8x4 router project

[Cynic-al]

Hi all

So I'm not a complete novice but a long way off knowing what I'm talking about! So this thread is picking the brains of people who have done this sort of thing before!

I want to build an 8x4 router, mainly for wood, maybe plastic, maybe the odd hole in long metal stock but I have a small CNC mill so I'm not looking to replace that. Initally I was going to do a plasma based on the Simon R design and got a lot of the parts made for that but then the material below came my way and I've decided a router would be more useful. At some point I will try move on what I've got for the plasma and start work on this.

I work for an injection moulding company, we used to have several Cartesian robots to load / unload the machines but as machines have been replaced we have moved to 6 axis robots, mainly ABB. This is the last one to be pulled out after 20 years of service. Rather than throwing it in the scrap like the others I decided it would be a great base for this project.

The main part of the robot was this 6m ali extrusion. Originally they have the half round guides with bearings on but the front one that takes all the weight of the robot tended to fail so we replaced those with linear bearings. I've cut these in half and I think, stood on end they will make a great base for the machine. I even went scrounging and found a spare pair of linear bearings that we saved off one of the other robots. This gives me two for each side which should make a pretty stable base for the gantry.





Then I stripped the Y axis, this is long enough for the 4ft and has a solid lump to hold the spindle assembly. I think the current bearing setup will be fine too.







Plus I have a pile of other bits which I will keep incase they are useful. The servo motors are good, the electrician offered me the drives and software but after several reminders I still don't have them. To be honest I'm not sure how useful they will be for a home CNC setup. If I can get them I will as they will only end up dumped in a heap somewhere but I'm expecting they will be of no use.

My next step is to get a spindle, I can't really design it until I know how high that needs to be off the bed etc.





So my questions to those who are experienced;

1. What spindle would you use? I was thinking one of the rectangular air cooled types with a variable speed drive and a collet?

2. Can I used the belts that are already on the robot? They are the steel wire reinforced timing belts. Or will they have too much stretch to be accurate? Do I need to swap out to a lead screw?

Thanks all!