Here we go again . . . MK4

[routercnc]

Time for one of the side jobs. The linear carriages are buried inside the Z axis box so there is no easy access for greasing them. So I designed some remote grease nipple parts, turned from some 10 mm brass bar. Here are some of the almost finished parts (4 off assemblies required, so 2 bits to go . . .plus threads need tidying . . .):


First job was to check the thread size and pitch for these 20mm hiwin carriages - turns out they are M6x0.75 (M6 fine).


So I ordered an M6x0.75 spiral fluted tap and an M6x0.75 die. Quick check to see that I got it right (using the nipples which came with it):


I had some errors transfering the photos for much of the next steps (files were corrupt) so I'll have to skip a few. First part being turned:

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Then screwed it tight into the carriage and scribed a line on the direction of the outlet tube, and a line perpendicular to that one. This is so the outlet tube points in the right direction (as you will see later), and so that I could align the centre in the vice (next op):


Then I made a fixture which would hold the part and used the perpendicular line to get it in the centre. The outer dia of the fixture was tight against the end stop. This all put the part in the same repeatable position, so I can machine 4 off flats and holes:


Here are the first 2 assemblies, tightened up and pointing the right way (phew!):


Trial fit:


View from the outside:


I'm just in the process of tidying the threads (undercuts, slight taper on first few threads, etc.) so they insert fully home. I've also got to add 2 flats on the outside near the grease nipple so that can be installed/removed with an M8 spanner.

The 4 upper carriages will have this system, but the lower 4 will have the bolts in until they need to be greased then an access panel will be removed from the underside of the Z axis (which keeps out the swarf as it is near the spindle), then the bolt removed and a long straight nipple extension screwed into each carriage in turn. So I only need to make one adapter for the bottom ones and keep it somewhere safe. That's the plan anyway.