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proddy
05-09-2009, 02:24 AM
hey lads, ive not been on 4 a while due to changin my ideas on a few things for my 1st build an am now seekin advise on these, im still lookin at doin 3d carvings

1, has any1 any thoughts on the "bearing an ally angle method" for the slides as shown on buildyourcnc.com???

2, has any1 any thoughts on the 3axis stepper motor complete kit for 128 quid on ebay???

3, would a stripped down plunge router work as a spindle or would there be too much "slop"???

4, is tr10x2d with delrin nuts sufficient as lead screws???

im still not sure wether to use a fixed gantry or not coz i wont need a table bigger than 400mm x400mm but its always nice to have a few extra inches eh:naughty:

irving2008
05-09-2009, 06:00 PM
hey lads, ive not been on 4 a while due to changin my ideas on a few things for my 1st build an am now seekin advise on these, im still lookin at doin 3d carvings

1, has any1 any thoughts on the "bearing an ally angle method" for the slides as shown on buildyourcnc.com??? It works OK, good enough for low accuracy wood carving at least, and cheap!

2, has any1 any thoughts on the 3axis stepper motor complete kit for 128 quid on ebay??? Which one? Need a link to it!

3, would a stripped down plunge router work as a spindle or would there be too much "slop"??? Some good stuff been done with cheap routers. Main issues (although i have no personal experience) is noise level and duty cycle - they are on much longer on a CNC machine than in manual use so heat can be an issue, so higher powered ones are thought better as they handle the load better. But beware of the weight factor, bigger ones can weigh 3 - 4Kg.

4, is tr10x2d with delrin nuts sufficient as lead screws??? Yes if you don't want too much speed. The efficiency is low compared to ballscrews so bigger steppers required to get high cutting speeds. On a 400mm work area a 1Nm stepper (with 1.5A drivers) will work with 10x2 + delrin (I have similar) but will be limited in speed, especially with a heavy router -I use a die-grinder as a spindle which weighs 1.7Kg. A 3Nm stepper gives more 'go' but won't be possible in your 128 stepper package, you'll be paying 40+ each for the steppers and are looking at 4A drivers!

im still not sure wether to use a fixed gantry or not coz i wont need a table bigger than 400mm x400mm but its always nice to have a few extra inches eh:naughty:

Fixed gantry, moving table is advantageous if the workpiece is significantly lighter than the router and associated Z and Y-axis gubbins as better cutting speeds can be achieved. It is harder to construct tho.

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proddy
06-09-2009, 12:21 AM
nice 1 irving

that kit is here
http://cgi.ebay.co.uk/3-AXIS-CNC-Router-or-Mill-Stepper-Motor-complete-kit_W0QQitemZ160359509079QQcmdZViewItemQQptZUK_BOI _Electrical_Components_Supplies_ET?hash=item25562b ec57&_trksid=p3286.c0.m14

i take it your die grinder isnt air driven

an i would have thought a fixed gantry would be an easier build

an i have nowhere near enough funds for lineear slides, so maybe i should be lookin at these instead??? http://cgi.ebay.co.uk/x4pcs-SC20-Housing-ID20mm-Samic-Linear-Bearing-CNC_W0QQitemZ310160248362QQcmdZViewItemQQptZLH_Def aultDomain_3?hash=item4836fdce2a&_trksid=p3286.c0.m14

irving2008
06-09-2009, 01:46 AM
nice 1 irving

that kit is here
http://cgi.ebay.co.uk/3-AXIS-CNC-Router-or-Mill-Stepper-Motor-complete-kit_W0QQitemZ160359509079QQcmdZViewItemQQptZUK_BOI _Electrical_Components_Supplies_ET?hash=item25562b ec57&_trksid=p3286.c0.m14

i take it your die grinder isnt air driven

an i would have thought a fixed gantry would be an easier build

an i have nowhere near enough funds for lineear slides, so maybe i should be lookin at these instead??? http://cgi.ebay.co.uk/x4pcs-SC20-Housing-ID20mm-Samic-Linear-Bearing-CNC_W0QQitemZ310160248362QQcmdZViewItemQQptZLH_Def aultDomain_3?hash=item4836fdce2a&_trksid=p3286.c0.m14


I'd want to know a lot more about that kit before I bought it. He claims 2.5A drivers then says the motors are 3A, but why use 3A motors if they cant be driven fully.

No my die grinder isnt, although i do have one.

Fixed gantry can be easier to build but needs more space than a moving gantry design. Gantry fixed in X, moving in Y, table moving in X, fixed in Y is probably the easiest combination.


You can certainly use 20mm round rail but be aware of the flex you get over any distance. a lightweight maching for milling PCBs or cutting balsa wood for RC planes would certainly be fine on a 400 x 400 workspace but anything bigger you'd be better of with these 16mm open bearings (http://cgi.ebay.co.uk/x4pcs-SBR16-Housing-ID16mm-Samic-Linear-Bearing-CNC_W0QQitemZ220475691483) and fully supported rail