DIY Linear Rails - Building from scrap on a budget of next to nothing

[longy]

Hi everyone, after having to put my 1500 x 1000 steel build on hold due to health and finance problems this summer, I still would like to built a cnc. Finance or the lack of any meaningful budget is something a lot of people who are wanting to build a cnc face. I would like to hear from other members that have gone that have gone down the roller skate bearings on pipes route, using wood or MDF how good or bad was your build ?


V-Groove bearings like the ones in the video below has anyone used them and will you be honest and say how good or bad they are ?



I have a shed full of plywood offcuts, steel pipe and tubes, plastics nuts bolts and the rest, I would love to explore more on building this way to make a machine to move one of my five routers around, does not need to accurate to less 0.05mm as I only want it to help with learning to use the design software and understanding mach3 better.

I intend to record and take as many pics as I can of the build so others looking to build can learn what's good and what's bad when on a tight budget.

Lets hear your views everyone.

Mike :)

[EddyCurrent]

I very much look forward to following the build, if you already have most of the stuff why not give it a go ?

[gavztheouch]

Definitely worth a bash, the cheapest builds look like the most fun!

[Neale]

I have built and am currently using an MDF machine built, more or less, to the JGRO design. Plenty of info if you do a Google search. Pro - materials to build are cheap. I went up a size on steel guide tubes, but it still uses skate bearings and threaded rod so didn't cost an arm and a leg. I did spring for bigger motors than recommended and reasonable drive electronics so that I could reuse these later. Fairly simple to build with ordinary tools, although I also used my lathe, milling machine, and 3D printer to produce parts (home-made motor couplings, anti-backlash delrin nuts, etc). Cons - it warps like nobody's business, and it's really, really difficult to keep the bearings in adjustment. Use of M10 threaded rod as a leadscrew may be cheap but the critical speed is low, so my maximum rapid speed is only 900mm/min.

I've done some useful work with it; I was using it today to make drilling jigs for some MDF furniture I'm building (the cutting area is too small to directly CNC cut the cabinet panels) and it's fine for that kind of thing. I've learnt an enormous amount from it (including a long list of what not to do!) at not a very great cost and had a CNC router available for use while planning the Mk2, which is now being built. I wouldn't stop someone building a wooden machine, and I'm sure that you could build something stronger than mine, but just keep in mind that it is going to have limitations and go into it with your eyes open.

[longy]

Neale, thanks for your honest opinion and advice. I had a look at the JGRP designs and did learn something from them. I'm not going to use much mdf only for the bed as I guess you mdf can swell as much as 4% even if sealed, left unsealed in damp conditions then 20% is not uncommon before it ruptures.

JAZZCNC, I don't intend spending much as I ain't got much to spent on the build.

Ger21, thanks for your input I would be interested to see some pics of your machine if you have any to post.

Silyavski, thanks for your input and advice. I have not seen the V casing on ebay can you post a link please. Also please post the pics of your Z axis please, yes I was thinking of using belt drives for the X and Y axis with liner round supported rails or profiled + blocks on the Z axis. NOTED your comments of V bearings LOL
Having costed up some stainless steel angle today as an alternative to round tube which I've several 4ft lengths I might as well buy supported rails as it would be cheaper.

Beone, thanks for your input. I know what you mean about shielded bearing and dust, as I was looking at a vertical panel saw with problems today and part of the problem was the bearings sticking apart from the resin build up on the rails, no wonder is was jumping out of the track. Can you post some pics of your machine please.

EddyCurrent, thanks for your input, yes I'll do some test and post them to the thread once I've got a machine built.

Mike :)

[JAZZCNC]

For learning sake then go for it and so long as you don't invest too much money or have too high expectations you'll be fine and should full fill it's purpose.

[Ger21]

While V-Rollers are more resistant to dust and debris, the bearings have a small amount of play in them, so they're not really any more rigid than skate bearings. I've heard that the CNC Routerparts machine in the video is less rigid than their skate bearing model.
My wood and skate bearing machine has been running well for over 5 years now. I've used it for many things, from wood, to phenolic, and even aluminum.
Mine is much more rigid than the JGRO model mentioned above, though. I highly recommend supporting the pipes in some way, as it will greatly increase rigidity.

[Neale]

I think that the Joe2006 design is better than the JGRO as it provides much better support for the steel pipes. Downside is that it really needs a CNC router to cut the parts sufficiently accurately! I was thinking of building one as my Mk2, but then decided to go welded-steel instead.