CNC experience - Oval Wheels
  • I love so much Dave’s clocks and I spent so much time looking at each clock that I have decided to build my own cnc machine in order to build almost all his magic time machines. I got a generic book about how to build your own cnc written by Patrick Hood-Daniel and James Floyd Kelly and as I figure out that the cnc can be build with inexpensive materials like MDF (with a total cost under $500 - including stepper motors and drivers) I have started my project at the beginning of this year. I created a dedicated computer from four different desktops recycled from garbage and after three months of working with MDF, bearings, and screws, I was proudly starting my cnc machine.
    The first attempt of cutting wheels was kind of a disaster since I did not know how to adjust the spindle speed, feed rate, and the deflection of the cutting bit as a result of the first two “speeds”. Dave helped me to pass this frustration. The following BIG frustration came with the next attempt when I figure out that my wheels are ovals instead of circles… This time I was so ashamed about my mistake that I did not share my problem with anybody. Searching over the internet for this issue, everybody advice me about “backlash”. During the next two weeks I tried desperately to address this new issue “backlash”, by redoing essential components of my cnc machine, dismantle and mounting back the cnc. Every time I put back together my cnc, I was under the impression that I have managed to solve the problem but my wheels were stubborn ovals. After more than two weeks of working at my cnc I got tired and my frustration reach the sky since I cannot see any solutions for my egg shape wheels. I feel so guilty for the money, time, and effort spent useless on this project, and on top of these thoughts I almost lost my interest in cnc and clock wheels.
    By chance, looking for some other info on the internet there was one single person suggesting to check if my Y axis is sharp perpendicular on X axis. This was incredible simple solution for my “oval problem”. I went again in my basement and look over my square tests. I have to admit that I have checked the square tests only for the dimensions of the y and x but not the angle between two axes. So to finish my long story, the big problem with my cnc was finally solved after one month of research and hard work on different components of cnc, only by adding a single washer in one corner of Y axis joint. This washer corrected the angle between the two axes making them to be sharp perpendicular. Now my wheels comes in a perfect shape maching Dave's plans.
    There are a couple of conclusions from my long story:
    1. Always try to make things in a simple way. If you love Dave’s clocks as much as I do, maybe is more efficient to buy directly a kit from Dave (that is guaranteed for best quality materials and cutting) instead of trying to build the clock from scratch. Moreover, buying the kit will save a lot of time and money.
    2. If you are stubborn to choose a complicated way (like myself) trying to reinvent the wheel, than DO NOT GIVE UP! There will be many frustrations, and many times you will feel alone in a world surrounded by professionals speaking foreign languages. The satisfaction of solving a problem by yourself is hard to explain…
  • I usually think this way: if you are not working, even a failure is good. Well, maybe not for your pocket, but you can learn a lot of things only trying.
  • Mihai
    Sometimes in life, the journey is more important than the destination, I also know the feeling of solving a seemingly unsolvable problem, and of course the rush when everything comes together.
    As you mentioned the way to check that the x and y axis are truly 90 Deg. to each other is to cut the biggest square your machine will allow, and then measure the diagonals, if they are equal then you know your axis are at right angles.
    But only $500 for a CNC router self build, that is incredible!
    Dave
  • I didn’t know the secret of checking the diagonals, and also the importance to check the sharp perpendicularity between two axes. Initially, I was happy to see that my cnc is cutting a square, and I thought "this is it". Much later I figure out how important is to check and perform each detailed test before starting cutting wheels. Good lesson but with a lot of wasted time, and birch plywood :)
    Indeed, the cnc does not look pretty but is working properly now, and it cost me maybe less than $500. The most expensive part was the electrical components (stepper motors, power supply and 3 axis driver board) $175 acquired from ebay (free shipping for North America and Germany), details here:
    http://www.ebay.ca/itm/Free-Ship-3Axis-Nema23-Stepper-Motor-270oz-in-4Leads-3-0A-Board-CNC-Kit-Mill-NEW-/200806516142?pt=LH_DefaultDomain_0&hash=item2ec10045ae
    For bearings I have paid around $50 from www.VXB.com (used 12 cheap skate bearings for BRA- bearing rail assembly) and another 6 bearings for each lead screw axis.
    MDF was around $50 for four boards 24”x48”. I have realized only when I finished building this machine that is far too big for what I want to cut. Like Dave use to call is a “monster machine” :)
    I have spent around $100 on three long aluminium angled rails and a long lead screw necessary for all three axes.
    The bolts, nuts, washers were quite inexpensive, maybe another $20. The router is a Ridgid 2400 bought as a second hand tool in very good condition – another $60.
    Dave helps me with the cutting bits from Sorotec. I recommend everybody these bits, very good quality, nice finish cutting, (5 to 7 flutes).
    Yes, I have paid around $500 for my cnc, like I already mentioned is not a pretty one, but I am very happy to see that is an accurate working machine, spent a lot of time, with many frustrations and happy moments, and as Dave mentioned: “the journey” was quite a pleasant one!!
  • I forgot to mention: for those interested to build a cnc machine, details can be found here:
    http://www.buildyourcnc.com/book.aspx
    Good luck!
  • I have been looking at the CNC 6040 Routers. They are about £750 and come complete including water cooling, PC interface cables power supplies, everything except the actual PC to get you up and running. Looked on You Tube and found video of someone cutting 20mm think Aluminum with one. Admittedly it took a long time : ) Has anyone any experience with one of these?
  • Salve ragazzi, mi chiamo Giandonato e sono nuovo del forum, UN SALUTO A TUTTI, chiedo scusa se scrivo in Italiano ma... non conosco l'Inglese (se creo problemi al forum smetterò di scrivere). Fate come faccio io, usate Google per le traduzioni.
    Si mi sono costruito una cnc (potete vedere sul sito: www.eurotrast.com, purtroppo sono una persona pigra a scrivere per cui il sito non è mai aggiornato.
    Uso diversi software, normalmente taglio alluminio Ergal da 15mm, adesso (rifaccio l'asse Z) taglio Ergal 20mm.
    Di solito uso punte da 3 o 4 mm, questo perchè fanno poco rumore ma bisogna fare passate da 0.5mm a 0.8 mm, è lungo ma non si rompono le punte e con l'ultima passata da 0.1mm su tutta la parete di alluminio si ottiene una finitura accettabile.
  • I have been looking at building a cnc router and have seen the 6040 routers as Ian mentioned. Again has anyone any experience good or bad from one of these models or would it be better to have a go at a self build ?
  • Have just taken a look at the 6040, it has some pretty impressive specs, it has ball screws on all axes a HF spindle and a very decent travel in all directions. And the price is more than reasonable, but buying a chinese CNC router is a leap of faith.

