Tuesday, July 2, 2013

Window Factory

 All of our wooden cars have wooden window frames, of course, and we often have to make replacements.  Want to see how it's done?  Click on the post title ("Window Factory") above.

Problem: This window has a badly rotted-out corner.  Both the bottom rail and the stile are bad.  And this is right where the spring window latch was located, so just filling the hole with epoxy won't solve the problem.  And since I hate stripping paint from these old frames anyway, that tips the balance in favor of making new frames.  A lot of the effort goes into setup, so we might as well make three while we're at it.

So let's pay a visit to one of the secret Hicks Car Works underground facilities.  The only power tools we'll need are a table saw with a dado set and a hand-held router with a 1/4" straight for mortising.  These frames will be painted, so almost any hardwood could be used, but we'll choose poplar because it's easy to work, relatively light, and stands up well.  Enough 4/4 stock for three frames cost a total of about $17.

First we rip the stock to size.  The stiles are left slightly too wide so the final width can be adjusted, and the bottom rails are much too wide, since the bottom edge will be beveled to match the window sill.

Next we rabbet all the rails and stiles, using the dado set.  The fence needs some sacrificial wood facing, since we have only a set of 1" flat cutters in this family heirloom dado set.

Now the rails need to be tenoned, if that's a word.  They are crosscut to the exact length needed, then the dado set is repositioned and the rails are fed through crosswise, nice and slow.  They come out looking like this.  One needs to be careful to get the spacing right on the two sides.

And then they are quickly trimmed to size with a handsaw.  That was the easy part.  Mortises are a little more challenging.  IRM's woodshop has a nice big mortising machine jealously guarded by Bob Kutella, but we can accomplish the same thing with a router, at the price of more time spent with hand tools.

The stiles are clamped into the vise, and a few boards nailed to the workbench serve as guides for the router.  A plunging router would be nice, but isn't necessary.  The router makes a 1/4" mortise with rounded ends, then a combination of squaring and widening the mortise with chisels, and trimming the tenons with a rasp, gives us a nice tight fit.

Let's place the fitted pieces on top of the old frame to check for squareness.

Now the frame can be glued.  We'll use a slow-setting two-part epoxy.  A band clamp works well for a project like this, and takes up much less space than large bar clamps would.  While the glue sets, we can work on the next set of parts.

After the glue is dry, the frame is trimmed, particularly the bottom edge as seen here.  With some sanding, it's ready for paint.

 Another detail is the sash springs, which are screwed into shallow grooves along one side of the frame.  These keep the window from rattling as the car rolls along, and also insure that the latch will keep it from falling.

The 1/2" groove is made by cutting some slots on the table saw and chasing it out with a chisel.

And then each frame has to have its number incised at the top, so we can always get it back in the right place on the car.


David Wilkins said...

You put Norm Abram to shame.

Anonymous said...

Really amazing what you do and what you did. Just think what you might do in our shop. Want to do a qualification run on our machines so you can have a set of the secret keys?

The work looks very good.

Bob Kutella