Fabricating a jig set for the 1968-72 Orange Matamp speaker cabinets. 

Time to get cracking and have a go at making some jigs. Once I’ve copied the necessary parts of my collection it can be half heartedly liquidated to provide capital for tools and a workshop space. No harm though, I can build myself some copies and have the bragging rights instead. In order to have excellent consistency in production it is necessary to make jigs so replicate the plans the same way quickly. These jigs provide a guide as to where to drill screw holes and cut out handles holes and are simple tools made from mdf. Once I’ve made the master panel I can copy it onto the mdf jig using the master as the template. This is an easy job on the pin router. If I had the materials to hand I could make one in a short time after hours at work. I can’t see them saying no to a free set of jigs of part of their heritage. One issue with replicating the godawful cut out handles of the originals is that the pin router can only produce round corners. This is due to the cylindrical flush cut bit and cannot be avoided with this machine. It is no great shame however as the handles are the crude st of rectangular cutouts with no bevelling of the edges. It looks like we’re going to have to bevel the edges. There is heritage for this though it may have been appropriated from Hiwatt for the 2006 limited edition Series 2000 set. Prior to 1969 I’m not sure I’ve seen a Matamp cabinet features handles. 15/1/18 The first phase of this process is complete and now we have a lovely jig that serves to cut the handle holes accurately and consistently for both the 4×12 and 2×12 enclosures. The only difference in the two boxes dimensions is the width of the top and bottom panels. This jig has enabled me to cut and assemble prototype examples of both enclosure. There is still work to do on the jig set as the baffle and back panel are yet to be cut and machined. These will be completed over the next two weeks hopefully. Below are the steps I took in constructing first of the jig.

First I marked off the top and bottom of where the handle is positioned followed by the sides. The battens made from the green mdf and are temporarily fixed along the resulting outline with brad nails and serve as a guide for the pin router.

Pinned in place the battens serve their purpose but offer little in the way of stability. I grabbed a couple of bits of scrap the same thickness and nailed them on to ensure a straight edge to the handle.

Worked a treat!

The handle holes came out near perfect. The battens were then stripped off and the board was mated with the sheet of green mdf that was to become the jig.

I’ve missed a couple of images off my list but these will be covered in making the rest of the jig set. However I shall describe the next step of the method here. The cut panel was placed on the sheet of mdf and the first two battens were fixed along the top and side of the pre cut side. This provided a stable support to add the remaining attendant furnished me with a perfect jig first time.

This has been a surprisingly easy process thus far. The baffle should prove to be more challenging as I’ve not located and cut circles up until now.

Above is the carcass of the 2×12 constructed using the sidea jig. A second and a 4×12 have been completed at home and will be machined at the factory this coming Thursday. Note, I have machined a radius on the outside of the handles. This makes a huge difference to the comfort of the person lugging it about. Subsequent relief on the handles will have a smaller radius. To ensure that the guide bearing has enough material to support it without wandering into the box carcass.

Above you can see the baffle marked out ready to cut. The process is listed instep below.

  1. Draw centre line.
  2. Divide the centre line by three and Mark off the horizontal axis to find the centre point for each driver.
  3. Measure 105mm from centre points and Mark off.
  4. Where the lines generated by step 3 bisect each other marks the pcd for the attachment holes on on the speaker chassis.
  5. In the same manner create another four points at 135mm. This is the line that the tool is set to the inside of.
  6. Drill out holes fitting m5 T-nuts to the eight points that are for attachment of the driver and at the centre of each driver position.

With the holes now drilled we can set the router and circle cutting jig and begin. You can see on the left of the tool the nail that sits in the centre of the cut which serves as the pivot point for this operation. Make a 4mm deep cut then flip the workpiece over and repeat until the waste can be removed. This gives me a master baffle that I can use to make a jig using the same steps as the one I made to reproduce the side panels. Above: completed baffle jig. The full set of 2×12 jigs is complete. Next step is to fabricate similar patterns for the baffle and back panel of the 1970 ish 4×12 seen in the case studies. After the second set is complete I will be making a jig set for the offset 4×12 which I believe belonged to Fleetwood Mac in 1968. I will include a 2×15 baffle as the offset 4×12 carcass served both designs.

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