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  1. #1
    Hi all :)
    My name is Graham and I'm new to all things cnc,got a 3d printer I built from a kit though so cnc on a very small scale then!
    I'm starting a build based on plans I bought from Joescnc website- now I know not everyone will like or agree with the build materials and I definitely would like to spend a lot more on the build .... the wife says no!
    So in the whole it will come from the plans but I'm hoping maybe there will be some input along the way as well.
    As I said it's based on plans that once bought gives access to the builders forum and has approx. 250 machines built or being constructed all based off of the plans- giving dxf files/templates for cutting various parts etc.
    The plans suggest a welded steel box frame base ,but as I don't weld I opted for a timber base.
    Constructed out of structural 18mm ply ready to take the aluminium rails when they arrive.
    so a few pictures of things so far then...
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    As you can see I doubled up on the ply thickness and the box section rails really improved the stability and strength.
    Click image for larger version. 

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    The rails fit together like mortice and tenon joints, the long sides are glued to the legs.
    Click image for larger version. 

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    The side rails are 10ft long so I extended them on opposite sides at the ends.
    The width is 5ft.
    Click image for larger version. 

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    I again doubled the ply for the cross rails and screwed them in dry so take down is possible for relocation if needed.
    so this is where I am at now-
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    The front rails are bolted with nylock nuts.
    I also scooped the front rails to allow an 8x4 board to go between the legs for storage, still need to add some rails yet.
    With a few sheets stored under there is should add some considerable weight.
    The legs have screw adjusters on them for levelling.
    So that's where I'm at now, I have some aluminium profile on order which I'm hoping will be with me soon.

  2. #2
    I posted on another thread but I'll comment here as well.

    Somewhere else I see you mention 3k. With that much you can get long way to building proper machine made from steel.
    Yes, it would be basic to start off with because of low budget but you would have a good foundation that truly can be upgraded as you go along without wasting money.
    For a fully finished machine with decent quality components and few bells whistle you'll need about 4-5K but this will give you a machine that will last for years even in small production enviroment but more importantly be reliable and repeatable/accurate.

    You will regret building this machine at some point that's for sure.

  3. #3
    So after much thought ,I have decided to go with the original plans- which are V bearings and Rack and pinion.
    This is purely a cost thing for me - the entire build should come in at under 2k. I can understand peoples views on linear rails and ball screws but as pointed out by some ,it would take the build cost to nearer 4k which I am not prepared to spend.
    Also the fact that this is an 8 x 4 machine for that price I can't see me having any 'Regrets' building it! like I have said before I would rather have a cheaper machine running than no machine at all.
    If there is some upkeep to maintain performance then so be it.
    Speaking to one of the guys who have built this he said he would build it again in a heartbeat.... but no need as its still running 7 years later ,now upgraded to aluminium carriages but still running V rails.
    So bearings are ordered and aluminium profiles and angle iron are in this week :)

  4. #4
    So after my rails apparently having had a tour around England before reaching my supplier, I finally managed to pick them up Wednesday ... a 9 3/4hr round trip:(
    So busy day today fitting them:)
    Click image for larger version. 

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    Bearings for V rails are on their way from USA so hopefully things will start moving soon!

  5. #5
    Hello fellow adventurous newb,

    I'm doing the same thing as you it seems (well it is a CNC forum).
    I wish i had more input for you , to help you on your way.
    I'm looking at purchasing Linear rails as i've used them before and the seem to give a better result (V Bearings on my Laser CNC work ok thou).

    My input is i've searched and searched and think i've found a supplier of rails which don't cost the earth.
    How much is the rack and pinion costing you??

  6. #6
    I just couldn't justify the cost for linear rails I'm afraid :(
    I have been looking at a UK supplier that is selling the rack MOD 1.0 at 74.99 for a 2m length pre drilled.
    I'm hoping that's a fair price as when I google rack and pinion I get car steering racks a lot!
    For the pinion drive i'm looking at a 3:1 drive plate module that I will probably order from cncrouter parts in the USA. No one over here seems to make them :( I think they are about 60 each+ postage and import tax.- I need 3

  7. #7
    So I'm looking at motor/driver choices and yes while i'm after advice can I ask that you switch off the 'best possible solution 'head and use the 'I expect that will be suitable' head!
    This is a kit for nema 23 4Nm with 48 psu instead of the 36v they offer with other kits.
    I know I will need screened cables as well but is there anything glaringly obvious missing?
    Sorry if it seems like i'm doing it all wrong but I'm loving my build so far as it's starting to take some shape :)

  8. #8
    Wow, thanks :)... Can I ask just one more question? The nema 24s should be fine, although 60mm size the hole mounting is the same but they have 8 wires! Is that 4 more than usual! Or is 8 OK (they only have 8 wired ones in UK warehouse)

  9. #9
    Quote Originally Posted by GrahamWhite View Post
    Wow, thanks :)... Can I ask just one more question? The nema 24s should be fine, although 60mm size the hole mounting is the same but they have 8 wires! Is that 4 more than usual! Or is 8 OK (they only have 8 wired ones in UK warehouse)
    Ok let me explain the difference between 4, 6 & 8 wire motors. Steppers can be wired in several configurations with each making a difference to how they operate. There are 2 commonly used methods #1,#2 and one not so common #3.
    #1 Bi-polar parallel (8 wire)
    #2 Bi-polar Series (4 wire)
    #3 Uni-polar (6 wire)

    8 Wire motor is known as Hybrid Motor and can be wired in any of the 3 configurations. Each Config will affect the current used and how the motor performs. (8 & 6 give roughly same performance but unipolar require drives that allow it, hence why not often used on modern machines)

    So if using 8 wire motor this would be wired Bi-polar parallel and requires roughly 2x the amps of Bi-polar series to give rated torque. However In performance terms it holds the Torque much higher up the RPM range than does a Series wired motor for the same given voltage.
    But like all good things this comes at a cost. You have less torque lower down the RPM range.

    What this means to YOU and US is that for Router where your cutting at higher feed rates and higher up the RPM range then Bi-polar parallel is best way to go.

    If you was building say a Milling machine then you'd wire in Bi-polar Series because require more Torque lower down the RPM range. Still uses 8 wires just wired differently. Also requires less current than parallel so lower amp drives can be used. However for the same voltage the RPM will be lower because inductance is higher due to how it's wired.! . . . Again back to can't have something for nothing.

    Now 4 Wire motors are Fixed by the manufacturer and you buy them either Bi-polar Series or Parallel wound. Often they are Series wound.
    The difference being that Series wound will require roughly twice the voltage to reach the same RPM as Parallel wound motor.

    Won't get into 6 wire unipolar because it's a throwback to old tech and drives so not really relevant here.

    So for best performance with a router, you want 8 wire motors and wire them Bi-polar parallel.

    If you look at the Datasheet on the Cnc4you it will show you how the wires are connected for each method. All 8 wires are used but joined in different ways.
    Last edited by JAZZCNC; 25-04-2018 at 06:16 PM.

  10. The Following User Says Thank You to JAZZCNC For This Useful Post:

  11. #10
    Many thanks again, most of the basics ordered now, steppers, drivers and 24v psu.
    Will look a bit more into Bob's.... Yes ub1 does look the bees knees but will take more kidneys than I can afford to sell! Lol
    I'll have a look at some others that have opto isolation:)

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