# Cutting odd shapes into a plywood surface.



## RCharles (Mar 19, 2009)

Hello

I want to cut some odd shapes into a piece of plywood. the plywood is 3/4 inch and the cuts would be 1/4 to 3/8 inch deep with the edges cut perpendicular to the surface.

I may do several different shapes and sizes but to get started I'll describe two:

1. A rectangle, with two sides 1.5 inches and two sides at 4 inches.

2. A trapezoid, with two sides at 1.5 inches and two sides at 3.5 inches.

3. An ellipse with major dimension of 3.5 inches and minor dimension of 1.5 inches.

Is there a way to do these kinds of cuts, at least the bulk of removal, with a router?

Thanks for any help.

Ray


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## juniorjock (Feb 3, 2008)

A router would be my guess Ray.


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## cabinetmaster (Aug 28, 2008)

Router would be my choice for sure.


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## RCharles (Mar 19, 2009)

OK, I'd love to use a router.

But just how is it done?

For freehand work, as opposed to a router table, I'm used to holding the router against guides specific to the cut. Haven't tried any true freehand routing but there seems to be a risk of the router grabbing and running off, ruining the piece. My problem here, for example, is how to create and clamp down a guide for a curved eliptical cut.

Can anyone be more specific on how to get this done?

thanks

Ray


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## juniorjock (Feb 3, 2008)

You have a good point Ray. It's not like you could make templates and use a flush cutting bit. Not really sure about that one.


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## juniorjock (Feb 3, 2008)

Good idea. That's what I thought about it. But if I'm understanding what Ray is saying, I don't think that will work.


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## juniorjock (Feb 3, 2008)

Maybe with a guide bushing. That would work wouldn't it?


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## juniorjock (Feb 3, 2008)

Ohhhhhh. You're right bentlyj. Pretty much the same thing. But that would do it. I'm not sure if I'm seeing this exactly right either. But your idea would work for sure.


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## LesB (Dec 21, 2008)

With those small sizes I would use the hardboard pattern, a template guide and a down cutting spiral bit to prevent the edges from splintering up ward.
Making a template large enough to accommodate the whole router base is overkill.


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## PurpLev (May 30, 2008)

I'd second LesB - router with a template guide and a hardboard pattern. just make sure your pattern is offset to accomodate the distance between the router bit and the template guide whether it'd be on the outside (making the template 'smaller') or the inside (making the template 'larger').

so a search on template routing, and template guides. should give you a bit more on that matter - fine woodworking and such sites have good articles on this including pics and tips that might make it easier to understand and follow.


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## LesB (Dec 21, 2008)

Purplev said it. I would use an inside routing template method. That way you can clean out the whole thing and not be concerned about running outside the pattern. The sizes of your patterns should make it easy to keep your router supported on the template to complete the whole cut in one operation.

I do the same thing for "butterfly" inlays and other simple patterned inlays using a guide with a 1/8" collar that slips on and off and allow for making the inlay piece and the recess for it from the same template. A 1/8" straight router bit is use for that the the bit is easy to break if you try to go to fast. They sell them as kits, guide, collar, and bit in one package. You can even buy pre-made templates but it is easy to custom make your own.


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## RCharles (Mar 19, 2009)

Hi all - and thanks for all the suggestions.

I'm not quite ready to start this project but do appreciate the ideas and help. I'll be studying this thread and set up a test piece to try two or three alternatives before attacking the final piece, which is a finished panel; it came with a wall system and is surplus but I only get one shot at cutting it.

Regards

Ray


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## LesB (Dec 21, 2008)

Bentlyj,
That is the one. Yours appears to be part of an adapter for your router base plate. Mine just mounts on my Porter Cable plate without the adapter.

RCharles may want to use regular template guides so he can use a larger bit to remove wood faster.


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## rhybeka (Nov 8, 2009)

hey Ray! I was hoping to bump this to see how your project is going? I've got one similar in mind and thought about picking up the hardboard to make my templates with this weekend. Any luck with yours?

-Becky


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## bobkberg (Dec 26, 2009)

Pardon my curiousity, but what sort of project is this?


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## RCharles (Mar 19, 2009)

Hi Becky and Bob

Thanks for posting and waking me up. Obviously I haven't been very active here in the past 293 days….

The short answer: I've been distracted and busy with several other projects (and vacations) and this project never got started. But I still have the materials and hope to get into it this summer.

The project is rather simple. A while back I visited a fossil area in SW Wyoming and dug up a dozen or so fish fossils. These are two-four inches long and one-two inches wide on a sandstone base. I also have a panel, left over from some furniture, that is about twelve by twenty and two inches thick; it's made from 3/4 inch plywood with a dark finish. My goal is to mill some pockets into the panel and glue the fish fossils into it. Each pocket will be an elliptical shape and slightly oversized and I will grout the edges after gluing in the fossil.

For the truly curious, here are links to the fossil beds in WY and pictures of some fossils.

http://www.kemmerer.org Kemmerer, Wyoming
The Fossil Fish Capital of the World.

http://www.orerockon.com/Green%20River%20fossils.htm A quarry you can visit; this web site also has several pictures of fossil fish, most of which are larger than the ones I found.

Regards and thanks to all who responded.

Ray


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## eastside (Jun 21, 2009)

Wow 295 days ago and brought back from dead. To Becky, bob and ray have you thought of a slip fence on the table saw? If you have a delta fence the slip fence is built in. Cut a template of the exact size needed out of 3/4 scrap, put 2 brads through it protruding 1/4 inch and stick it to your work piece and use the slip fence. The thickness of the template will depend on the height of the slip fence and the finish piece and if you don't have a delta then just make one out of a 2×4. Precut the finish pieces ¼ inch bigger on the band saw or jig saw it will lead to less resistance on the table saw. As I write this I wonder how many people still use a slip fence and I'm thinking that just the more elderly lJ members have maybe even seen or heard of this. This might make an interesting topic!


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