MT3 to ISO30 conversion on a chinese mill

So this is more like very entry level question, but I'm looking into getting one of those chinese 230kgsh milling machines (model WMD30V) and converting it to linuxcnc. EU seller gives this for around 3000eur while direct from china I could get same quote for 1800. Only difference is that it's a MT3 vs ISO30. As i have been looking around everyone seems to favor ISO30 to MT3 or R8. So before I'm getting bunch of tools for one or the other I got curious.

I have not seen anybody thinking or doing it, but would it be a thing to get MT3 to be machined to ISO30 angle or thoughts on why it would not be a good idea.

Why don't you ask of they can do an ISO30? They are usually pretty flexible.

Just be sure all the VAT and duties are allowed for when comparing prices..

I hoped for the same, and I already asked from chinese supplier and they said that MT3 is only possible. Almost all other specs are identical for EU selles including how it looks like.

And yes - VAT is included. it's 2500 and 1500 respectively without VAT. Chinese could have few % of import tax additionally, but thats fine.

I have a couple of MT3 machines and use ER32 or ER25 collets. You can build a tool release with a stack of bellevue washers and an air ram or butterfly air wrench.
See if they can include a bunch of ER holders...

Yes, this is one thing I'm afraid of - hard removal tools from taper. Is this the only reason for ISO30? I already looked at few systems to release tool better and I'm familiar with your recommended solutions. I understood that ISO30 would sit better and would have less chatter. Or this is not a problem with such a small mill? They don't offer collet set and I have been eyeballing collet sets from aliexpress so this is definately one of the tools I'm getting for the mill as soon as taper type will be locked on.I have included their catalogue of the mill and possible accessories that they provide.

EDIT: added external link. It seems attaching is broken in here. It says 1.6MB is image or file size limit, but would not allow to add even under 1MB file. Link to catalogue picture 

Couple thoughts:

• I'd prefer whichever shank is shorter - you run out of Z-clearance to insert/remove tools quickly on small mills
• 3MT has no possibility of adding an ATC later on, whereas ISO30 is interchangable (taper-wise) with BT30.
  • If the spindle is ground for the short straight section at the end of the tool holder (true ISO30), you can still get a BT30 holder with a pull stud in there.
  • As Rod pointed out, you're some belleville springs and an actuator away from a power draw bar
• If this is going to be a strictly manual mill and used 3MT tooling is cheap and available in your location, that's compelling. Otherwise I'd pony up the extra money for the ISO30.

So it seems it will come to the same thing as I have been reading for last 1.5 months-  if you really can , get iso30 , otherwise mt3. This will be closed loop nema mill with linuxcnc with manual rotarys so it will be possible to run it manual or automatic mode. Manual to actually learn milling and linuxcnc so not to waste time on boring and teadious moves like surfacecutting etc. ATC seems like a dream, but sounds expensive. Especially shelving 1000eur just to have this taper. MT3 will be aliexpres/china since it will not be cheap locally. ISO30 for sure will be considerably expensive locally. ISO30 Will be a little more expensive to get from ali as I have been researching. I do have mini lathe with mt3 so it would not be totally waste of tooling, but trying to make a reasonable decisions since it seems like a big splitting of paths of what tools-equipment to invest on.

Another consideration is service or parts.  If you go with the EU-sourced mill you may be able to obtain replacement parts easier than with the direct-from-China option - that might be worth the price different to you.

Regarding the tool changer... ISO30 has a steeper taper in order to self-release, that's the primary feature behind all the related tapers (CAT40, BT30, etc.).

If you do go with 3MT, it's quite possible to still build an ATC based on the Tormach TTS-style system.  You simply put a 3/4" 3MT collet in the spindle and the TTS holders (with 3/4" shanks) register against the spindle nose.

Upsides:

• repeatable Z-length
• compatible with ATC
• fast tool changes
• off-line tool length measurement
• comparably low-cost tool holders
• Very short shank (clearance during tool changes) compared to ISO30 or 3MT
• Easy to self-manufacture TTS holders (or even just flanges for 3/4 shank tools)

Downsides

• 3MT tendency to stick in the spindle and not release the TTS holder as reliably as the typical R8 taper.
• loss of rigidity using TTS vs direct tool in 3MT collet
• higher likelihood of tool pull-out under heavy cuts compared to direct 3MT or ISO30
• yet another tooling system to manage

Possibly #1 could be solved by an over-sized drawbar actuator that has enough 'grunt' to force the 3MT collet down.  The remainder are, of course personal cost-benefit decisions only you can make.