1250 x 1250 cnc router (from scratch)

[Danielroyal25]

Thats a good idea by over hanging the X rails. I guess you could also have a removable section in the centre of the bed to do the same thing, but will obviously limit the size of the material that is being cut. May take the idea up and incorporate it into my design. What length overhang would you say? diagonal supports could be added for a bit more strength too.
Im debating over the Z axis travel now too. i originally stated 300mm, what is the norm? or will it be best to go with less around 200mm. I will be mainly profiling, but will occasionally mill in 3D (modelling foam), if pocketing im guessing the depth of Z travel will be restricted by the tool length?

[Jonathan]

Im debating over the Z axis travel now too. i originally stated 300mm, what is the norm? or will it be best to go with less around 200mm. I will be mainly profiling, but will occasionally mill in 3D (modelling foam), if pocketing im guessing the depth of Z travel will be restricted by the tool length?

Make the Z-axis as small as you can afford to without compromising what you want to make. It is far easier to design a machine with a short Z-axis since the overhang is less, so the torque applied to the gantry, and hence in general the forces are lower.

[JAZZCNC]

What length overhang would you say?

Depends on other factors like the gantry design, bearing separation and Z axis etc but you don't need much has unless you create an offset gantry then the tool naturely tends to overhang pass the bearings.

Im debating over the Z axis travel now too. i originally stated 300mm, what is the norm? or will it be best to go with less around 200mm.

I've never needed or built over 200m in any Z axis. Like Jonathan says just enough for your needs and no more. The adjustable bed takes the need for long Z axis away in most cases and Jonathan has quite a long Z axis but I bet he rarely has need for it.? . . Other than being too lazy to lift the Bed.!

Tooling length will be a limiting factor and while you can buy long tooling it often costs a fortune and requires large spindle collets. You'' be hard pressed to find longer than 200mm flute cutters with less than 12.5mm shank sizes that routers or common ER20 spindles take and even then you probably find the price prohibiting.!!

[marbles]

Hi, I'm reading this part of the conversation about the long z axis with interest as i'm in the process of making a 1250 x 1250 with 500mm travel on the z axis. its designed specifically to cut deep styrene foam sheets where there is less resistance.

Where is a good source for long fluted cuttters like the ones your talking about and is it possible to buy a 1/8 to 1/2 shank adapter to take 1/2 cutters?