Big CNC - Revision history

Jon at 02:15, 15 November 2022

2022-11-15T02:15:23Z

Jon at 19:21, 28 September 2022

2022-09-28T19:21:18Z

Jon at 04:22, 28 May 2022

2022-05-28T04:22:50Z

Dannym-1: /* Tooling */

2022-05-10T13:54:26Z

Tooling

Dannym-1: /* Tooling */

2022-05-09T17:59:33Z

Tooling

Dannym-1: /* Tooling */

2022-05-09T17:56:27Z

Tooling

Dannym-1: /* Tooling */

2022-05-09T17:52:01Z

Tooling

Dannym-1 at 17:47, 9 May 2022

2022-05-09T17:47:17Z

Dannym-1 at 17:40, 9 May 2022

2022-05-09T17:40:53Z

Dannym-1: /* Tooling */

2022-05-09T17:38:09Z

Tooling

← Older revision		Revision as of 02:15, 15 November 2022
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	CANNOT CUT STEEL. Steel requires coolant which is not compatible with the MDF bed. Steel can create red-hot chips and sparks which can start a dust collector fire, a very dangerous situation.		CANNOT CUT STEEL. Steel requires coolant which is not compatible with the MDF bed. Steel can create red-hot chips and sparks which can start a dust collector fire, a very dangerous situation.
−
−	~~{{Required\|Big CNC}}~~

	{{ToolPhoto\|BigCNC.jpg}}		{{ToolPhoto\|BigCNC.jpg}}

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 The Big CNC is a custom CNC router designed and built by Danny Miller.  It has a maximum cutting area of 5' by 8'
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 * [https://www.vectric.com/support/tutorials/vcarve-pro VCarve Tutorials]
 * [https://www.youtube.com/channel/UCrwn2uKl16pnC-GMgB75Cag LinuxCNC Tutorials (video)]

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 {{Required|Big CNC}}
-{{ToolPhoto|BigCNC.png}}
+{{ToolPhoto|BigCNC.jpg}}
 ==Checklist==

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 Users must bring their own bits.  All CNC routing bits should be carbide, not HSS (High Speed Steel).  HSS will not damage anything but the performance on wood, plywood, plastics, etc is poor.
-An RCK-2249 surfacing/rabbeting bit is provided in the cabinet.  This is an excellent choice for surfacing lumber slabs (live edge table) and pocketing.  The 2 cutters on bottom of the bit plane the surface for a smooth face.  It is 1-1/2" and uses two different types of carbide inserts which you will want to bring along with screws if you want to get the best quality cut.  Larger diameter bits typically do not produce as good a finish, as any tram error (the spindle not being perfectly perpendicular to the surface) tilts the circle the bit makes which creates a slight scalloping of the surface and this requires more sanding to smooth out.
+An RCK-2250 surfacing/rabbeting bit is provided in the cabinet.  This is an excellent choice for surfacing lumber slabs (live edge table) and pocketing.  The 2 cutters on bottom of the bit plane the surface for a smooth face.  It is 1-1/2" and uses two different types of carbide inserts which you will want to bring along with screws if you want to get the best quality cut.  Larger diameter bits typically do not produce as good a finish, as any tram error (the spindle not being perfectly perpendicular to the surface) tilts the circle the bit makes which creates a slight scalloping of the surface and this requires more sanding to smooth out.
-https://www.toolstoday.com/v-11847-rc-2249.html
+https://www.toolstoday.com/v-11399-rc-2250.html
 The Diamond-Like Carbon inserts RCK-70-DLC and AMA-12-DLC are the best choice for surfacing lumber.  These inserts have 4 faces and can be rotated when one edge or corner is worn or damaged.

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 Metal nails are entirely prohibited
 Steel screws are an option.  Only high quality screws should be used- Kreg Pocket Jig screws are the best option.  Spax screws are also acceptable.  Cheap drywall screws are not acceptable, as they are very prone to break in the spoilboard.  Screws generally require predrilling to avoid engaging the threads in the stock or splitting the stock.  It is often possible to predrill with the CNC itself without a holddown if the stock is large enough.
-If you DO break a steel screw off in the bed, please circle the problem with a black Sharpie on the bed itself.  We will extract it before resurfacing but we need to know where it is before the bit finds it.
+Avoid using screws longer than needed for your stock.  This increases the stress and chance of breakage, also the spoilboard is usually a bit under 2" thick and we do not want screws to go all the way through it and strike the supporting framework underneath
 Video explaining tape-and-superglue holddown method.  No holes are made in your stock, and no glue soaks into your stock either if done properly.  The blue painters' tape adhesive is the only thing on the bottom of your stock and should release completely when done.

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 https://www.toolstoday.com/v-11847-rc-2249.html
-The Diamond-Like Carbon inserts RCK-70-DLC and AMA-12-DLC are the best choice for surfacing lumber.  This bit CANNOT PLUNGE it must approach the work from the side.  These inserts have 4 faces and can be rotated when one edge or corner is worn or damaged.
+The Diamond-Like Carbon inserts RCK-70-DLC and AMA-12-DLC are the best choice for surfacing lumber.  These inserts have 4 faces and can be rotated when one edge or corner is worn or damaged.
 Places to get bits in town

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 The Big CNC is a custom CNC router designed and built by Danny Miller.  It has a maximum cutting area of 5' by 8'
-Max Z height is approx 7.5" from nut to spoilboard, but this does vary as spoilboard is added or removed.  Note that the max usable stock height will typically need room for your bit to go on top of it
+Max Z height is approx 7.5" from nut to spoilboard, but this does vary as spoilboard is added or removed.  Note that the max usable stock height will typically need room for your bit to go on top of it.  e.g. a 6" block could potentially have a 1" pocket in it if a bit with a 1" cutting length is chucked.  However, that block could not have a 2" pocket because the bit would need to have 2" cutting length sticking out of the nut which would be 8", not even counting the clearance needed to ensure the bit does not hit the stock when jogging across the top.
 Spindle 3KW digitally-controlled VFD using an ER20 collet system.  Manual bit changes, no ATC.
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 * coatings (DLC, Spektra) reduce friction, cut slightly cooler, and last longer
 * Some bits have replaceable carbide insert cutting edges.
 Conventional drill bits can be chucked in the ER20 system.  Please use the tightest collet available, which may mean selecting a metric.  Any slippage between collet and tool will generally damage the collet.
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 All work needs a holddown solution.  We need to avoid embedding metal into the MDF bed as this will break the bit when the spoilboard is resurfaced.
-A Raptor air nailer firing nylon polymer nails is provided, along with the special-purpose Raptor F15 polymer nails.  This is only to be used for CNC, and must NEVER be loaded with metal nails.
+A Raptor air nailer firing nylon polymer nails is provided, along with the special-purpose Raptor F15 polymer nails.  This is only to be used for CNC.  The Raptor nailer was designed to use only the F15 polymer nails and must NEVER be loaded with metal nails.
 The polymer nails are approx 1.25" long and effective on plywood and MDF up to 1/2" thick.  It is possible to do 3/4" but this leaves little left to actually go into the spoilboard.  Some hard lumber or plastics may be too hard and the nail will break before penetrating.

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 CAM postprocessor should be "LinuxCNC", and not an ATC version.  If nonarcs is an option, this is recommended over the arc option, but arcs will work.  LinuxCNC used to be called "EMC2" long ago, "EMC2" postprocessors should work.
-Cuts wood, plywood, plastic, many other materials.  It is also capable of cutting nonferrous sheet metal and billets (thick blocks of metal stock) with proper feedrates and compressed air nozzle.  The compressed air nozzle will drive chips out of the cutting area so they are not re-cut by the bit and provide some cooling.
+Cuts wood, plywood, plastic, many other materials.  It is also capable of cutting nonferrous (aluminum, copper, brass) sheet metal and nonferrous billets (thick blocks of metal stock) with proper feedrates and compressed air nozzle.  The compressed air nozzle will drive chips out of the cutting area so they are not re-cut by the bit and provide some cooling.  For billets, while the CNC router may be capable of it, the Tormach is more capable as it is stiffer, lower RPM, and equipped with flood coolant.
 CANNOT CUT STEEL.  Steel requires coolant which is not compatible with the MDF bed.  Steel can create red-hot chips and sparks which can start a dust collector fire, a very dangerous situation.

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 * Some bits have replaceable carbide insert cutting edges.
-Video explaining superglue-and-tape holddown method
+Conventional drill bits can be chucked in the ER20 system.  Please use the tightest collet available, which may mean selecting a metric.  Any slippage between collet and tool will generally damage the collet.
 https://www.youtube.com/watch?v=gTUAAm0DFOQ
-Conventional drill bits can be chucked in the ER20 system.  Please use the tightest collet available, which may mean selecting a metric.  Any slippage between collet and tool will generally damage the collet.
+This is also a great option for holding down live edge slabs which have no place for a screw hole that would mar the final surface appearance.  In this case you might only tape-and-superglue 4 corners selectively onto some plywood or MDF tabs while off the CNC router bed, then nail or screw the tabs to the spoilboard to secure the slab.
 ==Resources==