Fitting a Sliding Sash?

[Geofract]

Is it normal to bespoke fit/adjust the bevel on the bottom rail of a Sliding sash window, where it meets the angle of the Cill?

I had expected they (joinery co) would have bevelled the lower rail, as per the old windows, but the lower rail is flat (90 degree). Apparently I need to do this on a per window basis. It's not the end of the world, I guess I can do that with an electric planer, I just hadn't anticipated that job.

 

[Jacob]

They should have finished it 100% on the bench including a trial fit of the sashes so they can go straight in after the frame is fixed.

 

[johnnyb]

of course they shoul just fit. this cill will be machine made at a definite angle therefore the bottom of the sashes should be the same angle . I'm guessing someone has made new sashes for an old case. then the adjustment advice is correct. also that is the fit of the meeting rail as well. ie how close the nibs on the meeting rail are can be adjusted by shaving the top sash top rail or the bottom sash bottom rail.
traditionally the whole thing is marked out together with the overall being from the front edge of the cill to the top of the case.

 

[Ollie78]

It's normal on fitting new sashes to old boxes. I always leave a bit extra for shooting them in, both for cill angle but also anything that might (almost certainly will) be out of square.
However, on a complete new window it should fit perfectly in the workshop before painting it.

Ollie

 

[owen]

A good way of cutting the bottom angle is to use a track saw, with an electric plane it is doable but a bit more difficult to get right

 

[Geofract]

Thanks everyone, I appreciate your replies.

As mine are old window boxes, then I can see why they've been left to fit on site.

I think I will need to bespoke fit the meeting rails too, which makes me a touch nervous, but I'll give it a go. I was planing on using a plane and sliding bevel to guide. Hopefully that's about right?

 

[LBCarpentry]

Sounds like they’ve provided you sash’s to fit into an existing frame. In that case, yes, they need to be trimmed and bevelled on site. The amount to remove from the bottom is governed by at which point the meeting rails sit flush. It can be quite a techy job for an amateur. Take too much off and your buggered…

 

[baldkev]

Use the bevel to take the angle off the frame and cill, transfer it to the bottom sash and draw those lines on the sides, joint them up across the back. That way you'll have a visual to follow.