Ok, you can guess the answer, because I wouldn't be writing here if I hadn’t concluded ‘make’ remained a compelling option (and wanted your help!). But I hope laying out some facts and reasoning will help others who come here with this question. And those who know better can correct/encourage me.

Since the arrival of cheap motion control systems gave birth to Home CNC, huge ingenuity has gone in to replicate the key expensive mechanical functions- linear motion and positioning. The standard solutions of profile rails and ballscrews were too expensive hence draw slides, bike chains, skate wheels, timing belts and V-slot. These have added to the part count and complexity of design but have (for some) found a sweet spot of performance and price that has attracted a lot more makers .

So in the maker ‘design around the problem’ corner we have people like Open Builds and Carbide 3D who offer a kit of parts based on skate bearing on V slot extrusion with timing belts or leadscrews. Today a Workbee or Shapeoko is available as a kit for around £1,400

To me this is a base line - For £1,400 I can be up and running in a fairly short time with plenty of support and a community to help me through the learning process. Granted the machine will have significant weaknesses, but at least I am cutting and learning.

However the continued superiority of the profile rail is evident in the multiple upgrades of these machines, resulting in the slightly bizarre solution of V-slot extrusion used as a base to bolt linear rails. Carbide 3D now offers a linear rails and lead screw or ballscrew upgrade for the critical Z axis. QED.

Meanwhile the increase demand for cnc systems has reduced the costs for key components like Hiwin profile rails and spawned cheaper copies. Add sites like Aliexpress and Banggood that allow access to the Chinese supply chain and the DIY builder can now use the correct parts, just of lower quality.

For some time it bothered me that few manufacturers seemed to be exploiting this route. After all the Chinese 3040 and 6090 machine that flood ebay are still mainly using unsupported round rails(Good enough for the market they target I guess?) The better Chinese makers like Omni CNC do offer linear rails and ball screws in the 3040, 6090 sizes but don’t have a UK distributor. Another Chinese maker, Quick CNC supplies larger machines (6090 and bigger) which are available locally. Their smallest 6090 is marketed as the Laguna IQ in the States, and is available in the UK as the Itech K6090T for £5,400. The suspicion is that ti would be mechanically good but electrically more suspect.

More recently I2R launched a new range of budget machines with their smallest 600x600 cnc available in the UK for less than £4k inc through Axiom in the US and StoneyCNC in the UK and sports linear rails and ballscrews. Felder, a quality woodworking machines brand have recently entered the budget end of the market with the badged Hammer 47.82 (around £6-7k I believe), though interestingly with leadscrew not ballscrews.So the market is getting more competitive and crowded.

So to buy a ‘semi serious’ home machine, I am looking at £4k minimum and probably £5-6k. This remains a big jump from the £1,400 Workbee. It seems therefore there remains a sweet spot for DIY solutions if by smart sourcing and support from people on forums like this, I can design and build a machine in a reasonably short time for around £2k that exactly meets my needs (and works!).

I should of course acknowledge that for some the journey is the point, and I do feel the pull to test myself by building my own, but I am trying to make a more rational calculation. Many of the builds described here are epic and must have left the builder forever changed (and better for it one hopes) but a cold calculation of time spent and opportunity missed (assuming you want the machine to make things) would put the true cost of the machine far in excess of the £10k for a decent industrial no compromise machine!

I started writing this to convince me to stop reading this forum and dreaming of building...but it seams to have backfired. So I will now try and distill what I have learnt here and elsewhere into a plan of action.