gineer67

I'm making a red oak hanging wall shelf unit and that has some curves in it. I decided to make templates from 1/4" birch plywood for the shelves and vertical supports, rough cut the shapes and then use a flush trim router bit for the finish cut. This worked well on the edge grain, but I have tearout problems on the end grain. The shelf vertical supports have a 3" diameter half circle at the top and the bit digs into the end grain with scary results just past 90 degrees around the circle.

I have thought about placing the template on one side, cutting 1/4 of the circle, moving the template on the other side and finishing the cut. I have also looked online at various bits to solve this problem. The bit I used has straight flutes. There are shearing bits where the flutes are at a slight angle and there are spiral bits as well.

Which is the best method to make this cut, moving the template or using a different bit? If you say a different bit, which is the best for this end grain cut, shearing or spiral? Please recommend size as well, if it matters.

Thanks,
Steve

jerry

I much prefer using template guides and spiral bits.
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Rick Mosher

Have you tried doing a climb cut (with the bit rotation) to take off the majority of the stock and then cleaning up the last little bit the normal way? I am not sure if that will work with the plywood but seems like it should be worth a try...

Bob Willing

I assume you are trimming all four side of the shelf. Start by trimming one end gain first than do the long side than the end grain than the other long side. If you are removing enough material this will clean up the end grain tear outs.

woodnthings

Your templates are 1/4" maple?. Your workpiece is red oak? The problem is tearout when reversing the direction around the circle in the pattern, since the red oak has a squirrly and errratic grain pattern? If all that is true, then you might try "bump cutting with the router" as shown by Charles Neil on Utube:
Your bit must be absolutely sharp and a spiral upcut would be best. Incremental cuts in this material is the only way to go without tearout. I've never seen this, but you could make sleeves for the external diameter of your template guides from almost anything round that you can drill the same diameter hole as your guide bushing. Start large, then work your way down to using just the guide bushing. bill

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