Sounds about right but really up to you. I always make vice jaws out of gauge plate, saves grinding them and usually about 3/8 inch thick.

Hi Steve, welcome to the forum. Go on YouTube, tap magnifying glass symbol and type in Joe Pieczynski. Think I'v spelt it right. All his workshop videos will appear. Look for vice stops and note how he fits a removable sliding clamp to the top edge of the fixed jaw. Seems a brilliantly simple idea but suggest it may call for a jaw that sticks up above the vice body by 3/8" or more. So you will need jaw material slightly wider than suggested. I would have made one long ago, if I could fit it but my vice jaws don't project high enough to enable it. So annoyed, thinking about replacing the commercially fitted jaws.

Good luck,

John

I'd say mild-steel is suitable for a first attempt, in fact a decent beginner challenge. I fitted plain mild-steel jaws to my Record Vice №4 in preference to its hardened originals because they tended to mark the sort of work I do. I also made aluminium faces for more delicate work, but buying a pair of fibre jaws was a waste of money: not used them yet.

I consider my mild-steel jaws to be disposable, because they do slowly ding up as David George describes. How long it takes to knacker a set of jaws depends on the volume of work done and how brutal it is. If mild-steel isn't good enough, you could case-harden it, or switch to gauge plate, or one of the tough steels; beware – tough steels can be a pain to machine, which is why gauge plate exists. The other big advantage of gauge plate is it is ground flat and parallel, important on a machine vice. Bright Mild Steel isn't so accurate, but my experience of of bits cut from the same rolling has been good enough for most purposes.

As to the sizes, jaws are usually slightly wider than the vice and deep enough to close without putting the screw to end-of-travel. What you suggest sounds right. One trick is to knock up some jaws in wood or cardboard and test them for fit, opening and closure before spending time and money on a potential misfit in steel. Once confident the template is the right size, then make the real one.

Provided they are parallel there's a fair amount of latitude in jaw making so don't worry too much. Might even be an advantage make your own – fit taller jaws or cut Vs in them to holding round stock.

I take it the vice was second-hand? If so don't be afraid to scrap it if it's poor condition: missing jaws may be the tip of an iceberg because vices are often badly abused. Get rid if it doesn't grip properly: jaws lifting badly or not parallel; twisted frame; rocking; worn screw / nut, or other obvious defects. Perfection isn't essential – quite often lifting can be fixed by tapping the work down with a mallet – but a machine vice that allows work to move or won't grip straight is a pain in the proverbial.

Dave

You have a lathe, so you could (easily?) make a couple of stepped studs to fit both the T nuts and the vise slots.

Nearly everyone would say that apart from the height issue, the vise fitted dorectly to the table is a better set up.

None of mine have a swivelling ‘feature’ while fitted to the mills.

Rather than "Drill and Countersink", if possible I would drill and tap the jaws so that the retaining bolts are outside the area used for clamping.

This is how the jaws are secured to the Vertex K Series Vices.

To ensure that everything stays square, it might be worth clocking the vice so that it is aligned correctly, along the table, before fitting the jaws.

The take just a light skim with an End Mill so that the new gauge plate jaws sit on accurately aligned face, when is finally fitted.

Why "Finally fitted"? because once there is an accurately aligned face, it can be used as a datum to mill the new jaws to size, before fitting. You might have to be very gentle milling the ends of the jaws when they are clamped vertical, because of the flexibility of the metal protruding from the vice.

It is worth having the ends and top of the jaws truly horizontal and vertical, so that they can be used as a datum plane for setting later work. .

The top and bottom of the jaws will be easier, since they can be secured to the vice body for machining..

If you wanted to add a little complication, you mill a Vee slot (Horizontal and / or Vertical ) in the fixed jaw as an aid to gripping round work.

For this you might need to make up a temporary fixed jaw from mild steel for these operations.

HTH

Howard