Fence Post Caps

An area to upload images of pieces cut using VCarve Pro
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Mobius
Vectric Wizard
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Fence Post Caps

Post by Mobius »

I finally got around to starting the project that was the original reason for purchasing a CNC router!

When I built my fence, I didn't take into account the size of fence post caps. I used 6x6 rough cut posts, and when you add 2 layers of Tyvek homewrap and aluminum flashing, the posts actually measure 6" x 6" (+/- 1/8"). 99% of all 6x6 fence post caps that I can find have a 5.5" x 5.5" inside diameter. Additionally, since I prewired my fence for accent lighting, I needed post caps that could be modified to hide some LED strips.

The solution was to build my own. These are made using the leftover scrap from the fence, laminated together and then routered out. It's a simple design, cuts down on machine time; but it still takes about 5.5 hours to make four caps from start to finish. I think they turned out great.

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Connor Bredin
Distinctive Dimensional Concepts Ltd.
www.distinctive-concepts.ca

Mobius
Vectric Wizard
Posts: 413
Joined: Wed Jul 09, 2014 1:19 am
Model of CNC Machine: CRP Pro 4848 Custom Build
Location: Drumheller, Alberta, Canada
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Re: Fence Post Caps

Post by Mobius »

I have enountered a problem cutting these out though. I generate the toolpath for the post cap with Cut3D. For the rough cut I use Raster X, with no profile cut. This works fine, but I would prefer to use a profile cut as this would allow the machine to move at full speed for longer, increasing efficiency.

The problem lies with the profile cut. If I import the Gcode directly fromt Cut3D to Mach 3, I can cut the post cap with no issues. However, I have been importing the cut3d file into vcarve pro so that I can nest 4 caps onto one material blank, and also add various other toolpaths (pockets, holes for aligning the material when flipping it over, surfacing etc.)

This is where the problem lies. When profile cut is selected in cut3d, the gcode generated while nested in vcarve pro is vastly different than when it is generated through cut3d. It seems to work fine in the preview, but gives me "Radius at end of cut differs from start radius" error when loaded into Mach 3. If there is no profile cut selected, everthing works fine.

Any ideas why this is?
Connor Bredin
Distinctive Dimensional Concepts Ltd.
www.distinctive-concepts.ca

PaulRowntree
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Re: Fence Post Caps

Post by PaulRowntree »

That Mach3 error message is telling you that Mach3 and VCP are not using the same convention for arc movements. Both work best with incremental arcs, not absolute. It is a simple toggle control inside Mach3 that sets this up, in Vectric programs it is set in the header code of the post-processor.
Paul Rowntree
WarpDriver, StandingWave, Topo and gadgets available at PaulRowntree.weebly.com

Mobius
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Re: Fence Post Caps

Post by Mobius »

I did try switching between incrimental and absolute already, to no effect. Im curious why the gcode changes between cut3D and vcarve, I have the same post processor selected.
Connor Bredin
Distinctive Dimensional Concepts Ltd.
www.distinctive-concepts.ca

PaulRowntree
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Re: Fence Post Caps

Post by PaulRowntree »

Mobius wrote:I did try switching between incrimental and absolute already, to no effect. Im curious why the gcode changes between cut3D and vcarve, I have the same post processor selected.
I believe that each Vectric program brings with it its own group of post-processors. They may have the same name, but they are not the same file. There are some differences between the features offered by the different programs. I believe it is possible for the gcode to override the Mach3 settings, so it is important to know what is being done by each PP

How old is your VCP and Cut3D?

