[Harryman]

Boo! Maybe I'm Jeff too....no, wait, still Harry.

Hoss, I don't need an alias, I'm perfectly happy representing myself as myself.

[Stepper Monkey]

Writing style? I don't know, maybe all of us "book larned" folks just all sound alike.

Anyway, we've moved from Strawman to Ad Hominem, and that pretty much uses up his entire range of discussion so it should be over soon.
Extending it out to include insulting an entire group would be a new and rather desperate but understandable extension of abusing that last tool. We'll see what comes next.
Hopefully I'm wrong and we can get back to our regularly scheduled discussions, but probably not.

[hoss2006]

913 posts between the "3" of you and not one pic, video, print, gcode, dxf, or screenset,
Thanks for the contributions fellas, kudos

[jalessi]

Hoss,

What you are implying is very mean spirited to say the least.

You know after you attacked the wrong person a simple sorry would be the right thing to do.

Attacking a group or profession might be taken as discrimination, please don't do that.

We all enjoy helping others.

You are a very talented guy, please dont let your ego get the best of you.

Jeff Alessi

[jalessi]

Stepper Monkey,

I think your comments are getting rude.

Please don't start a war.

Jeff Alessi

[The Blight]

Jalessi: Could you please use the edit button?

Stepper Monkey: Was that your own theory or do you have some facts to back it up? I might test your theory when I get back from vacation. Do you have any drawings I could work with? Something which might be a challange for a big machine. The machine I'm planning on making it on is a knee mill (tool room machine). So there is even more mass to accelerate. Right now I'm just curious about it, and I can see how you can be right, but my experience with these machines is that when taking cuts, the feed rate is set, and it doesn't just accelerate or decelerate in the middle of a cut. I have never seen that happen. I have done 3D milling before, but it was a fairly large piece, so it might not act the same way on a smaller piece.

Hoss: I don't believe Stepper Monkey has several user names.

For everyone: I'm sure the Taig is a good enough machine, and I don't believe anyone is really against it. It's just that the X4 fits Stew's needs better. Or thats what it sounds like.

Wow theres a lot of people reading this topic. Are there any moderators paying attention?

[Stepper Monkey]

Hoss, that was high comedy. I couldn't have come up with a funnier response to my last post were I to have written it for you myself. Maybe I'm YOU as well...

I would agree, Jalessi, I was indeed being rude. Perhaps not the most productive thing to do.

Stepper Monkey: Was that your own theory or do you have some facts to back it up? I might test your theory when I get back from vacation. Do you have any drawings I could work with? Something which might be a challange for a big machine. The machine I'm planning on making it on is a knee mill (tool room machine). So there is even more mass to accelerate. Right now I'm just curious about it, and I can see how you can be right, but my experience with these machines is that when taking cuts, the feed rate is set, and it doesn't just accelerate or decelerate in the middle of a cut. I have never seen that happen. I have done 3D milling before, but it was a fairly large piece, so it might not act the same way on a smaller piece.

Blight,
Fact or experience, a little bit of both. As for the facts, there are any number of textbooks that cover that quite well. As for personal experience, I only researched the issue because I was getting just the problems described and didn't know how to solve them, and found the solutions were pretty well defined by others so I tried them out. Since it also worked for me, so I tend to think it is valid as well for that reason.
Ideally feed rate won't ever vary, but it does, and especially with small cuts. It always decelerates and accelerates in the middle of a cut - whenever an axis changes direction! By definition, you are of course never at the programmed feed rate when in an accel or decel curve. With big cuts you only see it at the beginning and end of an axis travel, with short movements thats all you ever get for the most part. No axis ever accelerates and hits even close to its programmed feed rate in a movement only of, say, 50 thousandths unless propelled by explosives! Remember that in that distance it also has to stop and decel just as much, so it is only accelerating a fraction of even that distance. Eventually you will find the limits of the machine you have. Get into texture like celtic knotwork, basket weave, pebble grain, or textile pattern and you will hit it right quick. Just because you programmed a given feed rate in doesn't mean it will always be at that feed rate or even close.
Quick example, you can try setting your feedrate for twice what you normally do and recut the same textured piece. Then cut the feedrate to half of normal and try again. All three will take the same amount of time to finish as the feedrate isn't what matters, you'll never reach it except in rapids. Try tweaking your accel and decel curves even a tiny bit instead and the cut can take half as long or twice as long. What this means in the end is that the actual observed feed rates are radically different from simply adjusting the curves, and the curves are limited mainly by mass, among a number of other smaller things I didn't get into.
You can run programs that monitors actual feedrate in real time, and those numbers jump around a lot, a whole lot usually. They are usually a LOT slower than you'd think on average. PM and I can send some Gcode files your way and maybe a feed monitor, though Mach can be configured to do it as well.

