Am I being silly?

[ericks]

This is the best pic i have atm showing the connectors

[brman]

This is the best pic i have atm showing the connectors

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

[Neale]

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!

[brman]

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.

[JAZZCNC]

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.!

[Kitwn]

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.

[brman]

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

[Kitwn]

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

I used 20mm fully supported rails as they are cheaper and much more tolerant of alignment errors than Hi-Win. Despite coming off the tip the 65mm box section steel the long axis is mounted on looked flat enough to me and my 1m steel ruler so they are directly mounted onto the metal. The gantry is 2 pieces of 50 x 100 mm box welded together and though the surface seemed much flatter than I would have expected I used epoxy to level the face. Unfortunately this was before I knew about the West Systems 105 resin and 209 hardener combination and my chosen goo was too viscous. The result is probably worse than the underlying metal and will be re-done during planned upgrades later this year once we get into winter and the shed daily maximum temperature drops below 50C.

[brman]

I used 20mm fully supported rails as they are cheaper and much more tolerant of alignment errors than Hi-Win. Despite coming off the tip the 65mm box section steel the long axis is mounted on looked flat enough to me and my 1m steel ruler so they are directly mounted onto the metal. The gantry is 2 pieces of 50 x 100 mm box welded together and though the surface seemed much flatter than I would have expected I used epoxy to level the face. Unfortunately this was before I knew about the West Systems 105 resin and 209 hardener combination and my chosen goo was too viscous. The result is probably worse than the underlying metal and will be re-done during planned upgrades later this year once we get into winter and the shed daily maximum temperature drops below 50C.

Thanks, more food for thought.

[Neale]

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!