View Full Version : The basic shape of the F model ?
amori
May-08-2006, 12:44am
The basic shape of the F model seems to be a rounded-off tear drop + some "appendages". How critical is to get the tear drop shape accurate?
IS there a geometric standard?
I have not been sucessful at finding AutoCAD plans for my first mandolin and am now going to produce the plans myself and wondered if there was any "rules" regarding that tear drop shape? My proposed design simplifies and modernises the scroll, otherwise I would want it to be standard - if there is such a thing.
Thanks,
Murray
Greenmando
May-08-2006, 12:58am
There are some accurate blueprints available. The only need to be critical is if you are trying to duplicate the "Lloyd Loar" design. Rigel has modernized the scroll to their success.
Roger Siminoff (http://www.siminoff.net/pages/siminoff_drawings.html) has plans available on his site.
I have plans from the old Siminoff book, I was looking for plans on AutoCAD which I could not find and am now going to do them myself. I just wondered about how accurate the exact tear drop part needed to be.
sunburst
May-08-2006, 6:04am
It doesn't have to be very accurate in terms of structure or function or sound.
If there is a standard, it would likely be considered to be the shape of the original F5s; those signed by Lloyd Loar. There was some variation in the outline of those, though, so exact measurements are still not critical.
The "Hogo" plans are very accurately measured and drawn, and I might suggest contacting Adrian (the author of those plans) with your question. He's a computer guy too.
Think about what kind of case you want to put it in, and, unless you want to use a custom case don't get so radical that it won't fit a "standard" case.
How can I contact Hogo? I have tried the searh facility but I must be doing something wrong because I cannot find the right address. Either that or he does not respond to e-mail?
arbarnhart
May-08-2006, 9:11am
Go to classifieds and search for "plans". His contact info is listed in his ad.
BTW, many (most?) plan vendors don't want to provide electronic files as the risk of it getting out are too great. There is a free set of plans out there that are pretty good, from a size/shape perspective.
http://www.watsonbailey.com/plans/
Darren Kern
May-08-2006, 9:11am
Amori- click HERE (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=Profile;CODE=03;MID=72-1065006602) to go to his profile page, you can send him a private message from him. If the name at the top of the screen doesn't say "Send HOGO a private message", click it anyway. This happens from time to time, but the message always goes to the correct person.
Adrian W.
May-08-2006, 9:23am
I'm an Adrian, but not the Adrian that drafted the plans....anyway, I'm also interested in the geometry behind the F5 shape, but haven't been able to find very much at all. Trying to figure it out with compasses etc hasn't got me far either.
I am currently starting to try and get the outline into Autocad working from a paper blueprint, but I've only just started. I drew out a grid, and now I'm putting in points based on coordinates from two reference lines.....haven't got enough done to be able to say how well it will work though.
I'd like to be able to compare my version with other Autocad versions, but I was surprised to be unable to find anything out there.
John Jesseph
May-08-2006, 9:44am
Hi Amori-
Just make sure it fits in a case is all. #Any change from the "Loar" pattern (i.e. scroll change) makes the shape of the body less relevent. #I remember a discussion of trying to derive the shape of the F5 with geometry and classical proportion e.g. Francois Denis, but I just don't think that's the way it was done. #Just sketched out to someone's personal idea of what looks good, like a French violin. #I'd send you some loaner material if you lived in the U.S. #Elderly instruments sells Hogo's plans, but shipping to South Africa could be stifling.
martinedwards
May-08-2006, 9:56am
get a data projector and project a web pic onto a sheet of paper. check size using zoom to get the scale length roght, then trace. make sure that the projector is horazontal or you could get keystone distortion
Antlurz
May-08-2006, 11:51am
The Siminoff plans Greenmando mentioned are taken from a Loar Signed instrument.
Ron
arbarnhart
May-08-2006, 1:27pm
Well I have the Siminoff and the aforementioned (and linked) Watson Bailey plan is pretty close to that so I feel even a little better about saying it is close to "standard". They have PDF, GIF and CorelDraw versions out there. I used the PDF because you can select a small portion with the graphics selection tool in the standard PDF reader and print the selected region, allowing you to piece together a full size template using a regular size printer.
