Wadkin BRA - play in wedge lock

[guineafowl21]

Here is the machine:

And here is the 45-90-45 locking mech

There is rotational play in the arm even when the wedge locking lever is firmly located, and this is the case for all three positions, even the rarely used left mitre. So I think the problem is in the lever wedge, not the column cutouts.

The wedge does not bottom out radially, ie there’s a good gap between it and the bottom of the column cutout.

Using a marker pen, I can see the contact patch is at the lower edge of the wedge, so the play is at the top (greatly exaggerated in diagram - it’s about 0.1mm each side:

Should I file at the lower end of the wedge, or run it over a diamond plate, or something else?

 

[TFrench]

I may be getting the wrong end of the stick but it sounds like you need to add material, not remove it?

 

[guineafowl21]

I may be getting the wrong end of the stick but it sounds like you need to add material, not remove it?

The wedge still has some travel before it bottoms out in the column cutout, it’s just binding at the lower edge. I thought it would be easier to reshape it.

I’ve seen a gunsmith, in a similar situation, braze on a shim. He then used lamp black to assess the contact patch, filing away at the high spots until decent contact was achieved. I haven’t got brazing gear, but I thought of building up the surface with my arc welder and cast rods. This may result in ruining a rare part, however.

Another option would be epoxy for the shim, but I’m not sure if that would be strong enough.

 

[deema]

Do you have any other pictures of the wedge, something doesn’t look correct. Here are some picture of mine

The wedge is in line with the socket it fits in to, your looks to be too low.

 

[guineafowl21]

@deema I’ve had a look and yes, my wedge is lower than yours. However, the pivot bar isn’t bent and I doubt the pivot castings have bent. I assume my wedge was always in this position, but not sure.

I seem to remember trying the wedge on its own in the cutout, and it always bound at the bottom, wherever I tried it.

 

[deema]

It’s been a long time since I had mine apart, however, I think the shaft is eccentric to allow the wedge to sit square and true into the slot I think you need to experiment with rotating the shaft and locking the wedge in different positions on it. I think you will find it will sit true when positioned correctly.
I believe your problem is due to the wedge entering the slot at an angle and therefore not seating properly due to it being located on the cam at the wrong orientation.
I seem to remember having the wedge loose and rotating the shaft until I could get the wedge sat true in the slot and then tightening it onto the shaft followed by a few tweaks to get it perfect.

 

[guineafowl21]

Thanks @deema - mine may have been fiddled with, because there’s a very distinct depression, possibly drilled, in the shaft for the grub screw, and the shaft itself is plain, not cammed. It may be a replacement.