Am I being silly?

[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.