Replacing X-axis with C-Beam Linear Actuator?

Was wondering if the C-Beam Linear Actuator ( would drop in and replace the existing X-axis on the 1000mm x 1000mm X-Carve.

I read this post: Gantry Upgrade to C-Beam
Very informative, thanks AaronMatthews

I was curious if I could replace just the X-axis, and not the existing Y and Z. Basically not have to change the end plates and keep the Y-axis belt driven.

The X-Carve has been a source of frustration over the past few months. I am having accuracy and repeatability issues which I cannot seem to correct. I have checked belt tension, current to the motors, slowed the cutting rate, adjusted the V-Wheels, etc. Before every project I am crossing my fingers and hoping that it will come out correctly.

Today, the end of the pulley on the X-axis motor flew off (again). Since the pulley will need to be replaced, changing over to GT3 6mm belts was my first thought. Now I am thinking about using a linear actuator and not having to fool with the belt anymore.

Here is an example of the issue:

This pocket was cut perfect

Then the next operation, 5 minutes later, began to offset around 1/16"

I don’t think there is an easy way to reuse the gantry assembly with a c-beam. However, you don’t need to do as extensive a upgrade as I did. I came across a c-beam configuration that uses standard plates for the gantry.

Although if you are going to replace the X beam I recommend redoing the Z as well. I found a lot of wear and damage to the Z axis wheels and eccentric nuts when I took it apart.

Looking at the Y plates 2 of the mount holes line up and the wider cable hole likes up with the stepper motor shaft. You would have to drill out 2 more beam mount holes. If you went with the acme screw drive you would need to drill and tap the stepper mount holes and see if the bearing would work with the existing hole (it might need to be drilled larger)

Perhaps I should clarify.

I’ve had the machine since October of 2015. In that time I have replaced the X-axis belt 4 times, have now gone through 2 pulleys, and have completely torn down and rebuilt the machine 3 times. I run it approximately 5 hours a day 4-5 days a week, and every morning check the belt tension as well as the V-Wheels. Once a week I clean all the wheels with a brush to remove any wood/grime build up and then run a test pattern to ensure that the current to the motors is adjusted correctly. I also run the machine with a dust boot and vacuum system constantly.

Despite all this, I still get at least one piece a week that has major errors rendering it unusable. When its a piece of pine, not that big of a deal, just annoying. When its a piece of 14 inch wide 8/4 African mahogany, it becomes cost prohibitive to even use the machine.

I was hoping that by upgrading to a lead screw system it would minimize some of the constant calibration and provide me with a more reliable setup.

Thanks for the info. Are you happy with the upgrades you did? Do you think that it was worth the time and money?

I have not had a chance to really put the upgrades to use. (I just got the new spindle mount installed last night) But it seems a lot more stable. The Z axis mount to the Gantry is rock solid and the X and Z axis move smooth. The new y axis belt is solid, when I try to stall it by hand the Y motors slip before the belt does.

The first test cut I did powered through with no problems. I was having problems with my improvised spindle mount and wound up cutting much deeper with my 1/8" ball nose on the roughing pass than I normally would. It was cedar, which is very forgiving, but by the sound I was making a much more aggressive cut that I normally would.

In retrospect I could have saved a few $100 by going with the standard plate and using less wheels. But I think I having the load distributed over more wheels will pay off down the road. I should have more info to share after I do some calibration and projects this weekend.

Something isn’t right there. Are you breaking belts? Could you have a bad idler wheel? When I disassembled my XC the Y pulleys were really hard to take off. I think I may have actual been over tightening the Y belts?

You may want to try upgrading your belt and pulley. It was the cheapest and easiest part of my upgrade. The most time consuming part is recalibrating your steps per rev for the new belt.
(There was another upgrade someone did where they replaced the normal pulley set screws with longer Allen bolts. So they could use a larger Allen wrench to tighten them down with more force.)

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Honestly, I agree with @PhilJohnson. I have not broken a belt yet, because they are adjusted properly to ride dead center of the pulleys. They are rated for far more than you are throwing at them. I did the steel plate mod. I also used a dremel to carve a v-shaped trench in the shaft of my stepper motors (not all the way to the end of the shaft. The set screw digs into that v, and the pulley is locked down. On the v-wheels, I used eccentric spacers instead of nuts and use lock nuts. I am dragging a giant hitachi router around as well.

I am using a Gecko controller and 48v supply, but I don’t think that is relevant to the problems you are having.

Also, longer lead screw systems will slow your cut speed and you will be prone to “screw whip.” I migrated from lead screws to belts for that reason. Speed and accuracy.

On my smaller machine which is like a rock, I abandoned the Y end plates and mounted the rails directly to a squared base. I also used a z-axis assembly from Ebay. This machine can handle nearly anything and never needs adjustment.

I think working with what you have, you should be able to solve your problems.

  1. Grab your router and shake it violently up and down - see what moves… and then stop it from moving with rigidity mods.

  2. Make sure you have the correct size spacer inside of your v-wheels - some were too thick. If during your violent shaking you can hear your v=wheels clicking in and out - you need to put the correct size spacer between the bearings (search on forum for fiber washers).

  3. Lock your pulleys down with a v-groove in the shaft of your stepper and with loctite (even with the end of the pulley off, you should be able to use it – the belt should not be migrating toward the end - it should stay in the center - your pulley is out of alignment, your idlers are too far out of alignment or your stepper is not mounted flush to the plate. If you see fraying on the side of your belt, you are out of alignment.

  4. Tighten your belts until you can twang them like a guitar string (they better be properly aligned).

  5. Adjust your pots (it sounds like you did this).


FYI, My steppers have a flat spot for the pulley set screw to lock against. I know that some kits shipped out with steppers that didn’t have the flat spot and this causes problems… Does yours have one? If not it may be worth your wile to use a Dremel to make one or replace the stepper(s).

If you have a flat spot, that makes a groove easier. Put your pulley on, make sure it is aligned correctly, tighten the set screw. Then remove. You should see the mark left by the set screw. Use a dremel cut off wheel, to cut a very shallow groove across that mark. Now your set screw will settle into that groove. Apply just the smallest dot of blue loctite to the set screw… and you are now ready for worry free machining.