Secondary glazing

[Planeiron]

I was going to suggest stepping up through the bit sizes. Another technique is drilling through an acrylic mirror. An old CD can also work. I've never used the technique but have heard it being used in timber framing for drilling holes.

https://www.wwgoa.com/video/how-to-drill-perfect-holes-using-a-mirror-000912

 

[Windows]

I like the ring & mirror ideas. Going from 3 to 12 and also with one size in between didn’t help me though. This bit goes where you point it, it seems.

Is there such a thing as a bit with a long, blunt nose so that it actually has to follow the path of a pilot hole? It’s made me curious about bits with unusual geometries.

 

[Windows]

Looks like my mistake was trying to use the little driver which only has a hex bit holder instead of a chuck - too much play in it. Using the big drill with a proper chuck, I got similar results for the 12 mm bit as for the 3 mm bit. Not perfect, but close enough.

 

[Windows]

Started cutting M&Ts with a combo of hand saw & router. Did one M&T, changed the layout halfway through to better align with the rebates, decided to cut a bunch of tenons. Made a lot of dust. It’s going OK. Might have been easier to do the M&Ts before rebating

 

[AndyT]

Might have been easier to do the M&Ts before rebating

Yes. I've not done much framed stuff but I believe that for hand tool production the normal order after marking out would be to cut the mortises, then the tenon cheeks, then the rebates (or grooves,) then the tenon shoulders.

I don't think using a handheld router would alter that sequence.

 

[Windows]

I’m sure you’re right. I was planning to do more machines & jigs/templates, but I’ve ended up doing a weird hybrid. When I cut the rebates, I thought I maybe wouldn’t even mark anything on the pieces (ha!), but I drew a lot of lines today. For the one mortice, I just chiseled it out. For the tenons, I cut the shoulders fairly precisely with a flush cut saw, rough cut the cheeks with a ryoba so there wouldn’t be too much routing dust then levelled with the router. I experimented using a non-powered router at first, but the one I have is too small really and the depth setting on the electric router is easier.

 

[Windows]

This is the M&T layout that I decided on (numbers are mm).


It’s not centred, but that allows the edges of the M and the T to align with the edges of the rebate. When the rebates are already cut, this gives extra guides for keeping things aligned. It also manages to keep two of the tenon shoulders the same size.

 

[Windows]

 

[Windows]

The marking up on the tenons was done quickly and I didn’t worry too much about complete lines because only the shoulders were final positions cut by the saw. The other lines were really just guides for off-the-line hand sawing - the final dimensions were provided by the depth stop of the router and the hand sawing was to reduce the amount of dust and avoid having to take multiple passes with the router.

 

[Windows]

I’ve done a couple of mortices using plunge router & chisel. In the process of adjusting the fit, I could see that the rebate wasn’t full depth so used the router to put the rebate right.

I think if I was more prone to panic, I could have made things a lot worse. The initial fit was terrible - gaps at an angle around the shoulders - and I had a slight urge to start hacking at the tenon to make things parallel. But it wasn’t a big deal in the end. In addition to correcting the rebate, I had to clean up right at the tenon-shoulder join just a little and then the rest was minor adjustments in the mortice. Using the edge of the chisel as a scraper to remove some stray hairy bits of wood in the mortice was useful.

 

[Windows]

I’ve mostly got one casement with simple (non-wedged) M&Ts cut & dry fit. Still a bit of adjustment to do, but it goes together so I thought I’d check exterior dimensions. I’m going for 468 x 1013 mm, but I’ve only got 465 x 1007 mm and this may shrink a fraction as I adjust the M&Ts for a better fit.

3 mm on the width could be explained by wood undersize and rebates oversize by a smidge, but 6 mm missing on the height is a lot so I must have blundered.

I still need to check interior dimension to see what’s up.

I haven’t started on the frame so have some options, but I’ve cut all the rails & tenons. The remaining stiles only have rebates.

So I think I need to work out exactly the source of the error first. Then hopefully avoid it for the next ones. Which may not be possible for the width (in which case, frame can be built to cope with the new reality), but should be possible for the height.

For this current one, I guess I could increase the height by enlarging one or both mortices outwards and filling the extra space in the mortice. My stiles are overlong so that should be doable.

Everything’s going to be painted so no worries about patch being visible.

 

[AndyT]

In hand work, the conventional way to get a set of frames all the same size is to mark all similar bits at once.

Cut a set of rails roughly to length, plane them straight, square and to size, then stack them up horizontal, in pairs. Fix down with a cramp if needed. Then use a large square to knife in the location of the tenon shoulders across all the pieces.
Separate them, then extend the marks around the other edge and sides, working off face edge/side as needed.

Repeat a similar procedure for the stiles, marking mortise ends and overall length.

Hope this helps and isn't too late...

 

[Windows]

Thanks Andy. I marked up in pairs as you describe from face & edge (only one set of stiles so far though) - except I used a mechanical pencil, not a knife. For the stiles, I possibly miscalculated or misread a number. Something silly. I'll work out exactly what tomorrow. For the rails, I think it's going to be a couple of inaccuracies working in the same direction: any deviation of the actual size of the material from the 44mm I used in my calculation is doubled (because of two ends) as is any deviation of the rebate depth from the calculated depth. I was aware of the possibility of inaccuracies, but had it in mind that the result was going to be a frame that was too large that I would simply cut down to size. Wasn't really thinking about ending up too small.