Catnip's (John K) Bench


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With the outside arching of the top almost complete it comes in at 150 gm with a density of 0.32 gm/cc.   Since the pear had a higher density I decided to use some lighter density spruce. This will probably mean that the top will come in under 60 gm with the bassbar.  After completing the outside arching by eye I then check it with my arching templates to see how close I am.  There was a small correction on the long arch at the upper bout and no corrections needed on the cross archings.  The spruce has a small deformity (character) on the bass side of the lower bout.

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Checking the horizontal layout of the f-holes just to confirm the arching.  In laying out the f-holes from the center line sometimes a notice a slight asymmetry ( ~ 1 mm) with respect to the edges. This is probably due to some distortion with the rib outline after removal.  I determine the outline of the top after gluing the back to the ribs. This makes for a consistent overhang at the expense of a small distortion.IMG_1297.thumb.JPG.c54a4c489c7e4b96967e8255c7bd1336.JPG

After cutting the f-holes I also relieve (chamfer) the hard edges on the inside of the f-holes.

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With the bassbar installed the top came in at 63 gm with m5 of 334 hz.  Usually m5 is easily seen using audacity and tapping but for this top I had to specifically hold and tap with the microphone centrally located.  This tells me that this top has much stronger other modes and I also left the bassbar a bit higher (stiffer) than normal.

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There still is some final finishing to be done on the f-holes which I will come back to after I finish working on the scroll.  I have a nicely flamed quarter-sawn piece of pear wood that I can use to get two scrolls.  Cherry is also a close match for pear wood but cherry has wider flames.IMG_1302.thumb.JPG.51e92789b2b939cd6460ff342cba2833.JPG

I like to cut the sides of the pegbox with a bandsaw so I use the red lines as a guide which closely matches the wider bottom of the pegbox.  Then the slight taper of the sides is done using a rasp followed by scrapers.

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The last half turn into the eye is done using a gouge.

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The final profile of the scroll is almost done.  Next I will hollow out the pegbox before doing the fluting.

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Thank you for posting details of your methods.

Interesting to see you leaving a section of the neck flat a bit wider so you can use studs to align the fingerboard, and then trimming the flat width to match the width of the board. I've experimented with various approaches to aligning the fingerboard but I have not settled on a method. Each has advantages and disadvantages.

I got the impression you will remove the board then reattach it later. How do you realign it after the neck width has been trimmed.

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Yes, I always like to assess  the violin in the white before I do the finishing .  If you look at an earlier post (May 20) you will see that I use a locating pin drilled at 45 degree when the FB is initially lightly glued to the neck.  This makes it a lot easier to align and re-glue the FB permanently since I only need to align the FB with the heel.  Even still there may be a very slight overhang (maple ledge) which is easily cleaned up with a scraper. 

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For this next violin I will be using a maple back harvested in Romania.  Unfortunately there was not enough wood from billet to cut ribs but I was able to get a close match from ribs that I had.  I like to book match the ribs at the bottom block.

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Finally back to this violin making after some distractions.  The back came in at 101 gm with good flexibility.  This Romanian maple is very nice to work with... light and stiff.

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Although it is not necessary with a collapsible mold I do relieve the blocks with a flush cut saw and chisel (knock) out the corner wedges.  In the process the blocks are detached from the mold.

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The garland was 62 gm out of the mold and finished at 51 gm after trimming the blocks and the linings.

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After having glued the back to the garland I need to flat sand the top of the garland to achieve the appropriate rib height and to make sure the top fits without any wobbles. My extra large sanding board has 80 grit on one side and 50 grit ( have not used yet) and can flat sand ribs with overhang linings quite easily because the surface is so much larger in both directions.

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I use double sided tape to temporarily stick the top to the garland to finish the overhang to between 2.5 and 2.8 mm before I remove it for the purfling and outside arching.

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I also finish the corners using a small corner template specifically made for each different form  (this is my Medici model).  Sometimes I have to remake them for a specific violin.

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Just some more progress.  Using a small finger plane with a fine cut to rough out the graduations before I use my scrapper.  I find a 1mm (thick) scraper (4 edges) almost the same as using my mini plane. 

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This top (0.32 gm/cc) came in at 59 gm with an m5 of 340.  I decided to stop here because the plate has good flexibility and when I add the bassbar I might leave the bar a bit higher.  

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F-holes are almost done.  May do some refinements with fresh eyes.  Now its time to do the bassbar.  I have a lot of bassbars from various sources and some cut from billets that were generously wide.  I decided to do a quick measurement to get a rough idea of the density of the spruce using a cylinder and the float method.  Divide the length of the submerged part by the total length and it gives a pretty good estimate of the density all things considered.  If the bassbar is not square (even in dimensions) I just dry the bassbar and reverse the bar in the water and then take an average.  Some of my bars are too big to fit in the cylinder.  An average bassbar adds about 4 gm to the top plate.  A heavy dense bar can add up to  6 gm.

 

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For labels I just use fish glue diluted a bit with hot water.  I apply my label then I wet the top of the label with water and let it dry.   

I have decided to work on the scroll before I close the box.  I found a similar maple block  that was pretty much squared  to approximately 42 mm wide 54 mm deep and 270 mm long.   I use a left and right image of a scroll printed on full size label paper.  The image has vertical lines which allows me to align and check the left image with the right image.   I drill the holes right a away when the block is square half way each way with a 5/32 drill.  This allows me to test the alignment so I can make corrections early if necessary.

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After cutting out the profile, sanding the outline and finally marking the center line it is time to mark width of the scroll using a compass and my flexible plastic ruler.

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Again rather than using a handsaw and chisel as shown in Courtnall I draw "red" cut lines and use a bandsaw.  The red cut line is to compensate for the wider width of the bottom of the pegbox.

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Checking the alignment and the depth of the pegbox with a wooden dowel.  As you can see the left side has to go down a bit and back a bit.  I use a rounded rasp to move the hole followed by my half size reamer.   I also use 1/2 size "test" pegs.  Some corrections can be done with a reamer but there is a tendency to create an "oval" hole which will require a bushing if it can not be rounded.

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Here is the final result using my 1/2 size reamer.

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The scroll is more or less finished and it is time to move on to the fingerboard.  This is  my least favorite part of violin making because its tends to be the messiest part. 

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After scraping and fine sanding the fb comes at the usual 70 gm.

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5 hours ago, FoxMitchell said:

How is the fingerboard the messiest part?  

Working with ebony fingerboards is not easy.  Some times you are lucky and have a board that planes easily but it requires a very sharp plane with a small throat and a special jig to hold the board.  If it doesn't plane well the alternative methods are messy. There is a complex and subtle geometry to shape of a fingerboard which is difficult to see by eye and really requires a lot of template testing.  Ebony dust gets everywhere and requires a through clean up .... etc ... etc...

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15 hours ago, catnip said:

Working with ebony fingerboards is not easy.  Some times you are lucky and have a board that planes easily but it requires a very sharp plane with a small throat and a special jig to hold the board.  If it doesn't plane well the alternative methods are messy. There is a complex and subtle geometry to shape of a fingerboard which is difficult to see by eye and really requires a lot of template testing.  Ebony dust gets everywhere and requires a through clean up .... etc ... etc...

Ebony dust does get everywhere, yeah, the stuff is a nightmare!  ;)

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