Advice on buying Taig mill for use with Linuxcnc

I'm a Linux software developer. Have been for over 20 years. Over 30 developing for Unix so I'm comfortable with Linux.

I decided I wanted to upgrade my existing Seig X2 manual mill. I pondered converting but a) it's a project and I have too many other 1/2 to 3/4 stalled projects already b) I want to spend the limited time learning CNC c) researching, the Taig mills seem to hold their value on the used market.

So I was looking to get a Taig mill.

I like the idea of a package deal.

I've found the following:
- Deepgroove1: www.deepgroove1.com/
- Soigeneris www.soigeneris.com/taig-2019-cnc-mill-kit

but they are both selling systems intended to be used with Mach3. There isn't unfortunately much transparency regarding the manufacturer of the motors.

Deepgroove uses the Gecko G540. Soigeneris has their own STDR-4C "controller" which seems to be a box containing a Gecko G540 plus an Ethernet smoothstepper. I'm very familiar with the preempt_rt Linux kernels and a SmoothStepper would seem somewhat redundant with a real-time kernel.

Here are the questions I have:

1) Does anyone know of anyone who sells a package known to work well with Linuxcnc? Or what components would you recommend and from whom? The only machine I have in my shop is a laptop running Windows 7 (32bit - required for old electronics interfacing) so I'm probably looking at building a new PC for this system so I can get something with a parallel port. I would like to know what brand and rates of steppers I'm buying.

2) What is peoples view on the leadscrew (2019) vs ballscrew (5019) versions of the Taig? Deepgroove claimed backlash on the 2019CR (leadscrew) is 0.0001" and on the 5019CR (ballscrew) it's zero. Do these match others experiences. 0.0001" seems too good to believe and would seem to undermine the existence of the more expensive ballscrew version.

3) What is peoples view on open vs closed loop? I've read threads about missed steps etc with the open loop.

4) I'd like to get a 4th axis right away (rotary table plus removable chuck). Does anyone have a recommendation on a good unit for the Taig/Linuxcrc?. Deepgroove sells this : Soigeneris sells something based on the Sherline rotary table (with a tailstock) for $459.00 but has no pics but I imagine it's something like this . I also seen some cheap ($150-200) belt driven types on eBay. Mostly direct Chinese sellers so the quality and consistency can be variable at best.

The deepgroove one looks good, I'd take the backlash with a pinch of salt, but I'd opt for the ballscrew version as the backlash with more than likely be consistent over a longer length of time.

Intel NUC's seem popular, tho you would have to opt for a Mesa 7i92 mesaus.com/index.php?route=product/produ...ath=66&product_id=98
that will work with your G540, there's a few threads regarding that combo on the forum. Plus you get an extra 17 I/O pins with the Mesa card.
I have a ASRock J3355B-ITX www.newegg.com/global/au-en/Product/Prod...Item=N82E16813157726 that I use with a Mesa 7I92, I threw in a second PCIe Lan card for network connectivity.
I can't say I've noticed missed steps on my machine,either with Mach 3 using LPT, Machinekit on a BBB using PRUs or Linuxcnc. This machine is a BF20-L with 1605 ballscrew and 540oz steppers, a lot more metal than the Taig.

Maybe if you go with the deepgroove 4th axis they maybe able to do you a deal, if you're lucky.

The reason I'm mentioning the 7i92 is that I can't see ethernet going the way of the dinosaur for a while yet. So if your computer goes belly up find a replacement with LAN is going to be easier than a Parallel Port. Plus the Mesa card takes care of the generation of step & direction.

Anyways that's just my opinion...Basically it will come down to how much you want to spend.

I went down this road already (also as someone who has been developing software for 30 years (in Windows), running web servers under Linux for 20). I ended up getting a Taig Ballscrew CNC ready machine. Purchased steppers myself (automation direct, I think), purchased a Gecko G540 directly from Gecko, and built an Atom D520 MiniItx motherboard (wanted simple parallel port connection). This was all done a few years back. Worked fine, but the Atom performance was lagging (OpenGL display did not keep up when milling).

I upgraded recently (just this week) to using an i5 motherboard with SSD, and ended up using the Mesa 5i25 card + 7i76 daughterboard. Much better performance! I used Linux Mint and the RT kernel following BigJohnT's website.