Convert Bi-Fold Doors to Small French Doors

[Marc]

Hi There,

I've received my custom order Bi-Fold doors which I was planning on hanging like french doors with 2 hinges on the outside edge of each doors. I've mortised the doors and the jambs to mount the hinges and I am now trying to figure how much space to allow around the doors for them to open and close properly. I was thinking:

1/8" for the Top 1/4" for the Bottom 1/16" X 2 for both hinge side 1/8" for the middle where the 2 doors meet.

I know I will probably have to bevel the back inside edge of each door so that they open without rubbing each other. How much of a bevel will I need? How can I figure this out?

Thanks

Marc

[squarei4dtoolguy]

Your estimates of spacing sound pretty good. I usually see between 1/8 and 1/4 between panels. If you were planning on installing an astragle (spelling?) strip to cover the space between the doors, I'd go 1/4. If after you have installed the doors, they touch. Pull a panel up snug to the other and trace the line. Take the hinge pins out and set the door up for your largest hand planer. Use the traced line as your guide to bevel to. Or measure the distance from the edge to the mark and split the bevel between the two panels. I'm that picky.You should find that it is a very slight bevel, maybe 2 or 3 degrees. It will be a tighter angle for more narrow doors.

Tom in KY, with a french door that needs planing in my own house.

[Wes Stewart]

Trigonometry. Let width of the face of the door from the hinge point to the opposite edge have dimension 'A' and the thickness of the door have dimension 'B'. The length of the radius that the back edge of the door swings through will be 'C'.

C = sqrt (A^2 + B^2)

You don't give the width of the doors but for example, say they are

12" wide from the hinge pin to the opposite edge and 1 1/2" thick.

Then C = sqrt ( 12 * 12 + 1.5 * 1.5) = 12.093", so with zero gap between doors there would be 2 * .093" or approximately 3/16" of interference between them if you tried to open them simultaneously.

With only 1/8" gap then you need to back bevel each door enough to remove 1/32" on the back side. The required angle can be determined by taking the arctangent of (1/32) / (1.5) or a bit over 1 degree.

Of course this kind of precision is foolish when working with wood, and it's not quite exact if the hinge pin is proud of the face of the door, but you get the idea.

[Marc]

I wasn't planning on using a strip between the two panels but I would like to get the doors as tight as I can. I don't have any hand planers and so was thinking of beveling the doors on the table saw. Do you think that a bevel of 0"-1/8" from front to back of the 1-3/8" doors would be sufficient or should allow more? BTW the doors are 13-3/4" wide.

[Marc]

Thanks for the reply! Exactly the information I was looking for!

[squarei4dtoolguy]

You have a carpenter's best production answer and a good scientific formula to determine the tolerance required.

But if you are worried about the hinge pin location or the swing of the doors in relation to the pin location, Maybe you should find a scrap of ply-wood or a piece of 1x6. Draw the doors as you would want them to look and when you have the spacing that is acceptable, Use tramel points or a home-made compass to mark the swing of the panels. One point in the middle of the hinge pin location and the other at the furthest corner from the hinge where the doors meet. Then mark the other swing for the other door. If the radius marks cross then that is the amount you need to remove.

*_________________ I_________________I/

• being your hinge pin location and I/ pointing to the other point most likely to rub the other the other panel.

Tom