Could you post the gcode headers produced by the two programs (top ~20 lines of the file, before the toolpath really starts). Is Mach3 set for incremental or absolute?
Paul Rowntree
WarpDriver, StandingWave, Topo and gadgets available at PaulRowntree.weebly.com

Mobius
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Re: Fence Post Caps

Post by Mobius »

Here you are:

Straight from Cut3D:

( Roughing Toolpath - Top )
( Mach2/3 Postprocessor )
N20G00G20G17G90G40G49G80
N30G70G91.1
N40T12M06
N50G00G43Z0.1969H12
N60S17000M03
N70G94
N80X0.0000Y0.0000F100.0
N90G00X-3.8715Y3.8780Z0.1969

Imported to Vcarve with no profile pass on roughing:

( Roughing Toolpath - Top )
( Mach2/3 Postprocessor )
N20G00G20G17G90G40G49G80
N30G70G91.1
N40T12M06
N50G00G43Z0.1969H12
N60S17000M03
N70G94

Imported to vcarve with profile pass on roughing (does not work):

Toolpaths used in this file:)
(Post Cap CNC - R)
(Post Cap CNC - F)
(Tools used in this file: )
(12 = End Mill UC {0.5"})
(1 = Ball Nose {0.25 inch})
N120G00G20G17G90G40G49G80
N130G70G91.1
N140T12M06
N150 (Tool: End Mill UC {0.5"})
N160G00G43Z0.1969H12
N170S17000M03
N180(Toolpath:- Post Cap CNC - R)
N190()
N200G94
N210X0.0000Y0.0000F100.0
N220G00X-3.8715Y3.8780Z0.1969

They all set IJ mode to incremental.

I'm not sure why Vcarve pro converts the cut3D toolpaths to arcs when profile pass is enabled (to create this issue), when they should all be straight cuts.

Offending code from when imported to Vcarve Pro:

N370G00X-3.4697Y3.4775Z0.1969
N380G1X-3.4697Y3.4775Z-0.2500F30.0
N390G2X-85.2537Y90.0522I4.5874J-4.3906F100.0
N400G2X-82.9529Y90.4837I2.3008J-5.9185

N410G1X-3.2581Y3.5624Z-0.2500
N420G1X-3.1964Y3.5546Z-0.2500

Same line from the cut3D file:

N360G01X3.2581Y3.5624
N370G01X3.2659
N380G01X3.2966Y3.5604
N390G01X3.3271Y3.5547
N400G01X3.3564Y3.5454

N410G01X3.3878Y3.5343
N420G01X3.4176Y3.5190
Connor Bredin
Distinctive Dimensional Concepts Ltd.
www.distinctive-concepts.ca

Lukebbb
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Re: Fence Post Caps

Post by Lukebbb »

Where did you get the LED strips? The fence looks amazing. Where did you route the wiring for the post lights? What is the voltage and amp draw of the lights combined? Overall excellent work.

Swdstmaker
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Re: Fence Post Caps

Post by Swdstmaker »

What a great idea. I will be building a new deck soon and believe I will use this idea myself. Thanks for the great work.

Mobius
Vectric Wizard
Posts: 413
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Re: Fence Post Caps

Post by Mobius »

Lukebbb wrote:Where did you get the LED strips? The fence looks amazing. Where did you route the wiring for the post lights? What is the voltage and amp draw of the lights combined? Overall excellent work.
The strips were bought from superbrightled.com. I ran 10ga. Wiring through the entire fence just below the top cedar 2x6. The vertical fence boards dont go all the way up, which left a void where I could run the wiring. I drilled a horizontal and vertical hole through each post which allowed me to fish a 18ga wire to the top of each post, which I spliced in parallel to the 10ga.

The LEDs are all 12VDC, not 100% sure about the current draw yet as I havent finished all the caps (each cap has 1-3 4" strips depending on its location on the fence). I oversized my power supply, and it is located at the center of the fence which halved the wiring distance so the 10ga. should be sufficient for voltage drop.
Connor Bredin
Distinctive Dimensional Concepts Ltd.
www.distinctive-concepts.ca

Mobius
Vectric Wizard
Posts: 413
Joined: Wed Jul 09, 2014 1:19 am
Model of CNC Machine: CRP Pro 4848 Custom Build
Location: Drumheller, Alberta, Canada
Contact:

Re: Fence Post Caps

Post by Mobius »

Swdstmaker wrote:What a great idea. I will be building a new deck soon and believe I will use this idea myself. Thanks for the great work.
I plan on adding more of these to my deck as well, once I get around to building it. :-)
Connor Bredin
Distinctive Dimensional Concepts Ltd.
www.distinctive-concepts.ca

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