Flush Cutting Small Odd Shaped Parts

[jronman]

I am making some epoxy boards for serving trays or display. Final dimensions are roughly 18" x 10" x 1-1/2". I have made one before and included a picture of the final result. What I will be discussing today is the "river edges" (the wood that shares and edge with the green epoxy. I decided to try a new method to try and optimize labor time but I ran into a snag. In the new method I need to be able to flush trim odd shaped parts without cutting my fingers off or having a board flying through the wall. The parts have at least one curved side and are 1-1/2" thick. You can see how wide and narrow the curve could potentially get in the picture. Some of my boards now are even more narrow.

I have seen small parts holders for the router table but can they do 1-1/2" thick wood? Also I saw they are setup more to clamp the ends of square stock which is not going to work since my pieces are curved on one or more sides. Coping sleds might do the trick if they had 18 inches of capacity but most are only setup for maybe 4-6 inches at most from what I saw. I will probably cleanup the jigsaw marks with a spindle sander this time if one of my friends has one and figure out something for future batches of boards.

In my first board I set mt Shaper Origin cnc router to the inside setting of the two curved edges and worked my way, a shallow pass at a time, until I was through the entire 1-1/2" thickness of the board. It worked but was very slow. It took maybe half a dozen or more passes.

In my current boards I tried a new method hoping to save some time. The goal is to get the labor down so I don't have a ridiculously expensive board if I ever get around to selling them. My thinking was I could route a shallow pass with the Origin, use the shallow pass as a guide with my Carvex jigsaw, and flush trim to cleanup after the Carvex. Every board I make has a different "river" design and some of the parts can get quite small. I was having issues where the router table was wanting to throw the pieces esspecially on the starting end of the board. I was getting concerned that things were getting too dangerous.

Does anyone have any ideas on how to cut out the river portion safely without taking the amount of time it took to Shaper Origin the entire thing? Would it be safer to forego the jigsaw and do effectively the equivalent of a through dado? I am currently using a 1/2 inch diameter Woodpeckers ultra shear flush trim bit in my old porter cable 7538 setup in my Benchdog cast iron router table. I am using MicroJig Grip Blocks when I can. I would be open to a completely new method of cutting out the river too if it saved time and was safer.

 

[jronman]

Here is the picture

 

[luvmytoolz]

If I'm understanding correctly, to me the simplest thing and what I would do is machine a template and use that with a handheld router and large cutter with a bearing, or alternately clamp the timber to the template and run it over on the router table again with a large cutter with a top/bottom bearing as needed.

I do heaps of this sort of stuff and in most cases templates are your best friend, gives you exact and repeatable results without any fuss!

I would highly recommend the spiral carbide insert cutters from CSP Tooling here, they will last forever, are very cheap in my opinion, and are incredibly well balanced and will cut through 2" thick hardwood no problem.

If you're on insta I can link a couple of my videos showing one in action on some brittle hardwoods.

 

[Tom the Remodeler]

If you're looking for a hood with larger capacity for template-guided trimming, I recommend the Aigner Bowmould Hood. I have one for my shaper and love it, though you do need to match the template ring to your spindle size (30mm, 1-1/4", 40mm, etc....)...

Aigner Bowmould hood for 220mm tooling:https://www.scosarg.com/aigner-bowmould-ring-fence-guard-220mm

If you're using a router table, I bet you could adapt the more simple Felder curved shaper hood (along with the attendant curved moulding guard) to work with a router table:https://www.felder-group.com/en-us/shop/arc-cutter-guard-sc91606/curve-shaping-guard-sp91609

For straight work with a template, an "L-fence" on a table saw would make quick work of them.

Hope this helps.....

 

[Michael Kellough]

A pin mounted in the router table helps you maintain control of small parts.

In case you aren’t familiar with this,
https://www.woodmagazine.com/woodwo...uter-table-starter-pin-makes-routing-smoother

 

[woodferret]

With Shaper Origin, the best technique is the light 'template' channel, jigsaw leaving a margin, and trim router with a top bearing guide.  But that's for big enough boards that can sit on a STM1800 fine.

