round rails

[martin54]

Jazz I understand what you are saying but from the little I have seen during researching building a machine Profile rails are very expensive & this would be more likely to put me off trying to be honest. If you are lucky enough to have money then I suppose you may not think of them as being expensive but on the limited amount of money I have available it's just not really possible & at my age I would probably be dead before I could save up enough lol.
If I do manage to build a machine I'm not actually sure just how much use it would get or what sort of accuracy I would require. Yes I can think of one or two things I would like to do with it & I realise that once it is done I might be able to come up with other ways to use it but I still can't see it ever getting more than a few hours a month run time.

[wilfy]

Jazz I understand what you are saying but from the little I have seen during researching building a machine Profile rails are very expensive & this would be more likely to put me off trying to be honest. If you are lucky enough to have money then I suppose you may not think of them as being expensive but on the limited amount of money I have available it's just not really possible & at my age I would probably be dead before I could save up enough lol.
If I do manage to build a machine I'm not actually sure just how much use it would get or what sort of accuracy I would require. Yes I can think of one or two things I would like to do with it & I realise that once it is done I might be able to come up with other ways to use it but I still can't see it ever getting more than a few hours a month run time.

he's not saying to use profile rails or else.. but there is an inbetween which are known as supported rails... now they are still quite a big cost of the total machine, but through doing my own research i personally have decided not to scrimp on rails or screws..

having said that if you check out trickyCNC's thread you can see what can be achieved by not using supported rails and by using mdf to build the frame, i feel this may suit you somewhat better.

the reason i asked this question about the round rails was to clear some things up... the outcome is that my planned 20mm round rails wold be better replaced by 16mm supported rails and have less room for error at roughly the same cost

[JAZZCNC]

Jazz I understand what you are saying but from the little I have seen during researching building a machine Profile rails are very expensive & this would be more likely to put me off trying to be honest.

Yep quite agree but I never said profiled rails I said supported rails. Your new so probably didn't know that supported round rail is quite cheap when bought from china.

I've just been given prices for full set(3axis) of rails & bearings for a friend to build 700x700 cutting area machine and they cost $79 usd thats £49 plus shipping. Can't tell you accurately the shipping price because there were lots of other stuff on the quote but I reckon the shipping will be about the same has rails so for less than £100 you have accurate and relatively reliable hassle free rails.
By the time you have bought bearings,bolts,pipes,angle etc for what ever method you choose it will cost almost that much and I pretty much guarantee you won't be happy with the results and like I say high chance of still ending up buying the supported rails.

Hi Gerry

I mentioned you on another thread, where a member here was convinced MDF was too bendy and metal is the ONLY way to get accuracy . I made mine
from MDF torsion box/beam sections and was trying to explain that MDF can be made to not bend, and that you , - definately not a newbie - choose MDF to build your new machine.

The MDF vs Steel and accuracy wasn't the whole debate it was has much the cost and effort.

Gerry highlighted perfectly well just how much work needs to go into a wooden machine, Vacuum Laminating, epoxy resin, phenolic pads, etc non of it easy or cheap.! Then look at all the Work that goes into forming torsion box's. For Ger it's relatively easy has he has access to some very nice machinery and facility's along with probably very cheap source of wood compared to UK.!!. . . Most blokes in a shed don't and therefore the quality of build drops drasticly which it can't afford to with wooden skate board construction. This leads to a high failure rate and lost money most of which can't be recouped or reused on the next machine.

Gerry in all honesty now.!! If you had both options available IE full Access to machinery and resources would you build from Wood.?

Equally if you didn't have access to either equipment and had little to no experience using either wood or metal/Alu profile.! . . Say an office worker just looking for a DIY hobby in the back shed which of the two options would you say gave the best chance of success FIRST TIME of an accurate, reliable machine.?

As for rails ...

I agree that supported precision rails are the best, but a lot of people would be perfectly happy with the results from DIY supported pipe and skate bearing trucks, for example. or for a bit more, steel plate and CNCRP type trucks like CarveOne uses..

CNCRP type trucks cost more to build than buying supported round rail. The plate has to be good stuff can't be rubbish or it wears quickly and needs to be uniform in thickness else they bind. They are high maintenance regards keeping the plate free from chips,resin etc so need a wiper system in some cases.
I helped someone who started a build using this system with actual CNCRP (CNC router parts) components and it was nothing but hassle and high maintenance, constantly cleaning and chasing it with adjustments.
Swapped it out for Chinese round rail and hasn't touched it since and never give a days trouble and it cuts ply wood van linings all day long 6 days a week.

So all I'm saying is YES wood can work very well but it ain't easy and it isn't always cheaper.!!

[TrickyCNC]

So, to sum it up ...

....................................
So all I'm saying is YES wood can work very well but it ain't easy and it isn't always cheaper.!!

[TrickyCNC]

Something that you miss completely Jazz, is that for some people, the idea of building a CNC from scratch, and from bits and pieces lying around, and testing different methods etc. is just as much (sometimes more) enjoyable, than using the thing afterwards.

When it came to my Z , for instance, I had an old bed side that I had kept (would come in handy one day :) )


My Z works perfectly (cutting wood) , and is driven by allthread and a couple of standard nuts, with rails made from that bit of bed, and some skate bearings.

Also, some people want to cut steel, others are happy cutting foam - completely different design philosophy for both !

That's why I called my build "Scrap heap challenge" it's fun - and can be very accurate.