Red Oak, stuttering, bit change homing

I have searched but cannot find any threads that completely answer my questions.
just as a preface - I received and built my X-Carve 1000mm within the last 4 weeks - so from my understanding, that means the x-axis stiffening is not needed, has the new style eccentric nuts, etc…
I have done several smaller projects, and 1 sign, and have been very impressed - everything has been working great.
I was attempting my first actual 3D carve last night, the V-Carve sample Magnolia flower, and was getting quite a bit of chattering/stuttering during the rough cut with .25"EM (HighSpeed Steel 2F Upcut) when it would move in the X- direction, but all other directions seemed smooth.
I looked at the default settings in V-Carve(just started evaluating the Trial version) and noticed it had the Roughing at 80ipm, plunge 30ipm and .2"doc. So I figured with it being RedOak that it was just too fast, too deep , so I adjusted that to 55ipm,plunge 20ipm and .1"doc and was still getting some stuttering but was maybe a little better. I have calibrated the steppers in the last week, belts are good. I did notice last night the VWheels on the X Carriage may be slightly too easy to turn with one finger so I plan on tightening those a little more tonight and trying another test. So my question on this is what would the recommended specs for rough cutting red oak? Were my last settings still too aggressive? Could it just be the material itself, the way grain lays, etc? With only a slight looseness in the X Carriage V-Wheels it doesn’t seem like that is the only, or main, culprit. Also, I have only noticed this happen on this cut, everything else has been great - but I also have not anything else as aggressive as roughing out red oak to that level.
My second question is bit homing for the Finish pass. I had output the Roughing and Finish as separate g-code files. So I ran the roughing, it finished and returned to home, I changed to the finish bit (1/16" Tapered Ball nose 5.4° R=1/32") and since this was a separate file setup for this bit I homed it as normal - the tip exactly in the left corner. The finish pass went pretty well but it seems things were slightly shifted to the right. It’s not too bad, I can make up for it with sanding, but it just got me thinking "should I have not changed the XY home from the Rough Bit? Is doing it in two separate files not proper? Or is there a different way a Tapered Ball Nose should be homed?
Thanks very much for any light you can shed on these questions!

Plunge of 30 ipm won’t happen. The Z axis by default is limited to around 19 ipm movement rate in GRBL. If you adjust your max feed for Z, you could get it but I don’t recommend it. 19 ipm might be a bit fast for the stock Z axis. You could try 12-15 for plunge.

55ipm feed is probably okay for a properly tuned machine.

0.1" DOC for red oak is a bit aggressive for the stock Z axis (and really even some upgraded machines). Try 0.08".

A slight looseness in the Vwheels will translate to stuttering. Make sure those wheels are properly tightened. The new eccentric spacers with lock nuts should keep the wheels from becoming loose but they need to be tightened. When the machine starts moving, any looseness will allow for some vibration which will translate into chattering.

Hardwoods will tax the machine more and a 3D carve is even more taxing since it can involve both X/Y and Z at the same time. Did you do an Offset carve or a Raster carve?

For your second question, unless you’re using a 3 axis homing block or some other reference method, you most likely won’t get X/Y aligned exactly the same when you re-home. Eyeballing it generally isn’t good enough, especially for a 3D carve. With a 3 axis block, it recommends homing using the shaft of the bit and not the cutter portion for more consistency. I highly recommend the Triquetra block that Charley sells.

I don’t know how you’d do separate bits in a single file. I’m sure it’s possible but personally I prefer 2 files. If you can change bits without causing the X or Y steppers to slip at all and lose position, then you don’t need to redo X/Y zero, you only need to redo the Z zero for the new bit.

OK, will adjust the plunge - and make note that in the future that 19ipm plunge is really all that is available.
Will adjust doc to .08" for hardwoods.
Definitely will be re-adjusting those V-Wheels tighter tonight.

