Page 1 of 6 123 ... LastLast
  1. #1
    Know I'm probably whacko even thinking of doing this in this way, and my Scot's blood rankles against using hard earned dosh that is rapidly dwindling in the absence of any foreseeable income, but....

    I have read enough around this recently to already feel somewhat overwhelmed, so that's a challenge to be won!

    I don't currently have access to anything like a proper workspace, as I'm currently living in my touring caravan (long story that I'm not going to explain here).

    One corner-ish (1300 x 900) of the caravan will be allocated as workspace to get everything assembled and (ostensibly) working, and I obviously need to invest in a few more tools, and build a small wooden bench thingy.

    I don't intend creating any sawdust in the caravan for obvious reasons, but reckon wee amounts of nice clean aluminium swarf can be reasonably contained and won't do too much harm.

    This machine will probably only be used in real anger after I hopefully get to emigrate downunder to join my kids in Oz in a couple of years.

    So far I have only done tutorial-1 on Sketchup so please excuse lack of plans or level of plan detail initially.

    My hope is that the build will help me retain what is left of my sanity, but am also a tad worried that it may actually have the opposite effect, as it's already got my staying awake until morning birdsong!


    Requirements:

    1. To be used primarily as a hobby machine, but the way worldwide income prospects are looking in my field (IT-technical-mainframe-software-old-fart) who knows, this machine may even help provide some income in future.

    2. Mainly to be used for routing/drilling wood, but poly-plastics and smallish pieces of aluminium for making woodworking jig-thingies is bound to follow although less frequently than wood.

    3. Needs to allow for machining the top faces of pieces of wood up to around 100mm thick, as might be used for making workbench legs.

    4. Tool cutting area, measured tool centre to centre, needs to be 600mm wide but the length is less important... maximum 900mm would be nice... but I still have to define this within my limited workspace, considering rigidity and the cost of available rails and drivescrews, etc..

    5. Needs to be able to machine the top edge of boards that are clamped upright at the end of the X-Axis to allow for cutting of matching (M&T / finger / dovetail) joints.

    6. Fixed-Bed and Moving-Gantry machine with 3 Axes initially and speed is not that important for the initial build, though it would obviously be a nice to have.


    Thanks to the advice already received on this forum I feel my understanding has already advanced in leaps and bounds from where I was 4 days ago thinking of doing a build in MDF with unsupported rails and M8 drivescrews.

    Very recent additions to my vocabulary (not to suggesting my understanding is correct) include Profile-Linear-Rails, Supported-Linear-Rails, Ball-Screws, Trapezoidal-Screws, Acme-Screws, Backlash, Whipping, Resonance, Chattering, Breakout-Boards, Stepper-Drivers, Stepper-Motors, Mach3, G-Code, and others.

    My next post will hopefully have defined the hardware and components to be used, only after I've spoken to a helpful gent near Wakefield to help guide me in the right direction.

    Cheers,
    Andy

  2. #2
    I'm finding far too many variables floating around in my grey-matter, causing me to go off at tangents researching multiple different options of anything and everything, so am taking some decisions to lessen the load on my limited mental capacity.

    Have decided on the adjustable bed type design similar to Iwant1's, but will do the initial build on a flat aluminium frame in the caravan, and only weld up the steel frame when I eventually get it into a workshop before using it in anger.

    As I don't have machining facilities in said caravan, have bought a set of pre-machined ballscrews from linearmotionbearings2008 for about 330+duty:

    - 4pcs anti backlash ballscrews
    - RM1605-300/850/1150/1150mm-C7 (4 screws+4 balnuts+4endmachinings)
    - 4 sets BK/BF12 with locknut and circlip
    - 4pcs of 6.35mm*10mm flexible couplings

    Have also roughly decided on using the following, but will only buy these later:

    - SBR20 supported rails and SBR20UU blocks for all three Axes
    - PM752 drivers x 4
    - 3Nm NEMA23 steppers x 4 (SY60STH88-3008B ?)
    - Mach3
    - Ethernet SmoothStepper

    Meantime, I will work on the rough design in SketchUp, thanks to the help from the forum, and only determine exact dimensions when the ballscrews arrive.

    Btw, many thanks to JAZZCNC for giving me plenty of time and great info!

  3. #3
    Surprised you have ordered 1605 do you need higher resolution than 1610 provides.?

  4. #4
    Quote Originally Posted by JAZZCNC View Post
    Surprised you have ordered 1605 do you need higher resolution than 1610 provides.?
    Damn... That's a perfect example of how too many variables have been fogging my mind.

    You are spot on Jazz... Thanks...

    On the positive side my use of "have bought" was temporary poetic licence and I was subsequently distracted and haven't placed the order yet, so will change it to 1610.

  5. #5
    I'm busy with my design and have a query that references aspects of some incomplete bits within the circle in the attached pic.

