Kitchen island — pushing the limits of a 1000mm machine

[RohanSingh]

My girlfriend moved in recently, and we’ve been rearranging the apartment a bit and getting some more furniture. We decided to use my X-Carve to put together a kitchen island, and use it as an opportunity to experiment with CNC joinery.

She did the initial design (did I mention that she is awesome), but wasn’t sure what the dimensions of the X-Carve are. Result— a design where almost every piece is longer than the machine, and almost as wide as the machine as well

The top and bottom pieces there are 48" long, and even the sides are 36". But by cleverly working alignment holes into the design and some Fusion 360 CAM magic, I was able to setup a number of tiled cuts:

So far we’ve gotten three of the four largest pieces milled. It took a bit of experimentation to find good bits for milling out these joints. Whiteside’s 1/4" compression bit is making short work of things and leaving a nice finish:

We test-fit the joints earlier and they fit quit nicely. Actually, we originally dimensioned the fingers and the slots on those joints to be exactly the same size down to the millimeter, but realized the error of our ways during an earlier test. Now the fingers are half a millimeter narrower than the slots, and everything stands together on its own.

[MichaelColey]

Good luck with your project. Eager to see the final result.

[NicShimala]

I’m curious about that joinery on the ends. Can’t wait to see it all assembled.

[WorkinWoods]

yeah all those cnc joints on that website I have a special book with way more

they cnc chic like you say

[WorkinWoods]

get job on the design though !!!

send pics when all done I would like to see

[RohanSingh]

@AngusMcleod

Just looks like finger-joints with dogbones, but the dogbones seem quite pronounced – more than actually necessary. Possibly to enhance the “CNC Chic” effect.

I mean, this is the one of the first pieces of furniture we or anyone else will see when walking in, so I do want it to look nice

[RohanSingh]

@WorkinWoods

yeah all those cnc joints on that website I have a special book with way more

Awesome. Mind sharing what book that is?

[WorkinWoods]

I will have to find it but its all in german

[RohanSingh]

@WorkinWoods

I will have to find it but its all in german

Hahaha, not surprised. I believe the designer of the original “50 Digital Wood Joints” kit is German as well.

[WorkinWoods]

I think this is it

Google Drive: Sign-in

[WorkinWoods]

@RohanSingh

were you able to open?

[RohanSingh]

Ah ha, yup! I think this is the same guide that we used for the original design Thanks though!

[WorkinWoods]

is it? idk I thought that one had had alot more than 50 lol

[RohanSingh]

Definitely the same one, I recognize it from what my partner was using. But this project she’s the designer and I’m the machinist, so I didn’t look very closely.

I’ve been meaning to go through it for a while to try to sort out the joints that would be the easiest to machine. Maybe this weekend!

[NicShimala]

holy crap that’s an awesome book. so many ideas just can to mind.

[RohanSingh]

Be careful directly using any of the DXF’s or other models directly from the book though. We almost got into trouble with that.

The models are idealized and don’t have appropriate tolerances to allow the joints to slide together. Mark Meier’s post details his experiences with actually milling out some of these. I wish I’d read it much more thoroughly before carving.

[NicShimala]

@RohanSingh

Be careful directly using any of the DXF’s or other models directly from the book though. We almost got into trouble with that.

I figured. I opened up a couple different ones, i already saw it will need to be cleaned up with tolerances.

…and now i will get no work done today…

[MidnightMaker]

This is an amazingly cool project! It may be premature, but when you succeed, would you ask your partner if she would mind you sharing the file here? I think this is also important because it shows how you both managed to overcome the size restriction, opening up the 1000 mm² to carve large format parts. Until I can afford and have the space for a 48"x96" machine, tiling is a technique that I think we all need to become more comfortable with.

[RohanSingh]

Sure, I actually did the alignment holes and tiling myself so I’m happy to share. Take a look at the CAM setups here: Fusion.

Not sure how familiar you are with it, but for tiling to work, you need two things:

1. A reference location, such as a hole, to locate the piece as you move it through.
2. A reference edge, to ensure your workpiece stays square to the machine’s axes as you move it through.

The first thing I do for any of the pieces is drill some holes using a 1/8" bit. One of them serves as the reference location, and the other three let me put in screws to hold down the piece:

Note that the XYZ origin point is in the corner of the first tile above. But for the next tile, I have the origin set to the reference hole:

Prior to putting the workpiece onto the machine, I’ve had the machine drill some 1/8" holes into the waste board along its Y axis, and inserted steel pins. This lets me line up the workpiece to the machine Y-axis and give it that reference edge:

My workspace is constrained in that I can’t actually push the workpiece through — I have to pull it out and flip it around because of the wall in the back. But I want to be able to stick to the same reference edge of the workpiece. To solve this, I have the same setup with steel pins on the right side of the machine:

Then I mount the workpiece flipped around and screw it in. To set the work origin, I just manually jog the machine until the 1/8" bit is lined up with the reference hole:

At this point I run the toolpaths for the second tile. If everything works out, I have a perfectly lined-up and complete piece!

In practice, each tile might be off by half a millimeter or so, but it’s good enough for my purposes. There’s multiple possible sources of error:

• The tool deflection when drilling the original holes. This is hard to control for.
• My error when lining up the bit with the reference hole. This should actually be pretty low, since you can sink the bit all the way into the hole to line it up.
• Error introduced by slipping the X-carriage during tool change. This isn’t good for the machine and is probably the primary source of error, but since my actual carves don’t use a 1/8" bit, not sure what to do about it.

This is one of the pieces that came out the worst:

For the pieces that came out better, you can only tell where the tile division is if you really know to look for it. Honestly, I’m surprised by how well it works:

[RohanSingh]

Finally finished machining out all the pieces for this project, and we started sanding, staining and glueing. Here’s the first distinct piece that came together— it’s one of the two inner boxes in the design:

Overall I’m pretty happy with it! Everything fit together fairly easily for this box. For the next box, things didn’t come together quite as easily due to some warping, but strategically applying clamps took care of the issue. Lesson learned: don’t let pieces lie flat on the basement floor for a week