Bitzero v2 operation

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.

Yes, of course. something smooth vs something lumpy is no contest when measuring.

To my mind, this is an unintended consequences safety improvement. Pushing against the immoveable object (clamped stock) which is an external surface (cutter or dowel) is likely to result in squashed fingers if it goes belly up. The lack of resistant with V2 is a good thing because the device will just move in response to sustained pressure, however light.

Yes, it is sane to keep one hands away from moving machinery, or static machinery that can crush you, but the issue under scrutiny is the task to be achieved. If you have a Haas VF6 it will probe for you without your intervention or any danger to you. The Shapeoko SO3 is not a Haas and does not cost anything like a Haas to undertake many of the tasks which can give you a reasonably accurate approximation of the CNC experience.

The SO3 probing cycle must be carried out from within Carbide Motion. We know that CM will not run until it is connected and initialised. My router is on a separate on/off switch so I keep it off and unplugged at this point in the process.

Jogging can be achieved with 5 different settings and the movement of the carriage carrying the spindle is entirely within the user’s control. Only one of the settings available removes user control and that is the rapid positioning. The movement, once initiated, does not stop until it reaches the assigned destination point. If you were unlucky enough to suffer with a heart attack and collapse at the start of the carriage travel, You may get a hand trapped, even so, I suspect that would be the least of your concerns.

Having established that (for now) there is no other method of probing available which is included as an integral component to the software management of the cutting process. You can always set the cutter X, Y and Z position manually. A little more dangerous because it is carried out with the cutter in situ. Just brushing a hand against a stationary cutter can cause a laceration.

Finally, some self responsibility is in order. The SO3 is not a plaything and should be treated with the respect afforded to any piece of production machinery, especially as the trim router’s raison d’être is to hold and whirl a piece of sharp metal at speeds up to 30,000rpm.

We see people in the UK who trip in the street and demand to sue the authorities for some real or imaginary hurt. I would argue that they have a responsibility to look where their feet are going.

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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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That’s ok… it’s FOC. :grin: :beer:

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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”.

Hi Tim,
Yes, that is correct as has been demonstrated by @Gerry. This is where the combined use of a BitZero and a BitSetter is very handy. BitSetter knows the tool length and the Carbide Motion Software provides it with the ability to request a tool change during the work. When BitZero has done its stuff, it knows exactly where X, Y and Z axes are in relation to the workpiece. Effectively knowing where all of the zero points are and where to begin cutting the design.

With BitSetter, after the BitZero device has done its thing, it asks for a tool change and when the tool change has been completed, it measures the tool length and then knows precisely where to start, in relation to BitZero’s zero points.

Can you manage without a BitZero? Yes, it is possible to measure from the start point and zero each axis manually. (Zero All option in Carbide motion). Can you manage without a bit setter? Yes because one can physically run the zero routine every time one needs a tool change. The problem makes itself felt when you have more than one tool path in a single job.

You simply cannot have more than a single toolpath in Carbide Motion, if you cannot remeasure for zero and different tool lengths. The solution is to break the work into lots of individual files and just do the manual zeroing process for each file. As soon as you start making things with say… a rough and a finishing toolpath, it gets old very quickly.

BitZero is the one device that will help you to shorten your setup times. BitSetter is the way to dramatically improve your workflows.

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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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Yes, absolutely correct. The manual setting of Z is ok for one toolpath. I believe that Carbide Motion does not know what to do with subsequent toolpaths in the same file. I thought that I had read that the work-around was to break a file containing multiple toolpaths into several single toolpath files.

Peter, I hope you will forgive my pedantry. My take on setting the Z height manually is to view it as the operation required to determine the starting height for cutting. The Z height is not going to be dependent on the X & Y zero points. Setting the starting Z height is not measuring the tool length, albeit even when it is carried out with the desired cutting bit in situ.

