Help me understand upgraded linear Z axis travels

I’m seeing 6" and 8" upgrades available. What I don’t understand is what is the maximum z travel for the factory x-carve. I’ve seen 67mm, which equates to about 2.6", which doesn’t seem right, but maybe it is. What I want to know is: if I upgrade to 2" lift plates, will a 6" suffice? What is the 8" upgrade for? Also, I would think (at least my common sense would dictate) the more I increase my Y axis height, the more the Z axis will be unsupported when it’s lowered below the gantry, making it less rigid. Is this true?

When you say upgrade, are you talking about a separate Z axis made out of aluminum with an antibacklash screw like those available on Ebay? If so, they have longer travels than the acme rod and extrusion as found on the x carve. I bought one years ago and haven’t done anything with it yet. One of the benefits of the longer travel on my other cnc router with a porter cable router is that I can use 3-4" long straight bits. That isn’t feasible on an x carve from what I see so far with my own machine.

Yes, specifically talking about the CNC4Newbies Linear Z axis. I’m just trying to understand the purpose for the extra travel, and the consequences of raising the gantry to accommodate it.

So the increased travel allows for increased thickness by allowing more upwards travel. The limitation of the Xcarve is in both directions. Actual cutting is 65mm and travel isn’t much different.

Thicker materials require raising the router higher.

4” material may require 7-8” of travel depending on the bit.

If you put the Z below the gantry, you’re effectively negating the gantry lift because you’re limiting the thickness you can cut.

That makes sense. My concern was if you lift the gantry higher, you have to lower the spindle further, away from the gantry, and away from the fulcrum (essentially). I was curious if having the spindle that far below the gantry might cause additional torque on the X axis extrusion

I’ve not seen any issues on mine.

The wide slide attached with 8 screws and the gantry having 8 Vwheels tight against it, you’d break a Vwheel if anything.

But I’ve yet to see anybody who has had that problem.

I’m probably just over thinking it. With a 2" lift, will a 6" be sufficient? Any reason to get the 8"?

Depends on what you’ll be cutting.

I have a 2" lift and a 5.75" travel linear Z axis.

I’ve not run into any limits yet with what I cut.

That’s what I figured. I did not really see a need for 8" of travel, at least not for the premium charged.

Like others have mentioned, the biggest issues comes when you’re trying to combine a thick piece of material with a longer bit. Your options get extremely limited with that added travel space.