For everyone: I'm sure the Taig is a good enough machine, and I don't believe anyone is really against it. It's just that the X4 fits Stew's needs better. Or thats what it sounds like.

I thought we put that to subject to rest a while ago, when about everyone >including< myself suggested the X4 to Stew as best for him, regardless of Hoss's attempts at later faking quotes from me to the contrary. It is just a red herring, go back and look. Don't encourage him.

[philbur]

It’s not Steppers theory. A guy called Sir Isaac Newton came up with it several centuries ago. It’s called Newton’s laws of motion. Its probably the most relevant half page of simple common sense theory that anybody interested in the design or modification of mechanical devices could ever read and digest. Its simplicity relative to its impact on the modern world is nothing short of staggering.

3D milling requires constant changes in direction, either x, y or z or all three at the same time. Changes in direction involve acceleration or deceleration (that’s the definition of acceleration/deceleration). The larger the mass having its direction changed the greater is the resistance to that change. Detailed 3D milling involves many, many changes in direction in a very, very short distances. This represents high accelerations/decelerations (not necessarily high velocities). Small machines can achieve these high accelerations/decelerations much more easily because of the smaller mass being accelerated/decelerated.

Sorry for the lecture but it really is as fundamental as Newton’s laws of motion. Not something easily argued away.

Phil

Stepper Monkey: Was that your own theory or do you have some facts to back it up? I might test your theory when I get back from vacation. Do you have any drawings I could work with? Something which might be a challange for a big machine.

[under-dog]

Under-Dog: Only reasong 2 and 3 are valid in this discussion. Everything the taig can do, the X4 can do and then some. (Unless someone can show us that this is in fact wrong).

You have found a machine that fits your work, and thats good. If you have any plan to go further, you should go with the bigger machine so that you wont have to sit and regret buying the smaller machine later on. There is a lot of people here who have had that exact thought.

Bigger machines does not necessarily equal bigger tools. It just gives you the option of using bigger tools.

Stew: I'm sure that I would have chosen the X4, but thats because I see the possibility to work with bigger pieces and taking heavier cuts. But on the other hand there are a lot more taig users out there who have a lot of experience with that machine, so if there is any problem with it, you can most likely find a fix for it too.

So all in all. If you can see that you might want to work with something bigger, and you have the space and money, go with the X4.

I didnt realise I was getting into a mud slinging contest. i should have read deeper first before posting.

However:

If you notice I never slammed the X4 just stated the obvious. Yes if your intent is to make larger things then yes the larger tool is the option.

My point was this and I made itclear:that determination of what you are cutting is the first step.

Everyone gets so defensive on here when someone elses requirements may require a different tool.

And to your point again and mine if you look again. Yes if you are planning to cut something larger in the future go with something suitably sized. This is all relative in itself. For doing jewelry I could have gotten away with a sherline or something similarly as small. I went with the taig for this reason. That I wanted the capability to cut something just a bit bigger if the need came. One has to keep in perspective what exactly the scope of your work will be to properly make a determination.

If you dont you are dealing in absolutes. And in this case, holding to the theory that is being presented here. The X4 is way too small and we are all limiting ourselves with a desktop machine, or even a bridgeport knee mill.
The only way to go in this scenerio is some massive industirial machine the likes of which would be found on an aircraft carrier to make replacement props and such. Some sort of 1,000,000 monster that takes up a whole room.
Not sure if this really exists but it illustrates the point.

