festool rails

[ekuntze@mac.com]

my festool rails (800/2 and 1400/2) have two grooves, one at the 'end' with the opening to the top and one on about 2/3 of the width with the opening to the bottom (the groove used to guide the plunge-saw)
I tried to use a 'dog' with a nutstein in the groove with the opening to the bottom - however the nutstein does not fit in this groove, but it does very well in the other groove ... I measured and found the following: nut stein: 12.2 mm, groove1(opening to the top): 12.5 mm and the groove2 (opening to the bottom) 12.1 mm.  this is the same for both the FS800/2 and the FS1400/2)
Is this difference normal? shouldn't these grooves have the same inner diameter?  Anyone with experience with the dogs and nuts for these grooves?  Kind regards

 

[Coen]

The one to the bottom has to hold the clamps. The one to the top doesnt and having it's opening wider facilitates easier sliding of stops.

 

[Crazyraceguy]

There are some rail-dogs out there that are specifically designed to work in the lower groove, but I don't remember the name right off? From somewhere in the UK I think?

 

[ghhsolutions]

https://benchdogs.co.uk/products/guide-rail-dogs-grooved?_pos=1&_sid=0716f6baf&_ss=r

There is lots on YouTube about these.