Replies

1. 
   Jollyroger | Jan 16, 2005 08:13am | #1

   Sounds like you know your problem with that trimming too much wood off admission. I wouldn't take more than a sixteenth off with a straight edged bit. As far as cutting strokes on patterning - yes to all. Cut with the grain wherever possible and pray.

1. 
   Moosewood | Jan 16, 2005 04:42pm | #2

   Thank you for your suggestion of trimming no more than 1/16th". I will try this. Hope that I am more successful today than I was yesterday.

   Thanks again

   Rick

2. 
   mike4244 | Jan 16, 2005 06:19pm | #3

   Don't climbcut, rout the usual way. If you took heavy cuts with the bit you may need another bit. I am not sure exactly what your doing but if you can cut the waste with a sabre saw or bandsaw then you can rout in one pass with pattern bit.No more than 1/16" wide x depth of board at a time.Use 1/2" shank cutter if possible.

   mike

3. 
   Pondfish | Jan 17, 2005 12:44am | #4

   I use patterns frequently and find that the most important step to take is to take off small bites--no more than 1/8", and1/16" is better.  Back/climb/regular cutting makes little difference if you are only taking off a little bit.  Be careful with grain direction; scoring or reversing the side you are cutting from will avoid tearout where the grain is a factor.

   And it goes without saying:  use clean, sharp bits neither too fast or too slow.  I go just fast enough to avoid burning the wood.

    

1. 
   JHarveyB | Jan 17, 2005 08:33am | #5

   Another tip is to use a larger diameter bit. We have a 1" diameter "Chinese" trimmer bit (i.e., the bearing is between the cutting section and the router.) It provides a much cleaner cut than a 1/2" diameter cutter, as it is pushing the waste wood back on itself more (and pulling it out of the surface less) than the smaller diameter cutter. (when you are trimming that 1/16th inch.) Again, larger bit requires a larger shank for safety.

4. 
   Jimmbo | Jan 17, 2005 04:46pm | #6

   I've used that method to re-produced curved shaps with mixed success.  The problem I faced, and which you may face too, is that every curve has a good half (going out of the grain) and a bad half (cutting direction into the grain which tends to lift and tear).  Some wood just wants to tear out when you cut into the grain, even if you take very small bites.  I've tried climbing, but that did not improve my product much.  Try using a spiral or shear cutter if you are not.  Freud has strait cut bits with a twist that creates the shearing effect.  I believe the shear effect makes it cut the wood smoother with less of the tearing.  Or, cut it close but on the bad halves of each curve, leave it shy by 1/16th, and then transfer the piece, pattern still attached, to a drum sander and finish the "bad sides" of the curves there.  That's all I can suggest.

1. 
   JHarveyB | Jan 17, 2005 06:44pm | #7

   Oops, forgot a trick in my previous post. We use two different trimmer bits when the grain goes both directions. Use a normal trimmer bit (with the bearing at the end of the bit) for areas where the grain is right for it, and the "Chinese" trimmer (with the bearing between the cutter and the shank that goes in the router) for the areas where the grain goes opposite. This requires that you can flip the pattern and work piece over. Sometimes clamps get in the way of this flip. We often use double-sided tape to attach the pattern to the work piece. Then there is no obstruction to router access from both sides. (We have had good luck with the fabric based tape, and very poor luck with the plastic based tape; it doesnt have enough compressibility to compensate for any slight irregularities in the pieces.) The optimum is to have 2 routers set up with each of the bits, especially if you are making multiple pieces; then you can finish routing each piece without switchjing bits over and over again.
   Harvey

1. 
   DougU | Jan 18, 2005 02:16am | #9

   JHarvey

   I've done what you describe on many an occasion.

   Chuck up one router with a bottom bearing flush trimmer and one router with a top bearing flush trimmer.

   When it looks like the wood is about to tear out I turn the piece over and trim with the opposite bit.

   Works great.

   I am always a bit scared to use double stick tape, I often screw or nail the piece to  the template.

   Do you have any problems with the wood moving with the double stick tape?

   Doug

1. 
   JHarveyB | Jan 18, 2005 04:04am | #10

   Hi, Doug!
   I've never had any problem at all with the pieces moving relative to each other; in fact, there are times when I think I'm going to break something getting them apart. Two secrets: use the cloth based tape (as I indicated earlier) and clamp the pieces together for a few minutes to get the adhesive well connected to the wood. I use this technique to mount bowl blanks on my lathe, which is lots more stress on the tape, and again, the usual problem is how to get the pieces apart without damage to the bowl. That said, I always clamp the pieces together, and run the tailstock center into the blank at least till I've got the outside turned & finished, by which time it's balanced. For a large bowl, I'll hog out as much of the inside as possible, leaving a spout in the middle that goes out to the tailstock center, till most of the work is done.
   A real klutz can in fact knock a bowl off a faceplate, tho the attachment method is pretty irrelevant. I had such a guy working in my shop for a little while.
   ]
   Anyway, try out the tape for yourself. We call it the clamp when there is no room for a clamp.
   Harvey

1. 
   DougU | Jan 18, 2005 05:01am | #11

   Thanks, I'll give it a shot.

   Doug

5. 
   Routerman | Jan 18, 2005 01:55am | #8

   2 stage cuttings may buy you cleaner cuts. One cutter set here.

   Routing into or out of end grain is full of surprises. I have had material tear out in either direction with new cutters. Material that does that should be scrapped. Advice: for those critical, tortuous inside/outside radius cuts, make spares. At least you'll have some experience for the second shot. Use larger diameter cutters, saw as close as possible to the cut line before routing. For thick stock, (>1-1/4"), plunge rout the waste in stages. Routers & cutters don't cotton to full thickness cuts.