round rails

[JAZZCNC]

Also, depending on budget, and how much "DIY" you want to do, there are lots of other home made options, like angle and skate bearings, or steel tube, or steel plate and bearing tucks etc. etc.

With all due respect but in my experience thru helping others it 90% of the time leads back to the same thing.? Wasted time and money.!!
If they do get them working they are high maintenance and usually lacking in precision. I think I have helped folks who have used just about all the available options and all of them regretted it.
I know what your probably going to say " It's a cheap entry to CNC" BUT IMO it's also a good way to drive newcomers away has well when they try fail and give it up has a bad job.!! . . If they only knew before hand that for not lots of money and far less time they could have real rails and bearings that are far more accurate and reliable I know for sure they surely would have taken that route on hind sight.

Yes I know there are some very capable machines running DIY setups and someone you've mentioned earlier Gerry(Ger21) who I know quite well runs a very nice machine but think even he'll tell you it's not a simple affair and takes very good design, patience and care to get it right. . . . Do-able Yes, easily No, success rate Low, frustration levels high.!!

My advice save up and save the stress.!!

[Ger21]

Yes I know there are some very capable machines running DIY setups and someone you've mentioned earlier Gerry(Ger21) who I know quite well runs a very nice machine but think even he'll tell you it's not a simple affair and takes very good design, patience and care to get it right. . . . Do-able Yes, easily No, success rate Low, frustration levels high.!!

My advice save up and save the stress.!!

Did I miss something here?

My current machine is wood with skate bearings. I designed it 9 years ago, when DIY CNC was in it's infancy, and the only linear rails available were used from Ebay. While it's probably quite a bit better than most similar machines, the bearings are the main limitation.

Today, I strongly encourage anyone to use supported round rails at a minimum. With the inexpensive rails from China, it really doesn't make sense to go with anything less. If you're on a really tight budget, sure, you can use cheaper methods, but don't expect great performance, or quality cuts. If you have the skill to make the cheapest method work well, you probably wouldn't be using them in the first place.

As far as wood goes, I'm a big proponent of wood construction. But, as Jazzy eluded to, not your basic MDF design.

I'm currently building a (mostly) wood machine, with the goal of outperforming most of the extrusion machines I see. Both in speed, and strength and rigidity. It'll have HiWin linear bearings on all axis, and belt drive X and Y. Not your typical belt drive, though. I've designed a stepper version of the Servobelt

Building a high quality wood machine requires some high tech construction techniques (IMO). Anywhere that metal parts are fastened to wood, I have aluminum or phenolic "mounting pads". This keeps the wood from being crushed and maintains precision.
Most of the wood parts I use are made up of laminations to increase rigidity and stability. In addition, everything is sealed in epoxy to minimize moisture absorption, and subsequent movement. Whenever possible, torsion box construction is employed to again maximize strength and stability.

I am using some aluminum for mounting the linear bearing blocks, but in some cases it's bonded to baltic birch plywood, which let's me use thinner panels.

Oh. It's going to have two spindles.

Today I cut the parts for my gantry beam. It's about 1700mm long, made of MDF. Front and back of the beam are 1" thick, made up of a lamination of 4 layers of 1/4", glued with plastic resin glue in a vacuum press. Phenolic mounting pads for the linear rails were epoxied on.
My day job is in a cabinet shop, so I have access to a 5x12 Morbidelli router. This is what I ended up with. Sorry if this is off topic. If anyone's interested, I've been documenting the evolving design at CNC Zone for the last 5 years.

Start of a New Design - CNCzone.com-The Largest Machinist Community on the net!


New Machine Build Z² - CNCzone.com-The Largest Machinist Community on the net!

[TrickyCNC]

Did I miss something here?

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.

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.

There are even people out there very happily using drawer runners and allthread screws, and it does everything they ever wanted ! or, they use it to make parts for a second machine , etc.

On the other hand, Microcarve has extremely accurate machines with unsupported round rails - used to their limits - and made from MDF and plastic pipe ! LOL .