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  1. #21
    Quote Originally Posted by JAZZCNC View Post
    I try to help people avoid problems they cannot see by using all my experience of building machines and helping 100's no 1000's of people over 15yrs+ who have taken similar routes and nearly gave up due to either poor design and build frustrations or woeful under budgeting. You gave a Budget of £500 so all my advice was based on this. You also proposed design material that is neither cheap or suitable for a successful machine.!

    I understand the experimenting for experimentation's sake I do it every week in some way or another. But what I don't understand is why to do it when you are being advised by an experienced builder that there are better ways which won't cost any more money and in fact, will probably cost less.? All it would take is to experiment with a Welder.?

    I also don't understand why anyone would join a forum seeking advice then ignore it.? Also, don't get why someone would seek to build a machine but state they have no time or inclination to build one.? . . . This seems to me you just like wasting people's time so you'll get no more from me I'm afraid. Good luck.!!
    I am clearly not expressing myself very well.
    To be clear, your (and everyone elses) input is appreciated. I am taking note of it and it will not be ignored. I am not stupid, it is clear already that part of what I was proposing is silly. But that doesn't mean it was stupid to ask the question and it doesn't mean it was stupid to question to try to understand where the posters were coming from and try to put across another point of view.

    You might have noticed that the last few posts were me discussing with ericks his ally framed machine?
    You will not be aware that I spent part of my evening looking at steel prices and thinking about how that might affect the design. You will also not be aware that I also spent some time looking at whether a converted mini mill might suite me better. Until I actually start buying stuff nothing if fixed in stone.

    Am I wasting peoples time? I thought this was a discussion forum for, errr... discussions?? With that in mind, thank you for your input so far, it is genuinely appreciated (apart from perhaps that last post), it would be a shame but I will not lose any sleep if you feel you don't want to contribute any more.

  2. #22
    Quote Originally Posted by ericks View Post
    This is the best pic i have atm showing the connectors

    Attachment 27078
    Thanks, I think I have come across that sort before but will have another look.

  3. #23
    My first router was made from MDF. Look for references to "JGRO" with Google - lots of people have built them. It may be OK in the warm dry areas of the USA, but in a British climate in an unheated garage it has the structural integrity and long-term stability of cold-rolled cow dung. I built that machine (and around 7 years ago, it probably cost no more than £500) before I found this forum and based on glowing reports from people who had built one. I also saw a similar machine built from ply at an exhibition at about that time, which persuaded me to have a go. And, yes, it did do the job I built it for (basically, house-sign style of engraved plaque) and it built a number of models for my son's architecture degree. It is now firewood. I went steel for the mk2. Not sure why you talk about it not being very "modifiable" - angle grinder with cutoff wheel and a MIG welder and away you go. I wrote it up on this forum (search for "AVOR") and if you look closely you can how crap the welding is. Grown men have cried when they've seen it. Do you know, though? It's a bloody marvellous machine that continues to please me every time I use it. Probably cost around £2500 all told. Prices don't go down that much as the machine gets smaller although these days I would source more from China which would cut costs a bit.

    Hey, there's a whole range between toy and carved-from-concrete machines that some guys here build. I had a go at the first as well as something half-way through that range and I don't regret my early learnings. But I am glad that I had half an eye to the future and did buy a decent spindle, steppers and stepper drivers for the mk1 that could be reused. Even if that first machine bent under the weight of the spindle even before starting to cut!

  4. #24
    Quote Originally Posted by Neale View Post
    My first router was made from MDF. Look for references to "JGRO" with Google - lots of people have built them. It may be OK in the warm dry areas of the USA, but in a British climate in an unheated garage it has the structural integrity and long-term stability of cold-rolled cow dung. I built that machine (and around 7 years ago, it probably cost no more than £500) before I found this forum and based on glowing reports from people who had built one. I also saw a similar machine built from ply at an exhibition at about that time, which persuaded me to have a go. And, yes, it did do the job I built it for (basically, house-sign style of engraved plaque) and it built a number of models for my son's architecture degree. It is now firewood. I went steel for the mk2. Not sure why you talk about it not being very "modifiable" - angle grinder with cutoff wheel and a MIG welder and away you go. I wrote it up on this forum (search for "AVOR") and if you look closely you can how crap the welding is. Grown men have cried when they've seen it. Do you know, though? It's a bloody marvellous machine that continues to please me every time I use it. Probably cost around £2500 all told. Prices don't go down that much as the machine gets smaller although these days I would source more from China which would cut costs a bit.

    Hey, there's a whole range between toy and carved-from-concrete machines that some guys here build. I had a go at the first as well as something half-way through that range and I don't regret my early learnings. But I am glad that I had half an eye to the future and did buy a decent spindle, steppers and stepper drivers for the mk1 that could be reused. Even if that first machine bent under the weight of the spindle even before starting to cut!
    Thanks Neale. I had a quick look at JGRO and have to admit the design horrifies me for something that needs to be rigid. But I have already been beaten into submission by jazzcnc so will not be going down the wood route anyway. Well, I don't think so anyway..... ;)

    I have also had a quick read of the frame build on your AVOR. If you think your welding is bad you haven't seen mine! One thing I liked from your description was “If you can’t build it accurately, make it adjustable!”. This is something I have been thinking about but have not come up with anything I am happy will not affect rigidity other than semi-perminent epoxy. I do like your comments on epoxy though and that somehow makes it less daunting to me although I am still concerned it might be a lot of faff to get right.

