Open source group project, anybody interested?

[ptjw7uk]

In the drawing shown 2 bars each side and and 8 bearings each side the bar at top pulls the 2 sides together and will give lateral support.

Not shown attachement of bearings but this arrangement will allow spacers to be used between rods.

Peter

I would like to have a router using this method were the base fixed to a wall as per the saws in B&Q as I am running out of floor space!

[Ross77]

Still not sure where the problem is? The bearing blocks can take loads in all directions, (slightly reduced where the rail is supported maybe, but thats why I put them vertical rather than on their side)

I see what you mean In your diagram but not sure how that relates to the one I've drawn, dose that use skate bearings and unsupported rail?

I could put another rail underneath like in your sketch but this will add to the cost, And in that case Id rather use linear rails as they would be the same cost as 2 supported rails but are 4 way loading and much much stronger.

If Ive made a mistake I want to known, but at the moment I dont understand......

I have thought about the wall mount option but not sure how easy it would be to use.... Im sure I remember a design that could be stored on a wall tho.

[ptjw7uk]

Its just that I dont think that the sitting of the moving part on 2 rails just like a train then there would appear to be very little stopping it rising up unless you intend to use expensive ball slides which grips on their hollowed sides.
I thought the skate bearing system is a cheaper option plus use of unsuported rails although I am unsure myself how to fix them to supports without drilling right through them.

Peter

[Tom]

Ross, that's an interesting concept using off-the shelf alu sections. What about using one of the slotted alu sections like kev is doing at the moment (ITEM, or similar).

I was buying some router bits the other day from trend, and saw this video. If in doubt, copy the professionals! :) (have you seen the price of these machines from trend!!)

One interesting part of this machine (well, to me anyway!) is the relatively small Z travel, allowing a simple frame.

The vid may also contribute to the bearing discussion. I can't make out the bearing system on this machine (about 1min in is where the machining starts). Are they v bearings?

[ame="http://www.youtube.com/watch?v=Ue5PcqTwihM&feature=player_embedded"]YouTube- Trend CNC Machining Centres[/ame]

[Ross77]

Hi Tom, Yes I have looked at the Al sections and i do have some of the item ones, It just seems an expensive route (espessially if you go for the heavy range) once you get all the connectors fixings ect. If budget allows then use it. It sure is much easier and dose look very proffessional.

Cheers for the link that looks good, not sure on the bearings tho, they look similar to pnematic actuators but could just be a low profile rail. with that design the forces will be small so could be similar to the igus stuff.

The small z axis definetley helps as it reduces the loadings. I think the main point here is that it is being used as a router for fairly low precision work. which is much easier than the breif of this project to cut Al.

I only thought of the u channel as it can be accuratley drilled by an MDF machine and then bolted/welded together to make a strong frame.

I was pricing up the large uprights in 15mm Al and realised how expensive they are to buy and get machined. I figured that they only need to be that thick because they are 2 dimensional, if there was some bracing in the 3rd dimension then they could be a lot thinner, hence the 3.175mm U channel. I maybe wrong and someone else has already tried and failled.

Is it worth Re-clarifiing the goal, As I understand its a 2"x4" (cutting area?) mid range with Al frame(that can be made on an MDF machine if required) and uses supported round rail or linear bearings with ballscrews to cut Al.????? Probably £500 for frame and rails (ballscrews vs lead screw and motors/drivers optional)