Bitzero v2 operation

I just received bitzero v2.
It works.

  1. I have to attach the magnet to the bit and not to the collet nut (it doesn’t conduct I guess).
    Should I file off the coating on the collet nut?

  2. When X,Y,Z probing, as it finds the inner wall of the hole in the bitzero, it pushes the bitzero around.
    What is the preferred method of fixing the bitzero while probing? Holding it by hand?

thanks as always,


I’ve also had it move and have been holding it with my hand. It’s pretty slick and doesn’t weigh that much so it slides super easy.

Please contact us about this at

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I’ve had the same issue (here), but talking to Support would be best, as per @WillAdams suggestion.

The problem I had was with poor electrical contact between the probe and the BitZero (I use the magnet on the collet nut), but managed to resolve it gently cleaning the inside of the hole with steel wool. Not ideal for a new BitZero, I have to say!

At least raising this, and any other issue, with Support will identify any trends…

A reminder that anodizing metal often produces a non-conductive surface, such as (apparently) the collet nut in this case, and also some aluminium extrusions.

I doubt the BitZero v2 is coated or anodized, though. It is a different colour to the shiny BitZero v1, however.

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Some aluminium alloys oxidize faster and might give poor electric contact.


@richardfferraro or @mingle Did either of you get a resolution on the best way of fixing Bitzero while probing?

I am designing a corner hold-down bracket that blocks the movement of the bitZero from moving left (-x) or forward (+y).

I don’t like the idea of hands so close to the mouth of the alligator.


Well, this version of the BitZero is certainly an improvement. :smirk: :zipper_mouth_face:

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Seems like the design wasn’t tested on slippery stock.

I think they do the extra X&Y outer probes to take the diameter of the bit into account.

A soft solution for people who don’t like the movement might be to allow the probe diameter to be entered into Carbide Motion and just have it do the “push against the stock” probes. Oh, to better support the Raspberry Pi of course :wink:

I agree about the mouth of the alligator! There have been too many times when complacency has resulted in injury :drop_of_blood: :ambulance:

I agree, but it’s better to keep hands away from moving parts. Ask any Combat Engineer with his index finger missing from constructing a Bailey bridge!

Bit of a tangent, sorry :crazy_face:

I guess the dowel would be more accurate, but wouldn’t that be the case for the v1 if a dowel was used with that?

I think it’s a force (Newtons) thing. With the v2, there is no resistance to the push - other than your hand - making it very easy to move the BitZero, but with the v1 it’s pushing against the stock.

It’s a small thing, really. The reasons I’m happier with v2 is the magnet rather than the alligator clip (fixable with a little time and effort) and not having to earth it separately.

That’s my opinion, anyway :wink:

My concern using the dowels is that it requires one more tool change.
I have bad wrists and I suffer through the tool changes.

All that aside and all things being equal, the BitZero should function correctly. If the connectivity between the probe and the hole is poor, it will affect accuracy if unnoticed, or time out if pushed too far and requiring everything to be re-initialised. This wouldn’t necessarily be an issue with the v1.

Thanks for the lesson, though :+1: :joy: :joy:

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29 posts were split to a new topic: Senior Citizens Club

Im very new here and to cnc. My question is If you use the dowel supplied with the bit zero and then change… lets say to a 1/4 end mill… would the different bit change the zero?

Hey Tim!

Yes, it would change the zero.

With respect to Z, the only position the machine knows is the vertical position of the spindle. It knows this because it’s been sending it up and down instructions from the last time it was “homed”.

So long as the up and down instructions have resulted in movement, and it’s not been driven into something that prevented movement, it’s pretty sure it knows where the spindle should be.

However, it has no knowledge of where the BitZero is, or how long the thing in the spindle is.

In truth, you could pull off the spoilboard, suspend the machine on legs, and put a 1 metre dowel in the spindle and put the BitZero on the floor. It wouldn’t know it was a metre away. Just that the spindle is a fixed number of “ticks” from the homing position.

So if you took out that 1 metre long dowel and put in a 10cm bit, and then tried to run your job, it would have no idea where the bit was cutting. Just that you told it to move the spindle to a particular position for your project’s zero.

Soo… long story short - the Shapeoko has no idea where the zero physically is in space. Just where the spindle was when you said “this is zero”.

OK, I’m going to make myself look stupid, here…

When you use the dowel, it ‘touches’ the inside edges of the hole (left, right, back, front) and from those movements measures the centrepoint of the hole, which is the corner of the workpiece.

In my mind, this would be the same centre of the end mill you put in the spindle, surely?

You would need to re do the Z height manually, unless you had a BitSetter to do it automagically.

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That’s correct. X and Y should be fine.

Most people have issues with zeroing Z, particularly when changing a bit and the finding cuts are too shallow or too deep.

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This could randomly be true. :smiley: If you look at the cutting end of your typical endmill, you can see that it isn’t a circle, but the cutting teeth are arranged in a circle. So, while it cuts a circle it isn’t actually a completely round end. Right?

The dowel does have a completely round end.

So, when doing a zero trip around the inside of that BitZero depression, an endmill may exactly touch at its radius, but then it may be oriented in such a way that it touches in between cutting edges and that would be a smaller radius. The zero may be off.

A dowel doesn’t have that smaller radius. It is round. It zeros inside that depression the same everywhere it touches. See?

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