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Buying a CNC machine - advice needed!
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Author:  Dave Fifield [ Tue Mar 08, 2011 3:06 pm ]
Post subject:  Buying a CNC machine - advice needed!
Hi Folks,

I've been reading all the CNC forums/archives I can find (including this one, which seems to be full of excellent information!) for a few weeks now and I'm about ready to pull the trigger on a new machine. There are a lot of choices out there. I think I've read enough to know that what I want to get is a turnkey system that is more than adequate for lutherie (I will be doing other larger things on it as well), is well made, well supported, and comes from a reputable company (so I won't lose my deposit!). I wanted to get your input on my choice before I buy, since it's a LOT of $$$ and I want to make sure I'm not about to make a mistake!!

My #1 choice is.....ta-da......a K2 KG-5050EB 4'x4' machine with the 4HP spindle on an 8" Z-axis mount.

Quality-wise, it looks like this is one of the best. Value for money-wise, it seems about in the middle of the pack. Features-wise, it seems more than adequate for lutherie/signwork/soft aluminum panel work. The 4HP spindle comes with an ER25 collet which supports up to 5/8" shafted tools (correct?). What do you think? Does anyone have any input for me? Is there a "better" choice that I should be looking at?

The only "issue" I can possibly see right now is that this machine uses two of the axis controllers for the x-axis (two ball-screws) so there's no way to add a 4th (indexing) axis to it later. Right now I don't really see this as a major problem....

Thanks for your help!

Dave F.
Author:  Andy Birko [ Tue Mar 08, 2011 3:58 pm ]
Post subject:  Re: Buying a CNC machine - advice needed!
If you were looking for a smaller machine I'd probably be able to help more as I'm in the process right now myself (perhaps you saw my thread?). I looked at K2 for a while and they were my front runner but in terms of value they just didn't make the cut.

Adding a 4th axis (or I guess, a 5th) shouldn't be much of a problem at all. Assuming you'll be using mach, you can simply add a parallel port to your computer and add additional drivers. It would be a little cheaper too as I don't think you really need servos for a 4th axis (5th) as a stepper would do fine.

I just pulled the trigger on an almost turn key system from Xzero (24x36) . Haven't gotten it yet though so we'll see how it all turns out. Just for comparison, they've got a 40x60" machine for $3825 and a 54x60 for $4500 - frame only - roughly half the cost of the K2 frame. But, some assembly is required! :D

If you're willing to wait a few weeks, I can tell you how the full experience went.
Author:  Dave Fifield [ Tue Mar 08, 2011 4:53 pm ]
Post subject:  Re: Buying a CNC machine - advice needed!
Hi Andy,

Thanks for your reply. Yes, I've been following your path to owning your own machine! Your thread/postings have been helpful. I looked at the xzero stuff, but I was a bit mystified by thier website....it seems more like a DIY forum than a vendor with stuff to sell. Did I miss something? I decided I needed more of a degree of certainty and liked the K2 approach to doing business more. Besides, K2 are only a few hundred miles south of here, so I could drive down and bang on the door if I need to!

I did a comparison of the K2 to a Shopbot PRS Alpha with almost the same specs, and the K2 comes out many $$ less overall, for a system that seems much more robust and better made.

I'm still several weeks away from ordering. I have to do some spring cleaning, juggle some stuff around, and make space in my workshop for the new machine first. Should take 3-4 weeks from ordering to delivery according to Mike at K2. So, I'll keep an eye on your progress - keep posting regularly!

Cheers for now,
Dave F.
Author:  Andy Birko [ Tue Mar 08, 2011 8:42 pm ]
Post subject:  Re: Buying a CNC machine - advice needed!
Dave Fifield wrote:
xzero stuff, but I was a bit mystified by thier website....it seems more like a DIY forum than a vendor with stuff to sell. Did I miss something?


No, not really. He's not providing quite turn key products just yet. The K2's do look like very good machines though, I'll tell you that.

This might be of some help - I went to microcenter the other day and picked up a refurb Dell computer with a 90 day warranty for $150. Built in parallel port, pentium 4, 40g hard disk and a clean install of XP pro. No muss, no fuss. I installed Mach and the system tester ran perfectly and said it had excellent control of the machine.

You might be able to find used for less but there is some comfort in buying the refurb unit (kind of like there's comfort in buying a turn key CNC!).

I'll post once I get the thing assembled and stuff. There might be a slight delay in my spindle coming in so I might have to be content with pen plotting or something.
Author:  pfour414 [ Tue Mar 08, 2011 10:23 pm ]
Post subject:  Re: Buying a CNC machine - advice needed!
Dave,
If you live within driving distance, I would ask them if they have a model you want to order done so you can see it in person. For the amount of money you are going to invest, I would take a day trip down there and take a look. I owned a ezcnc router(very helpfull owner) and a romaxx before I found my current setup. The problem with both of those routers was flex in the z axis. The k2 looks similar in construction to the ezcnc I owned. If you can go down and see it, lower (or have them lower) the z down to cutting depth and gently push on the spindle to see if it flexes. This does not mean you can't cut stuff out with it, but it does mean you will have problem with chatter. From what I could see, this is 12,000 dollar plus machine, and for that kind of money, you have alot of things available to you. The positives of k2 are they seem to have good resale value. I resold my romaxx(got it on sale for 4000 or so) for about what I paid for it, but the price you are going to pay puts you in the realm of decent used cnc mills with todays economy. If you have any other questions, please ask.

Evan
Author:  Mike Kroening [ Wed Mar 09, 2011 10:10 am ]
Post subject:  Re: Buying a CNC machine - advice needed!
Dave Fifield wrote:
>snip<

The only "issue" I can possibly see right now is that this machine uses two of the axis controllers for the x-axis (two ball-screws) so there's no way to add a 4th (indexing) axis to it later. Right now I don't really see this as a major problem....

Thanks for your help!

Dave F.
Hi Dave,

As was stated earlier, adding another parallel port, breakout board, and step driver using a stepper will work for your 4th axis A , indexer. Currently, the way they setup using the 4th axis is they are slaving a stepper or servo for the X axis. This in turn uses the A axis. By adding the the extra parts, you will be able to shift the slave to the B or C axis and then use the A axis for the 4th axis. This will allow you to have the functions of the DRO for A in Mach3 or EMC2 which ever you are using as your controller software for your indexer. Have already done this on a friends machine with great success.

Just an FYI. :)

Mike
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