Replies

1. 
   notDusty | Oct 30, 2004 05:53pm | #1

                  Hi Quickstep ,

         It sounds like you only need to make one hole one time . My first thoughts are to keep things simple. Sure you could make a template sized so a router bit with a top template bearing would plunge and make the cut or, I think a good way to do this would be to make a dead on template and securely fasten or tape or hot glue it to the piece that gets cut out. Then I would score the edge or outline of the template with a sharp new utility razor knife or the likes , until a clear decisive outline exists.Then use a hand held sabre saw to carefully cut to the line from inside the outline. If you are careful you can cut right to the score line and file any that you miss. Make sure to test your template and make any adjustments before the real thing.

                       good luck                  dusty

2. 
   Jamie_Buxton | Oct 30, 2004 06:07pm | #2

   Two possibilities:

   a) Use the 1/8 bit and template, just as you suggest.  Cut maybe 1/8 deep.  Now you have the correct hole as far as anybody can see.   Then from the back, use the router with a bigger bit to cut deep enough to touch the 1/8 routing. 

   or

   b) Make a precise bezel which is only 1/8-1/4 thick.   Mount the radio the bezel-thickness further out the panel.  Make a crude hole in the 5/8 ply, and cover the crudeness with the bezel.

1. 
   royjcouvillion | Oct 30, 2004 06:54pm | #3

   Use a pattern following bit and a pattern.

   Get a 1/2" top bearing pattern following bit.  Home Depot has them.  It has a 1/4" shank to allow the 1/2" OD bearing to fit above the bit.

   Make and EXACT pattern of the hole you want to cut in 1/2" or 3/4" MDF.  I use MDF because of the very homogeneous nature of it.

   If you have room on your subject, make your pattern at least 3" larger than the hole.  If you can't screw it to the subject, make it even larger and clamp it.

   Remember, your corners will be 1/4" radius.  So you'll have to clean that up by hand.

3. 
   royjcouvillion | Oct 30, 2004 06:57pm | #4

   An additional thought.

   Rough-cut the hole first using a jig saw or spiral cut saw.  Keep your cut 1/16" - 1/8" away from the line.  That way, your router bit will not tend to walk and you'll have less tendency to split the plywood.

   Again, given the 1/16" radius, I think you'll have to do that by hand.

1. 
   mitch | Oct 31, 2004 04:46pm | #5

   if, during any of this process, you use a jigsaw and must cut from the finish side of the material, use a 'downcut' blade.  they cut on the downstroke so as not to splinter the top surface.  BE SURE TO TURN OFF THE ORBITAL ACTION OF THE SAW- they cut like c r a p and are very hard to control if you don't.  (found out by experience- luckily not on anything very important)  go slow and maintain firm downward pressure on the saw because the cutting action will not be pulling the material against the foot.

   m

4. 
   DougF | Nov 01, 2004 04:04pm | #6

   Quickstep,

   To handle the 1/16 corner radius, used a 1/8 drill bit and drill the corners out first.  then you can cut to the corner with perfect results.  I would heavily score the outline as suggested and using the finest scrowl saw blade you can find, a metal cutting blade would be best, clamp a cutting guide to the piece and cut to the corners.  It should come out perfectly with no tear-out.

   Doug