Z-Axis design and advice

[Mad Professor]

Thanks for your feedback.

So what you are saying is that my design is no good, and will not be upto the job.

I was hoping to reuse the unsupported rails, and bearing blocks that I already have.

What sized supported rails would you recommend?

Thanks for your time.

[Jonathan]

What sized supported rails would you recommend?

Might get away with 16mm, but I'd say minimum 20mm rails.

As it is the design will be much better than what you have made from plywood, but it has the potential to be significantly better with the changes already mentioned. Though it would be nice to use profile rails I don't think it's worth the money for this size machine as you will still be able to cut aluminium perfectly well with SBR20 rails on Z (as I do), just not quite as fast as with profile rails.

[JAZZCNC]

Thanks for your feedback.

So what you are saying is that my design is no good, and will not be upto the job.

I was hoping to reuse the unsupported rails, and bearing blocks that I already have.

What sized supported rails would you recommend?

Thanks for your time.

Not saying it's no good but it's not the best it could be and with a few changes could be made stronger.

Supported rail is far better.!. . BUT. . If you have them then just change the design so the rails are on the front plate and bearings on the rear.

You won't gain the extra support to front plate supported rails give but to be honest this is minor and secondery to the gain from less cutter flex thru the proposional extension not acting like constant length spring board which is what your design allows. The 20mm plate will be strong anyway so IMO with these changes you'll be ok.

If you do go with supported then 16 or 20mm will be fine.

[JAZZCNC]

Ermmm I've just down loaded your drawing and can see that your using 12mm round rail.!! . . . This would concern me and would seriously consider selling and upgrading to supported rail.

It's a lot of work and expensive aluminium to potentially waste and I'm confident to say it will significantly reduce your depths and feed rate in aluminium..:sad:

So times it's less painfull and expensive to cut your loss's and start a fresh.! . . . If you have a fully working Z axis now why not sell it complete to someone who doesn't need the strength or abilty to cut harder materials. Then treat your self to supported rails and ballscrew from china.? . . . Think you'll be surprised how cheap you can build a great Z axis for with supported rails and ballscrews.!!