With this theory the x4is too small so go with the biggest you can



To my point however. Every machine has a purpose and a niche. For some a smaller machine like the taig is enough or even overkill most of the time. For some it isnt nearly enough.

To the true nature of my origional statement. The taig has done well for me.
Reasonable priced and spaced. Big enough for the occasioonal larger(for me anyway)part. Its accurate for what i do, I have found it easy to use I didnt need a fork lift to get it in cherry picker to get it on the table. It tried and tested and I have always gotten responses to questions or issues.

I know what you all might say: but the x4 this and that you statement is not true. yatta yatta....... However, If you notice my last statement made no mention of the inadequecies of the x4 or any other machine in the known world, it merely presented what I like about the taig. Neither has it compared one to the other.

To you point the a bigger mill doesnt mean you cant use smaller tooling: Of course it doesnt! But the second part of the argument is taht you can cut bigger things with bigger tools. If the decision to buy a bigger mill is for this reason it is something to keep in mind. And there are certain items which will be of a bigger nature by default. No not cutters but : collets? Enclosure all get s a bit bigger.......things of this nature may be. And some smaller acceseories may need to actually be retrofit to fit a larger mill? possibly? as this statement it is educated speculation on my part....
But isnt the point of getting the larger mill to be able to cut bigger parts with bigger tooling making the fact tha smaller tooling will also work an irrelivent statement?


to conclude there is a proper tool for every job or every one. If your needs are different than someoone elses and you made a tool choice based on that need then you did the right thing. Be confident in you decision and try to help others understand what it is you like about it or even hate about it. Help them understand how to make a wise choice not just a "join our club choice".

[under-dog]

I guess I am the Evil anti-green giant then. I am of the belief that good tools create good work. When I have a problem that requires a tool, sometimes even one I may only use once. I either buy it or make it. That isn't limited to hand tools and CNC either. That goes with vehicles, tractors, even up to Bull dozers and Ditchwitch diggers. Even though I may never need to build a house, I have to tools to do it and I will not depend on anyone else.

Alot of folks would call me wasteful.... until I have something they need. I prefer to call it "Persistence in capability"

Us redneck, bucktooth southerners learned along time ago that most often, we are on our own to solve problems. So we do it, in the best way that was possible, with as much pride as we care to give.

I'm a person that has a need for all of the tools I have. You won't catch me in a Toyota prius, needing to rent a truck so I can move a large box. In fact, This week, I'm trading in my F150 for an F250 diesel. Just so I can move some metalwork equipment around. With the mindset that I will need the extra towing power to get more (and bigger) equipment home from around the country.

CJ,

Thank you for agreeing with me. That was my point exactly. You have needs that dictate you needing larger equipment, and a larger truck. Whether they are immediate needs or anticipated. I too am the same way but there are limitations. Am I going to buy a full size backhoe because i need to plant one tree in my back yard or remove a rock? No

I neither have the cash flow, the space nor the desire to do something of that nature. You may come back and say: well all you need to do is get a bigger yard and house and a bigger job to support the bigger toy habit and while your at it bigger needs to justify it. As I said not in the cards. Maybe you have some career advice to support this sort of initiative.

But I just replaced my old standard cab dodge with a new pickup to meet a new need. When I bought the dodge it was for doing work around the house and getting me back and forth to work. Thats all it was just me and my wife no dog kids or camper. I now have 2 kids now and a 24 foot trailer camper. My new needs required this: fit 4 people and dog comfortably plus gear and towing a somewhat sizable camper.

The truck I have now would have been over kill 6 years ago and would have sucked more gas----->money out of my pocket and all the extra cab space(there only just in case I might need it need it in my unforseen future) would have merely become a depository for crap and and unecissary an area to keep clean and maintain. Like I said the need changed and so did the tool to fill that need.


