Fun Weekend Project

[dbfletcher]

This looks like something we could easily do with the CW. Not sure I'll have time to get it done this weekend, but as long as we keep the starting cube at 2" or less, I think we can make the fixed and free floating cubes. I'm sure someone else will beat me to it, but as I get the jig & mpc's designed, I'll post here.

http://www.instructables.com/id/Turners-Cube-A-Beginner-CNC-Milling-Project/

[James RS]

http://youtu.be/TfV_APBk16Q (http://youtu.be/TfV_APBk16Q) Check this video from Steve Marin

[CarverJerry]

Ok, this will be interesting to see done on the CW......

[jaroot]

Just curious, why 2" or less?


This looks like something we could easily do with the CW. Not sure I'll have time to get it done this weekend, but as long as we keep the starting cube at 2" or less, I think we can make the fixed and free floating cubes. I'm sure someone else will beat me to it, but as I get the jig & mpc's designed, I'll post here.

http://www.instructables.com/id/Turners-Cube-A-Beginner-CNC-Milling-Project/

[edzbaker]

The CW can do it easy enough. But, It's really easy with a forstner bit, and my grandson (7 mo's old) loves them.

Ed

[dbfletcher]

Just curious, why 2" or less?

The CW is limited to 1" depth on cutout/drill operations. If you wanted to do hollow cube in a cube in a cube, you have to be able to go all the way thru half the thickness. This is assuming you want to do the entire thing on the cw. If you want to use other tools as well, the 2" wouldnt apply. If I am mistaken on this, please let me know.

[bergerud]

The nice thing about using the CW is that you would not have the tell tale drill marks on the inside cube(s). One could also add carving embellishments. Is someone going to give it a try?

[dbfletcher]

I am definitely going to try the "hollow free cubes", but not sure I will get to it this weekend. I assume the number of cubes gets determined by the diameter of the hole for each interior cube. I haven't tried the math yet, but I'm betting bergerud could whip it out in no time.

[bergerud]

Since we only have 1" depth drilling holes, the smallest the inside cube could be is the size of the outside cube minus 2". So lets say we make the outside cube 3" and the inside cube 1". This would require drilling a 1" deep, 1.414" diameter hole in each face. (The hole diameter is the square root of 2 times the cube side because the diagonal of a square face is the diameter of the circle.) The middle cube is between the small cube and the large one. Lets say we make it 1.75". It would require a 1.75*1.414=2.475" hole to a depth of (3-1.75)/2=0.625".

Now these are "ideal" calculations which would completely drill out the cubes. We want to stop a little shy of these depths so that the cubes have "tabs" and so that they are left trapped inside. If they are completely drilled out, they will fall out of the holes. Some experimentation is required. Decide how thick you want the "tabs" and decrease the hole depth to get them. (I guess you could also decrease the diameters to get the them.)

I have not done any of this so, until someone does, it is just theory! I think it might be interesting to carve a sphere in the cube. Think about that.

[bergerud]

I could not help but to play with the sphere in a cube. Here is my first pass at the problem. I have no idea how it will carve; I may try to carve it later today. There are no "tabs". The sphere could drop in with the last carve. If this does work, one could also drill another cube in the sphere.

[bergerud]

Check it out. Don't you just love this machine? There is no end to the cool things we can do. Here is the sphere straight out of the machine. My first six sided carve and it worked first time. Look how well the overlaps lined up. The second picture shows the worst overlaps. A light sand and it will be done.

[lynnfrwd]

That's awesome!!


Sent from my iPhone using Tapatalk

[dbfletcher]

Pretty kewl. I knew someone else would beat me to this. I got a new RC heli kit on friday so I ended up doing nothing on the cw and worked on building the heli all weekend. Id really love to see the cube in a cube in a cube (free floating) using the "plug idea" so you never have the cube floating while carving. Oh well..maybe next weekend. This one is shot.

[bergerud]

The cubed cube is still yours to do! But I do not understand about the free floating. If you completely drill out a cube, it will not be trapped inside. It will fit out the hole. I think you have to stop short of drilling out the cube and finish cutting the remaining tabs by hand in order that the cube be larger than the hole. The sphere does not have this problem.

[dbfletcher]

My understanding is you make a "stepped plug" that you insert in to the cube after your make your cuts. The will hold the inner cubes in place as you cut the other sides. I'm was planning on making three plugs so that the inner cubes where alway supported on three sides during the carving/cutting operations.

[jaroot]

Nice job Bergerud! Never seen it done with a sphere inside of the cube.

[gregsolano]

Can't wait to carve one, you never cease to amaze me. And I really appreciate that you always share.

[bergerud]

I thought I would try a different carve of the sphere in a cube. The first one had overlapping spherical caps. More was being carved out of the cube than was required. See what you think of the "tighter" carve. The caps are cut at 45 degrees on the side so they do not overlap. Which do you think looks better?

