Mounting the MakerMade Z-axis on M2 Sled

In the Summer of 2020, the folks at MakerMade announced their improvements to the classic Maslow CNC design. They called the new design "M2."

I had already built myself a Maslow CNC from a kit and a Ridged R2901 router. While my son and I worked on a mixed-media art project and a furniture project, it became pretty obvious just how unreliable the original Z-axis mechanism was. It was a no-brainer to buy a better Z-axis stage, so I became one of their "M2 Upgrade" pre-order customers.

(The upgrade kit didn't come with a pre-drilled M2 sled, but luckily I managed to barter for one.)

Here is the problem that this Instructable will help you with: The Z-axis assembly is fastened to the sled using six screws and six t-nuts. Unfortunately the t-nuts are free to slide inside the two extruded aluminum channels. So how the heck are you supposed to keep the t-nuts from sliding around?

Short answer: you carefully tape down the t-nuts with masking tape so they are perfectly lined up and stay put long enough to screw into them. Here I'll take you through how you do that with a minimum of frustration.

Supplies

Masking tape

Sharpie

Ruler (inches)

Step 1: Mark the Tape in 2 Inch Intervals

With a ruler, mark off three lines spaced 2 inches apart. I called them 0", 2", and 4".

I used wide masking tape, but if yours is narrow, you can just do this twice and skip the next step.

Step 2: Cut the Tape in Half

Step 3: Cut Notches in the Tape

You want the screw holes in the t-nuts to be clear of tape and adhesive, so cut notches in the tape, and fold them back under.

Step 4: Find the Center Reference of Each Aluminum Channel

There is a handy (unrelated) screw hole in the middle of the channel. Find that. It's going to be your center reference.

Step 5: Center the Middle T-nut Over the Center Reference

Step 6: Put the Tape Down With the 2" Mark in the Middle and Position All the T-nuts

Slide the three t-nuts so they are exactly centered on the 0", 2", and 4" marks. Do this for both channels.

Step 7: Press the Tape Down So It Holds All the T-nuts in Place

Do this for both channels.

Step 8: Position the Sled, Bottom Side Up, Over the Z-axis Assembly

You are going to have to eyeball the six screw holes so they line up over the six t-nuts. If you're lucky, the t-nuts won't move while you are doing this.

Step 9: (optional) If One of the T-nuts Has Moved...

...and you can't get it back into place with the screw...

Stick a nail, wire, or small screwdriver into the hole to re-center the t-nut, if you think it has wiggled out of place.

I was lucky, and they all stay put.

Try turning the screw backwards until it falls into the counter-sunk hole.

If the screw sticks out of the sled, it probably is not lined up with the t-nut.

Step 10: LOOSELY Screw in the Six Screws

Once everything is lined up, you can just screw in the six screws.

I would use a regular screw driver, not an electric screwdriver.

But leave the screws very loose. You need to be able to lift the Z-axis assembly a bit in the next step, and later slide it back and forth to align the router with the big center hole in the sled.