I have written another response to someone elses reply and if you notice in that response I made a statement just as I will do here. My origional post had no relation to criticism of buying a larger machine if the need is there. it was a :
1) critique of my experience with the taig
2) Logical advice with regards to how to determine what he needs for a machine.

If you hold true to this theory that you buy a tool even if you need it only once or think you might need it some day. Then you should own a taig too. The taig is designed specifically to work on smaller parts and not larger ones. Then wouldnt this make it a specific tool for a specific task. And the you have the x4 for making bigger parts.

I am sorry I bruised you ego with my origional post.

And sorry for this post but it was necissary as your response was fairly sharp tongued for no reason, yet had literally nothing to do with:

1: the origional post topic
2: the point that was being made in "my" origional response (It was an analogy to demonstrate a point and not an attack on anyone who drives something larger than a prius nor against someone who buys tools to fulfill a need) I could have used the "why use a samurai sword to peel apples when a knife will work.......? analogy to make the same point.


I suppose I just offended all the apple growers and samurais here on CNC zone
"I would like to offer an official apology now to these two cultures, which I both respect and admire"

[under-dog]

Hi All,

I am new to the forum, and new to CNC in general.
I am cad based drafting with basic CNC orgrammng skills and I will be setting up a workshop at home. I am looking for a 4 axis machine, for working aluminium, and steel to 1/4" with a 1/16" cut.

Currently in Australia, I reckon I have two choices of Mill:-
1. The Taig - http://www.taig.com.au/index.php?mai...roducts_id=429
2. X4 Plus - http://www.syil.com.au/product_X4Plus.php

It looks like the X4 has more whistles and bells , is this a good thing?

NB: The taig I can get for about $4.5K (5.1K with 4th axis)

Do any of you use either of these?
Which is the better start-up machine, pros - cons?
Any advice you can offer is appreciated....

Thx in adv,

Stew.

Sorry all for the last two posts.

I ranted in such a way to demonstrate a point.

The origional post was a legitimate set of questionsplease read the quote above in case any of us forgot the origional topic)

1)critiques on both machines
2)advice on which machine would work for him

However, people are so wrapped up in thier own egos and proving that they have done things the right way and that they can show the light to those that are "wronge". It seems that anyone doing things another way are not only wrong, but offensive to both thier sense of morals and way of life that they lash out blindly.

What we end up with is a mudslinging match over who does things the right way and the wronge way when it literally has nothing to do with the topic at hand. Does it matter what sort of tools, equipment or TV someone buys for thier own personal needs and desires? No, but I am sure a constructive critique of a particular machine that would be helpful in a decision making process, great, it seems like that would be more productive to what Stew is trying to achieve.

Its actually very funny and After I made my initial post(just read the initial post and answered without reading responses) and then went back and read the rest of the thread I realised I had stuck my finger into a misguided hornets nest. I was really interested to see the sort responses I would dredge up, despite the fact my post in no way made a personal attack on anyone or anything.

[cjdavis618]

Maybe you have some career advice to support this sort of initiative.

Actually I do. It has certainly worked for me. And gains wealth quite well.

1st of all, work hard to earn good money. (I'm sure all of you do!)

2nd, pay cash for as much as you can. With credit, Interest is only interesting to others.

No you didn't bruise my ego either. I'm just stating the code I live by. No harm was done and I took no offense to it. I totally understand where you are coming from. I'm just coming from somewhere else.

What's great is that we live in a country where we can do all of these things. Others here on this board may not be so fortunate.


As for the rest, man what a thread. :rainfro:

[The Blight]

It’s not Steppers theory. A guy called Sir Isaac Newton came up with it several centuries ago. It’s called Newton’s laws of motion. Its probably the most relevant half page of simple common sense theory that anybody interested in the design or modification of mechanical devices could ever read and digest. Its simplicity relative to its impact on the modern world is nothing short of staggering.

