Design Help Pt2 Required for CNC design/Build

[MikeyC38]

Thanks Jazzcnc for taking the time to review this. The photos are really useful. My drawings are incomplete at this stage as I will be using a single ballscrew on the long axis as per your photo with a plate underneath between the gantry sides . But the tip on adding the extra reinforcement on the long axis is taken and accepted. HiltonSteve's router/mill also had this. It also solves the problem of mounting the BF/BK blocks very elegantly and protects the ballscrew from muck! Many thanks!!

Again the comment on the material thickness on the Z axis is accepted and you given me some food for thought on the gantry side plate lay back. My original idea is to get the cg of the Z axis between the bearings on the side plate, but as you say well, cost of getting the plate for the gantry sides has to be taken into account!

I note your comment about reversing the position of the Z axis linear slides and bearings - I see in your photos you are using Hwin/THK slides which have better torque load characteristics than Supported round rail and linear slides. I'll have a think about that one.

Measure twice cut once is the adage!!!

Kind Regards
Mike

[JAZZCNC]

I spent some time experimenting with cutting MDF templates for the best layback and what you see in the pics is the outcome. I found it gives the best balance and can still be got from 12" x 3/4" plate from Alu warehouse with the minimum waste. Thou not exactly on centre of bearings it's pritty close.

Regards the Z axis I really would consider putting the rails on the front.! It does help regardsless of rail type used.
Remember the Z axis when extended is basicly a lever and a weak lever will bend and flex.!!
Like I allways tell folks.!!. . The machine is only has good as it's weakist part or component.!!. . . Unfortunatly I see lots make the mistake of building weak or inaccurate Z axis's. Which makes the rest of the machine no matter how well built or quality components used pointless because at the end of the day it's the Z axis which is at the sharp end taking the strain.

[MikeyC38]

Regards the Z axis I really would consider putting the rails on the front.! It does help regardsless of rail type used.
Remember the Z axis when extended is basicly a lever and a weak lever will bend and flex.!!
Like I allways tell folks.!!. . The machine is only has good as it's weakist part or component.!!. . . Unfortunatly I see lots make the mistake of building weak or inaccurate Z axis's. Which makes the rest of the machine no matter how well built or quality components used pointless because at the end of the day it's the Z axis which is at the sharp end taking the strain.

Good reasoning there JazzCNC...the placing the supported round rails on the moving part of the Z axis will add stiffness to that axis...

[MikeyC38]

Hi John S & JazzCNC

You guys have got me going now and its late (got work tomorrow :cry: ) but I have revised the drawings with your suggestions in mind... its begiining to take shape and make sense.

Thanks guys

Mike