MadModder

Well that ran happily for ten minutes

M6 x 20 mm stainless cap heads arrived in the post this morning so I've re-sealed the turret interface box

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Ade - there were a couple of reasons that I went with the SBR12 rails over rectangular rails.  First, they were cheaper.  Second, I've got some history with circular rails.  40 years ago I was working maintenance in a plant that made laminated plastic sheets.  There were several saws in the plant used to trim off the rough edges and cut the sheets.  The plant ran 24/7 at least 5 days a week, sometimes 7 days a week.  I remember that at least 2 of the saws ran on fully supported circular rails, the rest ran on cam follower rollers.  In the 3-1/2 years that I worked there I remember changing many cam followers, I don't remember doing anything to the linear rail bearing blocks other than greasing them.  I'm not saying that SBR12's are better, just that I trust those rails.

One thing that I just figured out today is that I don't need to bolt the X axis rails to the base, then square and level everything else up to them.  The side frames of the CNC are 2040 extrusions, so I can bolt the rails to the side frames and save much tearing of hair and gnashing of teeth.  I'm going to use the "Easy" button.  I also discovered that the M5 x 10 SHCS that I ordered were JUST long enough that they bottomed out in the slot of the extrusion before the rail was completely tight.  I was not looking forward to having to trim that many M5 x 10 SHCS - no matter how I would have done it.  Then I remembered that I had ordered a bunch of M5 washers, 0.5mm thick, for my RT7R project - and hadn't used them yet.  "Easy" button time again, but I will have to order more - soon.

Thanks John. There are still loads of hurdles ahead. The servo action of the tool disc when fully loaded with its 45 kg of tooling will no doubt not be so crisp and that's where things went downhill previously failing to re-lock.

Worked for me..

QQ - I've often wondered about a linear rail/bearing upgrade to my CNC3018 (although, quite honestly, probably the only thing that would stay original is the motherboard, and maybe the steppers); the rails I was looking at are rectangular in section (e.g. the MGN12 range), whereas you've used the circular version (SBR12?). Was there any particular reason you went with the round rail, vs. the flat rail?