George's 8x4 router-me-bob

[georgetheforge]

Thanks chaps-

What kinda clearance would you recommend?- obviously depends on what I'll be machining-!!

mainly 18/ 25mm ply and mdf, some poly/ foams maybe and maybe some ali if possible....

I wanted the side plates- rather than your solution- so i could keep the top surface clear for loading etc- i do have little triangular brackets which i forgot to make bigger when i was playing with the gantry height-

was tepted to 'split' the gantry so i had 2 sections with the ball screw between them fitted to the back of the front/ z plate. obviously that makes it heigher and was worried about twist/ aligning them correctly.... i did look at getting some 100 x 200 x 10mm RHS and getting the front lasered out to make a so a proper c section rather than an channel- almost like a chunky Unistrut....? then reverting to plan a having one of the rails on the front- bottom and one on the top.....?

[georgetheforge]

so heres the result of some playing around with the drawing-

main changes were thinking how to integrate the rotating ball nut- the idea is to sling it under the x rail ( which will bolt to the side of the table, so hopefully there will be some adjustment on the profiled rails. Ideally they'd sit on another tube to take the weight rather than just be on the bolts- any suggestions?!

i split the y axis and am planning on using 80 x 80 x 8 with the ball screw between the two, fixed to the front and back of y carriage, but this stops any bracing between the 2 rails, do you think this will be a problem?

i extended the z and moved the y upo to give more clearance- now 230mm travel which has meant massive side plates for the gantry-

jonathan, do you think the roating nuts will sit nicely where i've got them or do you think it's hideous-!

anyway- thoughts on this before i start ordering stuff would be awesome

[georgetheforge]

Hey Jonathan,

I did think about plating the back, but currently have the ballnut for the Y carriage elongated to attach to the both the back and front plates, I'll have a look at the gantry side plates, i did want to add in some angled brackets, but will look at your design again,

In terms of alignment, i was planning on bolting the 'x' rails to the 120x 80 and then bolting this through the table so there was some adjustment available with shims/ rizzla papers if required-! but agin may re think.

The rotating ball nuts are currently fixed to the carriage side plates with the 'fixed' bearings at each end...they just look similar to your ball nut design...

heres another rendering-

[georgetheforge]

So... an update on this....

think i'm going to have a rethink on the side plates as per Jonathan's points to bulk them up, and maybe look at raising the sides where the x rails/ ball screws live, i know the other thread regarding the loading of materials etc, but mine will go in a place where it wont be that easy to end load, a corner load would be preferable-!

what was the consensus on having a hybrid, so flush on one side and risen on the other- think that would work well for me?

have costed most of the bits- and reckon on a budget of £2k all in should get me something decent?