[nickr100]

hi all,

i have been lurking here for a while now as i wish to build a couple of cnc's, one hot wire one 3 axis router.

firstly let me introduce myself. i am an aircraft engineer by trade and have been flying r/c model aircraft for 22yrs. i want to build the cnc's because as the old saying goes 'if you want it done right, do it your self'. i have had many foam wings over the years that have been less than good. that made me start to manually cut my own wings with great success. the only down side i have found is the time consuming process of making templates for each design.

i feel that a cnc foam cutter would really increase the quality of the cut as well as the repeatabilty and changability of the wing core. this is where my problems start.......

i have spent a lot of time looking for designs and ideas for the mechanics of the foam cutter (the router will come later after the foam cutter is up and running) and i have these all designed. the electronics will come from hobby cnc but the other vital componant that i need is the one causing me the headache.

the leadscrews/ballscrews/threaded rods and nuts. what do i go for?? i would like a simple method of conecting the leadscrews to the motors. i want them to be relatively cheap, as in i am happy to pay a premium for a higher quality product, but not extortionate. i also want to be able to buy them in the UK or be able to have them shipped easily to the UK.

also, how do i support the leadscrew at the non-motor end?? i know i will probably need to have some sort of misalignment adjust as well.

lots of questions, and thats enough for just now

thanks in advance

nick

[harryn]

There is a LOT of info that covers your questions in the wood router section. There are lots of build threads, etc. where people have used many methods and kits.

I have probably put over 200 hrs into reading these threads, and while many are similar, each has made a contribution to my understanding of how to approach a project. In retrospect, I probably would have gotten further faster if I was a bit less stubborn and simply accepted what people said sometimes.

In any event, it also helps to look at how the commerical routers are built, such as K2 or mechmate.

[SteveC68]

Check out the pictures in this thread.

http://www.cnczone.com/forums/showthread.php?t=18613

I have already purchased a CNC board kit and stepper motors from HobbyCNC. I also bought some 1/2" ACME threaded rod from ENCO and some delrin flanged nuts (ACME thread) from ebay. As I'm also going to build a budget machine I plan on using the ball bearing drawer slides that are also available on ebay. The couplings can be made for very cheap (see the thread linked to above). I plan on supporting the threaded rod at both ends with some bearings that I also got from ebay. As soon as I finish construction of a new fireplace for the wife I will start construction on the CNC.

Steve

One more thing. Check out the yahoo group CNCFoamcutters. All questions will be answered there.

[Sleedo]

.... I plan on supporting the threaded rod at both ends with some bearings that I also got from ebay. As soon as I finish construction of a new fireplace for the wife I will start construction on the CNC.

Steve

One more thing. Check out the yahoo group CNCFoamcutters. All questions will be answered there.

Steve, it will be good to see some progress on your machine! Glad I could be of some help in making it happen . One thing I wanted to mention to you regarding the Acme leadscrew and bearings at both ends is to be sure the screws are true before you bolt everything together. The ones I received from Enco were not straight, caused quite a lot of friction when I had a bushing at the far end. I simply removed the support and allowed the screw to wobble, not elegant in the least but effective. Wish I had straight screws though.

Good luck,
EB

[SteveC68]

I know what you mean about a bent lead screw fixed at both ends. I built sort of a really dumb CNC laser scanner which is basically a bearing at one end and an electric motor at the other end of a lead screw. It has a small steel rod running parallel to the lead screw and a piece of wood/gantry that has a nut glued to it and a hole for the steel rod. There are two micro switches that I can move around and the little piece of wood actuates so that I can limit the travel of the simple gantry. The wood travels down the lead screw until it hits a micro switch and then the motor changes direction and the process repeats. I have an ebay laser attached to the gantry to scan stuff with. The lead screw is just some threaded rod from Home depot that is a little bit bent. It causes all sorts of problems. I will try to get the Enco lead screws as straight as I can before I install them. If that doesn't work then they will be free on one end.