Giant 20' x 3' x 2' router build

**gavztheouch** · 17-03-2014

What is the biggest diameter collet you can get in that spindle. For roughing out you probably want some large diameter tools.

**charlieuk** · 17-03-2014

all the aluminium i have used so far is ether 40/80 or 80/80 bosh compatible from kjn, i don't think changing the z will be to hard, i have some spare 40/80 i can use however the motor mount may have to go on the top like you have drawn which isnt so great as i have a hight restriction and need to keep it as low as posable so will have to see what i can come up with.

i dont think its going to be posable to do the y with one ball screw any were near the centre as the z will get in the way which mean needing two which would be a nice build but would cost something like a further £350 compared to about £60 ish that rack and pinion would be so will have to have a little think.

I think the max size bit would be 19mm but most i think are just 1/2" shafts so nothing crazy. foam likes to be cut quite quick other wise you get melting issues so you don't need big bits.

**gavztheouch** · 17-03-2014

Would it be possible to use a timing belt and ballscrew. The ballscrew does the main postioning work and the belt just prevents the gantry from racking?

**charlieuk** · 18-03-2014

i think a belt and ball screw may end up getting more complicated than r&p and i would rather try and keep it as simple as posable although i expect it would work.

Just thinking out loud...

If the z axis was mounted to one side of the y gantry and the same side as the rack and pinion and as close to the rails as posable would racking be such a issue?

At present the y rails are 360mm apart, would reducing that help and if so what sort of distance before racking would not be so much of a worry 100mm? 150mm? 200mm? im am just trying to get a good idea in my head of how much of a factor it will be.

many thanks

**FatFreddie** · 18-03-2014

I've been wondering along similar lines - if the gantry is stiff enough in the axis it's being driven in, is it necessary to drive both ends of it? Thinking of a design where the drive end bearings are wider spaced and the gantry is triangulated...

**charlieuk** · 18-03-2014

on the machine in the video they are running the x on 3 carriages, 2 on the top and one on the bottom with a belt drive along the top so i gess they have found a way around it, maybe that is why they only have 3 carriages ?

**charlieuk** · 22-04-2014

managed to get the plates made through the forum so i can mount up the x and y carriages and all so some adapters to mount the ball screw blocks to the ali extrusion, its taken a while but now should be able to get the x and y properly rolling.

The next step is going to be best to mount the rack and how i am going to do the motor mounts and keep things relatively simple. I guess i will also need to decide what motors i am going to use so i can get the mounting holes ect right.

Any advice here would be great. From what i see some people are using a pivoting motor mount with a spring to keep it in tension and others are just having a ridged mount that you set the meshing and then leave alone.

I have found this in the usa but i was hoping to use mod 1 rack and it looks like that is made for mod 2.

any advice would be great and many thanks in advance for any info you guys can give

best regards charlie

ps if any one is in the sussex area and can lend any help or advice it would be very much appreciated and repaid any way i can.

**charlieuk** · 25-04-2014

X and Y mounted up and rolling finally.

**Skysurfer** · 26-04-2014

Jeez, that's one helluva build!

**charlieuk** · 27-04-2014

sorry i ment to add this which is me just playing around with the z axis ball screw and seeing how it may work on the y, it looks like it could be quite straight forward to mount it up and just use a angle bracket of the carriage to the ball nut mount.