[easybuilt]

I like the tighter one. I think I'll try this tomorrow. Thanks for the unique idea.

[dbfletcher]

I also like the tighter one. Is it possible to make the tighter one and still have the openings be perfect circles? Or will that always force and overlap?

[bergerud]

I like the tighter one too. Of course it is more work to finish. The sphere does not just fall out and the clearances are tighter to work in. I think I will try and tweak it so there is a slight overlap to make sure the sphere falls out. As for the shape of the hollows, I do not think there is a choice for the shape at the sphere surface (see pics below). The rest of the hollow is just a (rough) 1/8 feather. I could work on the top of the hollow to make it either a square or a circle which transitions to the shape at the sphere surface. I could also think about what different sizes are possible and whether I could carve more spheres inside of the sphere. This has turned out to more than a "Fun Weekend Project". Thanks for the idea Doug.

[dbfletcher]

Just out of curiosity, are you using MathCad for your graphics? And I agree, this has been an interesting thread to follow.

[bergerud]

I use Maple to do my calculations and plot surfaces. It is a symbolic math program like Mathematica. I teach courses in how to do math with Maple. For carving, I can output the surfaces as either dxf or directly as gray scale png.

[bergerud]

The fun weekend project continues. Here are my latest sphere in a cube. The sphere and the cube are both 2 inches carved in cocobolo. The holes are square. Since the sphere and the cube are the same size, the sphere rolls when you slide the cube.

These are a challenge to carve and and will be a challenge to finish.

I am not finished with tweaking this pattern yet. The trick is to carve as little as possible yet have the sphere "fall out".

[Dan-Woodman]

You would have to carve that 6 times wouldn't you?

[chebytrk]

And how long (time) does each carve take? (Best or Normal?)


You would have to carve that 6 times wouldn't you?

[bergerud]

Yes, it is a six sided carve which takes 10 minutes each side on optimal. I plan on making a better jig which allows one to flip the cube around without removing the jig from the machine. It would be more accurate and not take as long to carve all the sides

[dltccf]

Yes, it is a six sided carve which takes 10 minutes each side on optimal. I plan on making a better jig which allows one to flip the cube around without removing the jig from the machine. It would be more accurate and not take as long to carve all the sides

I have been enjoying following your progress. Would you mind posting a picture of your current jig and, of course, the better one when it is done?

Thanks,
dave

[bergerud]

The jig is simply a square hole for the cube to fit in. A little double sided tape and/or press fit is all that holds the cube. As more sides get carved, the cube gets a little smaller and so masking tape is used to compensate. It is important to use the machine to cut the hole in the carrier boards. That way the machine cuts the hole and the pattern in the same place.

I like this idea enough that I think I will make a better jig which allows for the cube to be rotated to a new face without having to remove the jig from the machine. The process would then be faster and more consistent. (Like the jig I made for the three trefoil knot side carves.)

[Dan-Woodman]

This is very similar to the situation I had awhile back that I posted about my tractor tread tire making jig. I had an indexing setup on the jig that I could turn the tire so many degrees and cut another tread without taking it out of the machine, but the problem was it still went through all the measuring and bit finding . I was just running a new program everytime without removing it from the machine. I was going to have to run the program 27 times to complete the tractor tire, and it was just faster to do it on a router table.
This is another situation where we could use the "repeat" feature of the machine , if it was activated.
later Daniel

[bergerud]

A repeat would be nice. I remember once getting excited about the repeat operation I found on the machine menu but it was only for routing operations and not projects. 27 times is a little much! It does not, if I remember, go through the whole measurement. It remembers the board size.

[chevytrucking]

Would there be any advantage to making it a 2 sided carve and have a jig that just clamps from the ends? You could run the carves in pairs that way. Might not save anything though, just curious. I made a jig for making these out of firewood scraps once, now I'm going to have to try it on the CW.

5119751198

[bergerud]

Cool. I thought of a double sided jig but for sake of accuracy I thought repeating the exact same operation six times would be better. If I make a jig which does not require removal, it will be even better.

[liquidguitars]

wow nice!
Don't you just love this machine? yes.


A repeat would be nice

yes.

[bergerud]

Here is my attempt at an octahedron in a cube. It is not as nice as I thought it would be. It will be difficult to finish since the octahedron cannot move around much in the cube. It is just not very interesting. The sphere is a contrasting shape compared to the cube and it rolls around which makes it much more artistic and interesting.

[liquidguitars]

looks nice! well done.

[bergerud]

I finally am happy with the sphere in a cube, six sided carve, weekend project! See below, the carve fresh out of the machine. There are only the smallest tabs left holding the sphere. The final version cuts out a "clean" cube frame just big enough for the 2 inch sphere.

