what i said about invested time =result , was not criticizing the build, which as i said before inspires me too. So if i wanted to say something to kingcreaky i would have quoted him.
This was but a direct response to your words: "thanks for the time that you have taken to provide REAL information and show what is possible if you do not get bogged down with techno crap", cause according to me that needed an answer.
Cause it seemed to me that what you are saying implies that all the "techno crap" we brag here at the forum is not REAL.
Anyway it was not meant as an offence. First i wrote a long answer then i shortened it, so you will not think i am bragging and could make your own conclusion.
But here is the longer one:
Not every one on the forum will work wood with a router but even if so, a fast and precise machine is needed. What i say that many people expect their machines to make money, its not just a weekend hobby. But if you want to make money many times you need the best possible. Or you don't get the job.
Now let me give you a small example. I have friends making model boats that live nearby. last year they ordered mold for custom mast, say 4meters of 100x200mm aluminum, consisting of 2 pieces and further cut down to 2 meters ,joined together. This is a simple job, materials= ~400euro . Now put one 0 more and you will get what they paid for the mold here in Spain.
So that job could not be done on a machine which is wobbly, imprecise or will not make perfect finish, as there inside other parts fit, its cast from very expensive carbon fibre, and so on.
You get what i say? Only this missed job is more that the price of materials invested in a similar machine and half of the money i am investing in what i am building now. 2 jobs like this pay even the most expensive build.
Or i am a big fool that spends a month just to align my long rails and 400euros of epoxy + additional shimming. Not to speak of the 2m straight edge i bought especially and only for that purpose. I could have build another machine during that time.
So again i am saying it: invested time and money=result. And i would like the result to be the pleasure and $$$$. Not constant repairs, constant upgrades and so on. Nothing against fast and cheap builds. The thing is i have such machine already and i know the frustration every time before a job, during a job and later , when i want to take the big hammer and ... say f%%%k in one of the 4 languages i speak and write fluently
Ok well here's my 2 cents.!
I completely agree with Boyan(Silyavski) and get what he's saying completely. (Thou I don't agree with some of the OTT building happening which he as IMO done but that's another issue and is IMO others do and will disagree)
I also Know Matt and get exactly what he's done. Which IMO He's hit the nail on the head and I applaud him for building a machine to do exactly what it says on the tin, which is Chomping thru ply wood.
Now the thing that bothers me here comes from experience speaking and helping others and knowing how people see an react to build threads.?
Newbies don't see this machine was built for low level purpose(even thou it was stated at beginning) or will realise this machine is limited in accurecy.!!
They just see a machine built quickly and with limited budget and tools and think that it's easy.! . . .Only after getting far into the build or finishing do they realise there is a little more to it than just throwing some steel together. End result is at best they are dissapointed in the results as it's not what they thought it would be or worse doesn't work and they give up.!!
Unfortunatly building any machine with decent accurecy levels does take some effort and expense which is what Boyan was saying and 100% correctly IMO.
Now I've shouted loud enough for the "Techno Crap" and OTT building to be curbed and some degree of sanity and common sense to applied. But there are occasions like this one where thru NO ONES fault the waters get muddied.!!
I'm in NO WAY having a dig at Matt or the machine because it's done and is doing exactly what it was built to do.!!. . But New builders and lurkers I feel need to be aware that this machine is limited in accurecy so if taking this route don't expact high accurecy you see on some other machines.
Matt as Done a great JOB in the short time but there's a reason.?? . . . . .He's ADDICTED TO CNC and got OCD. (join the club)
Last edited by JAZZCNC; 23-01-2015 at 08:22 PM.
Jazz, Exactly he managed to build a machine 'that was fit for purpose', although like with all things lessons are learnt on the way.
For god's sake lets put this to bed, if someone wants to build a machine that is aerospace accurate and do it over a couple of years then 'yipppe I ay'
Edit: written before Earle's last post but posted after it.
Not that it matters but here's what I think.
If you look at Matt's first build log; http://www.mycncuk.com/threads/5174-...6501#post36501
you will see he has been through the techno crap stages like everyone else. Now he's in a position to make it look easy becasue of that experience and the other builds he did.
But New builders and lurkers I feel you need to be aware that this machine was build by someone who made it look easy, not because he cut out the techno crap but because he was experienced.
Last edited by EddyCurrent; 23-01-2015 at 08:40 PM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
One other point I'd like to make is that this quick build and getting away with lesser accurecy build level was largely due to components used like round linear rails and normally prohibitly expansive rotating ballnuts.!!. . It would be a very differant story if profiled linear rails and conventional ballnut had been used.
Again I'll Say it for clarity I'm Not having a Dig at Matt (or anyone really) in anyway shape or form he's done a great job. Just stated what I wrote for sake of others as usual.!
Last edited by JAZZCNC; 23-01-2015 at 09:08 PM.
Whats the advantage/disadvantage of rotating the ball nut rather than the screw? why did you choose to do it this way? Are there any more pictures of how you did it
Problem or should say disadvantage with them is the cost if you try to buy the real thing.? They are silly money. This design is Jonathans and they where made by him just search the forum for rotating ballnut and you'll see he's posted the design.
While DIY you still need to be pretty well tooled up and know your way around a lathe and able to work to good tolerences and still there is a cost involved compared to normal setup that IMO negates the cost saving of being able to use smaller motors/drives.
So the real advantage IMO is that you take away the risk of whip/resonance etc that comes with long screws. I'd certainly use it over other means like R&P for long machines but you do need to be proficeint with a lathe and engineering. Farming the work out to a engineering company would not cost effective as well IMO as there is a fair amount of time involved to make these.
Cheers jazz I will look into it more but like you say probably not cost effective unless you have a good lathe to hand
Just to be clear, the rotating nut concept doesn't eliminate the problem of the screw resonating, it just raises the resonant frequency so you can go faster. The main reason the resonant frequency is raised is it enables you to mount the ends of the ball-screw more rigidly than with bearings, so for it to work well you need to make good strong mounts for both ends or the screw, with some adjustment in them to help with alignment.
The negative side is that to do a sufficiently accurate job of machining the mounts requires some care, so they take a long time to machine - at least with the equipment I have.
By deisel in forum Probing, Digitizing & ScaningReplies: 9Last Post: 30-08-2014, 12:02 PM
By charlieuk in forum Linear & Rotary MotionReplies: 8Last Post: 30-04-2014, 03:31 PM
By crossleymarko in forum Machine DiscussionReplies: 10Last Post: 25-03-2012, 10:24 AM
By luke11cnc in forum General DiscussionReplies: 15Last Post: 30-12-2011, 10:45 PM
By BJ- in forum Opportunities Available & SoughtReplies: 0Last Post: 29-01-2010, 02:06 PM