Here we go again . . . MK4

[routercnc]

The uprights have been drilled out to 9mm to allow the bolts to pass through, and the ends have been machined flat both end to give 100mm length. You will notice there are only 7 of them - one was cut slightly short so I need to cut another one.


I've stopped work on the bed rails because tapping on the radiused edge of the RHS was proving to be a problem. The 5mm tap felt like it was going to break when it partly broke through the other side, basically cutting a thread only along one edge. I've got a plan B which is to machine the area out completely and weld in some threaded bosses. More to come on that one.

Back to the gantry. I've been making good use of my new lathe and made 2off ballscrew floating bearing holders. Here is a walk through starting with the drawing:


The part was hidden in here somewhere, just needed to get it out:


Turned the outer diameter to size, then drilled and tapped the M8 hole:


Then turned the part around, but was not confident on parting off the waste so cheated and used a hacksaw (lathe not turning).


Then onto the boring of the internal features:


As mentioned in another thread I bought a pair of calipers to check the critical bore diameter - it needed to house a sliding fit bearing, so I had to get it close. These are ~OK, but the adjustment handle is a bit low quality.


It seems to have a quick release slide facility - don't know if this is intentional or not? Maybe I'll replace it with a nice brass one now I have a lathe.


Here are the finished parts:


Bearing lightly pushed in a bit to check it will work OK:


Onto the adjustable brackets which are made from 25mm thick stock. I had to remove the clamp on the chop saw to fit it. This cut through 90% of it:

Then I turned it around and cut the last bit off:

Took about 5 minutes taking it steady. Very impressed with this saw.

Onto the CNC machine:


First one machined out:


Here it is next to the bearing housing:


Trial fit:



Last job is to counter bore and drill out the 4 mounting holes, then repeat on the second one. This screenshot is a bit out of date but the ballscrew mounts are on the far right of the gantry: