MDF CNC Router plans / parts for home build beginners

[mel_earp]

The cheapest I have ever seen is £2.99 and that is for 10. Obviously you are not going to get top quality for that price, but I bought a set for a fiver for something other than CNC and they work just fine (light duty) - smooth as silk and no play.

I haven't tried skate carriages, but I go on what people write and look for majority views and counter views. On the US CNCZone there are dozens of builds using this method and many look really good for a cheap build. I am quite surprised no-one here has chirped up to say they have done it. Also, the original buildyourowncnc uses this method, but they have changed to V-Groove bearings. Those videos might be of help to you. Some bits look a bit crude, but there is also some good stuff.

[pjl83]

Thanks,

I've found some in Nottingham on fleabay. I contacted the guy and I can go and fetch them :) That way I can see what they're like before I bye and also save on shipping!

[Ross77]

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.

Hi Steve, interesting project. You must have plenty of spare time

I've not used the skate bear guides but share your concern. To me the results would seem to be heavily depend on the workmanship and there could potentially be a lot of alignment issues (the poor results might put off some beginners)

What I do know is that the twin 25mm unsupported rails that I was going to use for my mill used a solid bronze bush on 1 side and 2 opposing skate bearings on the other and it always seems notchy when they are adjusted up tight. The solid bushing was silky smooth tho.

I know that unsupported rail are always shot down because they flex but considering the aim of this project and the small spans I'm sure it would be the best option to balance ease of use, cost and performance. There is the option for solid bushing or ball bearings that would provide the flexibility required.

With regard to using mdf, when I used to work for a car audio shop we built lots of custom Sub boxes and it was always apparent how much stronger the structure was when the joints were routed, glued and screwed so I would defiantly recommend this form of construction. if you dont mind me interfering I can help with options for stiffening the bed to keep Lee happy :heehee: (easy. dont remove a big chunk of material at max bending:rofl:)

Better shut up now, later

[Wobblybootie]

Another method that appears to be popular when joining MDF at 90deg is to use the 'Brass' rods and screws, as used in beds (the kind you sleep in) ...

[Robin Hewitt]

Just a thought :naughty:

If you are going to use skate bearings why not use good old hexagon bar stock to beef up your bearing faces?

[mel_earp]

Good idea. With the more usual angle configuration you end up having to mount the carriage on a 45 deg chamfer of some description. With this, you get the bearings at 60 deg and a flat on top/bottom. to mount the carriage.

With the bearings being at 60 deg, they would be best run on round or hex rail rather than 90 deg angle.

Also, does this mean that you are going to have to drill and tap the bar stock to fit the bearings? No big deal for you guys, but might not suite a beginner.

[irving2008]

Good idea. With the more usual angle configuration you end up having to mount the carriage on a 45 deg chamfer of some description. With this, you get the bearings at 60 deg and a flat on top/bottom. to mount the carriage.

With the bearings being at 60 deg, they would be best run on round or hex rail rather than 90 deg angle.

Also, does this mean that you are going to have to drill and tap the bar stock to fit the bearings? No big deal for you guys, but might not suite a beginner.

I'll refer you back to the first post "Also I will be prepared to either manufacture myself or get components made that people are struggling to make, not all the components but just the parts which will be difficult to make at home. How much will these cost? Not as much as you think! I am not here to earn a living from this just give people a chance to get started." This would be a good example of where others could help out. However even a beginner would benefit from investing a few quid in a cheap drill press adaptor to get a bit of accuracy! Drilling and tapping hex bar stock wouldn't be that difficult.

[mel_earp]

I understand the points you make Irving. If the target audience is the beginner then surely it is worth taking the views of the beginner - and I am totally a beginner who has made nothing CNC, just read a lot. From my perspective wood is good and metal is difficult (can't think of a suitable rhyme). For others it will be different and they will prefer metal to wood.

The common skate carriage is easily made because in the basic form you saw a bit off, drill four holes and bolt the bits together. As you go more complex then more chance of error or frustration.

And I do have a drill press.

[Wobblybootie]

However even a beginner would benefit from investing a few quid in a cheap drill press adaptor to get a bit of accuracy! Drilling and tapping hex bar stock wouldn't be that difficult.

Careful ... SWMBO bought me one of those from B&Q... the 43mm euro collar would not grip a 43mm drill with a piece of 240 grit paper wrapped around it and also the casting was 3deg. off centre. It may have been a Friday afternoon special, but Wolf or Draper offer better quality (for a price)

[pjl83]

I've been thinking about my own build plans and how I'm going to run the bed. I'm considering the skate method as it's simple and cheap. I then thought about using v-groove bearings and running them directly on top of a piece of angle. My sketch-up skills aren't great but hopefully you get the idea. It would be a moving bed with the top bearings attached to the gantry. It's only an idea I had today so they may be obviously floors that I'd not considered yet but it may be worth experimenting with?