Lowcost capable CNC - Make vs Buy?

[BDH]

Many thanks for the quick reply Jazz, I already have 2 milling machines but neither would be suitable for CNC. Looks like I'll have to look for another!
Brian

[Clive S]

Many thanks for the quick reply Jazz, I already have 2 milling machines but neither would be suitable for CNC. Looks like I'll have to look for another!
Brian

Why? what would the problem be.

[JAZZCNC]

Many thanks for the quick reply Jazz, I already have 2 milling machines but neither would be suitable for CNC. Looks like I'll have to look for another!
Brian

Unless they are weak flimsy things then I'd be surprised if they couldn't be converted to CNC and have probably been done before. What machines are they.?

[BDH]

The mill that would be most suitable for converting is a Graham Engineering one with a round vertical column but I thought that I would need to replace the leadscrews & nuts etc. As a manual machine with DRO it is very useful.
The other machine is a Tom Senior Major Mk2 ELT in horizontal mode.
If anyone has any ideas about how one of these could be CNC'd then I'd be most interested.
Brian

[Kitwn]

Andrew,
As my wife, an accountant, has often said, you have the triangle of Time, Quality and Cost. Decide on the level of any one and the other two are inversely proportional.

[Doddy]

Andrew,
As my wife, an accountant, has often said, you have the triangle of Time, Quality and Cost. Decide on the level of any one and the other two are inversely proportional.

Wow! Mine just nags.

[Doddy]

As of 9:30 - I guess your spreadsheet will be live and therefore subject to change as you respond to comments?

I note the comment re. suppliers, but buying from China - usually the best option - figure on getting stung for import duty especially for big/heavy/shiny items like these.

Those particular stepper drivers need DC so, depending on the transformer selection you might be cutting it fine (by £20 or so) for the rectifier & caps. Unless you've found a suitable toroidal transformer for £50. Hmmm, 36V?, and those stepper drivers?, you'll be compromising the potential performance - but that's a different question to the one you've asked here.

You've completely over-egged your CY cable costs - but that's no bad thing. You can cover the costs of all cabinet wiring and marking with the budget you have.

Oh, What about a cabinet to hold the control gear (+£75)? E-Stop ("oh shit!") button, miscellaneous switches, relays and bases, add £100 (or take that off your budget for the PC). Connectors etc, into the cabinet - add another £60, unless you're hard-wiring everything (I'd not recommend this option!).

You'll need a 24V and 5V supply also. Think if you're using DIN rail and terminals in the cabinet.

[JAZZCNC]

Ok well, your high in some areas and missing stuff in others but it will all balance out to be around that figure if you shop a little better.
Though be honest prices are changing all the time with the world being in meltdown so I'm going to revise my estimate and say £2500 might be a more realisitc figure with the spec your at now by the time it's finished.
However you'll have a machine that is worth double that amount and will blow the likes of I2R, Felder, Axiom out the water.

PC cost is way to high, £75 will get you a PC to run this no problem.

Aluminium can be sourced cheaper is you try local metal suppliers. I pay roughly 30% less than Ali warehouse ask, then you save carriage on top if you collect.
If you have any local engineering place it's worth calling in and asking about there Scrap bins, sometimes they what they call little pieces of scrap we call gantry sides.!

Just little things and savings like this all add up. 5 for less than your 3.

https://www.ebay.co.uk/itm/5x-Induct....c100010.m2109

Now you have gone with the Uc400 but this means you'll need a breakout board which you haven't accounted for. This is why I mentioned the AXBB rather than uc300 or 400. It saves you money and as everything you need.

The drives you stated like Doddy says are 50Vdc max so you can't use a 36V toroidal as you'll blow them up. Remember the 10% safety margin.
This is another reason why it's worth paying an extra $20 for the bigger drives/motors. You also don't need the Capacitors and bridge rectifier so your costs for PSU are just the toroidal transformer.

Regards customs and buying from China. Try to buy everything from same place, for instance, Fred at BST can supply everything but the drives/motors, as it will save you money on shipping.
I would build the Z-axis my self as it would be cheaper and better.

Customs will charge VAT on the (**)invoice amount declared(**), there will also be an admin fee of around £15-20 from the shipping agent.
Ask the supplier to keep the (**) low.

With a little careful buying, you'll get the costs down more but you have missed a few reasonably pricey things, like an electrical cabinet but like I say it will probably balance out with things you have overpriced.

[Andrewg]

Thanks Doddy and JazzCNC

Updated sheet to reflect your suggestions plus factored in 25% (VAT plus import fees) increase on imported items.....And indeed we seem to be hovering around £2,500 now, though with no attempt to push back much at this stage and I agree it is a well spec-ed machine.. I posted the link to GSheet as I couldn't work out how to post a table, but now it is a live tally of information accumulated in this thread.

Advice on sourcing from China noted and Fred at BST Motion had come up often enough here to know he is the go-to guy. When the time is right I will bother him for a full quote.(and hopefully trim the budget)

I have least understanding of the Electrics/Electronics (as you can tell from my first attempt at parts), but assume if I have sufficient budget, spec good components and take my time and the advice of this forum I will get through OK. Having sense checked the budget (growing but not out of control...yet), I am now focused again on generating a mechanical design I am confident I can make.....and as Jazz indicated it is all about getting the details right! Fusion 360 is your friend when you can get it to do your bidding! I've used it a lot for furniture design but importing parts and positioning and joining is new so on a bit of a leaning curve there.

So Jazz..what does that orange beauty look like from behind?

[JAZZCNC]

So Jazz..what does that orange beauty look like from behind?

Here you go watch this.