    I recently bought a chinese laser engraver, and I must admit it is more than worth its money. I did have to do some adjusting, and the manual was written in a most appalling english, but having experience with CNC I knew what I wanted and how to achieve it.

    Take a look at this review

    </6040 Review>


    He really knows what he is talking about and he covers the machines disadvantages/advantages very comprehensively.

    I would like to throw in a CNC router from the firm that I buy my routers bits from.

    Stepcraft 600


    Love the Germans or hate them, there is no denying that they are pretty good at engineering, and although I have not seen or tested the machine I would imagine it is more accurate than the chinese one.

    Dave
  • Looked into 6040 and came to conclusion that its not up to the job. So setting off on journey to build my own which should be as much fun as using it. Will start with mdf sealed base and get x y axis working first due to limited funds and fit z axis last.
    Downloaded Sketch up and learning on that. Anyone living in Yorkshire area who has experience of either building cnc or use in sketch up i would gladly meet for tutorial in exchange for beer tokens.
  • Good on you for building your own cnc. I have built a cnc and it worked well but the one thing I have learned about cnc is buy a cnc. I sold the cnc I built and bought a small cnc as I learned my cnc got bigger. I started with a Zen tool cnc I now have a K2 cnc.
    The Zentool cnc I have is for sale 750.00 cdn I also have a lot of cnc parts everything a person needs to build a cnc all parts 500 cdn hope this can help someone down the road of cnc