Opinion wanted on z-axis

[robtown]

Any thoughts on this:
https://www.ebay.com/p/CNC-Z-Axis-Slide ... 3019497624

I have an older ShopBot PRT, so I'm looking at making updates to the gantry and z axis.

[martyscncgarage]

Any thoughts on this:
https://www.ebay.com/p/CNC-Z-Axis-Slide ... 3019497624

I have an older ShopBot PRT, so I'm looking at making updates to the gantry and z axis.

If you don't want to fabricate your own, I personally see nothing wrong with it provided it has the travel you need.
There are other ebay sellers that sell these. I think round linear rails are old technology, but should still serve you well.

Marty

[cncman172]

robtown,

When you select a unit for your Z axis the first thing is to ensure you have enough travel as Marty indicated. The second thing is make sure it does not have backlash. Some units use a delrin plastic nut, other use ballscrew actuators which are very accurate. Something similar to the one in the ad below. Other considerations: Weight of your spindle, do you need a brake, are you going to use a counter balance, a gear head to ensure Z does not fall if power is lost, etc.

Russ


https://www.ebay.com/itm/4671-THK-LINEA ... k:139:pf:0

[cncman172]

https://www.ebay.com/itm/DIY-CNC-X-Y-Z- ... ctupt=true

This unit uses much better rails and looks pretty good and has 6.5" travel

Russ

[martyscncgarage]

https://www.ebay.com/itm/DIY-CNC-X-Y-Z- ... ctupt=true

This unit uses much better rails and looks pretty good and has 6.5" travel

Russ

Agreed, I like it much better.
Marty

[tpetricek]

check out http://www.automation-overstock.com/ for rails and ballscrew.
and https://www.industrialmetalsales.com for aluminum flat bar

You can build a z axis that is engineered by you to fit exactly what you need.