round rails

[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!