Replies

1. 
   sschefer | Jul 15, 2002 09:17pm | #1

   Sometimes when routing with at pattern and a bearing bit involves endgrain I find it will begin to vibrate just as I approach the end grain. Applying more down pressure at this point usually solves the problem. If I fail to apply the downward force it will bounce and cause a tearout problem like you have mentioned.

   Steve - in Northern California

2. 
   Elcoholic | Jul 15, 2002 10:19pm | #2

   Routing endgrain is just a bitch.  The ultimate cure is to use a reversable shaper.  I saw a TV show a while back on either Fender or Gibson and they had a dual spindle shaper, with each going in the opposite direction.  They were shaping solid body guitars as easy as pie. 

   Back to the real world.  The size and shape of the piece permitting, I'll make a combo fixture/pattern with toggle clamps and climb-cut the reverse and or end grain.  My buddy had a machinist make a set of 4 or 5 precision sleeves to fit over a 3/4" bearing that are graduated in very small steps (.010") to take very light cuts.  He says it works great.  I need to get a set too.  The crappy part is it was my idea in the first place!

   John O'Connell - JKO Handcrafted Woodworking

   Life is tough.  It's tougher if you're stupid - John Wayne

3. 
   quatersawn | Jul 15, 2002 10:54pm | #3

   Climb cut is the best way. slowly and lightly. Or you can try under and over bearing bits. The combination of them will get you all but the very last part of the radius on your hand mirror. I also have one of those 3" sanding drums with a bearing follower to sand it down as close as possible to the template, then use the router, with a new or freshly sharpened bit to give me the final cut. The over and under is a bit of a hassel to set up on the same router table, so if you can set up another one somehow, like maybe in your bench top, you just go from one to the other.  Like the poster before stated, you just route to a point, turn it over, out it on the other machine and away you go. Another thought is to set your router up with a pin follower the size of your bottom bearinged bit. then you simply turn the piece over on the same router. Good luck.

1. 
   questionma1 | Jul 16, 2002 12:17am | #4

   Bob and all, you have some very good  tips here and you have done the right thing by stopping what you were doing , regrouping, and gathering information about the serious problem you are experiencing. You could and can hurt yourself very badly discounting or underestimating grain patterns in wood. Not to mention screw your work up badly at the millwork process stage. To this day and forward on, let all that read and route, keep this in mind and respectfully keep thy concentration when cutting anything especialy end grain in your work areas. Please.

   Another tip is -additional to the ones above- get your self some 3/8's or 1/2" top bearing bits and clamp your work down tightly. At the critical grain points, do a backwards climb cut, to just barely finish off the final cut. Hold on tight and it should only be taken slow and sure. By doing it this way the worst you will end up with is a little fuzzy grain for the sanding process. You can revervse climb cut the whole thing if your working with some kind of wood prone to blow outs, but route according to the direction of grain, cut, sand, and machine as close as you can before that final pass.

4. 
   Lilshaver | Jul 16, 2002 03:57am | #5

   I suspect that it's not really end grain that is giving you the problem. Instead, it's almost end grain and you are traveling in the opposite direction that it is. This condition is unavoidable when routing around a circle.....you'll encounter it twice. As others have pointed out, doing a climb cut is a solution. A better one is to flip the piece over so that you can travel in the grain direction. This may not be possible depending on the kind of jig/pattern you are using.

5. 
   MichaelLomax | Jul 16, 2002 07:09pm | #6

   One solution to this problem that I have used is to get a downcutting spiral cut router bit.  These can be expensive but they help tremendously with the problem you are describing.  In addition, you can use every other trick listed by the other posters.

   lomax