3D milling requires constant changes in direction, either x, y or z or all three at the same time. Changes in direction involve acceleration or deceleration (that’s the definition of acceleration/deceleration). The larger the mass having its direction changed the greater is the resistance to that change. Detailed 3D milling involves many, many changes in direction in a very, very short distances. This represents high accelerations/decelerations (not necessarily high velocities). Small machines can achieve these high accelerations/decelerations much more easily because of the smaller mass being accelerated/decelerated.

Sorry for the lecture but it really is as fundamental as Newton’s laws of motion. Not something easily argued away.

Phil

Newtons laws eh? Show me the numbers supporting his theory. You can't just point to the laws of motion and say it's obvious without anything to support that statement. So go ahed Phil. Crunch some numbers and come back. You will have to include all the variables of the machine in case you forget. Simple isn't it?

I actually found your comment quite condecending. Your point me to Newtons laws and saying it's common sense like I don't even know about it. Now that it seems like you know all about Newtons laws of motion, I guess you will provoid us with the numbers. I will be more then happy to take measurements of our machines, and some other data so that you can get right on it. Deal?

And one last thing on this one. Stepper Monkey was the one giving the lecture. You just repeated it.

I have never seen a surface that requires you to change direction in the z axis every 0.1mm, but then again thats not what I or most people do. As long as an axis is moving in the same direction for every cut, it will continue along it's acceleration curve. If it has to change direction every 0.1mm or less, then it will never reach it's maximum velocity, or never even get close. That means that there will be less energy involved, and less energy to reverse it. This makes it slow, but it will still get there. If you have a very unstable machine, then you might start to see wobble because of resonance or just bad machine construction. The machine I'm going to test this on has box ways, so it should be as stable as it can get. It only has a spindle speed of 6000rpm, but we have an attachmed to get as high as 15000. Not ideal, but my guess is that it should work. I might be proven wrong and thats okey. I don't mind saying that I was wrong.

And again. It might not be the best sollution, but I don't think it's impossible. There are machines for different types of jobs. You are right about that. But saying that it's impossible is just being negative. Actually I know about some really small machines that can do some amazing work that most big machines can't do (not saying all big machines).

I'm wondering why this has even been brought up in this topic to start with. He was comparing the Taig to the X4. I have pointed to even bigger machines and said that they can do it. Why should not the X4 be able to do it? My guess would be that it was just badly constructed if there was something it could not do. I have yet to see something the taig can do that the X4 can't do. I'm suggesting overkill in one direction, while you are suggesting overkill in the other direction. Or underkill if you want. We are scaring people with "it will be too small for everything" and you are saying "it's too big for everything".

What most people make here does not need rapid Z axis movement and truely detailed work. So you can safely point them to the bigger machine (as long as they can afford it and have the space..etc) unless they know exactly what they want. I have said so before in this topic.

I would prefer drawings so that I could cam it myself. The machine I'm talking about has fanuc control and it's a really old one, but it's the most accurate and stable machine I have ever seen. I once read about a guy who achieved +/- 0.001mm flatness of a 350x350 sheet with this type of mill. It has both linear scales on all axis and feedback from the servos. And it is a tool room machine, so it can be used for mold making and other detailed work in really hard materials. I have even milled HSS on the same type (just manual).

Stepper Monkey: I have read several of your posts and I can see that you have a great deal of experience, so don't be offended by what I say. It's just that I trust proven facts more then just user experience. Most of the time people will tell you something they have "proven" wrong when they have only tried it once or maybe not at all.

I also did some searching on the net, and most people who do detailed 3D work are using routers.

[cyclestart]

I would prefer drawings so that I could cam it myself.

How about a cad file as well as a gcode file? There may be others interested in testing this concept. Attach here unless it's too large. The gcode file would certainly fit in this sites attachment limits. Most cad files should also.

This thread has gone off-topic and ugly. Otoh it brings up some interesting concepts. I'll put my money on a high-end VMC. However this is based more on a hunch than any experience with small scale work.

[under-dog]

Actually I do. It has certainly worked for me. And gains wealth quite well.

1st of all, work hard to earn good money. (I'm sure all of you do!)

2nd, pay cash for as much as you can. With credit, Interest is only interesting to others.

