For aligning the machine vice I set it roughly parallel using the bolt slots and a T-slot. Nip down the lefthand bolt and then indicate the rear of the fixed jaw. If the indicator moves tap the vice to bring the indicator back to the original reading. Repeat as needed. Tighten both bolts and do a sanity check pass. The whole operation takes less than minute to get within 1 thou in 6".

For aligning parts on the table I use two methods. One, a length of gauge plate in the T-slot as a fence. Two, I made a couple of cylinders with spigots that are a close fit in the T-slots. These can then be bolted as far apart as needed. The two cylinders were ground as a pair, so they are within a tenth of each other. My mill is industrial, so the T-slot is aligned with the ways. The methods don't work if the T-slots and ways are not aligned.

Andrew

Much the same as Andrew here with regards to dti on the vice fixed jaw and a couple of round bosses with spigots that can be fitted to the tee slots.

A trick from YouTube if you have power feed is to nip down one vice nut but leave the other slightly loose. Use the power feed to move the table back and forth with an indicator in the spindle on the fixed jaw, tapping the vice gently as you go until aligned. If you don't have power feed then ignore!

But personally I have put an alignment key on my vice.

John.

I also bolt mine down, you don't just have to use them for work along the table you can also set them at right angles or at an angle set with a square or DTI. I could do with making some taller ones but usually just stand a tall block in front. If your tee slots are out then just make the spigot a bit smaller, rest a straight edge against them and adjust until the straight edge runs true.

I made some tenons for my dividing head and tailstock, but I don't use tenons on the machine vice (although the slots are pre-machined) for three reasons. One, when not in use the machine vice often sits lengthwise on one of the other mills and I don't want to ding the table/tenons. Two, sometimes I need to set the vice at an odd angle. Three, the T-slots vary in width slightly across each table and from mill to mill, so I'd rather set the vice properly each time to eliminate the last couple of thou.

Andrew

I use a 12 in long hardened and ground parallel in the vice jaws and clock over the whole length,i use a Mercer dial type indicator,In my early days first job, all the vices had tenons they were used on 2 Victorias with identical tenons,the method does not work so well if the vice or vices have to be used on 2 or more mills with variation of tee slots. When the vice is set true with the parallel ,I then use my edge finder against the parallel and set the edge of the fixed jaw to zero on the index dial, the parallel is 2 x 1 ins and protrudes about 1/2 inch out of the jaws.

"I've not got hard stops on the table."

I should have been more explicit. By "hard stops" I meant at the end of the lead screw (threaded rod) which moves the mill table i.e. the point at which the table wont move further. It is the reference point for repeated measurement.

"Doesn’t your method rely on the laser axis being absolutely co-axial with the body? I’ve had a couple of laser collimaters for my telescope, and even with those the dot describes a circle on a distant wall, if the body is rotated in a v-block. "

Apologies for previous brevity again. I don't believe that "being absolutely co-axial with the body" is too critical providing the laser pointer is held in the vice jaws at the same angle to the horizontal (hence shining on the cross lines on wall). The cross lines in the workshop are about 4 metres from the laser source so when lined up, it repeats the original, DTI-based, set up accurately enough. I do check from time to time and haven't found significant change. Below is a picture taken of the laser spot centralised.The image is poor as the laser spot didn't focus well.

One of those many jobs awaiting my getting 'a round tuit' is to mount the laser pointer in a substantial block which would sit within the vice jaws at the correct angle and orientation just to save a few minutes each time.

For critical parts it is possible to have a set of soft jaws that you can machine once the vice is mounted. Think of them as a simple jig for the part you are doing. Another option is to hold a sacrificial piece of material in the vice that is then machined to give a datum surface or other feature that a part is positioned by. I recently did some profiles that were done by drilling a piece of scrap aluminium alloy with 2 holes for ground dowel pins to position the workpiece on where it was then held down with a couple of through bolts. It didn't matter how well the vice was set up, the dowel holes were in the correct position unless the vice was moved again or the temporary jig in the vice was moved.

Martin C