how much can i safely cut off a wooden door's width?

i have been given a secondhand solid hard wood door.sorry i dont remeber the exact dimetions, but to make it fit the frame i have, it effectivly needs 30mm of each side.is this feasable or will i cut into the internal structure of the joints that make it up?
i know its hard to say without seeing it in person but someof you may well know how much material there is to play with..and obviously it will muck up the current lock hole but i think i can get round that.
cheers in advance..

Try it and see?

Also look on the ends, can you see the width of the stiles?

the ends just look like a single block of timber?
i was just trying to guage if this was an obvious no/no…

Chances are you’ll cut into and expose the bottom of the mortises if it’s constructed in that way. I guess if you painted it, then this won’t be a huge issue.
It was free….give it a go.

Sounds like you’ve no option other than to give it a go doesn’t it?

Save the offcuts, if you are left with holes insert bits to fill them. There’s prolly a proper woodworking term for this.

Depends on how much has already been taken off already.

I took approx that amount off a door, perhaps more like 1.5 inch so maybe a tad more than you. It exposed a set of three dowels top and bottom on each edge. In fact the off-cuts showed that we only just exposed the dowels as the drilled hole for them was only just exposed. The door is hung and not open very often so you don’t see the dowels. No apparent loss of strength. This door was a 1930’s 1 over three type door. Don’t know if the same applies to more modern doors.

Best advice as above is to look at the ends.

slowoldgit – Member
Save the offcuts, if you are left with holes insert bits to fill them. There’s prolly a proper woodworking term for this.

Yes there is, its called, using offcuts to fill the holes. 😀