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Discussion Starter #1
I want to use a 3/8" rounding bit with bearing to round over the end grain of a box. The box is pine with 1/2" box joints, and ready to route. I realize I must make skim cuts to sneak up on it's final shape. I am planning to hand route using a guide fence.

My question is, should I adjust the depth of the bit to final depth, then sneak up by changing the fence setting until the guide bearing contacts?

OR

Should I start out by having the guide bearing contact the box and sneak up on the final cut by adjusting the depth?

Which method would produce the smoothest cut, and why?
 

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Easiest is to increase the depth a little for the final cut. You don't need the fence, let the bearing do the work. You'll know after the first one if you need to do it in multiple stages. Clamp a board over the end where the bit will exit or you could blow the grain out there. Have the board's edge flush along the top and the end of the board flush (or close) with the end.
 

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Gary have you done a test on another board to be sure what it will look like? You will need to know how far to let the bit out so all the corners will be the same.
 

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Discussion Starter #5 (Edited)
If I understand, you are saying to use a well clamped sacrificial board against exit edge to prevent tear out. Keep the bearing against the edge with each cut. Lower the router bit slightly vertically with each pass to sneak up on the final cut.

I just wanted to find out what is meant in every ones opinion how to handle shallow passes. It seems that lowering the bit (exposing more) with each pass will produce a cleaner cut.

I have noticed the round over bit I am going to use has a shear angle of about 5 degrees, which should throw the chips in the direction of the router as well as outward. The shear angle could contribute to a nasty kick back if routing in the wrong direction. Any other thoughts?
 

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Excellent question, Gary. I've never really known the best way. Thanks for posting.
 

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I think you have it covered. Feed direction handheld is left to right but if you were feeding the wrong way it wouldn't kick back. It would just try to pull you with it and the bit would start skittering along the surface. There will always be resistance when you are feeding the right way.
 

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The bearing itself pretty much can serve as your fence, just adjust the bit. Without a bearing, set the bit, and adjust the fence. Either way, final pass needs to be minimal. Often just a little additional pressure is enough to clean things up nicely
 
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