Craig, you are doing some really nice work there. I think your arching profile shown in the pic could use some tweaking, though. The transition from the convex arch to the flat (or slightly concave) zone around the edges looks extremely sudden to me. Personally I find basses sound best when the plates have gradual, rather than sudden curves. Hope this is helpful!

Thanks for the input Arnold. I made a new center arch and tried to flatten out the curve at the transition area as you described. Arch #1 did seem abrupt. Arch #2 is a lot smoother but I may tweak it some more. The top and bottom arches are much flatter at the ends and may not need adjusting.

I spent this weekend wasting away the spruce top by hand. I do not mind the grunt work; its a welcome change from the finicky stuff to come.

10/22/08
 

I seem to have misplaced my camera; hope to find it soon so I can update the thread.

Currently, I am still carving the top by hand; its slow going but a good way to learn. It is tricky navigating the grain direction with all the hills and valleys. The spruce likes to tear out so I try to keep the tools very sharp.

More pictures coming soon....

10/26/08
 

Very rough shaping at this point, top plate is still very thick.

Need to refine the shape and figure out the edge thickness. It is 10-15 mm thick around the edges, so I still have a long way to go.

(I found my camera)

11/18/2008
 

Photo #1
Winter is here.

Photo #2
Top carving. Roughed it out, then started to work on the "east-west" or horizontal arching. Here is the C-bout arch getting close to the outline of the template. My plan is to establish the top, middle, and lower arches, along with the long arch. Then, blend them together into a beatiful bass top.

You may notice a pitch pocket of some kind has appeared in the top. It was not there when I started to carve, but slowly revealed itself as the top got closer to the finished size. I may have to do some type of repair.

Photo #3
This is my arsenal. So far I have stuck to the hand tool method for shaping the top. Doing this by hand, IMO, might be a better way to learn the subtleties of plate arching, (as opposed to using power tools).

11/26/08
 

Picture #1
I fastened the top plate to an old table base. This enabled me to work around the plate without having clamps and bench legs getting in the way.
Gracie (the dog) has been with me from the start, usually she just curls up in the corner wile I whittle away.

Picture #2
The top plate, in all its "fully carved" glory.
(still have to carve out the inside)

Picture #3
Working the edges. Violin makers spend a lot of time discussing "edge treatment"; it may not be as big of a deal in bass making, but, nice edge work is one of my goals on this instrument. I am using gouges to get the proper scoop and roll wile at the same time, maintaining plate thickness and reserving a place for the purfling. Also, one must keep in mind the overhang distance. There is a lot going on at the edge of a top.

Nice looking handiwork there, Craig. Just as food for thought, you might be interested to know that most makers install the purfling before forming the edge hollow and bead, so that their purfling tools have a solid, flat surface to ride on. Are you installing purfling? If so, what method are you going to use to cut the channel?

According to the box it came in, I have an "Ulmia Furnieradern-Nuten". Made in Germany. Its a channel cutter for inlay work I purchased years ago for furnituremaking.

It will need to be adapted to work on the bass, but in general, the tool functions the same as the ones they sell for cutting grooves for purfling.

I will regret it later, but, I will probably end up chipping out the waste by hand. Once again, I've chosen the slow method!

12/8/08
 

This thread is proof that not everything on the internet moves a the speed of light!

The purfling is on hold, I ordered material and waiting for it to come in.

Still working on the arching; trying to get everything to the finished profile before hollowing out the underside. The high tech lazar shots give an idea of the curves on the top.

I left a lot of material on the edges so I can attempt a more sculpted treatment there. I am hoping it will look more "hand carved" than a production factory bass.

The last photo is just a teaser; I wanted to see how the top looks on the ribs. The underside still needs to be carved. Also, still have to remove some of the glue residue on the ribs.

Purfling 12/22/08
 

1) This is not a luthiers tool, but it got me through the job!
The cutters worked well, but the fence had to be modified so it could follow the curves of a bass.

2) Shop made purflings using different thickness veneers. They were glued up in forms that matched the contours of the bass

3) The preformed purflings waiting to be installed.

4) First purfle!
Cherry wood was used in the center to match the ribs and back. I did some preliminary edge shaping with small files; this is an attempt at a "sculpted edge". I hope it doesn't look too thick or get in the way of the bow.

5) The purfling is a bit on the heavy side compared to other basses, but I think it will blend just fine. Sometimes bold can be good.

Nice work Craig. The form-laminated purfling is such a crazy idea that it makes sense! Of course the standard way is to glue up flat sheets, then bend with heat as you need. But the result is all that really matters. What's the width and depth of the purfling?

The purfling comes in at a heavy 3/16", or 1.12" or 7/64". The black is .30", and the cherry is .50" (My dial caliper measures in .00"). Its looks wide on the spruce side, but blends in nicely on the cherry back! It looks like two separate black stripes when inlayed in to the cherry wood.

Channel 2 mm deep, edge 6 mm thick, after trimming the edge to 5mm, there should be 3-4 mm of material under the purfling. How deep should I go? Does the depth create the so called hinge effect?

5mm is thin for the edge. 7 is more common.

The hollowed out scoop is at 5 mm, and the rolled over outer edge is 8 mm.
Chandlers plans call for 4.5 plate thickness next to the ribs, and 6 mm plate thickness next to the ribs at the f holes. For now, I'll try to keep it on the heavy side.

Measurements?
 

Check again. .50"/.500" = 1/2". Do you mean .050" and .030"? Missing a zer0?

.050" is like a G string or so in diameter and .030" is like a high C string.

I think I'll switch to the metric language.

Black veneer .70 mm, Cherry 1.24 mm, total thickness 2.64 mm.

ok..
 

You were just short that extra zero I mentioned. You had it listed at 10x the size without it.

.70mm = .0275", 1.24mm = .0488 , total = .100"/2.64mm

In dividing for MMs, use 25.4 instead 2.54 or you get 10x like with the Caliper misread.

04/01/09
 

Glued (and clamped) the last of the purfling in the top.
My son thinks it looks really cool.

04/01/09
 

Graduating the top.
I made a special table/cradle to hold the top plate.
Today, I will start to carve out the underside of the top deck.

I see you have posted a graduation drawing. That thick ridge down the center is not traditional,. It is typical to work in more of an oval manner out from the thickest center zone. I believe the drawing is from the Chandler book, which contains some good basic info but is short on specifics. You will want to cut your f-holes while the top is still a bit heavy. Otherwise you will be cursing everytime a little tear-out episode happens on the inside.