Greenmando
May-08-2006, 1:38pm
I have plans from the old Siminoff book, I was looking for plans on AutoCAD which I could not find and am now going to do them myself. #I just wondered about how accurate the exact tear drop part needed to be.
I understand the new book has corrections that were needed.
Bill Snyder
May-08-2006, 5:20pm
Import a jpg file of a mandolin you like the basic look of into AutoCad and trace it. Or you could scan your Siminoff plans in and import that and trace it.
I just have an inexpensive drawing program, but I have done similar things with photos of instruments that I liked the basic size and shape of.
Antlurz
May-09-2006, 12:27am
I just wondered about how accurate the exact tear drop part needed to be.
I guess the answer would be, "By whos criteria? What are you trying to achieve? A copy of an original F5 or just a mandolin? Unless you are attempting to build an exact duplicate, it isn't important at all except to satisfy your personal tastes. It certainly won't keep you from building a good sounding instrument unless you make a big altertion.
If you want to alter the shape, you are the only one that needs to be satisfied. On the other hand, if you want a high quality copy of an original F5, then it makes sense to do some careful measuring.
Ron
amori
May-09-2006, 12:40am
>>many (most?) plan vendors don't want to provide electronic files as the risk of it getting out are too great<<
I can understand that. It just takes a while getting used to the different attitudes between different types of luthiers, the violin guys are quite happy to swop plans. I have myself on a number of occasions send AutoCAD files to other enthusiasts around the world.
Anyway, no harm done. The http://www.watsonbailey.com/plans/ look promising. I just have to figure out a way of converting the GIF or Corel file into somthing I can import into AutoCAD.
For the record, I do NOT want to copy the plans. I am designing my own shape mando, I just would have liked to compare the final size with that of an original.
arbarnhart
May-09-2006, 4:44am
If you just want to compare, view the PDF in Acrobat at 100% and go into graphic selection mode and copy/paste the outline. I assume AutoCAD will let you paste raw graphics as background or in a panel or something (how else would you get logos an what not?). Even if it won't fit on one screen, you copy "chunks" that overlap with something that makes it easy to align in the ovelapped region.
Hello,
I'd answer the first question in this thread.
There are some geometric principles that make the shape pleasing to the eye.
1) You want to make the bend between the treble side corners symmetric. If you don't the shape want look very balanced.
2) because of the 1) you should not make the basic "teardrop" shape perfectly symmetric about the body centerline. It really looks better when the widest parts are matched in symmetry, but the parts at the upper point are not, with the treble side being more "cutaway" and the bass side a bit straightening towards the scroll. The widest point of the bass side curve can be a bit (1/4") closer to the tail end than the other side.
3) on the scroll you want the button be in the lower left quadrant of the scroll and the radiuses should change gradually from largest radius at the side furtherst from the centerline to the radius of the button.
That's my $.02,
Adrian
I've been using AutoCAD for about 15 years and have never needed to import anything. I have tried a good number of options and have not come up with an answer yet. One can't seem to paste Jpegs and the like. I'll come up with an answer soon I'm sure....
Amori,
one more tip.
Import the pics into Photoshop, resize to correct size, and use paths to trace the shape, they can be exported to .ai files, which are vector files that can be open with Corel or Illustrator and saved as dxf. I've used this a lot in the past and still I cannot find a better method... You can import Jpeg into ACAD or Corel, but Adobe products are the easiest to use. Be sure what version of ACAD dxf you're exporting to the newer dxf formats make a spline of the curves which may be hard to work with, the earlier (10 and less) versions produce polylines.
Adrian
Thanks Adrian. I'll give it a try, problem is I don't understand all this PC terminology. Although I've been using 3D VIZ and AutoCAD for yonks, I don't really know much else in terms of computers. I use 3d VIZ for all my furniture design (www.designsunlimited.co.za).
Murray