Ever since I installed the linear rail Z-axis, my spindle hasn’t been mounted perfectly perpendicular to my bed. The old mounts were a tad flimsy and not 100% identical.  The widening of the mounting holes also didn’t help with respect to overall rigidity. And they were too closely spaced apart imho … Other than that they weren’t really aesthetically pleasing to put it politely.

So… Yup you guessed it, time for some new and improved mounting brackets. The design is based off the Z-rail mounting block measurements and was whipped up pretty fast. It will use the same bolt for both mounting and tightening, which I can’t remember having ever seen before. But hey, I like simplicity and elegance. It minimizes the distance between router and Z-rail (about 5 mm), in order to reduce torsion due to the weight.

I started out doing 2 passes, one for the narrow gap, and then a larger diameter bit to do the legwork. It turned out that was a mistake. The noise was horrifying; it seemed the bit was rubbing rather than cutting.

I kind of salvaged one bracket, but ended up scrapping it anyway and starting over …

This time I cut everything with a proper 1/8″ VIPER endmill. But it wasn’t all smooth sailing. The stock is 15 mm thick, so cutting a narrow groove this deep really requires efficient chip collection. In order to minimize risk and get the cleanest cut possible, I chose to do a double profile pass, which resulted in a 6 mm slot. This effectively always gave the chips somewhere to go, but it also doubled cutting time. However, this was a concession I was willing to make because the result was relatively important!

Another minor problem I noticed was that the flutes of my endmill were only 10 mm long. This, combined with my spindle not being perfectly square to the bed, resulted in the bit drifting slightly outwards when it got to a certain depth. This is illustrated in the picture below. For the back face, this was an issue, so I did a quick facing pass to get it as flat as possible.

And voila!

Next challenge: cutting holes for the bolts, all the way through, while keeping perfect alignment.

I found some 80 mm M6 Allen head bolts that were the perfect size. I positioned the back faces of the brackets perfectly square on my bed and used the Shapeoko to drill 5 mm deep guiding holes. Then on the drill press (no pics), I deepened the holes down to about 20 mm. This way, I was sure the point where the bolts come out of the backside are perfectly aligned and where I want them to be.

Same thing for the front side, but the toolpaths were somewhat different to account for the bolt head. I used the drill press again, but this time with an M7 drill, just to make up for slight misalignments where the 2 drilling operations meet inside the part. And I drilled almost all the way through to just about 5 mm shy of the other side.

 

I have to say, I was worried this last part would have been a nightmare, but if you take your time setting everything up, it seems it is perfectly doable!

I satin finished the brackets with steel wool. Above you can see a finished one on top of the second one straight off the machine.

So … out with the old, and in with the new!

Making sure Everything lines up. Check! O yeah and I added some threaded holes to the side too, just in case I ever want to mount something to the side.

Results:

 

Bracket SVG here!