The jig has a square hole for the cube to fit in and tightening knobs on both ends which vise the cube. The jig stays in the machine during all six carves. I set the jog to touch default to (on) and jogged to the middle of the cube face for the first carve. After the first carve, I enter the project again and just before the machine touches, I press stop. This is when I change the cube to a new face. (This is the only time the jig is centered and the cube can come out the top. I simply move the carriage out of the way by hand.) As the cube gets carved, it gets smaller by a 1/64 as each face gets carved. (0.00 is not zero but 1/64) This must be taken into account as one flips the cube. The two tightening knobs allow one the tweak the cube back and forth. As the cube gets smaller, it can also be tweaked side to side. This is an exercise in accuracy.

[dbfletcher]

Looks great! Do you think sliding a 1/64 shim between the bit and the surface during the jog to touch would eliminate the cube getting smaller? or that an exercise in futility?

[bergerud]

I think the shim would work but, I like the face being planed. Another idea would be to leave an uncarved edge. The edge could be sanded off later during finishing but would keep the cube centered in the jig during carving. Also, this would stop the fraying of the edge from the carving bit.

[eelamb]

Those look great, keep up the good work.

[BBrooks]

Bergerud,
Thanks for starting this fun thread. I had made these with my drill press before but never thought of using the CW. I made a jig that was 18" long that holds the 2" x 2' cube,
threaded insert for a bolt to lock the piece in and when it finishes drilling a hole it will leave the piece hanging out of the machine but still under the rollers. Loosen bolt, flip cube
and rerun the project. This is for the simple cube inna cube.
What I found was I got creep that way, .062" up to .125". It would not run centered each time. (Yes Al, I have masking tape on the jig. :) ) When I run the project, remove the jig, let it measure each time, it comes out perfectly centered each time.
Did you run into similar strangeness during your testing? I know your jig is centered. I am thinking with mine on the end, even though under the rollers, must have been right on the
end of being under both rollers and wiggles a bit.
cheers,

[bergerud]

I did not have the creep you talk of Bill. I have carved the cube a few different ways. I have done 6 separate carves with the pattern centered. That was a lot of button pressing and I just felt lucky if the carves lined up within 1/32. After I altered my jig so that it could remain under the rollers during the cube flip, the results were more consistent. I am still experimenting. I think I will try to jog to a center mark, record the x and y numbers and re-key them in for each carve while staying under the rollers. That might be an experiment for you to do to see if the board creeps even when you specify the coordinates.

(It was Doug Fletcher who should get credit for starting this fun thread.)

[bergerud]

I finally finished my rosewood version of the sphere in a cube. I changed the carve to leave an uncarved edge around the cube. That way the cube stays the same size for all 6 carves and position in the jig is more accurate. (Note that the draft is set to small. This leaves small attachment tabs. If you turn off the draft, the cube frame will be slightly thinner and the sphere will fall out with the last carve.)

[gregsolano]

What a great grain pattern and beautiful finished project with the rosewood. I have still not gotten to making one but I will.

[Capt Bruce]

That looks just elegant Bergerud,

Now I know what the first thing is that I'll be carving when I return from disaster deployment. Now where will I find a piece of worthy wood . . . Thanks for sharing the pattern.

[lawrence]

not much of an "out of the box" thinker are ya?

;)

Well done, as always you stretch the machine to new limits
Lawrence

[mtylerfl]

I finally finished my rosewood version of the sphere in a cube. I changed the carve to leave an uncarved edge around the cube. That way the cube stays the same size for all 6 carves and position in the jig is more accurate. (Note that the draft is set to small. This leaves small attachment tabs. If you turn off the draft, the cube frame will be slightly thinner and the sphere will fall out with the last carve.)

Very, very, very NICE! Gorgeous wood.

[bergerud]

Thanks guys. The wood is Cambodian rosewood. (according to the guy in the alley I bought it from!) It is the same wood the trefoil knot (avatar) is made from. It is very fine grained and dense. I only wish I could find more of it.

[dbfletcher]

Look what showed up on Thingiverse yesterday. Looks oddly familiar! I think the saying goes "imitation is the sincerest form of flattery"

http://www.thingiverse.com/thing:21695

[bergerud]

This is a revival of the old "Fun Weekend Project" thread started by dbfletcher.

An engineering student of mine milled me a cool cube out of aluminum which is more in line with Doug's original idea. I could not resist giving it a try on the Carvewright. The edges were too thin on my first attempt; here is my second attempt. I used the jig I made for the sphere in the cube posted earlier in this thread. I used the drill function with the 1/8" cutting bit and since the holes are nested, there is some air cutting. Here is the mpc in case anyone would like to give it a try.

[mtylerfl]

That's pretty dang cool!

[ladjr]

That is cool. nice job

[bergerud]

Thanks guys. Here is an ebony cube. The wood sure mills nicely. This is pretty well straight out of the machine.