Peter KG's Bench

[Peter K-G]

I'm inspired by the "shoe polish" Strad, so I pushed this back plate to graduations a like.

 

Arch height 15,8 mm

102 g, M5=345 Hz

 

Sound post area 4,4-4,5

Middle 3,8 - 4,1

C-bout edges 3,3 - 3,6

 

Upper regions 2,0 - 2,5

lower regions 2,1 - 2,7

Edges 2,3 - 2,5

 

 

https://plus.google.com/photos/107031328716467771098/albums/6004049360404932001/6010783358420990770

[Peter K-G]

11.5 Final stage of the back plate, drying in UV box at 40 °C, ~2 % RH. The plate has lost 4 g and EMC is about 3 %, M5=350 Hz. I made charts of the tuning procedure Extrados/Intrados (outside arch/inside arch) The Extrados figures are under copy right.

 

http://www.thestradsound.com/ongoing/violin-march-2014/back

https://plus.google.com/photos/107031328716467771098/albums/6012105150560867809

[Peter K-G]

Many hours in workshop today, joined the top plate

http://www.thestradsound.com/ongoing/violin-march-2014/top

 

The joining plane is supreme, but gluing & clamping is still a stressful task for me, cant really ever know if it is a good joint.

[curious1]

Many hours in workshop today, joined the top plate

http://www.thestradsound.com/ongoing/violin-march-2014/top

 

The joining plane is supreme, but gluing & clamping is still a stressful task for me, cant really ever know if it is a good joint.

I would suggest that you just rub your top joints instead of clamping. I don't care for those clamps much.

If the joint is good and the glue is strong ia rub joint should work perfectly.

[Peter K-G]

I would suggest that you just rub your top joints instead of clamping. I don't care for those clamps much.

If the joint is good and the glue is strong ia rub joint should work perfectly.

 

I like the idea but haven't dared to do it yet. As I now feel I have the "perfect" joining plane and system - clamping the halves together and 5 - 10 strokes with the No.7 plane -> done. Then rubbing would make the joining procedure take total 10 min.

 

I did the rubbing first, so on the other hand the clamps shouldn't do much harm if they don't press too much?

 

Biggest problem is getting any clamps to push straight. I had to slant the edges a little bit to get the clamps to push more on the ridge side, i.e. rub joinig would be the solution.

 

Thanks,

[Peter K-G]

Cut out the top and some Wood to get a feel for it, Lovely Wood!

 

One way to test if the joint is good is to take some of the pieces that comes of from the gouge and brake them. It never brakes in the glue joint, so I guess it's good

 

 

 

https://plus.google.com/photos/107031328716467771098/albums/6012180690838755937/6012600489807608498?pid=6012600489807608498&oid=107031328716467771098

 

https://plus.google.com/photos/107031328716467771098/albums/6012180690838755937/6012600708472597778?pid=6012600708472597778&oid=107031328716467771098

[Peter K-G]

There has been a lot of talk about working time lately, purfling bending, cutting, glueing 35 min

 

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6015193963815679634?pid=6015193963815679634&oid=107031328716467771098

 

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6015193887290105410?pid=6015193887290105410&oid=107031328716467771098

 

 

And I ain't fraid of no (glue) ghosts

 

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6015196101603193986?pid=6015196101603193986&oid=107031328716467771098

[Peter K-G]

Found some time to work with the top arch and edge. I was inspired by Roger's posts in Roger's edge method thread

 

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6018580658008498482?pid=6018580658008498482&oid=107031328716467771098

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6018580710895112098?pid=6018580710895112098&oid=107031328716467771098

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6018580770665099810?pid=6018580770665099810&oid=107031328716467771098

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6018580825683611170?pid=6018580825683611170&oid=107031328716467771098

 

Almost done but tuning is difficult due to constant change in humidity and temperature. The wood should have been dried longer too, MC%  it is still 11-12% and it feels "wet"

[Peter K-G]

Arching done. 5,5 h in UV cabinet. M5 have risen 15 Hz already. Storing tone wood outside in a shed is not right. Even if the wood is from 1996, it behaves like fresh wood. Small drops of resin is also squeezed out on the surface. Need to season it by dehydrating it to 0% a couple of times and see what happens. 

[Peter K-G]

Update on Wolf notes

 

http://www.thestradsound.com/ongoing/updateonwolfnotes

[Fjodor]

Arching done. 5,5 h in UV cabinet. M5 have risen 15 Hz already. Storing tone wood outside in a shed is not right. Even if the wood is from 1996, it behaves like fresh wood. Small drops of resin is also squeezed out on the surface. Need to season it by dehydrating it to 0% a couple of times and see what happens.

He siir bra ut!

I have started a new violin and chose one of the 1996 tops and a birch back. The top seem to have about the same properties as yours, so it will be interseting to see what you end up with. What arching height did you use?

[Peter K-G]

 

The arch height is now 15.8 mm, I expect it to end up around 15-15,5 mm, when I do the final tuning. It has now been in UV cabinet for 2,5 days and lost 9 g. I will continue until 0% MC. I think it will take a week or so. This to prevent undesirable results when finished.

