A5 design detail

[sprucetop1]

I'm building a 14fret-to-body f-hole A5 after completing a couple of 12 fret ovalhole mandolins. I can see that the top minimum thickness in the recurve area goes all the way around the top, but does the recurve continue under the fingerboard extender (just on the bridge side of the flat platform that the extender is glued to), or does the recurve reduce in the area under the extender? It's a stylistic issue as much as anything, but I haven't found a clear picture that shows this detail. Advice gratefully received....thanks.....John

[Jim Hilburn]

I've seen it done that way before but I think typically the recurve gracefully ends as it approaches the neckblock area.
Keep in mind that you want extra strength and stiffness in the area of the srting line.

[sprucetop1]

Jim...thanks for advice and as well as keeping that area stronger, to my eye, a reducing recurve in that area should look better too. I'l just have to carve away carefully until it "looks right".....

[sunburst]

I don't continue the minimum area all the way around the top, but instead leave some extra thickness along the string line, both at the head block and at the tail piece. Some call that a "spine", and it is a structural feature because there is a lot of string tension on a mandolin.
I've never continued the recurve under the fingerboard extender, but as Jim said, there are those who do. I'm told that mandolins sound different when done that way...who knows...
Builders do it differently, and you are free to also.

[sprucetop1]

John...thanks for comments and yes, I definitely left some extra thickness along the string line in both my ovals at the tailblock end....but of course with the fingerboard glued to the top in that design, the recurve query at the headblock end doesn't arise and I didn't think about it on the A5 until carving in that area today.

[Spruce]

Looks like the Loar A5 has a bit more meat in that area....

[sprucetop1]

Wow!...a thickness chart for the Loar A5......THANKS Spruce.....

[Spruce]

Wow!...a thickness chart for the Loar A5......THANKS Spruce.....

No problem....
And thank the late great John Sullivan...

[Hans]

Sprucetop, if you are using those specs, you are going to have to make a 15 fret neck AND use the LoarA5 body. The bridge must sit forward of a normal A5. Notice the pushed forward ff holes AND the bridge must be forward. The grads are also pushed forward. Most A5's built have a shorter neck block, and consequently the bridge must sit back farther.

[Dale Ludewig]

Hans is right. Spruce is right. John is right. Make sure the center line right down the top is goosed up a bit in thickness, IMHO. Especially at the bridge and behind it. You don't want it to buckle.

[sprucetop1]

THANKS to all you professionals for excellent advice. I'm using the Siminoff A5 plans....so I should have said 15 frets-to-the-body.....John

[Hans]

You might want to compare the Siminoff A5 peghead to the peghead on the Archives of the original. I don't know how old your plans are, or if Roger changed them, but I talked to him about it several months ago...seemed to me there was quite a difference. I just scaled up the photo until the tuner post spacing was right.

[sprucetop1]

My A5 plans are recent and there's a corrected version of the peghead shape included.....John

[Spruce]

My A5 plans are recent and there's a corrected version of the peghead shape included.....John

Those plans are good to have, but try to get ahold of a gob of pics of the original instrument...

It's simply one of the coolest instruments in existence, sounds great, and has a bunch of interesting quirks that are worth looking at...

[Mike Black]

I wonder how many other people snatched that awesome picture up? I know I immediately saved and printed it off. Thanks for posting that Bruce! Also grateful that John took the measurements.

[Tavy]

I wonder how many other people snatched that awesome picture up? I know I immediately saved and printed it off. Thanks for posting that Bruce! Also grateful that John took the measurements.

+1 from me too

John.

[Spruce]

I wonder how many other people snatched that awesome picture up? I know I immediately saved and printed it off. Thanks for posting that Bruce! Also grateful that John took the measurements.

John had great, but sadly unfulfilled, plans to build copies of the Loar A5.

He was able to live with the instrument for a few days and take extensive measurements and Hacklingers, and I was really looking forward to what he would have come up with...

Not to be...

So-ooo, I'll be doing the building instead...

I have about 5 sets of wood that he glued up to match the original instrument, and I think I have all the tools ready to roll...

I built 20 or so mandolins back in the 80's, but haven't built one since...

No way will I approach what John would have done, but I think I'm ready to roll...

Sorry to hijack the thread, but I'll be asking some similar questions about A5 design details here pretty soon too....

[sprucetop1]

Look forward to your queries and progress reports Spruce..........John (UK)

[Ben Milne]

That's a really cool plot... i assume it is an outside view, not an inside view?
Even if it only ends up as one of desktop backgrounds every now and then...
thanks I look forward to the Progress reports.

i guess anything other that these grads would make it only kind-of-A5-ish then wouldn't it?

[Mike Black]

John had great, but sadly unfulfilled, plans to build copies of the Loar A5.

He was able to live with the instrument for a few days and take extensive measurements and Hacklingers, and I was really looking forward to what he would have come up with...

So Bruce... Do you have anything else that you can post to let us all see behind the curtain of the awe inspiring A5 Loar?

Personally, I think more builders should use the Loar A5 design. Only a small handful actually do. It's definitely my favorite.

[sprucetop1]

Another query re. the Loar A5 design.....the sideways drawing from Mr. Siminoff shows that the bridge location is forward of the apex of the soundboard curve, due to the A5's longer body when compared with the standard F5. The bridge is shown to be located on the downslope of the soundboard. Was the original instrument arranged like this, and if so, do contemporary builders reproduce this detail?....thanks.....John

[Spruce]

So Bruce... Do you have anything else that you can post to let us all see behind the curtain of the awe inspiring A5 Loar?

Not really...
I have John's Hacklinger of the back...

I have a whole collection of pics, but I think I probably got most of them from this site...

They are essential for getting those quirks right...

Can someone comment on the accuracy of the Siminoff plans??

[Hans]

[QUOTE=sprucetop1;734334]Another query re. the Loar A5 design.....the sideways drawing from Mr. Siminoff shows that the bridge location is forward of the apex of the soundboard curve, due to the A5's longer body when compared with the standard F5. The bridge is shown to be located on the downslope of the soundboard. Was the original instrument arranged like this, and if so, do contemporary builders reproduce this detail?....thanks.....John[/QUOTE

Why yes...


[IMG]http://i723.photobucket.com/albums/ww234/ivoroid/A5C-5.jpg[/IMG

[sgarrity]

That looks as if Hans bought the Loar A5, removed the headplate, and replaced it with one of his own! Does it get much closer?? WOW!! I've seen pics of it before and would love to see it in person some day.

I'm a big fan of the Loar A5 design as well and wish more people would use it as a template. There are pics of a recently completed Duff A5 that bears strong resemblance and my Heiden A5 has some elements of the design but Mr. Heiden certainly wasn't going for historical accuracy in his design. The Red Diamond A5s are similar as well. Mark Taylor did his series of copies a few years ago. I'm sure I'm forgetting a few.....

[sprucetop1]

Hans....that is a wonderful mandolin and THANKS for posting the pix......they give me a goal to try to aim for.....John