Monday 23 June 2014

DLP Lap Steel Guitar - 4 - Some Cavity Work

Having shaped the head angle recently I decided to move on to routing cavities for the pickup and electronics.  I was also wanted to make a bridge and nut out of a piece of 12mm  by 12mm aluminium angle.


I started with the bridge and nut by cutting two lengths of aluminium to size and rounding over the corners before drilling and countersinking 2 holes in each piece. I then polished the two pieces and they are ready for slotting for the strings.


Next I marked and drilled two holes for the volume and tone pots. I plan to keep the control cavity as small as possible.  Its a thick piece of wood to drill through but the drill press made light work of the task.


For the cavity cover itself I made a cover from a piece of copper printed circuit board what hasn't yet been etched.  I cut out the shape by hand then refined the edges on the drum sander attachment on my drill press.  I then drilled two holes and countersunk them before making a router template to create the cavity.

 
I want the cover to sit flush or slightly below the back of the guitar so I made an oversize template and then used the collar attachment on the router to guide the cutting bit.  The template was 2.5mm oversize, the exact same size as the gap between the outside of the collar and the edge of the cutting bit.


The template cutter and oversized template made a for a nice easy, clean route.  What this doesn't demonstrate is just how long it takes to create a simple template like this, however in the long run it should pay off.


The indent for the cover routed beautifully, it sits just below the back of the guitar which is exactly how I wanted it to turn out.  Cherry is a hard wood but lovely to route and machine.  I routed the rest of the cavity using another template and finished it off with a sharp chisel as the router bit would not reach all the way down.  The pots sit perfectly at the bottom of the recess with just enough clearance for the wires.


Next I made another template for the P90 pickup cavity, well I actually already had a P90 template but I spent some time refining the inner edges to ensure the router runs perfectly smoothly over the edges, this time I will be using a router bit with a ball bearing on the shaft which will transmit every imperfection to the cavity edges.


Initially though I drilled as many holes as I could on the drill press to reduce the amount of material the router has to remove.  With the drill bit set  stop at a predetermined depth I could ensure all the holes would be the same.


Then I used double sided tape to secure the template to the top of the guitar and carefully routed away the remaining wood in a couple of passes.  I think the result was perfect, and the pickup slides in beautifully with the minimal amount of clearance around the edge.


The top is finally starting to look like something special now.  My final job this weekend was to drill the six holes for the machine heads.  There is a little chip out at the back but the machine heads should hide that anyway.


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