On a job like this it is often better to start with oversize stock, cut the difficult feature, in this case the Vee and then bring the overall down to size.

As you have it set up already I would say rough out the Vee to give a decent size notch. Place a ground rod (cutter shank) onto the horizontal cut & touch off on the top of that. Then with a bit of additional trig you should be able to work out how much lower the cut needs to go in relation to the short edge of the block.

In the example below the finished position of the rod is 55mm from the end, as you say you can set X then with the rod resting against the finished X face and roughed Z face measure the length, subtract from desired and the cut should be 1.414 x the difference between measured and desired. You can use more decimal places if you want teh accuracy such as 1.4142136

An alternative – I’m not suggesting it’s better than Jason’s method, but might be easier…

If you have a Vee block, you could sit the Vee on the rounded-over/deburred upper corner, and clock its upper surface (its base), for use as a Z datum. (Also another way of setting the block’s angle.) A bit of trig., and knowing the Vee-block’s dimensions then allows you to work out the vertical distance to the machined feature’s horizontal surface.

If the position of the V is the most important measurement I would sit the piece in a vee block and clamp to an angle plate. Then by taking a cut only on the end of the cutter to a fixed depth, the job could then be reversed in the  vee block and the same cut taken on the other side of the vee, it should at least be central.

Perhaps the bottom of the vee could have slot rather than a sharp corner, this would make the whole thing easier to produce.

Andy.

On 28 October 2025 at 22:55 He Who Dares Wins Said:

 

Problem is that I have blocked everything up accurately…………….

I thought the issue was locating the vee in the ALREADY set up work

Not the best way of doing things but start to cut the vee and once deep enough put a dowel in the vee use a depth micrometer to see how close you are to the desired position, adjust z and x to arrive at the correct positional dimension but not deep enough. Once that’s done you can move z and x the same amount and the actual vee position will not move.

Tony

By far the easiest route would be to drill and ream a dowel hole, or tooling hole at the Vee location. The dowel hole would assure centrality and using coordinates to locate the hole it can be sited a known distance from the Vee faces.

Using an edge finder against the dowel the vertical centreline can be found. With feeler gauges, the end of the cutter can be set to the top of the dowel and this will give the horizontal centreline. Then machining the Vee faces becomes a breeze.

Regards

Gray,

Blowlamp’s suggestion is excellent. A machinist’s chair type edge-finder would be another way to go about it but of course you need to have one, or make one.

That is where my method would still work, just a bit of different trig to get the amount you need to lower the tool whatever the angle of the work.

I dare say Blowlamp’s could also be made to work if the trig was altered, though if the angle became very shallow you may loose accuracy touching off on the shallower sloping edge.

Try this: Clamp a flat to the under edge that is sloping up to the right in your diagram. Sit a clean good square block (or other known shape) between that and the uppermost surface. Actually a round might be best. This gives you an new good top point with an offset that is easy to calculate from the size of the workpiece and the size/shape of the block.