How to hold work-pieces at strange angles for drilling. A special Vice ???

[Mr shiney]

I made this recently for this exact purpose. I restore motorcycles and have the same problem on a regular basis. I use a clamping kit on 5/8" UNC bolts to hold stuff to the plate. You can pretty much fix anything to it at any angle. I set the angle with a digital protractor.

It just clamps into a regular milling/drilling vice.

 

[Mr shiney]

I will add the technique I use on cylinder heads is to hold them flat to the face of the plate on the machined face of the head with long clamping bolts coming through and the some flat bar on top to pull it tight.

I then use a small milling centre drill to create the initial pilot hole using a collet chuck. This prevents wander and ensures I go in bang on centre. After that it's a case of slow and careful and increasing the drill size enough to get the extractor in. Left hand drills are very good for this as they apply all the torque in the right direction.

I normally start with heating the stud with a number 1 welding torch with the oxy/acetylene kit and the cool with releasing oil and the pretty much always come out with ease.

I will dig some pictures out later if I get a chance of it in use.

I had to do a repair recently on one that had been bridged with a hand drill and they owner had gone through the oil gallery. Drilled out to m12 the machined a plug which I then TIGd into place and then drilled and tapped for a new stud.