No you didn't bruise my ego either. I'm just stating the code I live by. No harm was done and I took no offense to it. I totally understand where you are coming from. I'm just coming from somewhere else.

What's great is that we live in a country where we can do all of these things. Others here on this board may not be so fortunate.


As for the rest, man what a thread. :rainfro:

Good sound advise. Exactly my mantra as well. My credit card actually pays me to have it. I use it only because I get rewards and have never paid a dime of interest. Between me and the wife we get about $600 or so a year in gift card rewards.

As far as working yeah between the main job and freelance: Average about 70 hours a week not counting travel.

And we are not that far off from where we are coming. As I said it is all relative. You are looking at someone who owns 4 sets of basic tools. One for garage, one for the basement shop, one for the camper and one portable one in case i need to take it in the truck.

So we good? No harm no foul

[Stepper Monkey]

This makes it slow, but it will still get there.
Of course it will, but this ignores the actual primary effect - that you don't get a feed rate compatible with bit life.

"That means that there will be less energy involved, and less energy to reverse it."
Again, not if you are running at the correct speed. Besides, it is irrelevant as this still ignores the primary point that two headstocks of different masses, running at the same speed - whatever the speed - will have the larger mass involving the most energy and therefore be more difficult to change vector.

"you are saying it's too big for everything".
No, I'm saying it's too big for one very, very specific something it was never designed to do. (Then I mentioned an idea that might make it work anyway) This was never an attack on an X4 or any specific machine. It was a requested explanation of one very simple engineering concept as to why it is sometimes advantageous to build machines small for some specific purposes. People take that personally it isn't my fault.

"thats not what I or most people do"
Just because fewer people do it does not invalidate the concept. It's physics, not a popularity contest.

"He was comparing the Taig to the X4"
As it has been pointed out by several people repetitively already, NO, I WASN'T. That topic is long gone, with everyone including myself suggesting the X4. Since you were wondering where this topic came from, it was a response to a very general blanket statement about general machine design. I then replied with a very general answer for those curious about my reasoning. I gave it.

"It's just that I trust proven facts more then just user experience."
Unfortunately you leave no option to communicate ideas at all then. First I avoiding using easily dismissed personal anecdotal evidence and was attacked and the attempt made to invalidate my points simply for instead using solid, basic known general concepts like mass and inertia, things I didn't think were in doubt as "proven facts". It was then demanded that I show experience or I was, I believe the quote was "talking out my ass". I dare to then mention any personal experience and it is now invalidated because I am not using "facts". I think we need to make up our minds here.


Primarily, I thought Philburs statement was brilliant. I wish I could have said as much in so little space. No more really needs to be said. That this isn't enough information by itself for the lightbulb to go on in more peoples heads and for them to be able to then instantly apply it to their own machines and determine its precise relevancy to them shocks and saddens me.
You are obviously a resourceful and curious guy - no offense, but you SHOULD know who Newton was and how to apply his theories and formulae yourself. No "number crunching" is necessary unless you want to do it for yourself. He gave you the formulas to apply to your own experience, they are well known and not in any doubt, and easy to look up if you don't remember them. Go apply them to your own machines and get the precise numbers if you wish to see them.
He just gave you a very powerful tool to test the truth of the statement, now you criticize him for not doing the work for you too? I would much rather be given the tools to apply to any circumstance in life to gain understanding myself whenever and to whatever I needed to apply them than some random numbers without context.
He wasn't intending to be condescending at all I'm sure, and I thought your response was pretty harsh. Think of it this way, which takes more energy to stop, a baseball moving 50mph or a semi doing the same? C'mon, do you really need the numbers to understand that? Stop to think what you would think of a person who told you that they didn't trust you when you told them it was obviously the truck? That it was only your opinion. That without numbers is wasn't a "proven fact" yet? It's the same thing here, exactly actually. Just that concept. He was just trying to help.

[Stepper Monkey]

How about a cad file as well as a gcode file? There may be others interested in testing this concept. Attach here unless it's too large. The gcode file would certainly fit in this sites attachment limits. Most cad files should also.