BitSetter, on the other hand is measuring the length of the cutting bit and then using that tool length in conjunction with the BitZero measured Z height of the workpiece, to determine the adjusted workpiece starting height… which has to take into account the length of the tool in use. X, Y accuracy will presumably be improved by using a dowel sized nearest to the cutting diameter of the chosen endmill bit.

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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You? Pedantic? Never happen! :rofl:

You’re correct, though. I should have been a bit more specific and try to keep it simple.

As far as I understand it, the BitZero does what it should do, but at any time the bit (or dowel) is changed, the Z height needs to be re-zeroed. The X and Y should remain the same unless you move or change the workpiece, unless you’ve got a guide in place for repetitive work, for example.

I think CM does know. If there is a requirement to change the cutting bit during a project, you’d need a separate toolpath for each bit, and re-adjust the Z height before each new cut. With a BitSetter installed, CM understands the bit change, prompts for it, then pings it over to the BitSetter to re-zero the Z height before continuing with the next toolpath.

Again (me being pedantic, this time!) I don’t think it will matter. If the BitZero is doing it’s job properly (and only the designer of the BitZero can confirm this, really) it should find the corner of the workpiece, irrespective of how big the dowel is (as long as it fits inside the hole!) The cutting bit can be larger or smaller than the probe, because it’s the toolpath that determines where the cuts are made, based on the tools geometry. To extrapolate on @CrookedWoodTex comment, using a dowel will provide a more accurate corner of the workpiece than an endmill.

And this is why, without a BitSetter, separate toolpaths are necessary and, therefore, resetting the Z height for each bit change.

Morning Peter. :wave: :smile:

Yes… spot on and I have no argument with this (pedantic or otherwise) :grin:

It looks like we are on the same page. :smile:

Yes! But this is the key phrase… "With a BitSetter installed"

Careful… you are heading to a different book. :wink:

Yes, agreed. The magic is in the device dimension, which is a known, and can therefore be a specified given, regardless of dowel size.

Now you are in a different library. :crazy_face:
pendantry mode on.

Yes, if you want to use a 1/2" dowel with a spindle that can take it, there is no problem, even if you are going to use a 1/32" bit. The use of a 1/32" bit would suggest that you are carving very fine detail and that in and of itself would suggest the need for a reasonably accurate measurement. In the example provided, the 1/2" dowel would not provide sufficient accuracy and your work starting point could be off by as much as 15 times the 1/32" diameter of your bit.


I found the original and definitive posting (very short) which informed my position anent Carbide Motion not being able to deal with multiple toolpaths without BitSetter.

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Good morning!

I think the two sizes of dowel are provided for convenience, so you’d use the one appropriate to the shank size of the bit, rather than accuracy?

This thread is beginning to look like a @jepho vs @NewToThis discussion, although I think we’re generally of the same opinion

Anyone else prepared to comment?

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It’s possible the two sizes are provided for different collets rather than for any accuracy.

The measurement inside the circle should be sufficient for the machine to figure out the size of the dowel and therefore compensate for that to estimate the XY centre.

I agree that the calculation is harder with a bigger dowel since it can touch the edges of the circle in a complex way.

I think the thing that is currently a circular hole in BitZero 2 should in fact be a square hole. Maybe in BitZero 3?

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Well, I commented, but it was not discussed further. :thinking:

Your discussion here seems more like a critique of the design of the BitZero-2. :smiley: @Gerry is correct; the different dowel sizes are a convenience so you can do your zeroing without changing collets.

One thing to be sure you do is wipe down the contact surfaces occasionally. Sawdust is an insulator, the zero “hole” will catch dust, and you will get into a re-initialization situation quickly.

The only thing further I have is that you should get the BitSetter without hesitation. You can use CM without it (by zeroing traditionally), but CM will still have a few innocuous prompts about zeroing and changing bits, etc. Just don’t activate BitSetter in the Settings.

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The circle should make for very simple calculations which are minimized if the BitZero is placed at an angle.

A square hole would only work if the unit were placed perfectly squarely everytime and would magnify any deviation from square.

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