Flush trimming small pieces with router

[Matt Palloy]

Hi,
I have two questions:

I'm using a pre-cut template pattern to flush trim four small pieces of 3/4" thick maple (6" triangle-like shapes) on a router table. I cut the pieces slightly larger than the template and am routing them flush. I find that the router bit catches and rips off the corners. Any ideas?

Thanks,
Matt

[Ken Fitzgerald]

Matt,

I'd make a jig to which you can clamp the small pieces. On the jig, have a piece of wood that is butted upgainst the ends of the triangle. Then the ends of the triangle can't break off. Let the edge of the jig either follow the the fence while trimming.

[pat warner]

Would expect nothing less. RT edge-planning = lots of energy transferred to the work. Tearout, splitting etc is common on small pieces. Thickness of material probably ~3/4", right? Taken all in one shot, right?
You're doing many? Then I'd fixture the templet/work package so I could hand rout it and stage cut it in small increments (in thickness). That is usually a collar/plunge procedure. Folks will say bandsaw closer to the templet and you should.
Notwithstanding, the key to high energy routing is routing in stages, trust me. Was there.

[Jeff Monson]

A backer at the points as Ken suggested is a good idea, routing against the grain is more than likely where you are having issues. When I template route and have to go against the grain, I use a flush trim with a bearing on the top and bottom. I make the cut that goes with the grain, flip over the work piece and adjust the flush trim as the template will be on the other side, this will give you another cut with the grain, avoiding going against the grain and tearout. That with a backer at the points should give you good results. A climb cut will also work, but I avoid them on a router table.

[Stephen Cherry]

First of all, I would consider orienting the pieces the other way, so that the the sharpest points are not cross grained. This would be better if it were plywood.


On an inverted pin router, this would be easier because you could plunge first right at the tip of one of the little doo dads, and make a cut part way, then cut down hill to finish off the little parts.

With a normal router, I would consider using two patterns per part- the first to cut out the back side of each of the points- with the pattern extending the line past the shape of the part- and a second pattern to cut the other side of the points , also with the patterns extending the line of the parts. Something like this, with the left pattern used first, the red indicating the cut, and the heavy black indicating the shape of the patterns:

cut.jpg

[Floyd Mah]

I see this problem as the reverse of the usual "I'm going to make this project solely with hand tools and nothing powered by electricity." If you choose power tools, don't use the router to finish. A drum sander will allow you to approach the final shape (make your router cut so that the workpiece is left oversized) and then use a piece of sandpaper on a dowel. Make sure you rotate the sanding drum into the corner instead of outward, or you will face the same problem with the router of ripping the corner off. The non-electrical approach is to use a sharp chisel or carving chisel and finish the corner by carefully paring.

[Matt Palloy]

Thank you all, that helps. I think I may revert to the sandpaper/drum sander method, instead of routing to a template, because the edges of the pieces are so long and thin.