MDF CNC Router plans / parts for home build beginners

**HiltonSteve** · 27-05-2010

Originally Posted by John S

Virtual village UK - rho
From Hong Kong

He's me thinking it was the village down the road ?
.

Not on your own.....

**HiltonSteve** · 29-05-2010

Been playing with a few idea's and I have attached a quick render and also a 3D PDF file to help you understand what I am thinking.

To open the PDF you may need the latest Adobe reader V9 (free to download), you will be able to spin it round, zoom in and out and take it apart. Easier than doing loads of drawings from various angles.

I have used the IGUS N profile 27mm for all the slides, not 100% sure that this is the way to go though.

This is just a concept drawing, 18mm MDF all round and I have tried to make everything as close to actual size as possible so that I can get an idea of how it will fit together.

Anyway take a look and let me know your thoughts, I have a few things that I am not happy with but it would be interesting to get some more opinions.

**Lee Roberts** · 30-05-2010

Hi Steve,

It’s looking good, I’ve not replied but I’m following :).

I think one thing that sticks out as a possible concern to me is that, when I built my rockcliff machine the 13x13” Y Table (the bit you put your work on):

Click image for larger version.

Name: DSC02329.JPG
Views: 6664
Size: 361.2 KB
ID: 2218

Started to bend and go banana shaped in a very short amount of time. I did have an unnecessary pocket along the length and I think this helped it on its journey to becoming banana like. My concern is that yours may do the same, an option to stiffen it all up maybe to add some ribs under the table the same shape as the Y Axis ball screw floating end plate in your model.

I would prefer if the machine was a flying gantry type as well, if you think about it the design at the moment needs a bigger foot print then if it was done as a flying gantry type.

So I’m thinking, take off the support footer for each of the gantry side plates, mount them at each end of the Y Table (possibly even double them up), use two lengths of MDF that run underneath/in-between the rails and Y Axis plate, this would then hopefully give you the clearance for the ribs.

Just my observations mate, what do I know :confused:

O nice Z Axis design as well, i like it

**Zephyr** · 31-05-2010

I have a suggestion about sealing MDF.

As most of us know from experience (there are a lot of MDF 'bananas' around), MDF is hygroscopic and will absorb moisture from the air. If it absorbs water from the air unevenly and/or the MDF sheet is not a uniform thickness it will warp. Sealing it all over against moisture absorption could be the answer to preventing it warping.

One sealant could be plain old boiled linseed oil which, if put on correctly will polymerize like plastic and it’s also a little flexible as well. It's also cheap.

Clean the dust of the MDF. Round off any sharp corners if possible.

The first coat can be boiled linseed oil diluted 50:50 with turpentine or white spirit put on fairly quickly (to prevent warping). Wipe it on with a cloth and leave to dry (supported on blocks) in moving air away from heat or direct sun.

2nd coat can be 75% boiled linseed oil 25% turps. wiped on quickly with a cloth. Don’t leave pools or surplus on the surface - they won’t dry properly and won’t polymerize.

These 2 diluted oil coats will go into the MDF and provide a better key for the next coats.

Next use neat linseed oil wiped on with a cloth and again taking care to remove any surplus. The MDF should then be fairly well sealed but the more coats you put on the more effective and long lasting the seal will be. 3 or 4 more coats at least of neat linseed oil wouldn’t go amiss.

I know it’s time-consuming but people without much money to spare would rather spend their time and it’s low tech.

Don't seal moisture inside damp MDF. Make sure it's as dry as possible and the ambient air isn't humid either.

A very light sanding with fine glass paper between coats will help to key the coats but vacuum-clean the dust off.

Remember safety. Wear rubber gloves, don’t breathe in the fumes or dust, dispose of oily cloths safely - either in a bucket of water or wash them out thoroughly and dry them outside. Oil-soaked cloths are a potential fire hazard.

I'm not suggesting you try this on an important or complex part. Try it on a test piece first.

I hope this helps and that I'm not 'teaching people how to suck eggs'. Let me know if I am and I'll shut up. If anyone tries it I'd be interested in how well it worked for them.

Regards.

**John S** · 31-05-2010

What about the waterproof versions of MDF for critical components. ?

**Robin Hewitt** · 31-05-2010

Originally Posted by John S

What about the waterproof versions of MDF for critical components. ?

Steve, up on our industrial estate, makes custom furniture to fit your house using MDF and wood mouldings. He always uses a green coloured variety of MDF because he can't afford to have it warping.

**Wobblybootie** · 31-05-2010

That sounds interesting ... Fancy a stroll along there if the weather is nice Robin? ... :whistling:

Only joking ... I shall google and ask a chippie type contact for further info.

**pjl83** · 02-06-2010

Originally Posted by mel_earp

With a set of 8 bearings at a fiver or less, this is pretty cheap and low friction.

Can I ask where you found this price? I was looking at the "piece of angle skate" option but couldn't find a price like this??

Thanks
Paul

**irving2008** · 02-06-2010

Originally Posted by pjl83

Can I ask where you found this price? I was looking at the "piece of angle skate" option but couldn't find a price like this??

Thanks
Paul

Try here... how good they are I dont know... or good old fleabay

**HiltonSteve** · 03-06-2010

Has anyone ever built any of these skate bearing linear guides and had decent results?

Just don't like the look of them but not had any experience with them either.