  5. #25
    I've followed a similar path the Neale, the first machine was a useless plywood and MDF contraption that at least proved I was capable of puling all the components together into a working machine. The current design is a steel frame which is mostly bolted together though the second gantry I built for it is welded using a dirt cheap stick welder that I bought for the job having never welded before. I used a technique I call 'bird poo' welding due to it's appearance. Grinding down the lumps and smoothing things off with car body filler followed by a coat of paint hides the evidence! It works fine.

    I managed to source all the steel from the local tip so it was a cheap option for me! The design of the machine was partly dictated by the available material.

    I followed Neale's excellent advice about making everything adjustable and the trick then is working out how to measure all the errors in a systematic way to isolate each source of error. There's still more to do but it's getting better in stages. I'm only cutting wood so my ultimate target accuracy is to put the tip of the tool where I want it be within a whopping great margin of 100 microns.
    An optimist says the glass is half full, a pessimist says the glass is half empty, an engineer says you're using the wrong sized glass.

  6. #26
    Quote Originally Posted by brman View Post
    But I have already been beaten into submission by jazzcnc so will not be going down the wood route anyway. Well, I don't think so anyway..... ;)
    Well, my work here is done then.! . . . . Some times people need to be given the shock n aww treatment to get them to listen. My only aim is to help not only you but others also reading this post. If other long term members of this forum are honest they will tell you a lot of what they learned or machine designs they use or some version of it came via me or the person they learned it from got it via me.
    ie; "Building in lots of adjustment". "Buying quality components to save money". "Using steel and epoxy" " Mixing Steel n profile" " High sided machine frames rather than flimsy gantry sides" among others.

    Also, I doubt those that started with wood/Mdf, or bought a shity component package, knowing what they know now would do it again or advise anyone else to do the same even if they did learn from it. . . . We don't drive cars with stone wheels because our cave-dwelling brothers learned how to build the wheel do we.?

    So it's your choice if you choose to ignore my advice because like you, I won't lose any sleep if you do ignore it. But I guarantee you will have several sleepless nights and hair-pulling frustrations if you do proceed and try to cut corners or not listen to those with experience. Again good luck.!

  7. #27
    Just to show it can be done - Lego CNC machine.

    But I don't think anyone would recommend it! It's great that you picked up the point about adjustability from my other thread but as Jazz says, it's something I learned from this forum. I believe that my machine had an idea or two of my own - don't think I've seen another gantry design where the ballscrew runs through the end uprights, for example - but I'm not entirely sure that I might not have seen that somewhere. I shamelessly picked ideas from many other machines/build logs. That's probably my strongest recommendation.

    Remember - copy one person's ideas and that's plagiarism. Copy many people's ideas and that's research!

  8. #28
    "Imitation is the sincerest form of flattery"
    An optimist says the glass is half full, a pessimist says the glass is half empty, an engineer says you're using the wrong sized glass.

  9. #29
    Quote Originally Posted by Kitwn View Post
    I've followed a similar path the Neale, the first machine was a useless plywood and MDF contraption that at least proved I was capable of puling all the components together into a working machine. The current design is a steel frame which is mostly bolted together though the second gantry I built for it is welded using a dirt cheap stick welder that I bought for the job having never welded before. I used a technique I call 'bird poo' welding due to it's appearance. Grinding down the lumps and smoothing things off with car body filler followed by a coat of paint hides the evidence! It works fine.

    I managed to source all the steel from the local tip so it was a cheap option for me! The design of the machine was partly dictated by the available material.

    I followed Neale's excellent advice about making everything adjustable and the trick then is working out how to measure all the errors in a systematic way to isolate each source of error. There's still more to do but it's getting better in stages. I'm only cutting wood so my ultimate target accuracy is to put the tip of the tool where I want it be within a whopping great margin of 100 microns.
    So did you use profile rails or supported rails? And did you use resin to level or some other technique? Just curious about different options

  10. #30
    Quote Originally Posted by Neale View Post
    Just to show it can be done - Lego CNC machine.

    But I don't think anyone would recommend it! It's great that you picked up the point about adjustability from my other thread but as Jazz says, it's something I learned from this forum. I believe that my machine had an idea or two of my own - don't think I've seen another gantry design where the ballscrew runs through the end uprights, for example - but I'm not entirely sure that I might not have seen that somewhere. I shamelessly picked ideas from many other machines/build logs. That's probably my strongest recommendation.

    Remember - copy one person's ideas and that's plagiarism. Copy many people's ideas and that's research!
    Yeh, but there are so many build logs and youtube videos out there so it is deciding what to copy that is the problem. After all, there are a fair few wood machines that people appear to be proud of

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