Derek McCormick’s Violin Blog

Making a violin and other violin-related topics

The Bass Bar

Splitting bass bar

The bass bar is important both structurally and acoustically. A piece of spruce is split rather than sawn. This is to ensure that the grain runs straight along the complete length of the bar. The split piece is then planed down to about 5.5mm in this case.

Bass bar 2

For fitting, the front is clamped into a frame which holds it without distortion. The bas bar will run along the bass side of the front, running under the position of the bridge foot almost but not quite parallel to the centre join. It is important to get really good contact between the lower surface of the bar and the belly. Using the unshaped bar as a guide a series of little blocks is glued in place so that the bar can always be placed in the same position as I begin to shape it. This is done by chalk fitting. The area where the bar is to be sited is chalked and when the rough bar is put in place and very slightly moved longitudinally. Where the bar is touching it will be marked with the chalk and these high points are removed by knife or small plane. This process is repeated and gradually more and more of the bar is chalked. Finally when the whole bar is marked (and therefore in good contact) you breathe a sigh of relief, open a can and heat up the glue! For me at least bass bar fitting is not one of the most exciting episodes in making a violin!

Bassbar 6

The bar has been glued in position and left overnight. After removing the locating blocks the bar is ready to be taken to its final shape.

Bass bar 5

The bar has now arrived at its final shape using a small plane and scraper. It is now 270mm long, 13mm at the high point, tapering down to 3mm at the ends. In cross section it is tapered from the 5.5mm base to give an arch-shaped profile.

Advertisements

May 11, 2009 Posted by | (12) The Bass Bar | Leave a comment