Metal re-inforcing in uPVC sash window - how far into corner to drill?

[Careful_Bodger]

So, if I wanted to add sash jammers or restricters, say, how far does the metal section run into the corner (usually) to ensure the fixings locate into it?

I read somewhere that during profile welding, the metal does not run all the way into the corner, which is fair enough, but how far?

TIA

 

[crank39]

About 100mm away

 

[Careful_Bodger]

About 100mm away

I assume that is the minimum recommended distance from the corner for a fixing hole. Is that correct? If so, how close is the metal to the corner weld - surely not 4"?

 

[crank39]

Yes and yes

 

[Careful_Bodger]

Yes and yes

Wow - really important info! Thanks!