What are the limits for attachments here anyway? Cutting with sub-.020 mills can add up to some big g-code files. Get down to .005 mills and the files go over 10 meg pretty easily even for small pieces. It makes sense to just upload the raw files as I never trust using other peoples g-code either - too much chance for incompatibility or something going screwy with the postp translations. What cad formats?

I don't mind giving out as many files as you like, I have years of models for people to try out cutting, but I warn you it will break a lot of very expensive mills at first even just getting the machine tuned for it. Also, since you can readily explode weak power supplies trying cuts like this, unless you are pretty confident of the quality and overhead available on your supply. If its condition is in doubt at all or it is at all close to undersized or hot running, don't try it! Magic smoke can result.

To avoid the pain of paying for a lot of bits I would suggest that a dry run without bits could be done as easily on the same test code, just to see what the feed variances and feed averages really are as that is all that is really important here to collect. That data and the total time to completion of the run would be the real telling numbers, whether or not you were cutting material. That might not be the case with larger tools, but as these tools can only tolerate such insignificant side loading, the cutting loads on the machine are so minute as to be pretty irrelevant and won't likely change observed behavior noticeably when running either with or without a bit. We should log them too, as I really am interested in the data, be interesting to publish.

[barack]

faking quotes from me to the contrary. It is just a red herring, go back and look.

I did look and noticed that you go back and edit almost all of your posts
even after someone replies to your original post.

[The Blight]

This makes it slow, but it will still get there.
Of course it will, but this ignores the actual primary effect - that you don't get a feed rate compatible with bit life.

"That means that there will be less energy involved, and less energy to reverse it."
Again, not if you are running at the correct speed. Besides, it is irrelevant as this still ignores the primary point that two headstocks of different masses, running at the same speed - whatever the speed - will have the larger mass involving the most energy and therefore be more difficult to change vector.

"you are saying it's too big for everything".
No, I'm saying it's too big for one very, very specific something it was never designed to do. (Then I mentioned an idea that might make it work anyway) This was never an attack on an X4 or any specific machine. It was a requested explanation of one very simple engineering concept as to why it is sometimes advantageous to build machines small for some specific purposes. People take that personally it isn't my fault.

"thats not what I or most people do"
Just because fewer people do it does not invalidate the concept. It's physics, not a popularity contest.

"He was comparing the Taig to the X4"
As it has been pointed out by several people repetitively already, NO, I WASN'T. That topic is long gone, with everyone including myself suggesting the X4. Since you were wondering where this topic came from, it was a response to a very general blanket statement about general machine design. I then replied with a very general answer for those curious about my reasoning. I gave it.

"It's just that I trust proven facts more then just user experience."
Unfortunately you leave no option to communicate ideas at all then. First I avoiding using easily dismissed personal anecdotal evidence and was attacked and the attempt made to invalidate my points simply for instead using solid, basic known general concepts like mass and inertia, things I didn't think were in doubt as "proven facts". It was then demanded that I show experience or I was, I believe the quote was "talking out my ass". I dare to then mention any personal experience and it is now invalidated because I am not using "facts". I think we need to make up our minds here.


Primarily, I thought Philburs statement was brilliant. I wish I could have said as much in so little space. No more really needs to be said. That this isn't enough information by itself for the lightbulb to go on in more peoples heads and for them to be able to then instantly apply it to their own machines and determine its precise relevancy to them shocks and saddens me.
You are obviously a resourceful and curious guy - no offense, but you SHOULD know who Newton was and how to apply his theories and formulae yourself. No "number crunching" is necessary unless you want to do it for yourself. He gave you the formulas to apply to your own experience, they are well known and not in any doubt, and easy to look up if you don't remember them. Go apply them to your own machines and get the precise numbers if you wish to see them.
He just gave you a very powerful tool to test the truth of the statement, now you criticize him for not doing the work for you too? I would much rather be given the tools to apply to any circumstance in life to gain understanding myself whenever and to whatever I needed to apply them than some random numbers without context.
He wasn't intending to be condescending at all I'm sure, and I thought your response was pretty harsh. Think of it this way, which takes more energy to stop, a baseball moving 50mph or a semi doing the same? C'mon, do you really need the numbers to understand that? Stop to think what you would think of a person who told you that they didn't trust you when you told them it was obviously the truck? That it was only your opinion. That without numbers is wasn't a "proven fact" yet? It's the same thing here, exactly actually. Just that concept. He was just trying to help.

