[Help Thread] 4x4 Discussion

[Bas Verseveldt]

First of all the colour scheme on this cube is incorrect, two opposite sides need to be switched. I would recommend doing that, because otherwise you might get used to an incorrect color scheme!
Since you are a beginner here is some 4x4 notation: R denotes outer slice, r denotes inner slice, Rw is both outer and inner slice (so Rw = R r). In this case, I would place green on front and yellow on top, and do R2 (B U B' U' b2 U B U' B' b2) R2 to match the edges (the part between brackets is called a commutator), then do parity alg r2 U2 r2 Uw2 r2 u2 and then a U perm R2 U' R' U' R U R U R U' R. That should solve the cube.

 

[BlueSeal2]

First of all the colour scheme on this cube is incorrect, two opposite sides need to be switched. I would recommend doing that, because otherwise you might get used to an incorrect color scheme!
Since you are a beginner here is some 4x4 notation: R denotes outer slice, r denotes inner slice, Rw is both outer and inner slice (so Rw = R r). In this case, I would place green on front and yellow on top, and do R2 (B U B' U' b2 U B U' B' b2) R2 to match the edges (the part between brackets is called a commutator), then do parity alg r2 U2 r2 Uw2 r2 u2 and then a U perm R2 U' R' U' R U R U R U' R. That should solve the cube.

thanks so much bro! totally worked!

 

[T1_M0]

I'm suffering from internal lockups. When scrambling and solving, an inner layer sometimes gets stuck and I need to do small turn in the other direction to get the alignment back again. Is it probably some small internal pieces out of alignment? I would take it apart immediately but I just lubed it all the way and wouldn't like to put it back all the pieces in lube.

 

[xyzzy]

I'm suffering from internal lockups. When scrambling and solving, an inner layer sometimes gets stuck and I need to do small turn in the other direction to get the alignment back again. Is it probably some small internal pieces out of alignment?

You might be missing one (or more) of the internal edge pieces, which would cause lockups, catches, and pops to be a lot more frequent than usual. Either the missing piece wasn't assembled together with the puzzle (e.g. you lost the piece) or it just isn't where it should be (e.g. it fell into the gaps between the other pieces while you were reassembling the puzzle).

If you pull apart the edges slightly, you can see if there's a "hole" where an internal edge piece should be; check all 24 locations to be sure.

It's also possible that the nubs on the core aren't aligned; the nubs on opposite faces have to be pointing in the same direction, or you'll get constant locking up on wide/slice moves.

 

[T1_M0]

You might be missing one (or more) of the internal edge pieces, which would cause lockups, catches, and pops to be a lot more frequent than usual. Either the missing piece wasn't assembled together with the puzzle (e.g. you lost the piece) or it just isn't where it should be (e.g. it fell into the gaps between the other pieces while you were reassembling the puzzle).

If you pull apart the edges slightly, you can see if there's a "hole" where an internal edge piece should be; check all 24 locations to be sure.

It's also possible that the nubs on the core aren't aligned; the nubs on opposite faces have to be pointing in the same direction, or you'll get constant locking up on wide/slice moves.

It just began a few days ago and I've never disassembled this 4x4 so I don't know if anything could be missing or something in the core misalingned. I'm gonna disassemble later.

 

[T1_M0]

You might be missing one (or more) of the internal edge pieces, which would cause lockups, catches, and pops to be a lot more frequent than usual. Either the missing piece wasn't assembled together with the puzzle (e.g. you lost the piece) or it just isn't where it should be (e.g. it fell into the gaps between the other pieces while you were reassembling the puzzle).

If you pull apart the edges slightly, you can see if there's a "hole" where an internal edge piece should be; check all 24 locations to be sure.

It's also possible that the nubs on the core aren't aligned; the nubs on opposite faces have to be pointing in the same direction, or you'll get constant locking up on wide/slice moves.

Hey, I reassembled the cube... no pieces weren't missing. The lockups only got worse and a certain direction now doesn't want to turn at all (it locks up every time when I turn some other layer in between. Could the nubs be the reason for this, even if this started without disassembling (I don't think they have turned themselves just so). Please help me with this :confused:

 

[T1_M0]

Hey, I reassembled the cube... no pieces weren't missing. The lockups only got worse and sometimes a certain direction doesn't want to turn at all (it locks up every time when I turn some other layer in between. Could the nubs be the reason for this, even if this started without disassembling (I don't think they have turned themselves just so). Please help me with this :confused:

 

[One Wheel]

Hey, I reassembled the cube... no pieces weren't missing. The lockups only got worse and a certain direction now doesn't want to turn at all (it locks up every time when I turn some other layer in between. Could the nubs be the reason for this, even if this started without disassembling (I don't think they have turned themselves just so). Please help me with this :confused:

Sounds like most likely the nubs are misaligned.

 

[T1_M0]

Hey, I found this one nub which sometime goes sideways. When turning the white layer, it moves freely and sometimes goes in its place, sometimes sideways in the middle. How could I get it to stay still? :confused:

View media item 307

 

[One Wheel]

Hey, I found this one nub which sometime goes sideways. When turning the white layer, it moves freely and sometimes goes in its place, sometimes sideways in the middle. How could I get it to stay still? :confused:

View media item 307

That would cause exactly the problem you're describing. What kind of cube is it? Most likely there are splines of some sort on the core that are supposed to keep that piece from turning, and the splines are stripped off, so you'll need a new core.

