My first CNC for cues was a Sherline. Although I did some very nice cues with it I probably ruined 1 out of every 4 cues that were built. The gibbs for travel are way to short and their X and Y drive screws with the brass adjustments are totally unacceptable. The nuts for the drive screws would last for about two cues. I also used a P/C laminate trimmer but this also caused much aggravation as the weight of the mount would put the Z axis in a bind and loose steps. I ended up making my own X-axis table and changed all the drive screws to 0 backlash units and had to redesign the machine to use them. Also, when the jig that holds the cue is mounted to the table it must be balanced or the gibbs will bind and the table will not move. I had a real Rube Goldberg set-up with a pulley and a bucket of weights to counter balance the jig. Mine worked but you had to sit next to it anytime it was running, without any hearing protection, and your finger on the escape button so that when you heard the stepper motors loosing steps you could stop the machine before it started cutting in the wrong place. With the little stepper motors and using a 1/32 end mill, sometimes I had 8 hours of cutting pockets on a cue and then you couldn't hear for two or three days.
I bought the machine used for 2,000.00 and probably put another 1,500.00 in it and it was still horrible. The main reason I bought itwas because it had AHHA software, the same as Sherm, so I knew he could help me with the learning process. I bought Sherlines CNC radial table for around 800.00 and it works great for a fourth axis. I can run it off it's own computer or put it in slave mode and run it off my reguler operating program.
A couple of years ago, I started reading tutorials on CNC on the internet, went to an exotic metal scrap yard and bought metal I thought I could use, got on e-bay and bought ball-screws, linear rails and bearings, large stepper motors and most all else that I needed and built my own Gantry CNC system.
The travall on my machine is 34" X 34" with a 15" Z travall. It's four axis, has Thomson precision 1" ball-screws with zero backlash, 1000 inch ounce Pacific scientific steppers, Parker drivers, NSK linear rails and bearings and a Precise 0 to 75,000 rpm variable speed precision grinder mounted to it. All parts in my machine are top quality and were made for heavy industrial use. I built my own power supply and used Parker drivers for dependability and long service.
I already had my cad/cam software, the AHHA cnc software for running the machine and the Sherline fourth axis so I never had to buy that stuff. Everything else that i bought on e-bay and the scrap yard to get this machine running came to less than 3,500.00. It is an extremly accurite machine I might add.
If I was going to build this again I believe I would take a different approach. Instead of building a Gantry system from scratch I would watch e-bay for a verticle CNC mill who's electronics have gone south. Bridgeports and other Verticle CNC machines have BOSS or one of the other industrial operating systems and when something happens to them they are extremely expensive to fix. They go off on e-bay all the time for 2,500.00 to 4,000.00. get one of these, strip all the electronics and put on a PC system for a fraction of the costs. They already have linear bearings, ball-screws and motors. You end up with a machine that is 10 times stronger and better built than the align-rite for less than half the money.
Dick
