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Dangle_kt
25-10-2016, 04:54 PM
Hi All,

I have been merrily getting my fill regarding all things CNC, and the fact that these incredible machines can be ran by hobbyists in their garage - I'd always envisaged an engineering degree and 3 phase as a bear minimum!

I am in no way qualified, am an office monkey but am a keen motorcyclist and built my own locost "kit" car a few years back, so I'm not completely ignorant, but do have loads to learn.

After much reading via google, I stumbled across this treasure trove of a forum, so I have registered.

I would love a Tormach CNC Mill, but having done the maths on the $ to and import duty/VAT that seems a long way off happening - it would already have been eye watering even if the pound was as strong as it was a few years back, so have been trying to find suitable 2nd hand hobby machines that are accessible to a novice in terms of software and setup whilst having the ability to grow with my skills/ambitions.

I aim to make motorcycle parts from alu mostly, but would also love to be able to build the parts from steel for a largish cnc router (for woodwork able to take large plywood sheets ideally) - though that is by no means a deal breaker.

I have seen a nice Denford Novamill, but I think these use proprietary software which is hard to convert over to more modern packages - I read one conversion thread with wiring diagrams that blew my mind - I'd kill myself even attempting that with anything plugged into the mains!

In terms of requirements, I'd love to sense check them with the collective brains on here:


domestic electric
mach3 ready or similar (plug and play - no conversions etc.)
solid, reliable machine (so probably not one of the cheap chinese machines I am seeing on ebay?)
A common choice so I can benefit from the widest collective experience


So, after reading my intro, and my requirements, can anyone offer more requirements I have missed, give me a helpful steer towards suitable machines and a rough idea on budget to get up and running?

Thanks in advance!

m_c
26-10-2016, 12:32 AM
Retrofitting a machine isn't that bad, but it does help if you have a reasonable understanding of electrics.
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Novamill's are well built machines, but they are a bit limited in terms of work area. Especially height between the table and spindle, more so if they're fitted with a Coventry Quick Change system. A common mod is to fit a raising block between the column and base to increase height. They are a reasonably straight forward machine to retrofit, as unless they have an ATC, the electrics are pretty basic for a CNC.
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A Denford Triac, is the next size machine up from a Novamill, and is a far more capable mill, however it depends on what size of parts you'd like to machine, as to what would be more capable.
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Outwith Denfords, but staying with small mill type machines, there are a couple Chinese import options (Sieg KX machines & Syil machines). Other option is a router style machine, but to handle aluminium regularly, they have to be well built. Zapp Automation have started doing kits, or you're looking at building your own (or paying someone to build one for you).

Dangle_kt
26-10-2016, 11:48 AM
Thanks MC, that is really helpful.

I have enough on a learning curve regarding using the machine without having to build one first, so I am going to go with the fully sorted route. I have had a look for the triac based on your message and have found one on ebay for 3,500.00 with no tooling, but converted to mach3 (though needs a licence key)

I ideally want a mill, as some of the parts I'd like to make are a little more complex than 2d - and whilst I'm sure it could be done of a router, if I'm spending the money I may as well get the right tool for the job.

m_c
27-10-2016, 12:51 AM
That Triac is overpriced. For that price, I'd want a newer one with a BT30 spindle, 8 position tool changer, built in coolant, and lots of tooling included, along with details of how it's been retrofitted to run Mach.
Similarly spec'ed non-modified Triacs normally go for under 2000 on eBay auctions, and a no-detail retrofit adds no value to the machine. It may even de-value it, depending on what's been altered.
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Provided the seller is selling it with the Coventry Quick Change chuck still installed, new holders are in the region of 80 each, so tooling cost can quickly add up. It is a pretty good quick change system though.
One thing to be wary of, is Triacs came with 3 different spindle tapers. Earlier ATC models came with a BT35 spindle, later ATC BT30, and then non-ATC ones might of came with either of those, or even an R8 spindle. BT35 tooling is pretty hard to get a hold of, as it's now a rarely used size.
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Routers are not limited to 2D. A well built one will handle 3D work just as well, if not better than a mill, it's just they usually run far higher speed spindles, which means you have to run smaller cutters. For aluminium, routers can often be a better option if you're doing a lot of finer details where smaller cutter sizes are needed.
For example some basic figures from a speed&feeds calculator, gives a 6mm HSS endmill a recommended spindle speed of over 11'000RPM in 6000 series aluminium. A 6mm carbide endmill is over 20'000RPM.
Obviously those spindle speeds are dependant on the machine being able to move fast enough to maintain a meaningful depth of cut.

njhussey
27-10-2016, 03:25 PM
Have you seen Dave's very well built router? Here? (http://www.mycncuk.com/threads/10298-Mill-Router-For-Sale?p=84583#post84583) It will cut aluminium all day long and do 3D work and is in your budget.