continuing build thread for Gore Medium body SS

[John Parchem]

Having finished my Dred I have three projects that I want to start

• Lowden O (template from Ken)

• Trevor Gore Falcate braced steel string, following his build proceedures

• Modern Classical (reduced width at the nut a bit , fret board radius, bolt on\off neck, maybe a cutaway

I am going to try to arrange my shop to do two at once. I am for sure going to start the Gore guitar. I keep going back and forth between starting the Lowden or advancing my classical guitars into the new millennium. We shall see.

[ken cierp]

The Gore bracing system is a project in of itself -- interesting.

[John Parchem]

I thought to use this post to start and to maintain my build thread for a Gore medium body steel string to his plan foro the Build book. I will try to follow the procedure as best I can from the book, although I can not promise I will do things in the same order, but I will at least follow the dependency graph laying out the steps.

This week I will be building the required jigs and body molds and what not but decided to start selecting and preparing the plates.

I have decided to use a Tasmanian Blackwoold set I got from Australian Tonewoods and a Lutz top I got from High Mountain Tonewood.




I followed section 6.2 Tap testing the panels for the top. This is done to get consistent stiffness form plate to plate. The vibration frequency of a plate is proportional to the Young's modulus (a measurement of stiffness). Also required are the length width and thickness of the plate.

I think I am getting good spectrum plots. The unglued plate is sanded smooth, and it needs to be rectangular. The are three different tap measurements that need to be. The long direction vibration and the cross grain vibration and a corner to corner or twisting vibration. Holding and tapping the plates in the correct location emphasizes the specific mode that is being measure.

I ended up with the following results for the top


Long Grain fl


Cross Grain fc


Twisting vibration flc


Here is just the calculation for the back plate



I think it will be awhile before I do the interesting work as I am working on jigs and forms. The 3 meter radius dish is throwing me for a loop, but I will find someone to make. I will probably have them make a 10 foot dish so that it is understandable. I have a 32 foot dish, so if no one complains I will pretend that it is a 10 meter dish. I mostly completed my body mold, still need to add the hardware.

[ken cierp]

This will be a great log -- thank you

[Kevin in California]

I've not seen this design before, this will be GREAT to watch, GO JOHN!

Kevin

[John Parchem]

Thanks guys, It should be interesting. I have carbon fiber ordered.

I made some progress of my bending forms. I decided to also make a cutaway form. I have a cutaway clamp on my fox style bender. I need to get some pipes to finish them off. I also need to wait for my 10 foot radish dish of that I can profiles the sides.



In the mean time I decided to see how it is bending spruce is for the tighter of the two falcate braces. I first tested a scrap 1.7mm strip of spruce I had. I was able to bend it no problem so I cut and thicknessed a few wider strips. I sprayed them with super soft II and bend them. I do not think it lasts very long, otherwise I will have soft braces. I will see in a week or so.








I am really excited about the lutz top and the Australian Blackwood back and sides.






I tried to use hot hide glue to glue the top together I am not sure if I was fast enough as the joint was not very good. I ended up glue it with LMI white.

[John Parchem]

The back is going to have a 3 m radius. I did think about making the 3 meter radius dish using a 3 meter length or so of stranded steel guide wire attached to my router and a beam I have on a deck that is a bit over 3 M. I thought I would attach a tent like wire setup to a router motor using a 3 inch pipe clamp. I would use the router as a plum bob to center the dish and set the height of the bit on the outside edge of the dish. Then my thought is I could happily route away. I am sure it would have made quite a mess. Ultimately I have one being shipped to me.

Speaking of messes I did epoxy the stack of falcate brace strips. They turned out OK. In the future if I stick to the falcate bracing I will make a couple of molds and use a band clamp to laminate them.






On to the neck