What 'decent' Milling machine?

[Chaz]

I think quite a bit technically is. Denford have been pretty good at providing documentation and so forth. So, in principle, you can probably wire a breakout board to those drives, if they're working.

However, the electronics are often pretty old and basic. Most of the conversions I've seen seem to replace everything, except perhaps the motors and maybe the transformer.

Personally, I'd budget for replacing all of the electronics.

Thanks, including motors?

[Jess]

I think if the motors are working (at a guess, they probably are), then I think they'll be just fine.

I'd emphasise the 'budget for' though; worst case, you might have to fork out, but obviously, every penny you don't fork out, is a penny you can spend on your vices (and clamps, endmills etc.,)

The problem with the stock electronics is that it's basic (eg., the drivers are probably only half-stepping etc.,) and conservative (voltages are lower than necessary etc.,). So, it's not going to run as smoothly or as quickly as it otherwise could.

Having said that, it's also quality stuff; so it's often worth flogging the bits you don't need on eBay, especially if they're working - last I looked the motion control and driver boards seemed to fetch a decent price.

On my very small Denford, I've only replaced the stepper drives and DC supply (the original was part of the original drive board). I've been able to keep the door latches, e-stop, various relays, spindle control board, transformer etc., The main reason I replaced the drive board was actually that it was a real pain to interface to. After a couple of months of 'is it the drive or is it the BOB or is it my wiring' hassle, I broke down, bought a Gecko and had the machine working (with LinuxCNC) in a couple of days.

[Chaz]

I think if the motors are working (at a guess, they probably are), then I think they'll be just fine.

I'd emphasise the 'budget for' though; worst case, you might have to fork out, but obviously, every penny you don't fork out, is a penny you can spend on your vices (and clamps, endmills etc.,)

The problem with the stock electronics is that it's basic (eg., the drivers are probably only half-stepping etc.,) and conservative (voltages are lower than necessary etc.,). So, it's not going to run as smoothly or as quickly as it otherwise could.

Having said that, it's also quality stuff; so it's often worth flogging the bits you don't need on eBay, especially if they're working - last I looked the motion control and driver boards seemed to fetch a decent price.

On my very small Denford, I've only replaced the stepper drives and DC supply (the original was part of the original drive board). I've been able to keep the door latches, e-stop, various relays, spindle control board, transformer etc., The main reason I replaced the drive board was actually that it was a real pain to interface to. After a couple of months of 'is it the drive or is it the BOB or is it my wiring' hassle, I broke down, bought a Gecko and had the machine working (with LinuxCNC) in a couple of days.

Thanks. Sounds reasonable. Does anyone have quick numbers for the cost to do this? Considering there is a converted (Mach3) Triac on Ebay for £3250, how much cheaper should I get this to make it worth while?

[Jess]

Someone might have better numbers if they look for the actual specifications/cheaper suppliers/use a slightly larger envelope for calculations, but I'd guess you can probably easily spend £500-£800 converting one depending on the parts you use even if you're 'just' replacing the stepper drives and you've got a few of the things you'll need.

These aren't recommendations as I've not personally used these - I'm just using the prices as a guide:

Geckodrive G213V drives (80V, 7A digital step drives) are $166 each, and an Ethernet Smoothstepper is $180. So, three drives and motion control board run to $678; once you get it shipped and Customs and Excise take their chunk of flesh for Duty and VAT, you might as well assume that that figure is already in GBP. Alternatively, you can get 80V, 5.6A drivers from Zapp Automation (a UK supplier) for £84 each, which with the smoothstepper and shipping sounds like it comes out to about £450.

On top of that, you might need breakout boards and you'll definitely need various cables, wires, mounting brackets, a mounting plate for all the gear and many, many cups of tea. So, yes, it's very easy to spend more than you meant to getting it working, so it's definitely worth doing some proper working out.

It gets rather difficult comparing the value of Triac models; one might have an automatic tool changer, another might be fully enclosed, another might be 13 years newer etc., If we're comparing against the one on eBay with the lurid guards, then that seems to have a coolant system installed. These are all potentially useful, but their value to you will vary depending on what you're doing (and some are easier to retrofit than others!)

What power supply does a Triac mill require BTW? If it's more than you can get from a standard 13A mains plug, you could get a nasty shock in the form of a bill for installing one of those circular sockets (unless you're lucky enough to already have the right one).