like Gibson did, mine are all double acting. And I vary tone woods and bracing as I see fit.

One thing I did learn is to build guitars to fit available cases. Custom cases are very expensive and very long delivery. I've made that mistake three times, you would think I would learn.

I bought my plans quite a few years ago when a friend asked me to build him a J45 replica. The build fell thru, I put the wood in the basement and ended up using it on an OM which I documented here. The plans went into a desk drawer and I sort of forgot about them until your thread came along.

As far as reading the article on line, I don't think the GAL does that. I'll PM you a thought.

 

I'm lucky to get out of bed, much less, build a guitar..

 

Well a little explanation is in order I suppose. I have a longtime love/hate relationship with Gibson products. Loved my grandfather's Byrdland and 1920 L4, hated (even despised) some workmanship I've seen. Too small bridge plates inside,sloppy and badly glued bracing and for God's sake screws in acoustic bridges? Upside down bridge tonekillers, mustache bridges on J200s, sheesh and don't EVEN get me started on electrics of massive tonnage with brittle necks. And last but not least the disrespect shown for Bill Lawrence creations, especially my beloved L6.
Off my pedastal but I will suggest the 24.625 scale length, VERY comfortable to me at least

Dave

 

Nice!

 

Thats a tough call and there are lots of different options. My 1957 plans show unscalloped braces 1/4 across the base and approximately 1/2 inch tall. The sides are tapered to 3/32 on the top. The plans also state that "pre 1955 models featured braces that are scalloped and higher".

Remember that these were production guitars, there wasn't someone individually tapping and shaving and trying to optimize each guitar. These were braces that worked, didn't blow up and were fairly easy to do. I typically use that as my starting point, then try to figure how if I can make it better (and how to do that).

There are some folks who can reach inside the soundhole and modify the braces, Bryan Kimsey did it to my old D18 and it made a big difference. I can't, the best I can do is sand a little on the sides or the tops of the main braces and that doesn't make much of a difference. My suggestion it to tap and flex and shave until you think its time to stop, you probably won't do any damage and probably your guitar will still be on the stiff side.

Carry on, its looking good.

 

You can take a small plane and taper all those braces from high to a low point at the sides. That will make the top flexible and lighter. It'll sound good, like a guitar...