Mortice door latch problem

[Nightjar]

I'm in the process of replacing a bathroom door for my partner and it is one of those jobs where everything that can go wrong has gone wrong.

The latest problem is the mortice door latch. She has chosen the door handles she likes, so they are a non-negotiable item. The problem is that the shaft that comes with them is 1/4" square, while the follower (the bit with the square hole in it) on any tubular door latch that I can find is 8mm. The result is that the shaft partly turns within the follower and does not retract the latch fully before the handles reach their stops.

When I had an engineering workshop, that would not have been a problem; I would have taken a bit of 8mm key steel and milled the ends down to

1/4" square. However, anything I can do now, such as wrapping the shaft in a bit of copper pipe offcut, will be a bodge. Unfortunately, online searches either throw up mortice latches with 8mm followers or the follower size is unspecified. I have tried various searches to find an adaptor shaft with 1/4" ends and 8mm centre, but without success.

So, does anybody know of a tubular mortice latch with the centre of the follower 2 1/4" (57mm) from the door edge that definitely has a 1/4" square follower, or know of an adaptor shaft I can buy?

[Tim Watts]

Could you not just file the 8mm bar ends down to 6.35mm ?

Door handles are not precision engineering :)

[Nightjar]

The bar I have starts out at 1/4" and, in any case, I no longer have metal files or a bench mounted vice.

[Richard]

Try here:

they have a phone number for help or advice.

HTH

[Tim Watts]

I'd buy an 8mm bar off ebay.

A dremel would do it and be a good excuse to buy one.

[Brian Gaff]

Not a lot of help, but the last handle set I had had a plastic sleave, very thin and fragile, with it which was supposed to solve the two dimension issue. However the crap plastic lasted about a year then fell to bits creating the problem you describe. It does make one wonder why they have two almost but not quite sizes. I fixed it by bodging. Yes, I wedged some little shims of metal on two sides and put aralditearound it. Sorry. , not a good look, but nobody can see it when the handle set is screwed back over it! Brian

[Windmill]

I did exactly that to allow me to use some crows-foot wrenches (bought long ago from the US) for which I didn't have the required extension bar.

Rather than only filing by hand, I mainly used a grinding wheel in an electric drill.

And surprisingly, given my lifelong lack of skill at filing to get a desired shape, it worked first time.