I am pleased that you like it guys.
Yes the oversized cross member really does make the gantry very stiff. Not going to be any flex there. I still need to align all the the plate soeverything runs square to their relevant axis's, then I will drill and ream for dowel pins on each side to keep them that way.
I didn't work from any plans. I looked through the members gallery at all the different styles of machines people had built and chose the style that I felt would meet all my needs. In particular it was important to me that I had plenty of clearance between the table top and the lowest part of the gantry cross member along with lots of Z travel so I could do more 3D routing in the future.
I knew building higher might cause more vibrations in the system but if it did I would just run slower cutting feeds.
Basically I started out with the Z-axis since I only had a ballscrew and linear rails long enough for that part of it. As I started to buy more parts from ebay and other places the design progressed. I would design each part in Autocad first then machine it making any changes as I went, then modifying the drawings as required. It adds time to the build but I wouldn't have been able to keep tight tolerances if I did it any other way, plus I know if a part will fit properly before it is machined and having the CAD drawings will allow me to incorporate and additions much easier in the future.
I am a machinist for an N.D.T. company and we sometimes make Ultrasonic scanning systems that are very similar to a CNC router or plasm cutter, except instead of a table you have a water tank and instead of a router your have ultrasonic probe. Having experience in building these scanning systems really came in handy when I designed and built my router.
I will say that if I would have done anything different I would have used large linear profile rails, like THK instead of the Thomson round rails for the X-axis.
I found that the Thomson round rails ended up being alot more work for me to use since I started out with just standard rails that did not have the mounting holes drilled and tapped into them. I had to drill and tap all the holes myself and let me tell you that the case hardenen on them is tough and pretty thick.
Thank goodness for carbide center drills. I will be keeping my eye out for some more of that Thomson rails support profile so I can make my rails supported all across the whole length. What I used was just some left over pieces we had lying around the shop. I was surprised how expensive that stuff is if you want to buy it new. Just not in the budget at that time.
Will also consider changing the THK rails I have on the Y-axis for larger ones if these ones don't stand up. They are kind of small being 9MM.
Thanks
