3/4 Scale Brian May Red Special Project Part 4: Body CNC Cut

I sourced a Honduras mahogany (Swietenia macrophylla) one piece body blank measuring 21″ x 14″ x 2″ (533 x 355 x 51 mm) from Exotic Hardwoods and planed to 40 mm thick at a local joinery workshop. Before I dispatched it to Cut CNC of Uxbridge, Middlesex U.K. for 3-axis CNC routing, I had to make a judgement on where the cut would be positioned in the blank to achieve the most pleasing grain structure on the finished body. To help with this process, I made a paper template and positioned this over the blank. Two possible options became evident. The first one maximised the amount of linear grain in the uncovered part of the body while the second positioned an approximately parabolic grain feature symmetrically about the body axial centreline. My preference was for linear grain structure on the entire top and bottom faces of the guitar body like the original Brian May Red Special, but after some deliberation, I decided that option 1 would not yield sufficiently linear grain and I resolved that it was best to centralise the feature so selected option 2.

Because there were some undecided details at the time of routing, I had no previous experience of 3-axis CNC routing with this (or any other) company and I wished to keep the cost down by minimising the complexity of the cut, I deliberately didn’t design in too much detail (such as ledges for the control plate, edge rebates for the binding, neck mounting holes, pickguard mounting holes, jack socket aperture and knife edge mounting plate). This left some intricate hard carving to be done. The most challenging of this was carving out the 5 mm rectangular recess in the front face of the tremolo cavity. This might have been achievable with CNC but because it is an axial/horizontal cut, it would probably have to have been done on a 5-axis machine, but even then, there might not have been sufficient clearance for a cutting head so I decided to not even explore this possibility with Cut CNC. The first job I tackled was to carve 2 mm deep ledges for the control plate to rest on and leave the plate flush with the surface of the guitar. The result is illustrated below with the uncut mahogany neck blank and the original BMG Mini May neck.

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Part 5: Aluminium Control Plate
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Part 3: Body and Neck Design