 

[T1_M0]

That would cause exactly the problem you're describing. What kind of cube is it? Most likely there are splines of some sort on the core that are supposed to keep that piece from turning, and the splines are stripped off, so you'll need a new core.

How would sanding that nub off affect the cube? I mean, what's the real function of them and does the cube perform well without one of them?

 

[One Wheel]

How would sanding that nub off affect the cube? I mean, what's the real function of them and does the cube perform well without one of them?

The cube would not work if it didn't have any, and would be severely impaired if it only had one or two, but there is some redundancy, so I'm guessing that you could get away with sanding one off.

 

[T1_M0]

The cube would not work if it didn't have any, and would be severely impaired if it only had one or two, but there is some redundancy, so I'm guessing that you could get away with sanding one off.

But what's the function, how do they affect? I don't get it xD

 

[One Wheel]

But what's the function, how do they affect? I don't get it xD

They are so when you turn the cube along the middle slice the core turns with one half of the puzzle. A 4x4 is just a 5x5 with a hidden layer, and if the hidden layer was turned relative to the rest of the puzzle you could only turn parallel to that misaligned layer.

 

[T1_M0]

View media item 308Okay, I finally found the problem. This space is damaged (the other one marked for comparison) which causes the nub moving back and forth. I'll try sanding the nub down. If that won't work, at least I know now which part I need to replace. Thanks for your help! @One Wheel

EDIT Sanded it down, problem fixed!

 

[Rubik's cubed]

Hi guys, I recently purchased a YJ guansu and I took it apart to lube it. I got it back together but now the wide and slice turns don't work. I tried fixing the little notches but it doesn't seem to work. Does anybody know what the problem might be?

 

[One Wheel]

Hi guys, I recently purchased a YJ guansu and I took it apart to lube it. I got it back together but now the wide and slice turns don't work. I tried fixing the little notches but it doesn't seem to work. Does anybody know what the problem might be?

Your alignment mechanism is off. I believe a Guansu uses a standard alignment mechanism, which means if you take the core and center pieces out and rotate the core around each of the three axes the nubs on each of the 4 centers that are perpendicular to any given axis need to be on the same side.

 

[dboeren]

I'm getting back into cubing after a long absence and trying to recover back to where I was 2 years ago and then start moving forward again...

I've re-learned how to solve my 3x3 using Roux. I have never learned CFOP. At one point I knew the beginner's method but have not used it for a long time.

My next step (along with improving my Roux) is to re-learn how to solve my 4x4 and then to generalize up to 5x5, 6x6, etc...

The method I have in my notes from 2 years ago is a reduction based method, but what I've found out is that most of my notes were based on my level of knowledge at that time and I don't always understand what I wrote then Here's what I have...

1 Solve centers (create center pairs and join them)
2 Pair dedges
Place dedges across from each other, pair them, shuffle them to another side, then repair the center damage
3 To solve the last two dedges on the front L/R:
Dd R F' U R' F Dd' (Dd means BOTH layers, like a wide turn on a 3x3)
4 Solve using any 3x3 method
5 Final parity fixes: (need to unify notations)
Front/top dedge flipped:
z d' m D l' u' 2R' u l u' l2' b' 2R' b r' R' 2U y' m' u x2 z'

Top front/back dedges swapped: (lowercase is inner layer) GOOD!
Uu2 Rr2 U2 r2 U2 Rr2 Uu2


Right now I can solve the centers fine. Pairing the dedges is coming back to me, I'm able to do it but I lack the more explicit notes I once had about exactly where to put other bad dedges to prevent breaking them. I should be able to get that nailed down fairly soon. Once it's reduced to 3x3, I solve it using Roux, then apply a parity fix if necessary. As noted, I need to unify my parity algorithm notations. Currently I was just able to solve my 4x4 but I have to follow the parity algorithms slowly by hand until I relearn them and the dedges are clumsy too.

Note that I'm more concerned with easier learning/less algorithms than being super-fast, this is just for solving and not for competition.

That's all just background. Here are the questions...
1. I'd like to eventually do 5x5, 6x6, and maybe even 7x7 but I do not expect to go higher. Should I learn a better method that will scale from 4x4 to 7x7? What would that be? I'm kind of looking at Meyer as a possibility but not sure the relative advantages of this compared to reduction.
2. Do odd cube sizes still have parity? I've heard that if you learn 4x4 and 5x5 that basically gives you the ability to solve any size, is that right?
3. Given that I only know Roux, how screwed am I once sizes are big enough that I can't do M slices anymore? At what size will that happen?

Thanks!

 

[xyzzy]

Note that I'm more concerned with easier learning/less algorithms than being super-fast, this is just for solving and not for competition.

Have you tried cage or sandwich (or similar centres-last methods)? These methods don't require many algs just to solve, and they generalise to large cubes in a very straightforward manner, but from personal experience, they're also much harder to get fast at (and then you'd need quite a few algs).

 

[dboeren]

I have not heard of cage or sandwich methods, but I'll look into them. btw, I just ordered a Qiyi 5x5 so in a few days I'll find out whether M slices still work at that size or not.