    The back part of the Y-beam and the top part of the X-carriage is going to be formed out of 152x51x9.5mm aluminium angle, which is coloured yellow.

    I had decided to put the ballscrew-nut housing midway between the X-bearings as depicted by the grey block, but am now wondering whether it might not be better to maybe beef up the end of the Y-beam, attaching it securely to the vertical angle on the X-carriage, and simply make that into a ballscrew-nut housing, which would result in more "direct" drive to the Y-beam? The fact that this is towards the end of the X-carriage may not be ideal, but would it be acceptable or likely to cause problems?

    Cheers,

    EDIT: Have now cancelled that idea and am going back to Keeping it Simple!
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	$$CNC-Design-4.jpg 
Views:	8065 
Size:	23.0 KB 
ID:	6437  
    Last edited by WandrinAndy; 30-07-2012 at 01:59 AM. Reason: Edit - Have now cancelled that idea.... KISS

  6. #6
    Does anyone perhaps have a legible dimension data sheet for Chai's 1610 ballscrews?

    I have a copy off eBay but these old eyes canna read the dimensions even after sharpening and increasing the image size.

    Particularly interested in the BK12 and BF12 bits.

    Thanks,

  7. #7
    Here's the end-machining drawing I got from Chai a couple of years ago:

    Click image for larger version. 

Name:	end machining.png 
Views:	1429 
Size:	18.2 KB 
ID:	6490

    Which dimensions do you need from the rest?
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  8. #8
    Quote Originally Posted by Jonathan View Post
    Here's the end-machining drawing I got from Chai a couple of years ago
    Thanks Jonathan. I had already saved those up off a previous post of yours I think.

    Quote Originally Posted by Jonathan View Post
    Which dimensions do you need from the rest?
    I'm after the size of the BK and BF support blocks, and particularly the dimensions from the centre of bearing to each of the edges. My current design looks like too tight a fit for these blocks, so would like to know what I need to cater for.

    How do you guys normally accurately align the bearings and ballnut?

    I'm guessing I need to allow some leeway in order to be able to adjust during setup.... Is this normally done at the ballnut or at one of the bearings and if so which bearing?

  9. #9
    Found the dimensions I needed for the BK12 and BF12 mounting blocks.... they are 60x43 and the bearing centre is 32.5 from the base. So just the one remaining query:

    How do you guys normally accurately align the bearings and ballnut?

    I'm guessing I need to allow some leeway in order to be able to adjust during setup.... Is this normally done at the ballnut or at one of the bearings and if so which bearing?

  10. #10
    Quote Originally Posted by WandrinAndy View Post
    How do you guys normally accurately align the bearings and ballnut?

    I'm guessing I need to allow some leeway in order to be able to adjust during setup.... Is this normally done at the ballnut or at one of the bearings and if so which bearing?
    Yes some leeway is exactly what you need. Ideally you have 'leeway' in the plane perpendicular to the axis of the ballscrew, not just in one direction. So to answer your question, a bit of both. If you mount the bearings in slotted holes then that gets adjustment in one axis, to get adjustment in perpendicular direction you should be able to use the small amount of clearance in the ballnut mount to adjust the ballnut centre height, but clearly it depends on the mount.

    If one bearing is fixed, then spin the ballscrew so the ballnut is at that end, move it back and fourth a little to make sure it centers then tighten up the 6 ballnut bolts. Spin ballscrew so ballnut is at other end, now tighten that bearing mount so it aligns to the ballnut and the other bearing mount by default. If the ballscrew gets noticably more difficult to turn (by hand) towards either end then there is an problem with alignment, so loosen the nut/bearing depending and try again. A tiny amount of misalignment will impose a high radial force on the ballnut which well cause excessive wear since they're not designed to tolerate radial forces.
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  11. The Following 2 Users Say Thank You to Jonathan For This Useful Post:


Page 1 of 6 123 ... LastLast

Similar Threads

  1. tools for 3d wood carving
    By chris in forum Marketplace Discussion
    Replies: 5
    Last Post: 18-01-2014, 04:23 AM
  2. BUILD LOG: Monster fixed gantry router for aluminium & wood
    By jonboycnc in forum DIY Router Build Logs
    Replies: 9
    Last Post: 12-01-2014, 11:26 PM
  3. BUILD LOG: Aluminium Extrusion CNC Router Build
    By joshendy in forum DIY Router Build Logs
    Replies: 9
    Last Post: 10-04-2012, 08:26 PM
  4. BUILD LOG: Planning and build of my "8020" aluminium CNC Router
    By monza in forum DIY Router Build Logs
    Replies: 14
    Last Post: 06-02-2010, 11:55 PM
  5. Source of Wood to build a Solsylva 37x25 CNC
    By MikeyC38 in forum Gantry/Router Machines & Building
    Replies: 8
    Last Post: 06-07-2009, 11:42 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •