I've built this machine 100 different times in my head!!!

[Jonathan]

You should consider incorporating adjustment of one of the X-axis ballnut mounts to gain better alignment of the ballscrew. Currently you're relying on the accuracy of the frame, rail position and all sorts for the distance between the rail and the ballscrew to remain constant. In reality the tolerances on all these build up, so it's easiest to make sure at least one of the bearing mounts (clearly the non-driven end is easiest) position is adjustable in the Y-Z plane to ensure you can align it accurately. If not you risk the mechanism binding towards each end which will put a large force on the ballscrew/nut...

On my Z-axis I currently have 520mm long 20mm NSK rails, so the additional height of those helped. If you go up to 25mm plate for one of the plates on the Z-axis that might help to get the required pocket depth without sacrificing strength. Using that strategy I recently made a Z-axis using 25mm profile rails with only 2mm clearance between the plates. Also if you get the Z-axis parts machined there's not really any need to use the more expensive tooling plate - I would mill the surfaces for the rails and blocks to get them flat and in the same plane.

[Iwant1]

I was just thinking about that adjustment last night. I was going to slide the gantry to the driven end of the x axis, locate the ball screw bearing block there, then slide the gantry to the non driven end and get the position for that screw bearing block. Suppose great minds think alike lol.

Great advice about getting 25mm plate. Does that mean it would be safe to remove 15mm of material? If I don't need EcoCast then what would be suitable 6082 plate, 5083 plate or 6082 flat bar. Also how accurate does the 10mm plate that goes behind the gantry have to be? sorry for so many questions.

I basically was reading in lots of forums that 15mm profile rails would be plenty strong for all axis, but never thought 20/25mm would be better for filling spaces between z plates.

Originally I was going to make the z axis the way I'v drawn, then use a working machine to mill out what we are discussing for a version 2 machine. Thanks for offering, I will pm you about your pricing once I've re drawn it.

[JAZZCNC]

Like jonathan it's nice to see someone who's actually done the leg work and payed attention. . 10/10. . Big respect. .

Agree with Jonathan on every thing he's said except not using the Ecocast.! Even thou you will machine the bearing mounts etc unless you surface and make parallel both surfaces your still going to have troubles and in-accurecy. The problem comes from the cheaper plate not being uniform thickness so you can't be sure it's the same thickness (Or flat) all along it's length. This means buying much thicker than needed so it can be surfaced and still have the required thickness to be strong.
I used to do just this but since the Ecocast has been easily available in small qty then I don't bother any more and it cuts out some of the work involved and makes things that bit easier.

To be honest the 20mm plate is still fine regards strength even with the neccesary slots cut, I've made several with 19mm 6082 and slots etc and they are more than strong enough for even the most demanding jobs.! (Within reason) See pics of what you may have seen before just not striped down like these.?
(obviously more thickness will be stronger but not 20mm gets the job done.!!)

The only other point I will mention is the belt setup and the lack of protection from chips etc.!!
You probably know my machine use's this setup and I'm guilty of not covering the belts and while it's never been a problem, other than grabbing my teashirt a few times and trying to eat me, I would still advise you to cover them up before using the machine.! . . .I'm pretty sure the constant pounding from chips etc has or will shorten the belts life so worth doing before using the machine otherwise like me you'll never do it after machines put to work.!!

Anyway great work and can't wait to see it turn into reality. . .

[Iwant1]

Redrawn the z axis with new 25mm plates for the rear and front. Also included registers for the NSK rails and slides although they are only 1mm. It is a very tight fit and looks much sleeker now at only 64mm depth. I suppose If I had to then I could sink the bk/bf blocks a few mm into the rear plate, just where the blocks go. Its not easy to show but the ball nut's flange head sticks into the front plate by a few mm, which could be a good thing if the hole is machined accurately.

The spindle cutter head has now moved 30mm towards the y axis and now rests between the x axis bearing blocks. Pictures showing the new design and also how far the z extension could be dropped. Its around 250mm, not that I would need that much, but the rails are long so might as well use them. I try to put as many detailed pics up for all novices to see, as this is what I was looking for while doing my research. Hope it helps someone.

Adil

[JAZZCNC]

Ermm.!! . . . . Been looking at this thinking don't seem quite right.??? . . . I'm sure it's correct because you've obviously taken lots of time over it but I'll ask anyway just in case.!!

The bearing/rail height seems low.? from the dimensions on the drawing it appears to be about 16mm this is very low even for 15mm profiled rails and surely can't be right.? Do you have the bearings set in pockets.?

[Iwant1]

Thanks for noticing how small my profiled rails are. I mentioned earlier in the thread I didn't realise that they came in such low profile dimension. I got them for £70 from ebay for two slides and 4 rails as 15mm width and 550mm length. I've attached some pics to show their dimensions with respect to the bk/bf blocks. This is why I'm in a pickle over using 25mm plates for the z axis with 15mm machines out from each.

Do you think I should sell them on and get slightly larger rails.

[WandrinAndy]

I've attached some pics to show their dimensions with respect to the bk/bf blocks.

As a novice who has never seen any of these components in the flesh so to speak, those dimensioned pics have really helped me and reminded me that I need to get a digital caliper... thanks Iwant1... I'm following your build with interest btw, and want one too!

[JAZZCNC]

Do you think I should sell them on and get slightly larger rails.

I wouldn't go that far but they certainly are not ideal in the respect they make the pockets deep.!!

There is one thing I'm not to sure about and it's hard to tell from the pics, is that they don't look like the 4 row type bearings.? This makes them that bit less ideal and less able to stand the strain that a Z axis will come under.!! If 2 row type then I think for a Z axis then yes I'd sell them and get 4 row type more suited and making the job a bit easier.!!

[Iwant1]

I'm trying to make the build as strong as I can or will ever need. There's no specific need for this router, just for fun. Many of my mates ask, 'what's the first thing you're going to make?' I tell them a plaque saying 'test cut', lol. There's no budget to it, just being wise with money. In the end I'm sure it will cost near £1500 once spindle, plate ali, steel tubing, pulleys and belts are factored in. So far Chai took £550 and Zapp took £250 for the electrics.

Time is always a problem as the family want some dad time in the evenings after work. Suppose I'll have to get my 2 and 4 year olds to help mix up my screws and loose my tools. Funny how all kids love work shops, so many things to play with.

Adil