Again. I did never say it was optimal. It still gets the job done. You stated that it was impossible. It might not be running at the optimal speeds, and feeds, but the job gets done. If you are doing this every day, then of course you will get a machine that fits.

I was over overexagerating. Why even include a discussion involving high speed 3D engraving in a thread like this? Most people dont use it, and so it is not relevant when the person who made this topic never expressed a need for it.

Yes he was (Stew. The one who created this topic).

I never said I dont trust experience at all. Again you are putting words in my mouth. But lets take this to the extreme then. To move a certain amount of mass, you need a certain amount of energy. Increase the energy, and you can accelerate it faster. Right? So if you had motors capable of accelerating the head of those speeds the job demands, then there would not be any problem. Well that is if the mechanical parts can take the stress. Do you know if these big machines have motors and a structure strong enough to do this? Do you have the numbers? Done the math? Nope. You are just guessing.

I know about Newtons laws of motion, but just mentioning them is not an arguement in itself. You have to show WHY it's not possible. Right now you are just speculating over it. Do the numbers, and show me how much deflection there would be at the required speeds, and how big a servo motor would be needed to move the axis at that speed, and what spindle speeds you would need. I can take a look at my mill, and several other mills and say that they can't do it, but when I look at a 4000kg VMC, it get's damn hard to determine weather or not it can do the job. I'm not talking about your machines running Mach or any other hobby type machine. I'm talking about professional machines that are built for quality.

I criticised him for comming in here and throwing such a powerfull tool at me as an arguement in itself when he has not even done the maths. For all he knows, he could be wrong. Have you done the maths? Nope. You have your experience and your so called facts, but I have never seen it applied to CNC machines.

I guess you are some mathematical genious Stepper Monkey when you don't even need to calculate how much stress you can put on a machine. I guess engineers are over-rated then. Why show people facts instead of just telling them what YOU know. I know about Newtons laws, and I can see where you are comming from, but I can also see that you are just throwing it around as if it was a fact by itself. I know that more mass in motion = more energy. But you can make structures big enough to handle that kind of energy, and use motors big enough to produce the energy needed to move the mass.

There is a pretty big difference between a baseball and a truck. Small machines have small motors. Big machines have big motors. Fit a big motor on a small machine, and you can get it to accelerate fast. If you use the same power/head weight ratio on one of those tiny heads, you will have just as bad performance. So if you can fit an even bigger motor on the big head, you can get it to accelerate just as fast as the small one. It takes more energy, but it is not impossible. You stated that

Physics make it impossible.

. So stop telling me to learn Newtons laws of motion.

I might have been a bit harsh on Phil, and I'm sorry about that. But the way he said it sounded condecending.

I will still want to test your theory on a large CNC mill. Are you still holding on to your theory about it not being possible?

PS. as a little joke. Maybe god can do it?

In reply to your 2nd post:
Step format would do. Or if you have solidworks, or PRO-E, just post it in the standard format.

And again. This is not going to be run on your standard home made CNC machine. I'm going to run it on a high end CNC mill. So my bet is that I won't be seing any magic smoke or hear any complaining from it. When the part is made, I might also get some help to measure it on a Zeiss 3D scanner or a Smartscope just to check at what tolerances I'm working at. Depends on if they have the time in our QC department.

Wont be making it until I'm back at work again. I also have a lot of tasks to get done when I get back, so in about 3 weeks I should have started working on it.

I also took a look at the video Hoss posted where the X4 is doing some 3D milling. It's doing a good enough job.

[cjdavis618]

So we good? No harm no foul

You betcha!!