My vise isn’t at 90 degrees

[old martParticipant @oldmart]

At least the jaw is tilted in the best direction for holding work, does the gap show up when the moving jaw gets close to the fixed one?

[Neil LickfoldParticipant @neillickfold44316]

Did you check the squareness of the Fixed jaw block ? Did you do a blue test of the block to the bed by chance? Did you also check that there is no binding on the side of the screws through the vice base to the Fixed jaw block?

The fixed block can be squared up if you know the amount out that it is off true. Then set it up on an angle plate, and use an indicator to get the correct compensation, then mill the surface so that when assembled ect it will now be square. You actually don’t want it dead square, but a couple of microns with the top touching before the bottom. The load of the jaw closing and distorting the vice body, will then become square.

You can measure this deflection in your vice, by clamping up a square, running an indicator over the surface and see the amount difference. Then tighten the vice to the amount that you normally would. Then look at the amount difference again. With this info you can then correct the vice to get consistent results for your machine.

Neil

[moonmanParticipant @moonman]

Well I spent the evening ripping the vice to bits and found some wonderful stuff.

Every edge you see is chamfered, every edge you cannot see isn’t. Resulting in a burr which would mean the fixed jaw would rock once you unscrewed it from underneath.

I gave it all a good clean up, stoned in some chamfers and checked again for squareness, it’s much better, a tiny bit of tilt remains but by the sound of it that’s fine. I can only assume it was a bur preventing this from the start.

My mill was also slightly out of tram and I was correct, there’s 2 thou of nod. I have some shim stock on the way and intend to fix that but I’m not looking forward to it, I can see this being a huge pain in the rear end.

[DiogenesParticipant @diogenes]

Maybe not – can you not run the head down and rest it on a wooden bearer, and release the the bottom bracket-bolts enough to fit a strip of shimstock in?

 

[BazyleParticipant @bazyle]

There is a lot of ideas on tramming on this current thread on HSM.

https://bbs.homeshopmachinist.net/forum/general/2125292-checking-tram-on-round-column-mill

[PeteParticipant @pete41194]

2 thou out in nod over what distance? If that’s a circle the width of the table in the Y axis, then that’s way too much.

Your vise is normal, most milling vises are built with that slight inward leaning bias on the fixed jaw to help compensate for the vise bed and rear jaw deflection as the vise is tightened. In fact it’s probably not nearly enough. If something seems incorrect or inaccurate, do some analysis about why that might have been done on purpose before making unnecessary corrections that might make things even worse.

Take something like a 123 block and a set of parallels. Place the 123 block in the middle of the vise jaws and a set of parallels that will position that block about 1/4″ – 3/8″ deep into the vise jaws. Now set up a dial indicator zeroed on the upper rear of the fixed vise jaw. Tighten the vise to around the same as you would for any larger part. The deflection numbers on the indicator you’ll see are a combination of the vise bed and rear jaws bending and movement. And yes, even the vise beds do bend once the closing pressure goes past about 20-25 ft. lbs. If my first two off shore 4″ mill vises were any example. Both I thought were surface ground very accurately, however the cast iron quality and internal structural design made all that effort just about pointless.

I’d also throw out that factory alignment key under your vises fixed jaw since it fits so poorly. Machine a new one that’s a light snap fit for the full depth and width of both slots. Then replace both Allan head cap screws with known industrial brand name quality. Those OEM cap screws are all garbage because of the poor alloy and heat treatment. I’d also fly cut the moving jaws wedge face. Doing that will allow the wedge that helps pull the moving jaw down to be adjusted much tighter and work far more efficiently. You still won’t get zero jaw lift on the moving jaw, but it will work a whole lot better than it does now.

There’s a good video about checking a milling vise here. https://www.youtube.com/watch?v=l5m-kA_Oq_4

[Bernard WrightParticipant @bernardwright25932]

I bought a 100mm Universal vice from one of our very well known suppliers, BUT I didn’t put it to use at the time of purchase, literally 18 months later, when I contacted the supplier regarding its terribly out of truth manufacture/assembly, my answer was it was more than a year old, as though it had become this bad since I’d bought it. I know most usable commodities have a usual 1 year warranty, but a manufactured in fault should have been addressed by the seller to my mind. Needless to say I don’t purchase from them again.

However, I have used its main constituent parts for other duties, I’m all for repurposing tools.

Talking of machine vices and particularly jaws, all of mine are in-place machined to the axis of the miller, including the tee-slot positioning tongue, so no chance of out of squareness there then….

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