Window Sash Pulley

[Eko]

I live in a 100+ year-old home with no shortage of projects. The current one involves a complete refinishing of two original double-sash windows and frames, and replacing the hardware (pulleys, counterweights, and sash cords). I've replaced sash cords and counterweights before which is easy and straightforward. However in this case I also need to replace 8 pulleys. Normally this would be a non-issue, a simple swap. But the new pulleys have larger plates with a corner radius and are not rectangular like the old ones so obviously I need to modify the mortise size and shape slightly. I'm trying to decide how best to do that.

My initial and obvious thought was to use a chisel. My chiseling skills are modest but solid. Though the thought of cutting 32 consistent corner radii by hand is daunting. But the ability to go slowly and (hopefully) reduce the chance of cutting too deep, wide, or long is definitely a positive. The alternative is to use a trim router which would just fit. I like that the depth of cut would precisely match the original and it would make cutting the corner radius for the plate cleaner and quicker. Of course without a template it would be very easy cut it too wide or long. Though I suppose a little wood filler would take care of any (small) mistakes. Still, I would prefer to make precise cuts and avoid any patching after-the-fact if possible.

If anyone has experience with this sort of thing or knows of a different/better approach I'd like to get your insights.


Thanks,

Todd

 

[Duckler]

Would it be possible to use one of those power-files? THe ones that are like a mini-beltsander.
Perhaps a Forstner bit in your drill could do the rough form.
Might help to see some pictures over here.

 

[waho6o9]

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Google has some interesting ideas for your pulleys. Seems like a fun project, all the best.

 

[Crazyraceguy]

If the router does indeed fit, I'm thinking a template and bushing would be the most accurate. Failing that, I would look for a gouge with the same radius as your brackets. This will definitely help with the consistency of doing it by hand.
I would guess that the newer version was made with a router in mind, where it could be totally machine cut. This would take the manual labor/chisel skills out of it totally, speeding up the process and taking the need skill away.
There is still a little required. Unless they sell a matching template, someone has to do that. Oh, and of course you need a router.

 

[Michael Kellough]

This pulley simply requires a shallow mortise made by a 3/4” drill.

In the old days when your house was built the carpenter would have used a Jennings pattern auger bit to drill/cut a series of overlapping shallow holes to make the mortises for the pulley, but would have stopped a little short of the ends to make the square cuts with a chisel to accommodate the hardware of the day. You’ve probably seen the evidence of this tool, if not in your windows, then in the mortises of your door hardware. Now the manufacturers make the ends round to eliminate the last step.

You still only need a drill, and a Forstner bit to make the ends of the existing mortises round, assuming the new hardware requires longer mortises than the existing excavations.

If you have a drill press and make good measurements it’s easy to make a jig for the Forstner bit (if careful you can make do without a drill press). A simple hole through 1/2” thick stock is plenty to guide the Forstner bit. The one caveat is that the original mortises are probably not as consistently laid out as you’d hope, so you might need to modify the jig with sight lines that pass exactly through the center of the jig holes to help you align those jig holes with the existing mortises.

 

[Packard]

I read once that having a house with sash weight windows was the functional equivalent to removing your front door in terms of heat loss.

Apparently the uninsulated section that houses the weight is the culprit (multiplied by all the windows).

As much as I admire a fully restored window, I don’t favor replacing sashes. There are some very nice friction systems that are available that maintain the original appearance. They allow for replacement of the missing insulation, and are faster and easier to do.

Perhaps trying that for one window first, and then evaluating the appearance makes sense. You can always add new sash weights if the result does not meet your approval.

 

[Eko]

Failing that, I would look for a gouge with the same radius as your brackets. This will definitely help with the consistency of doing it by hand.

@Crazyraceguy Using a gouge is a very interesting idea and would certainly make cutting the radii easier and consistent. And it's low-tech which I like.

 

[Eko]

This pulley simply requires a shallow mortise made by a 3/4” drill.

In the old days when your house was built the carpenter would have used a Jennings pattern auger bit to drill/cut a series of overlapping shallow holes to make the mortises for the pulley, but would have stopped a little short of the ends to make the square cuts with a chisel to accommodate the hardware of the day. You’ve probably seen the evidence of this tool, if not in your windows, then in the mortises of your door hardware.

@Michael Kellough I have seen some evidence of this on some of the door mortises but I wasn't aware of a Jennings pattern auger bit. I learned something new.

I do have a drill press, Forstner bits and a lot of extra 1/2" stock. I think I'll try making a jig and do some testing. This has possibilities.

As for possible alignment issues with the original mortises that's almost a given. This house is almost ridiculously overbuilt but I don't think there's a 90deg, plumb line, or perfectly aligned anything to be found. Close in many cases, very close, but not quite.

 

[Eko]

I read once that having a house with sash weight windows was the functional equivalent to removing your front door in terms of heat loss.

That's an interesting point and something I've never thought about until you mentioned it. In my case the walls are only lightly insulated so while the weight boxes may indeed be a weak point in terms of insulation they aren't the biggest offender. Replacing the windows isn't a viable option for us. And despite the cons we like traditional weighted sash windows. It's part of the charm and old-world craftsmanship we want to preserve.

 

[Michael Kellough]

What is your geographic area?

 

[Eko]

Great Lakes region.

 

[Michael Kellough]

Great Lakes region.

Like Packard, while I applaud your efforts to preserve the character and details of the house, I wonder what your heat source is.

 

[Eko]

To be sure the house "breathes" much more than what some would consider acceptable, certainly by new construction standards. There's no question the weatherproofing could be improved but as it stands the heating cost is not excessive for the size and is in line with and in some cases less than our neighbors' similarly sized and constructed (very) old homes. I imagine the storm windows contribute a degree of insulation value, though perhaps not enough to offset the uninsulated weight boxes. Actually, the most obvious and problematic energy leaks/drafts occur around the doors. Another project I've been working on recently.

Even in below zero temps. we've never felt the need to raise the thermostat beyond the high 60s.

 

[Packard]

Like Packard, while I applaud your efforts to preserve the character and details of the house, I wonder what your heat source is.

I kind of thought everyone was going to gang up on me for my suggestion. It is nice to have a reprieve.

 

[Packard]

Tom, from This Old House, walks two apprentices through the installation of a sash replacement kit. The home owner opted for replacement of the window too, but I don’t think that is required. The kit looks pretty sophisticated. The installation appeared to go quickly.