Cheapish CNC router kits.

Patrick Hood-Daniel is offering a CNC router kit for $405.00 (unassembled, not including shipping from Houston TX, motors, or drive electronics.)

[buildyourcnc.com]

The machine is mostly made from MDF and fasteners, and has a 2'x4'x?" working area.

This is the introductory pre-sale price. The post sale price is $550.

Patrick is a decent sort and his machine will probably make a great repstrap; it's good enough to make the kits he's selling.

In theory this should go in the "Stuff for Sale" forum, but he doesn't know I'm writing this up (yet). If this posting offends folk, I'll move it.

Sebastien

Truly wonderous.

You have just given me a whole bunch of ideas for bearings & slides. I guess obvious when you have seen it but not until.

cheers

aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.

While were at it, lets mentions these folks

[www.cadcamcadcam.com]

3 Axis servo system for $900. These motors are intended for power and have a fair bit of speed as well. Much beefier then required by the REPRAP, but still a servo system for not much money.

Hehe

A touch beyond my current means, interesting though nonetheless.

$900 dollars for what is a system using cheaper motors than steppers strikes me as a touch steep.

The gearing looks pants too, planetary or epicyclic gearing (If you have to have it) is much better. This is why it is chosen for top end precision servomotors.

There is a very good argument for over specifying your DC brushed motors and using PWM (which you would be using for servo control anyway) and reducing your gearing requirements. This also gives much better top speed results and lower mechanical losses. It all depends on where you want to take your positional feedback from.

cheers

aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.

Sebastien

I have scraped together enough cash to order up the parts I need to repair my drill press. (castings shattered irretrievably) so hopefully I can do some more playing with bearing trucks etc when the parts arrive.

In the mean time, thinking about the trucks Patrick was making up with aluminum angle do you think there is any mileage in RP'ing these as a triangular prism bar shape with fixing holes along the rear side, so they could be self tapped to whatever. Such a part could make the Rep strap or an equivalent a whole bunch simpler ??

cheers

aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.

Interesting website! Pretty good prices. BTW, his bearings are standard M8 skateboard bearings.

I had an interesting talk with a skateboard shop owner on Saturday when I picked up a handful of those bad boys. The cheap ones (~$1/each) are grease packed and last a few months on a skateboard. How that will translate out into service life on a CNC router is anybody's guess.

I asked if the more expensive bearings were dry and the shop owner said that he hadn't run into any skateboard bearings at any price that weren't grease packed. What that means is that eventually you will pound the grease out of them and they will wear out.

Yup, nothings forever.

Given the maltreatment my kids manage to dish out to whatever there current in thing is, I cannot honestly see lightweight CNC kit coming anywhere near the peak shock and G forces kids manage to dish out to Skateboards. 48 Kilos of juvenile dropping 0.5 to 1 meter complete with skateboard apres grind, is quite a high peak loading. Even distributed across that many bearings.

I wonder which give out first, Seals, Grease of the Hardened ball Surfaces they must chip given such punishment. ?????



aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.