Mechanical build was going well until I went to mount my end plates with the MakerSlides. Basically the mounting slots are too close together. So looking at the MakerSlides through the slots of the end plates I'm seeing this
( o) (o )
or this
( o ) (o )
Where I'd hope to see
( o ) ( o )
Does that make sense?
My M5 bolts have to be really forced through the slots anyway - even after removing all the paint - and the tight clearance between the end plate and the tapped hole is forcing the bolts in at an angle so they won't catch the tapped thread properly. The holes are tapped fine, I can get bolts in easily when there is no obstruction. Even if I'd screwed up the tapping of the holes I don't believe they'd take them significantly off centre.
I've had to drill out the corners of the top slots with a 6 mm bit to be able to get the frame together at all but obviously this is really unsatisfactory and doesn't give me 6 mm across the full width of the slot for adjustment. The gantry will move but it's pretty stiff.
I'm kind of really disappointed to be honest ... I think it's a given that there will be lots of inexperienced people building this thing but to think the parts start out inaccurate even before I get my clumsy mitts on them is worrying!
Has anybody else run into this problem. Is there anything I can do to confirm or otherwise the end plates I have? Would it be possible to get a couple of replacements? I don't mind paying. I just feel like I've spoilt my end plates now but it wasn't really my fault!

(Sound of violins

Unless the tapping of the holes can take them significantly off centre if done poorly? (Although I think I did them well!)