New jaws for my milling vice.

I have "inherited" a very large milling vice with the machine I just brought.

The jaws have seen better days and could do with a new set - what would be the best material to make them from and any recommendations as to how to true them up to the old vice.

I replaced the jaws on my 4" Abwood with BMS. 3/8" x 1.5" section. They're held on by the original screws. A light milling cut was taken off the tops and sides after fitting. They've served well for some years of generally fairly light use.

Edited By Clive Brown 1 on 01/12/2020 11:57:25

I would use Mild steel or preferably gauge plate for amateur use, in industry the vice jaws are in my experience toughened to withstand wear.

Not sure what you mean by 'true them up to the old vice' I would make the jaws parallel & shim the vice base if the jaws were out of square to the machine travel but that is another issue.

Tony

You might be surprised just how long a set of mild steel jaws last, they can easily be machined in situ. Gauge plate or precision ground stock will be hardenable and distortion can be low but probably not zero. If they need trueing after hardening then a surface grinder would be useful. Mounting a cup wheel in the mill could be worth a shot to just clean up the top edge of the jaws but a mill is not a grinder and like grinding on the lathe protection and cleanup should be scrupulous.

Mike

Once again thanks for all the prompt and informative suggestions.

Mild steel will be my choice -

The true them up reference would be to make the faces of each jaw parallel with each other - i was asking i- f once ive made a set of jaws and fitted them would it be common practice to then mill each jaw whilst in the vice so the faces then sit parallel to each other ?

I didn't mill mine. A good bit of BMS usually is to a decent standard of flatness. I thought that I was not likely to improve on that very much, and also there is a risk of distortion if only one face is machined.

The jaw seatings on my Abwood seem to be quite accurately machined and the new MS jaws will grip a feeler <=.003" all over.

Gauge plate would be my choice for replacement for the hardened standard jaws that I would expect on an industrial vice.

The object is to have the vice jaws at the same level on the tops and ends, and meeting face to face when the vice is closed up.

Perversely, this is more likely if the vice is worn, allowing the moving vice to swivel and self align!

Ultimately, the object, for most of the time, will be to have the fixed jaw aligned with the plane in which an end mill cuts.. Being idle, rather than spend a lot of time winding the table to and fro an "adjusting" the position of the vice until the jaw clocks with Zero difference from end to end, I made a sort of "goal post" fixture to align it.

If the vice has the facility for keys on the underside, keys, or dowels (stepped if need be ) could be made to locate the vice on a suitable Tee slot, making life so much easier.

To align using my goal post fixture, the vice is placed on the table, but not clamped down. The vice grips the "goal post" (which is dowelled into a Tee slot ) before being clamped down. The goal post can then be removed. In my experience, the vice jaw will in line within a " Thou", with the original hardened jaws.

HTH

Howard.

I would take the vise to bits, clean, lubricate and adjust any gibs first. After making your new jaws, mild steel is fine for home use, line up the vise before fitting them. The fixed jaw is ready to be skimmed on the face and top. Then leaving the smallest gap between the jaws to allow the milling cutter in, skim the face of the moving jaw. Then do up the vise so the jaws are clamped together and mill the tops so they match.

This method will work with the type of vise that has the moving jaw running in ways that reduce missalignment.

How about using a couple of parallels? Should be accurate enough.

Parallels as jaws? They would be accurate enough, but could be difficult to drill and if there were any errors in the seating, they would just reproduce it.

Most vice are well made as the body is easy to machine square with the correct machinery it is usual to just make jaws from gauge plate or mild steel case harden and grind flat to return to good use. However if it has been misused by using it without jaws, to get a slightly oversize job in for instance, or used for welding etc it will need checking. Put the vice after striping, stoneing, cleaning, adjusting and oiling on the mill and without any jaws on use a dial indicator to check for run out and squareness. I have a bottle square which I would also use to check for squareness. Personally I would make replacement jaws from gauge plate with plenty of thickness to allow for socket cap screws with an allowance to let the jaws stick up above the body and stick out both sides equally. Don't forget to champher the bottom edge to allow for any radius etc on vice body. Make sure the holes are central and equal but with a slight clearance to allow for adjustment. Unless you have a large and heavy duty accurate machine or surface grinder I wouldn't try to machine a large vice body as it can open a can of worms like alignment etc.

David

Thanks for all the answers - I have already taken it apart and cleaned 50 years of "growth" from the internals. It is very well made and it shows only slight wear - it is a Domer Mill vice - I have only found one reference to it on the internet and that was not exactly the same.

The jaws that are in it look like they are reversible - they have a "waffle" effect on one side, the flat side does show marks and the odd drill bit miss aliment accident.

As ive given it a new lease of life I thought i'd treat it to a new set of jaws.

I made some aluminium jaws for a 100mm Bison vice, they are waiting for a delicate job. Tufnol would also make good soft jaws.

The type of vice like the ARC versatile vice has a moving jaw which can end up out of parallel to the fixed jaw if the workpiece is held at one end of the jaws. In this case it would be better to produce a jaw fully finished except for the top, which is matched with the fixed jaw when the jaws are clamped together.

Edited By old mart on 02/12/2020 14:02:21