Coping Crown Molding

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Dale1944
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Joined: Tue Aug 26, 2014 3:03 am
Model of CNC Machine: CNC Router Homemade

Coping Crown Molding

Post by Dale1944 »

I have been putting on installing crown molding in the master bedroom for some time because I need to cope several corners. I don't want to fiddle with a coping saw or an angle grinder or a Dremel tool. I would think that this could be done on my CNC. Has anyone done this? I searched but could find nothing.

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highpockets
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Re: Coping Crown Molding

Post by highpockets »

You can get the necessary angles from this site.
https://www.blocklayer.com/crown-molding.aspx

Seems like a whole lot of trouble, but what ever...
John
Maker of Chips

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JoeBlow
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Re: Coping Crown Molding

Post by JoeBlow »

Now this is a very interesting question. As a Finish Carpenter by trade, I install a huge amount of crown molding each year. My favorite task actually :D How cool would that be for me to pull a cnc out of my work van at the jobsite and start coping joints. lol

I actually think this is feasible though. Enough so that I will give this a try (not the part about bringing my cnc to work).

The hard part I think will be to bring the appropriate profile into the software. These are the steps I will try....
1. Cut an inside 45*. Keep in mind that the majority of crown has a 38* spring angle so reference the chart Highpockets linked and utilize the numbers for cutting crown on the flat. I never do the upside down and backwards game myself. Much greater control cutting on the flat in my opinion.
2. Now I can accurately measure the profile. This will certainly require some trial and error. Assuming I'm using standard 5 1/4" crown, I will need to transfer the cove, step and ogee into the software.
3. Create your vector and use a profile toolpath with a 90* v bit. Keep in mind that the crown will need at least a 45* back bevel which is why I would use a 90* v bit.
4. Set the profile vector at 31.62* and mill away. The crown will need to be mounted face down on the cnc and milled from the backside.

This should be an interesting experiment.
Patrick

The hurrier I go, the behinder I get

Dale1944
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Joined: Tue Aug 26, 2014 3:03 am
Model of CNC Machine: CNC Router Homemade

Re: Coping Crown Molding

Post by Dale1944 »

I never thought about putting the molding face down -- I was thinking of building a ramp. Your idea is much better!

Making the copes on the CNC, and then using a scarf joint to get the required length should make this possible for a homeowner (me). I am thinking of taking a photo to get the outline into Aspire. Make sense?

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gkas
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Re: Coping Crown Molding

Post by gkas »

Dale1944 wrote:
Thu Jul 02, 2020 5:46 am
Making the copes on the CNC, and then using a scarf joint to get the required length should make this possible for a homeowner (me).
You can use Tile Toolpaths to create long strips of Moulding. No need for the scarf joints, unless you want a really long piece of moulding, or just like making scarf joints. :D :D :D
Dale1944 wrote:
Thu Jul 02, 2020 5:46 am
I am thinking of taking a photo to get the outline into Aspire. Make sense?
That works great. You can easily use vector drawing over an imported photo. It's a great way to improve your drawing skills. That's how my wife gets ideas for me to frame her needlepoint.

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