Pegasus 12" Build Notes

[uncle_bob]

Hi

Now you are up to doing the X carriage. The instructions go through this pretty well. The main thing here is to *carefully* check out the Z nut traps. They can't bind (thread onto) the rods. They also need to have enough material left to hold the nuts. Before you put them on the assembly, mate them up with the nuts and rods. My guess is that the rods will thread into the traps. The answer is to open up the holes a bit with a hobby knife. Don't overdo the process. You still need to have the entire assembly supported off of the material you leave.

Second thing to do: When you put the set bolt through the Z end stop, put a very normal M3 nut *above* the wooden arm and below the head of the bolt. At some future point you may need it to tighten things up.

The final step is to take a close look at the two pieces of V-slot that the X carriage is going to ride on. They need to be equally spaced and at right angles to both end assemblies. There is a bit of judgement involved in that process. When you mount the carriage on the rails, it's easiest if the eccentrics are set so the "fat" part is to the inside of the assembly. This spaces the rollers as far apart as possible. The same is true when you put the whole assembly on the uprights. It's not as easy to do this if you didn't mark the eccentrics right up front.

The instructions run through putting the upper frame on pretty quickly. It's not quite as much of a three person process as you might think. Having a second pair of hands does help. When you get it on, stop and double check that the front is indeed in front. Also double check the spacing of the uprights in the middle of the left and right sides. It's not a magic distance as much as having the *same* distance at both top and bottom on both uprights. You also need to check all the diagonals. If something is not square, fix it now.

At this point the main frame is square and all together. Double check all of the corners. Make sure they are flush and solid. You can feel gaps better than you can see them. Check all of the L connectors to be sure both set screws are tight. Check all of the right angle connectors (except the ones on the Y tracks) to make sure they are solid and tight.

Stop, go have dinner, watch a TV program, do something else. Come back and double check the whole / flat / square / flush thing again. It is the heart of the whole assembly. Grab your level. Check the table. Check the top and bottom frame arms. They should all be level. Flip the assembly on it's front face (hang on to the Y carriage). Check the uprights on the back side. In this position, they should be level.

Yes, that's a lot of checking. You do *not* want to come back and do all that later. Any change you make to the frame throws off all the other alignment. Re-starting the whole process is no fun at all.

So much for now.

Bob