Replies

1. 
   TomT226 | Nov 06, 2005 03:55pm | #1

   Sounds like the bit is crawling out of the collet.  Ciean the collet, re-tighten and take shallower passes.  Make the last a finish pass.

   P. T Barnum said "there's a sucker born every minute."

   Politicians replace "sucker" with "voter."

   NOTA.org

    

2. 
   Routerman | Nov 06, 2005 03:58pm | #2

   If you miss the thickness centerline when depth adjusting (north/south) there will be a vector (force with direction) on that cutter either up or down. The cutter is trying to center itself.

   Given the power, control, and a big router necessary for such a big cutter, you probably can't sense the tool bit trying to center itself. Given a light router and loose cutter in the collet, the scenario your describe is quite possible. Moreover, and in my view, a Dee-handle router is the worst choice for control around a workpiece. A grip on the Dee and one on the knob near the substrate makes it very easy to teeter the machine, especially as your round the turns. There, there is less the 35% of the router on the work. Nobody could keep a router flat under those condtions.

   A router table would be a better choice for that cut.

   ****************************************************

   Clearly I missed the "router Table" in your message. The problem is you're taking a full thickness cut and the fence has to be offset for that operation. I think that is the only problem. See the jointing link for more on the setup for full thickness cuts like jointing & bullnosing.

   Router

   
   

   ---

   Edited 11/6/2005 8:03 am ET by Routerman

3. 
   mudman | Nov 07, 2005 02:06am | #3

   When you say deeper, Do you mean the bit moved up and down? Or do you mean that it cut into the work more. It sounds to me like you are describing the later. If so The first thing that comes to mind is the fences are not even or parallel.

   Mike

1. 
   Cheatah | Nov 07, 2005 04:09am | #5

   Mud:

   I do mean that the bit cut deeper into the work piece. I am using one full piece of melamine for the fence. So I am confused as to why the bit cut deeper. My test on a piece of scrap showed good results. The real piece ( a 17" x 10" frame and panel) yielded lousy results.

   From the other posts it sounds like I should only use quality bits and make sure the collet and shank are real clean.

   Still, I am afraid to use the bull nose bit again.

   Thanks for your input.Thank you,

   Cheatah

1. 
   mudman | Nov 07, 2005 05:49am | #6

   If the bit was moving up or down in the collet you wouldn't be having those problems. The PC router table is not the sturdiest think out there and I suspect that either the fence or the router moved. Th emost likely thing is that one of the lock knobs on the fence loosened and allowed it to move. Or maybe the router itself moved under the table. Check all the screws and bolts to see if that is it.

   Again the above is only correct if the cuts were deeper into the board, not that the profile you were routing moved up or down.

   Mike

2. 
   sawdusterII | Nov 07, 2005 05:53am | #7

   Your fence is set to far back, exposing  too much of the bit.  the fence must be set so that at the equator of the bullnose, no material is being taken.  If one molecule is being removed an outfeed fence set one molecule forward would be required to prevent a one molecule snipe.

1. 
   forestgirl | Nov 07, 2005 06:49am | #8

   SD2 -- fantastic imagery and description.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

1. 
   sawdusterII | Nov 08, 2005 02:52am | #14

   blush

3. 
   jako17 | Nov 07, 2005 07:13am | #9

   All it is, is SNIPE. If you have only one piece of mcp as a fence and you are running a bullnose therefore shaping the whole edge. You should have the out feed fence forward of the infeed by the depth of cut.Read again the last paragraph of routermans post and follow it.Note that your fence should be in two parts to do this cut.Just for you own piece of mind lay the work back on the table with the power off and run it past the bit .What's the betting the damage starts at the point the work leaves the support of infeed fence(if there are two parts) or at the point that there is more stock past the bit than before it, if indeed it is one piece of mcp as you say.You might also consider reading up on router set ups while you still have fingers.

4. 
   charlesm | Nov 07, 2005 04:04pm | #11

   With all due respect to routerman, you don't need a split fence to perform this operation unless you are intentionally jointing the edge as you create the bullnose. Both the split and continuous fence require that the outfeed portion be exactly aligned with the smallest diameter of the bit (see sawdusterII's reply). Otherwise you will get snipe (fence too far back) or less than a full profile cut (fence too far forward).
   Charles M

   Freud America, Inc.

5. 
   highfigh | Nov 07, 2005 04:35pm | #12

   If the bit ever rides up, you might check to see if the bit bottomed out in the collet. If it did, it can't usually be tightened completely and this can cause the bit to ride up.

   If you aren't using high quality bits, remember that the more agressive the cut is, the more you will notice the fact that the bit isn't up to the task, safely. Also, when cutting small pieces(I know the piece you did wasn't really small), make sure you use a push stick or block. Don't put your hand too close to the bit or where your hand could go if the piece kicks out. (T&G bit, left index finger, a year ago February)

   "I cut this piece four times and it's still too short."

1. 
   Cheatah | Nov 07, 2005 04:55pm | #13

   Knots Gang--

   Thank you for all your words of wisdom. I appreciate all the responses. I am going try the bull nose bit again tonight or tomorrow night.  I will be making many test cuts and taking very light passes. And use a feather board.

   Again I appreciate the feedback.

    Thank you,

   Cheatah

1. 
   BG | Nov 08, 2005 03:12pm | #15

   cheatah,
   Thanks for raising this issue, I've had similar results/frustrations and couldn't figure out why.
   Weather you adopt the Routerman approach and shim the outfeed to support the stock because of depth of cut...or adopt the SawdustII/Charles approach and limit your depth of cut to less than one nats hair off the face of your bullnosed edge...
   learned a lot, thanks

4. 
   kesac | Nov 07, 2005 02:51am | #4

   As soon as you see a change to your cut, you have to stop, immediately and find out why.  A bit of crud on the shaft or in the chuck that compresses when you tighten the chuck will also allow that bit to come lose.  At that point your tool begins to do what ever the laws of physics insist upon, rather than what you had intended intended.

   I had a bit once that literally bent over while in work, and it was all I could do to get my hands off the trigger before the router came out of my hands.  That was going on 10 years ago, and I am still scared of no brand name bits.

   Clean the shaft of the bit.  Clean the collet and chuck, and use known good bits, and you will do well.

    

   Spell checker doesn't think collet is a real word here.

5. 
   WillGeorge | Nov 07, 2005 03:33pm | #10

   But to my surprise, the same thing happened all four sides even on very light cuts.

   At first I was thinking the grain changed direction on the panel but 'all four sides'??..

   I assume the panel is flat and no twist.. I hope..

   See Routerman's post.. I think that he has your real problem

   I use router tables all the time but hardly ever a bull nose bit.. However, I think that the PC table has a very small surface and maybe somehow you are 'tippin' the work near the end of the cut or otherwise moving from the fence...

   I rarely use them (if necessary I do) buy you may want to use a feather board to hold down the stock..

   Try passes that only take about 1/16 off or less.. I have been routing for years and I still take light cuts ALWAYS.. Not like a good friend I know.. His 'light' cut is about 1/4 inch! Geeee.... But then again he has a shaper...

   
   

   ---

   Edited 11/7/2005 7:36 am by WillGeorge