Quote Originally Posted by Nr1madman View Post
Ive read that Ali extrusion isnt flat enough to mount rails to (but Ive seen many builders do so) What do you think about machining a flat steel strip maybe 30-40mm wide, 4-6mm think and mount this between the rails and extrusion? Just drill through and use a longer bolt for the rails? Or would I just get the same imperfektion in the steel when I thighten the bolts?
Depends on what precision your looking for.? If mostly cutting woods, plastics etc with the occasional bit of aluminium profiling etc then Aluminium profile is perfectly fine.
There are a few things you need to take into account thou. Rail width and slot size need to be matched. For instance I wouldn't use 10mm slot with 15mm rails as this can cause problems due to profile slot having rounded edges. You need plenty of rail each side of the slot.
I use lots of profile with 8 & 10 slots but always with 20mm rails and don't have any problems.