The Y-axis sleds are what that attaches the Y-axis carriages to the X-axis.

I started out with some aluminium plate that had been faced down to 8mm thick.

Then I did a 2D profile of the part, leaving tabs to keep the parts secured in the stock.

Oops, or not. What happened here is that the Z-axis on the CNC fell substantially, I believe due to excessive vibrations from the very long end-mill and relatively deep cuts I was taking. This was the first real part I'd run on the CNC mill from g-code (as opposed to just moving it around with a pendant), and first time I'd used this long end-mill, and I had my feeds/speeds all wrong. Another lesson learnt. :)

Luckily there were enough tabs remaining to hold the parts to the stock, just not as securely as I'd have liked, so there was some chatter on later operations.

I addressed the feeds/speeds, touched off again, and was back in business.

The part was then flipped so that the bottom side could be machined.

The relatively poor finish on the bottom of the part is due to the missing support tabs (the photo looks worse than they actually are, as they're covered in cutting fluid and swarf).

Boop.

Finally the pockets for the threaded inserts to sit in.

That was it for the machining of the sleds. The tabs were cut on a bandsaw, and cleaned up on a belt sander.

Threaded inserts were then pressed in with an arbour press.