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  #1  
Old 03-15-2017, 11:03 PM
nevetsw18 nevetsw18 is offline
 
Join Date: Jul 2011
Location: T67
Posts: 79
Default Hobbyist CNC reviews?

In the spirit of adding another tool to the box, has anyone purchased or used a consumer grade CNC machine that they could recommend?

I'm considering the StepCraft (https://stepcraft.us/product-category/machines/) and an OX Metal (https://www.smw3d.com/ox-diy-cnc-kit/)

Thanks!
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  #2  
Old 03-15-2017, 11:48 PM
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DaleB DaleB is offline
 
Join Date: Sep 2012
Location: Omaha, NE (KMLE)
Posts: 1,639
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Oh, the fun you'll have.

Several years ago I bought a micRo M3 from the now-defunct LumenLabs. I got one of the last few out the door before they folded up their tent and faded off into the night. It's a leadscrew-driven machine that uses a flex shaft tool for the spindle. I've beaten the you-know-what out of it milling mostly ABS plastic (cases for ham radio kits) with the occasional wood, HDPE, aluminum and a fingernail or two. It's still ticking along like a Swiss watch, which is good since the parts are not available anywhere if it ever breaks. In theory I could make all the parts for it, but the labor and precision required is apparently what did the company in to begin with. Fortunately it seems to be nearly bulletproof. Here's what I have learned...

Buy the biggest machine you can, and if you run out of machine it will probably be the Z axis that you wish you had more of first. Right now I'm wishing I had a 4' x 8' Shopbot, but that's just because I'm doing some woodworking.

Don't buy a cheap POS driver board. Those 5-axis Chinese eBay specials? They don't even make good paperweights. A Geckodrive G540 is worth every penny you pay for it.

If you don't need to mill wood or metal, a 3D printer may be enough. I need the CNC machine for my kit business, but a 3D printer would get a lot more use for my own stuff if I had one.

A Dremel or Foredom/WeCheer flex shaft tool is OK for plastic, marginal for wood and barely adequate for aluminum. You will not regret going with a more powerful spindle motor. And you will need a speed control no matter what you choose.

I haven't tried any of the machines like the ones you're looking at. What I would be most interested in is the repeatability of the thing... if I move the tool to all four corners ten times, will it return to the exact same spot EVERY time? Within what tolerance? I see some crazy accuracy claimed on some machines, but the real question is how much mechanical slop and backlash is present, or will be after a few hours of use.

Wish I had more specific and current help to offer. I like the leadscrew drive like the Stepcraft, though I would ask them about what those leadscrews drive and how the backlash is taken out of the system. I haven't seen one of the belt drive machines up close. A leadscrew machine can have better motion resolution, a belt drive machine could move a lot faster. I wouldn't run away from either one of those, especially with a decent spindle.
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  #3  
Old 03-16-2017, 12:45 AM
larosta larosta is offline
 
Join Date: Dec 2010
Location: Redlands, CA
Posts: 111
Default Desktop CNC

Take a look at the machines from Shapeoko:
http://carbide3d.com/shapeoko/

The Shapeoko machines appear to be well made and have pretty good support:
https://shop.carbide3d.com/collections/machines

I have a "C beam" machine from parts from Openbuilds:
http://openbuilds.com/

It's OK but took a lot of work to pull together using other parts for the drives, software, controllers, etc.

If you want to to roll your own controllers and drives, Arturo Duncan at CNC4PC is a good resource and has pretty good prices:
https://cnc4pc.com/

MACH software and gecko stepper drivers are highly regarded:

http://www.machsupport.com/

http://www.geckodrive.com/



A precision collet and nut will reduce some frustration.
Precise bits:
http://www.precisebits.com/gateways/...tsNutsHome.htm

A Dewalt DWP611 router is pretty close to a spindle and a good $ value.

A big step up from the desktop/benchtop machines is from Tormach. Not a full up CNC machining center but pretty capable and well supported.
https://www.tormach.com/



- larosta
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  #4  
Old 03-16-2017, 07:34 AM
slngsht slngsht is offline
 
Join Date: May 2016
Location: Purcellville, VA
Posts: 147
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These router based machines are better suited for doing CNC plasma than actual machine work.

many years ago I built a couple. I did one large frame one for a friend who used it for glass inlayed wood doors, and a smaller one for myself for doing CNC plasma work. They're great for wood, marginal for any real aluminum work. forget about harder metals.

*disclaimer: I have not played with any of the specific machines listed above*

this was my own machine - you can still see placeholder for router, but it was used for plasma. The main thing i need to add to it is a suction system for holding the piece in place.

https://www.youtube.com/watch?v=5CenNU6Z8jU
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  #5  
Old 03-16-2017, 09:55 AM
xavierm xavierm is offline
 
Join Date: Aug 2005
Location: Los Angeles, CA
Posts: 423
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In addition to the others that were listed -

Platform CNC - http://www.grunblau.com/PlatformCNC.html

Mostly Printed CNC (MPCNC) - https://www.vicious1.com/assembly/

Shapeoko - http://carbide3d.com/shapeoko/

Kronos CNC - http://www.kronosrobotics.com/krmx02/


I started building a Kronos but ended up buying a Platform CNC kit. I'm thinking of building an MPCNC for my nephew's school.

There are tons of DYI ones. If you know someone with a CNC, have them cut the parts out.
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  #6  
Old 03-19-2017, 02:55 PM
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n82rb n82rb is offline
 
Join Date: Jan 2007
Location: fort myers fl
Posts: 602
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We have two multicams with vac tables in the shop. Great tools but probably a bit pricy for what you want.

Bob burns
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  #7  
Old 03-19-2017, 04:07 PM
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rzbill rzbill is offline
 
Join Date: Nov 2005
Location: Asheville, NC
Posts: 2,400
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A little drift but still flatbed CNC related.

A few years ago, I was over in Germany visiting a custom (very) high speed robotics manufacturer for plastics packaging. They showed us a huge granite surface plate upon which they laid up carbon/honeycomb sandwiches to make big square 'boards'. Afterwards the boards were CNC water jetted into shapes that snapped together like corrugated boxes to which they added a bit of a "flox like" glue in the corners to make very rigid and lightweight carbon 'arms" for their robotics. These things really smoked for speed which is important for a commodity market like packaging.

Combination of very simple methods to make some cool stuff.
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  #8  
Old 03-20-2017, 05:36 AM
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Lenny Iszak Lenny Iszak is offline
 
Join Date: Sep 2008
Location: Palm City, FL
Posts: 199
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I built a CNC router using a K2 frame and Probotix controller and motors and Mach3 software. It works great for foam, plastics, wood and very light aluminum work.
Routers are not rigid enough for metal work. If you want a serious tool, look into converting a milling machine.
This thing easily extended my RV-10 build by at least a couple of years. First the build, then all the learning and fiddling, then you feel like you can make everything yourself
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  #9  
Old 03-20-2017, 11:49 PM
nevetsw18 nevetsw18 is offline
 
Join Date: Jul 2011
Location: T67
Posts: 79
Default Thanks for the Responses!

Many thanks for all the responses! I've discovered new rabbit holes to explore and research.

My primary desire for a cnc comes from the the thinking that I'd much rather layout and measure in a cad program and let it cut .02 sheet rather than measuring and cutting with snips.
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