Z-Axis depth limits

Hi everyone,

I’m new to this, so I was hoping someone could help answer if the X Carve would be able to create one of the projects I have in mind, with my one concern being the Z Axis plunge depth. I would like to use the machine to create boxes out of a solid block of wood 3" tall. The cuts would be <= 2.25" deep.

I know that this depth exceeds the workspace dimensions of the system (2.6"), but that there are also some solutions for increasing the workspace height (Need more Z cutting heigth, say 6"). I would probably use the approach of fastening the waste board under the bottom rail instead of on top of it, and hopefully increase my usable height by .5-1.0".

My concern is that even if I create an extra .5-1.0" of usable height by lowering the board that the spindle mount will be too low and still interfere with the milling, that the spindle won’t be able to come down close enough to the block, or that the drill bits will be too short.

Can anyone advise?

Thanks!

One aspect of your plan to consider is the length the bit sticks out of the collet. Unless I’m missing something, cutting to a 2.25" depth means the bit must stick out farther than that. It might be possible if you use a router that will hold up to a 1/2" diameter bit to help reduce wobble (chatter).

In the above case, the spindle (router) will need a clearance of about 6" above the base of your CNC to account for your material and the bit length.

@JoshC - It depends on how you are milling as to how long the mill needs to be. If you mill out a spot wide enough that no part of the spindle hits while you are going to the depths you speak of, your only other problem is the vertical travel (reach) and how far the mill sticks out from the spindle which will subtract from your overall useable Z-axis range. One simple solution is removing the waste board, and securing the piece directly to the table and getting another inch or two that way. You could also shim the frame of the X-Carve up higher off the table once you remove the waste board to get additional height. Of course, you could always order or make custom mounts to raise the height of the Y rails - giving you more overall height, but not any more reach. In other words, the Z-Axis screw is your most limiting factor. I was looking at mine the other day wondering what it would take to get a longer ACME thread for it so I could increase the Z-axis reach. Inventables sells longer Maker slide, but only one length of ACME rod.

Tricky.
You can get longer bits or use some kind of Router Bit Extension, Drill Bit Extender or End Mill Holder to add the necessary length. But his doesn’t change your workspace, it just shifts it lower.
Too low and the bit won’t be able to clear the top of your material.
If the total cutting area of your project, from the top of the material to the bottom of the final cut does not exceed the work area of 2.25" it should work.
If not you will have to modify your Z axis to be longer, so it can lift the spindle motor (and bit) up higher to clear the top of your material.

I would not use longer bits or extenders with the stock spindle. The more the bit sticks out the more stress it puts on the spindle and can cause chatter and other issues. So upgrading is a must.

If it was me I would get a cheep extender* first and give it a try with the stock bits. See if I could get things lined up to pull it off. Then invest in in some longer end mill bits if I was going to do a big production run.
(*I am assuming that a cheep extender is not going to have the precision necessary for high quality results and that special ordering longer bits would be cheaper than using professional end mill holders.)

If you can’t laminate the project consider using the cnc router to make hand held router templates for deep plunging if that’s the way you are going. I would never use an extension on a cnc router its just a disaster waiting to happen. Cheap and precise do not go together.

I don’t think it can be done with a standard machine even with the waste board under the rails that only gives you an additional 20 mm of Z head room. I don’t think you have the Z travel distance. If you put the biggest end mill that will fit the standard spindle with enough length to get to the bottom of your pocket it will hand down below the gantry rails and you will not be able to your Z0 because with the spindle all the way at the top of Z travel you tool will still be below Z0.

Dave

@DavidSohlstrom - The waste board is 3/4" (roughly 19mm) thick, the rails another 20mm. So removing the waste board gets you another 39mm (1.5") of possible depth of cut since you are now cutting to the bottom of the rails, not the top of the waste board which is already on top of the rails. Depending on how far the tip of the mill comes down from the spindle, you almost never have a full range of the Z-rod available for vertical travel. Thus, lowering the 0 of that axis will get you back some of the length you lose due to the length of the end mill. Like I said earlier, the only truly limiting factor in this, is the length of the Z-Axis threaded rod.

OK I stand corrected on the amount of Z height gained. I don’t have my machine yet so I not sure of the max travel that the Z carrage can travel in the Z maker slide.

Dave

@DavidSohlstrom - No worries. I am not 100% sure myself since I am using a different router than most others for my spindle. I just know the max travel is limited by the Z-axis screw since I was thinking of buying a longer piece of maker slide to extend mine, but then realized that even with a longer Z-axis slide, it would just slide right off the threaded rod once it reached a certain point, and BOY wouldn’t that be fun with a running router? :smile:

That indeed would make for a fun time in CNC land. If you take a look at my build thread in assembly you will see that I am doing a complete custom Z and raising the whole thing up at least 50mm.

Dave

@DavidSohlstrom - Yeah, I am guessing “Loose router roulette” would beat “belt sander racing”. If you are lucky enough not to know what that is, it’s what happens when you plug in a belt sander that someone left with the trigger locked in the on position and it goes sailing across the room, lol. I’ll have to take a look at your other post about the Z axis.

Let me say something short if you don’t mind. X-Carve is CARVING machine, only cuts carved pieces at the end in favor, nothing more than an inch, and at least 5 turns for 1 inch, feed rate of 15 inch/minute. That’s the safe heaven.

Unless you’re making a parabolic cut, trying to cut down 2 1/4" is going to be a bad time. I’d think the amount of deflection you’re going to get from having a bit extended that far on a machine like an X-Carve is going to be large. You might be better served with a jig and a drill press?

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Wow, great advice everyone. Thanks for all the input!