For smaller items, flip the board around, double side tape it to a stable surface.  Run a bottom bearing bit so you don't have to worry about protrusion into the subsurface.  Down-cut towards the bearing if you're running a spiral.  Also step down to micro-size bearing cutters if portions call for it, but always start with standard sized cutters first.

 

[jronman]

With Shaper Origin, the best technique is the light 'template' channel, jigsaw leaving a margin, and trim router with a top bearing guide.  But that's for big enough boards that can sit on a STM1800 fine.

For smaller items, flip the board around, double side tape it to a stable surface.  Run a bottom bearing bit so you don't have to worry about protrusion into the subsurface.  Down-cut towards the bearing if you're running a spiral.  Also step down to micro-size bearing cutters if portions call for it, but always start with standard sized cutters first.

For smaller items you recommend not using a router table? I don't own a trim router. The smallest router I own is an OF1400. The one in my router table is a Porter Cable 7538 speedmatic 3 hp plunge router. The bit I was using is a Woodpeckers Spiral 2-Flute Compression Flush Trim, 1/2 in diameter, 1/2 in shank, 2 in cutter length, and bearing on the tip. The two problematic pieces were mostly end grain on the curve which could also be why I was having more trouble with having control of the pieces. It was also the first time I have ever done a flush cut on pieces that thick. The template seems like a good option. I might need to make a custom router sled with the ability to swap in different curve profiles. I also probably need a bit with a bearing on both ends of the cutter or at least one on the shank end so I can have a downhill cut at all times.

 

[rvieceli]

Just so we’re clear on this. You are gluing the board together and then making the cuts and trim on the assembled board, correct?

If you are trying to cut and rout the curves on a single strip of the board, there is no safe way I can think of to do that.

So basically the method I would use is to completely glue up your board. Make a template for the curves, use a bandsaw (or jigsaw) to cut the board apart close to the curves you want. Then stick the template to the board and trim to final size.

Ron

 

[woodferret]

For smaller items you recommend not using a router table? I don't own a trim router. ... The two problematic pieces were mostly end grain on the curve which could also be why I was having more trouble with having control of the pieces. It was also the first time I have ever done a flush cut on pieces that thick.

Not a general recommendation, but it's in regards to flush trimming.  Use the 1400 if you want - if you're comfortable with balancing it.  Using the above-board method lets you use the weight of the router to do climb cuts against cross/changing grain.  While you could technically do it on a router table for simple geometries, it's not something I'd recommend.

* I think the 1400 still has the table widener.  You might want to consider looking into that to help for off-edge operations.  Item 493233.

 

[jeffinsgf]

For smaller items you recommend not using a router table? I don't own a trim router. The smallest router I own is an OF1400. The one in my router table is a Porter Cable 7538 speedmatic 3 hp plunge router. The bit I was using is a Woodpeckers Spiral 2-Flute Compression Flush Trim, 1/2 in diameter, 1/2 in shank, 2 in cutter length, and bearing on the tip. The two problematic pieces were mostly end grain on the curve which could also be why I was having more trouble with having control of the pieces. It was also the first time I have ever done a flush cut on pieces that thick. The template seems like a good option. I might need to make a custom router sled with the ability to swap in different curve profiles. I also probably need a bit with a bearing on both ends of the cutter or at least one on the shank end so I can have a downhill cut at all times.

You're on the right track with getting a bit with bearings on both top and bottom and always working from edge grain to end grain. Starting on end grain ranges from sketchy to dangerous. Coming around a corner from end grain to edge grain is at very best a 50/50 proposition. If you always work along an edge and come around into the end grain --- then stop before you go around the next corner --- you'll have better results.

Also, as someone else mentioned, if you're not using a starter pin, start using one.

I just did some animal cut-outs and used exactly the method you're outlining...cutting halfway through with Origin, band sawing close to the edge, then flush trimming.