How to align 'universal' window espag keeps, front to back?

[Crimea]

I've fitted my new espag, but am struggling to work out how to correctly align the keeps, before I screw them down and leave permanent screw holes in the casement - maybe a few mills out. Annoyingly, the espag cams can't be adjusted, as the espag is a simple u-rail system.

I don't know the manufacturer or profile of my ancient double glazing (at least 20 years old), so I haven't been able to find the matching keeps and have had to plump for universal ones, including packers.

Do I have to resort to sticking some Blutack on the fixed frame and try to leave cam marks in it to check the position?

How do the pros do this?

 

[pinenot]

Don't the remote engage bosses/hooks have some adjustment on them, or the keepers slightly tapered inwards? ...pinenot

 

[Crimea]

Sorry for the late reply.

No, there isn't any possible adjustment of the cams. This is the espag:
http://shop.windowrepairshop.co.uk/Offset-Standard-16mm-Rail-Width-Espag-Rods-by-Avocet-WMS

The keeps have slightly tapered entry points, to pull the casement tight, like all keeps I guess, but my concern is that they could still be several millimetres out, even if the keeps do pull the cams/window casement in a little bit.

I just hoped there would be something to make this a bit easier than measuring as best as I can and guesstimating it.

 

[pinenot]

Look at the holes in the cams (as facing you in the pic.) you'll see these are actually hex headed (or similar) to take an Allen Key, the holes are marginally off centre, this is to allow a small increment of adjustment/fine tuning of cams to keepers/locator plates. Setting out is based on centralizing i.e. the measurements provided in the link you posted show the cams central to the arms, when measuring from the window frame checks, the keeper setting should be sett out the same.
copy/print the diagram (actual size) from the link, make sure of its scale, add on the window frame, now you can take the centre line of the assembly, check your keepers are not offset, transfer this dimension to your frame(s) and fit the keepers...pinenot