Actually not sure on the Offset vs Raster? I just adjusted the bit settings, etc in the sample/test file provided by Vectric for the V-Carve Trial version and downloaded the g-code from there.

Ok, homing based on the shaft versus the tip of the bit makes sense why it slightly off. So I probably should have only adjusted the Z for the Finish bit.
Thanks for all the info!

It was basically just stuttering/chattering like it was struggling a little but was still moving, never stopped. I just made the logical assumption that if it was chattering like that I must be going too fast, too deep, or both. So you are able to do 80ipm at .08" with no issues? That’s good to hear.
As far as modified or not - mine is new which I thought from what I have read means the X gantry enhancement/stiffening is not necessary anymore?

This brings up something I have noticed though - this will go a little off topic to my questions, but…
I try to do as much reading/research on the forums as I possibly can before I will post a question - for the obvious reason of trying to not be annoying, etc… , but also because I’ve noticed some people on here can be quite brutal in their responses if they think you didn’t search. The issue I have seen is that when I search for a particular topic I may find a few threads somewhat related but a lot are from 2 years ago! It makes a little tougher for us “new guys” to determine what fix may or may not be applicable due to the machines being so different now as opposed to 2 years ago. Such as the stiffened X gantry, eccentric nuts, router, XController, motors, connections, etc…
So, just wanted to throw that out there that sometimes its hard to determine what may be applicable to a problem seen today when the thread found is a couple years old.
Hopefully no one takes that the wrong way though - I definitely think this forum is awesome and contains a ton of good info. You in particular PhilJohnson, I refer to some of your threads on almost a daily basis! :grinning:
Thanks very much for the info! I really appreciate you and JustinBusby responding so quickly!!

Yep, seems to be exactly what JustinBusby was alluding to as well. That I should not have homed that tapered ball nose to have the tip of the bit exactly in the bottom left corner - should have left the XY where it was from the initial .25EM roughing. Oh well, this is just all part of the learning curve so I can eventually, hopefully, get to the knowledge level of you guys!! :grinning:

Wow! Ok, understood. Yep, I misunderstood that initially, thought it meant the X stiffening, motors, etc… that people mention.
That is some serious upgrades!

That is certainly my hope. I hope to, like most on here I assume, bring in a little side money at least by making signs, 3D carves, etc to sell to neighbors, co-workers, friends from church, etc…
My next thing is to purchase V-Carve Desktop, just couldn’t afford that extra few hundred when I ordered.
I’ve gone thru a lot of the tutorials and it seems really awesome. Looks like there are some other free routes(F-Engrave, Fusion 360) for designing/g-code/v-carving but nothing seems as easy.
Trying to learn F-Engrave now but it is not very intuitivel, and the instructions can be a little cryptic.

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Yep, just focusing on Easel and now have done a few of the test files from the V-Carve trial.
A friend of mine built his cnc and has a 4’ x 8’ bed on it and uses Aspire. I don’t have the room for anything that big and I could never justify the cost of Aspire - of course if it was my daily job or at least a significant side job that would be different. Of course it would be cool to do that as a full time business - I guess that perspective always changes though when it becomes a “got to do it” job as opposed to an “enjoy to do it” side gig. :slight_smile: I guess for now I will just keep coding away.

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Thought of a couple other questions:
In the case of the project I was mentioning - the magnolia flower, doing the rough pass with .25EM at maybe 60ipm and .08"doc - what would be the stepover you would use? And the rpm?
Right now I typically run the Dewalt at about 1.5 to 2, never higher than 2.

Thanks very much for the advice!
I hope to use the high speed steel bit to do some cutting on aluminum sheet, etc. Have you done much of that? Any recommendations on ipm or doc for aluminum?

Thanks! With all of the helpful advice you guys have been giving I should have plenty to work on this weekend!

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Look at ramping toolpaths into the material instead of dropping the plunge rate so low. There are several videos on YouTube that explains ramping.

Where did you get your belts and Pulleys from? Also did you have to change anything when setting up easel?