 

The wood is too "fresh" because it has been stored in an outside shed, as you know. If you don't have an UV cabinet it could be wise to wait a year or dry it gently in the Owen, not cooking it yet because core is still at least 12 % moisture, it could destroy the wood if too hot

[Fjodor]

Thanks, I have stored the wood next to a heat element in my work shop. It has not lost any weight now for some weeks. But maybe it would be wise to wait a bit still.

[Peter K-G]

Do not use the wood yet Fjodor!

 

6.6 The wood has been in UV cabinet for 6 days and stopped loosing weight, humidity up to 45-50 %. I knew I was going to be in trouble with this top. Nothing that I can't handle, but moist wood should not be used as tone wood. It warped lengthwise almost 1 cm.

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6021853062525314290?pid=6021853062525314290&oid=107031328716467771098

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6021853118791263922?pid=6021853118791263922&oid=107031328716467771098

Fix:

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6021853228709140306?pid=6021853228709140306&oid=107031328716467771098

[Patrick KREIT]

Do not use the wood yet Fjodor!

 

Très sage conseil de Peter, qui sais exactement de quoi il parle.

 

www.kreitpatrick.com

[Fjodor]

Do not use the wood yet Fjodor!

 

 

 

Do not use the wood yet Fjodor!

 

 

I guess I have to trust you, that warping does not look so good!

The problem is, that I dont have any other dry enough spruce for the moment, and i want to make a violin

Guess I have to harass LK and his woodpile

[Peter K-G]

Guess I have to harass LK and his woodpile

 

Yeah, but the best ones is on the shelf that we can't buy from.

I manage to negotiate an absolutely magnificent back from that shelf though, I will make a Soil Stradivari copy of it next winter 

[Peter K-G]

8.6 Graduated close to finish 74 g, 340 Hz, It will be around 70 g when finished (to match the back ~100 g), 345 Hz at 6% MC. In and out of UV cabinet and clamping it to a board with two wholes in upper and lower bouts (see picture) straighten it up to control warping. Blowing with a hairdryer inside when the plate is clamped to the board enables the wood to dry from the inside, contributing to straighten up the edges and keeping the arch height at it's reference. The transverse stiffness (speed of sound) is low in relation to longitudinal. This was already indicated when tuning extrados with a delta of 140 Hz between M0/M5. M2 is now only 150 Hz. This will increase when the wood has been artificially seasoned for awhile in UV cabinet. It is very likely that the violin will need re-tuning after a couple of years.

 

Album (the last 6 pictures)

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937

 

Blog

https://sites.google.com/site/peterkgviolins/ongoing/violin-march-2014/top

[Peter K-G]

BTW Fjodor,

 

The cycloids you are looking for, comes naturally out of a caterny like low longitunial arch and STL (Straight Tangent Lines) described earlier in this thread. Pretty much the same comes out from Sacconi's arching drawings. On this top they are almost perfectly in line with both.

[Fjodor]

BTW Fjodor,

 

The cycloids you are looking for, comes naturally out of a caterny like low longitunial arch and STL (Straight Tangent Lines) described earlier in this thread. Pretty much the same comes out from Sacconi's arching drawings. On this top they are almost perfectly in line with both.

Your cross arches looks close to a curtate cycloid curves, have you tried to compare them to a printed out cycloid at different points? What I like about the cycloid curves is that they give a definate system for the whole arching of the top and back They can vary a lot in shape when using different widths and heights ie. Where you place the low point of the scoop and how high the arch is. I have also used a catenary for the middle part of the top long arch, but it stays flatter a bit too long to create that kind of STL lines. I think I will experiment a bit with the long arch on the next one

[Peter K-G]

The STL lines starts closer to the middle point on back plates and more far from the middle on top plates (tops and backs have different longitudinal curves). If you look at Sacconi's or similar arching schema you will find the STLs where the distance is equal between the lines

 

(this is not exact, but you get the idea)

 

On this violin top the ccycloids are almost exactly near corners if you substract the purfling channel

 

[Peter K-G]

Regarding the tonewood we have, I'm going to suggest heat treatment to reduce resin and hemicellulose. I'll be back on this.

[Peter K-G]

Just got a birthday present from my wife This is the "second" book every violin maker should have

 

 

ps.

Now that I got the book I took a look at the arching lines and numbers and realized that they are not equal spaced in Z axis, which they have to be, for the illustration of STL lines in previous post, to be true.

[Peter K-G]

13.6 f-holes and bass bar preliminary set and re-tuned to 340 Hz, (305 Hz without bass bar, f-holes cut and wings formed)

 

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6024429601206338994?pid=6024429601206338994&oid=107031328716467771098

 

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6024429739210715026?pid=6024429739210715026&oid=107031328716467771098

 

https://plus.google.com/u/0/photos/107031328716467771098/albums/6012180690838755937/6024429666583233714?pid=6024429666583233714&oid=107031328716467771098

 

 

[Fjodor]

Just got a birthday present from my wife .

Birthday congratulations !

How do you plan to heat treat the wood? (I am not sure my wife let me use the owen to bake wood )