Thread: Advice - timber and ideas for window making

A lot of questions Lucas!

Making sash with basic gear is not an easy task, even for a seasoned cabinetmaker, that frame needs to remain flat and corner joints sound. However, anything is possible if you go at it carefully & methodically. Through, wedged, M&T is the traditional corner joint. If you use any sort of moulding on the outside & inside as per standard practice, it complicates cutting the shoulders of the M&T joints - quite do-able, but needs care & patience when done by hand, if you want seamless joint lines. The alternative is to make the frame and add the glass rebates & moulding with a bearing-guided router bit, but the resulting "masons' mitre" in the corners looks pretty amateurish to my eyes.

Your wood requirements are somewhat conflicting. Oil is not a durable finish for exterior surfaces, so you'd be better off choosing a durable softwood like Western Red Cedar, imo. Is the ember risk not heightened by oil/paint anyway? Whatever, the small thermal advantage you'll get from wood sash will probably pale into insignificance when compared to the heat-loss through the glass, unless you intend to double-glaze. (If I lived in a fire-prone spot, I don't think I'd be using wood anywhere on the outside, tbh!) Up where I come from, Cardwellia was a common choice for window sash, it's a hardwood, but it's not super durable if exposed to weather, it likes a few good coats of paint. Australian red Cedar was another, way, way back, soft but very weather-resistant.

Casement structure is pretty standard, take a look at some existing casements & you'll quickly get the idea. They derive their structural integrity from being fixed to the framework of the building, so they are not very elaborately made. Older casements usually had the sides sitting in a shallow trench in the sill & top, but modern ones are mostly butt-jointed & screwed.

5. Any ideas for the narrow pieces to go between the sliders to keep them on track?
Not sure what you mean here - are you referring to the jambs (the moulding the sash close against), or are you intending to make double-hung windows? The jambs are usually nailed to the casement. On the old rope & pulley type, there was usually some access provided so that the rope could be replaced down the track. The ropes deteriorate & break, eventually, which is why you see so many propped up with sticks...

Cheers,

Hi Lucas
Happy New Year

Lost Art Press have a book called Door and Window Making. It's available in both hard copy and electronic format. It's a 112 MB down load.
Although the book is published in the US, the content is essentially a reprint of a thoroughly English publication originating from the early 20th century. In other words it covers how to build a window the right way. The only modifications you will need to make is increasing the thickness of components to accommodate double glazing.
The book is highly recommended as it covers both the design and construction of sash windows -- especially how to layout the components for fabrication.

straight up, if the new windows have to pass some form of certification test by either the local council or bush fire people it might be best to forget about making your own windows right now -- the certification process will more than consume any potential savings from making them yourself.

Originally Posted by LucasT

My timber skills are limited but I'm a quick learner ) and I'm keen. I have worked a lot in steel, taught myself to weld, am pretty good at fine details. I have a wood lathe and have made a few bowls, plates and rolling pins. I can rout an edge or a hole but haven't made a mortise/tenon joint yet but have watched a few on youtube and think I could do a reasonable job.
If I go ahead with this project I'll make a few windows myself (as many as I can) and will also pay my young adult sons and one of my staff to make some and take the load off (I have a busy business and limited time). My sons did wood work at school and are happy and capable at the basics.

in reality, given the learning curve, I think you should either build all the windows yourself, or pay one of your adult sons to learn how and do all of the work. It might be an option to pay an adult son to do all the timber dimensioning for you, but that is a skill that is rarely taught at school, where because of the risks, the dimensioning is done by the teachers.
Paying a staff member would, IMO, just be outright stupid. Building timber sash windows is skilled work -- you would be far better off paying a skilled commercial joiner to build all the windows for you than hoping to get acceptable quality from unskilled staff. Or, IMO worse, paying the staff member to acquire the necessary skills. Either way, in an OH&S sense you are responsible for any injuries suffered by teh staff member while building your windows.

My questions.
1. Timber recommendations and source? I'm thinking 30X70 and 30X90 for the sashes and 25X220 for the frames (I realise I'll need to join boards). I would appreciate recommendations and ideas for suppliers.

in respect to dimensions, please refer to the Door and Window making book

2. I'm thinking to buy a table saw like a dewalt 491 and possibly a thicknesser if I end up with un-dressed timber for the right price. I can buy a biscuit joiner to join boards to make the 220mm frames. I have an old plunge router to so some mortise/tenon joints for the windows. I have other projects down the track to use the tools later - book shelves, kitchen cupboards etc. Or I could sell them after the job is finished. Does that mix of tools look sensible?

No.
I'm being deliberately harsh precisely because your wood working skills are limited and you are taking on what is in effect an exercise in small scale production.
As I interpret what you want to do, you are fitting custom dimensioned windows into an existing opening. Although you might be able to start with dimensioned boards, the finished window components will be some other dimension.
I suggest that at a minimum the tooling you will need
a) a cabinet saw.
b) a 8 inch jointer, but a 10 inch wide unit would be better.
c) a thicknesser -- a combo unit like the Jet JetJPT-310 12 inch Jointer Thicknesser with spiral cutter head https://www.carbatec.com.au/machiner...th-spiral-head would, I think, be a better choice for both the jointer and thicknesser.
d) a hollow chisel morticer -- probably a floor standing model
e) router table and router, or shaper. A shaper will allow you to cut much bigger moldings and rebates than is easily doable with a table mounted router.
f) drum sander.
g) very nice to have -- 10 inch miter saw
h) power feeder for the shaper or table mounted router.

The above list is based on your production process being
1) dimension rough sawn boards. Tools required -- miter saw, jointer, thicknesser, table saw, drum sander to remove the marks left by the other tools.
2) cut the joinery -- this is what the hollow chisel morticer is for
3) create the required rebates and moldings -- this is what the router table or shaper is for. Depending on the number of components and your time frame, it may pay to have two machines -- one setup to do the rebates, the other to do the moldings.
the order of (2) and (3) might be reversed.

3. Sashes - Is it crazy to consider making mortise/tenon joints for every sash? nope. That's why I suggest you acquire a hollow chisel morticer. Or would it be smarter to use half-lap joins (glued and screwed)? nope. Definitely not smarter unless you intend selling the house immediately after you finish making the new windows. My inexperience leads me to spend a bit longer and make proper mortise/tenon joints - but is this unrealistic with my limited tools and experience?

your plan is realistic IF you are prepared to tool up and spend the time learning and then making. See previous comments.

4. Frame joints (probably using 25mm timber). What's a good join for the corners? Do you think a simple box join with screws is adequate? Or a finger joint? lots more work. Or is there a better join you'd recommend?

there is a right way to build timber windows and lots of wrong ways -- using screws to substitute for good joinery is just one of the many wrong ways.

5. Any ideas for the narrow pieces to go between the sliders to keep them on track? I'm thinking I rout a groove and tap and glue in a 6mm piece of hardwood.

please obtain and read a copy of the reference I suggested at the head of this post.
There are other, more comprehensive references, however, typically they all date from the beginning of the 20th century.