Definately a scrapyard challenge

[routercnc]

Hi Bruce,

In reply to post #73 I would delete the box section and the 2 angle sections. I would then replace them with either an RHS (rectangular hollow section) of similar depth to the plate, or stack one box section on top of the another and bolt the rails&plate to that. Looks like it would be a reasonable fit based on your drawing.

With the RHS option you could potentially delete the plate, but I think on balance I'd still leave it in.

Hope this helps,
Barry

[Jonathan]

The last drawing looks good to me so long as you bolt both the plate and box section to the gantry sides.
That spreadsheet is rather good. Same formulas I used earlier in this thread.

[motoxy]

Thanks Jonathan. I feel that at last I am getting close to re-starting this project. How heavy 4 core do you recommend for the spindle?

Bruce

[Jonathan]

How heavy 4 core do you recommend for the spindle?

1mm^2 is fine, but I used 1.5mm^2 CY since that's what I have for the stepper motors and it's more efficient to buy the same for all. It's important to use shielded here and earth it well.

Edit: Forgot to mention the reason you don't need so thick cable even though the current to the spindle is higher is it's mains voltage.

[motoxy]

Thanks for that Jonathan.

[motoxy]

Right, here is redesign 5-1.

Obviously I will need to figure out the best side pieces for the gantry. Am I, sorry, are we heading in the right direction?

Bruce

[Jonathan]

are we heading in the right direction?

You've gone for a pretty generic arrangement now, which is fine.
It will be stronger to put the bearing blocks for the Z-axis on the Y-axis and the rails on the spindle plate. This sort of thing (mine):

Between you and mocha I have a pretty good idea about how to progress.

Time spent discussing his machine was well spent then.

[routercnc]

Hi Bruce,

I meant one of these to keep your re-design work to a minimum. But what you've since drawn is also good.

[motoxy]

Routercnc - Thanks for that. The latest soluton allows for the screw nut to travel between the rails which keeps the overhang to a minimum. Apparently I still have a bit more work to do on that.:whistling:

Chip - I realise it may be a bit belt and braces but what I have learnt so far is that strength is paramount. The back plate will assit in the end supports and reduce any rotaional force on the boxes....maybe

Thanks for the comments guys

Bruce

Forgot to mention i order the cabling. I dare not order any other materials as there is still time for a few more designs.

[motoxy]

Cleaned up the drawing a bit and corrected the plate thickness on the spindle mount. I have placed the rails on the spindle plate. I am not sure that I understand why as the increase in plate dimension and the rails being further from the center of the gantry would surely put more pressure on the gantry rails. I am obviously missing something here.

Bruce