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« on: May 18, 2007, 01:34:33 AM »
Well, I have had the lathe a week and after getting it set up in my garage, I finally have been able to play with it. It is very solid, weighs about 450 pounds. It took myself and four friends to lift it on the bench. But having that weight it is very rigid for a benchtop. I got the very first lathe they shipped out and as such they have not had a chance to write a manual for the CNC part. There is a manual for the standard lathe. But, Richard Lowe has been extremely helpful and I have made a number of calls and he has helped me out a lot. To answer the comments of DAlgie, the ball screws are completely covered with metal covers. I think they had them uncovered just to show for the pictures. The x axis stepper does stick out a little but it is not as much as it seems in the pictures. It causes no problems. The appearance of the lathe looks every bit as good as the pictures and seems to be very well made.
One of the things I learned from Richard was that you have to be sure to take off all the packing grease off the ball screws before operating.
Again, Richard sent me a profile for this lathe that he wrote to install in Mach 3. i did a few small cuts on Aluminum and was very impressed with the smoothness of the surface. It has a 1.3 hp motor and so has plenty of power. I tried a .100" cut and it handled it with ease. I haven't tried, but Richard says he has taken .050" cuts in steel, with no problems. I then wrote a small program to cut a hemispherical surface of 1.25 " diameter. It worked well and gave a beautifully smooth hemisphere. When I went to run it again I found a little glitch. On making the fast traverse the Z stepper motor stalled. On checking with Richard he helped me to adjust the velocity and acceleration of the Z axis. It was set a little too high and also he thought I should adjust the Gibs as the Chinese tend to have them pretty tight for shipping. After playing with this a while I found good values for velocity and acceleration that worked well. Then I started checking for accuracy of cuts and found they were off a little. So another call to Richard and he told me I have to tune the stepper motors. ( I am new to this game and didn't realize this). So he helped me. There is a formula in the Mach turn manual that tells you how to calculate the values for z and x. So we calculated and tuned the motors. This gave more accuracy, but not good enough. So you can check the values by putting on a good dial indicator and then do it by trial and error. After Playing around with this awhile I again came up with good values that gave good accuracy. (Generally within .0005 to .001 inches in both the x and z movements over a 1 inch travel.) I think the reason that the calculated value was not as good as it should have been is that we were not sure of the exact value of the pitch of the ball screws.
So I wrote another more complicated program that bores into a 1.1 Inch piece of Al and has a 20 degree taper inside that goes in from x=.902 for about . .350 and then makes several steps going to smaller and smaller diameters. It came out really nice. The surface on the very inner steps was a little rough because I was using a small diameter boring bar and took a little too big of cuts to do the finish.
So, overall I am very pleased with the lathe so far. I found out that this price of $3499 was an introductory price for this first shipment and after that the price will go to $4495. As I use it some more I wrill write in and let you know how it goes.
As an aside I got a call today from a company I had checked in with several months ago on getting a Dynamite lathe. He said it was only $45,000! When I told him I got a new CNC lathe for $3499, he didn't believe me. Of course mine is not nearly as sophisticated as the Dynamite, but I think it will do erverything I want to do.
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