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Step 5Drill, Cut and Polish the Aluminum Plates
If you happen to have a laser cutter capable metal, I encourage you to use it. But if not, here's how to do it with a band saw.
First, prepare the metal by sandwiching it between two sheets of 1/2" plywood. Use masking tape to hold the layers together. Doing this give you something more substantial to hold onto as you cut, and it prevents the buildup of metal burrs on the cut metal edge. Using spray-on adhesive, glue the plate patterns onto the wood.
Before cutting, drill the five component mounting holes on a drill press. Use the appropriate drill bit size for the part in question - the switch, pots and jacks all require different size holes. Drill a pilot hole in the exact center of the mounting hole for the valve (it will be widened later using a step bit).
Install a 15tpi blade on the bandsaw and run it at 3000 fpm. Cut out the main section and the valve section. Make sure you cut on the right line!
With the plates cut out, remove them from the plywood sandwich. Smooth the edges using sandpaper or a file. Test-fit the plates in the wood case - the fit may be tight or not fit at all - if so, keep filing and sanding the metal until it fits perfectly.
The potentiometers have small keys that prevent them from rotating in their holes. Insert a potentiometer into its hole, and mark where the key will be. Ideally, the pins should be pointing towards the middle of the metal plate! Drill the holes with an appropriate sized drill bit.
The valve plate will need a bit more work as well. First, clamp it down and using a step bit, widen the hole to fit the tube socket. Alternatively, you can use a scroll saw with a metal cutting blade. Mark out two mounting holes for the socket and drill those as well. In a vice, clamp down the plate and bend it to a 90 degree angle, to match the notch at the top of the case. Be very careful when you measure the position of the bend, to get a good tight fit.
Once the fit is good for the main and valve plates, you can polish the metal. Using a buffing bit and a dremel (or by hand if you like!), polish the aluminum to the desired luster. Be aware that the more polished it is, the better the stencil transfer will work, so go for a mirror-like finish if you can. Wash off any buffing compound with soap and water, then thoroughly clean the metal with alcohol.
First, prepare the metal by sandwiching it between two sheets of 1/2" plywood. Use masking tape to hold the layers together. Doing this give you something more substantial to hold onto as you cut, and it prevents the buildup of metal burrs on the cut metal edge. Using spray-on adhesive, glue the plate patterns onto the wood.
Before cutting, drill the five component mounting holes on a drill press. Use the appropriate drill bit size for the part in question - the switch, pots and jacks all require different size holes. Drill a pilot hole in the exact center of the mounting hole for the valve (it will be widened later using a step bit).
Install a 15tpi blade on the bandsaw and run it at 3000 fpm. Cut out the main section and the valve section. Make sure you cut on the right line!
With the plates cut out, remove them from the plywood sandwich. Smooth the edges using sandpaper or a file. Test-fit the plates in the wood case - the fit may be tight or not fit at all - if so, keep filing and sanding the metal until it fits perfectly.
The potentiometers have small keys that prevent them from rotating in their holes. Insert a potentiometer into its hole, and mark where the key will be. Ideally, the pins should be pointing towards the middle of the metal plate! Drill the holes with an appropriate sized drill bit.
The valve plate will need a bit more work as well. First, clamp it down and using a step bit, widen the hole to fit the tube socket. Alternatively, you can use a scroll saw with a metal cutting blade. Mark out two mounting holes for the socket and drill those as well. In a vice, clamp down the plate and bend it to a 90 degree angle, to match the notch at the top of the case. Be very careful when you measure the position of the bend, to get a good tight fit.
Once the fit is good for the main and valve plates, you can polish the metal. Using a buffing bit and a dremel (or by hand if you like!), polish the aluminum to the desired luster. Be aware that the more polished it is, the better the stencil transfer will work, so go for a mirror-like finish if you can. Wash off any buffing compound with soap and water, then thoroughly clean the metal with alcohol.
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