Self Centering Vice

Peter,

Kurt supposed to be one of the better makes of vises but even they probably have their limits. Impressive accuracy quoted. Imports from the cheap labour areas of the World will always trail a long way behind as also rans. Trouble is, people who cannot afford quality become dazzled by low prices and buy and later regret it. My prefence as previously stated, is for a fixed jaw to use as a datum.

I really like my Kurt vice.

Andrew

For the way they are used for CNC work you are not bothered by having a back, side and bottom ref hence they are ideal. Probing will get the block set to a ref by averaging out the two sides, front/back and top. You then machine all 5 exposed surfaces.

Remember this video everyone thought was great a couple of months back for trueing up 5 surfaces on a manual mill, its the same method that the CNC does.

So to sum up so far then, the are more use on CNC when working from unmachined blocks, can be of good quality like the Kurt but if you have a fixed jaw vice already may not really add enough to warrent an additional vice.

No one has talked about capacity. Do they not tend to be bigger workpiece wise for similar footprint and I seem to recall better anti lift performance on the jaws?

regards Martin

I think I’ll call it a day for this thread. Apart from from Ian most of the comments have been singularity unhelpful if rather amusing.

The question was:

“I’ve often thought this would be a handy addition for my milling machine. Anyone got one, what do you think of it?”

It wasn’t “would you find it useful”.

It’s not all bad though, the expert opinion from someone who doesn’t have one was very funny. And I’ve also learnt from further investigation that they seem to be very popular in production environments so obviously the expensive ones must be reasonably good. Sadly out of my budget though. Once the lockdown is over I will visit a supplier to examine one of the more modestly priced examples in the flesh so to speak. In the meantime Ian if you do get round to checking your example perhaps you’d PM me with your observations?

we used them all the time, a matched pair with hardened vee jaws for milling keyways in shafts etc as they give great repeatability and they can grip on different diameters on the same shaft but bring the shaft to the same centre point each time, thus the same depth of cut and on centre, made by Edgewick , Herbert, etc

OK, Vic .... I, for one, get the message.

Bye.

OK then Vic here we go

Warning ! - I am not a Metrologist (and those here who are will probably faint with horror) but this is what I did to test it.

I clamped the vice to the edge of my small workshop surface plate (now well over 20 years old and showing it) and set up a long reach 2" Dial (Imperial) Gauge with a 3/8th packing piece clamped in the vice. I was in two minds on the wisdom of using my Jo Blocks (in a vice?) for this job but the gap at the bottom of the vice was too large for them to sit squarely and that decided me (so they stayed in their box). I have some fairly accurate (but not very pretty) packing blocks that I use (obviously) to pack things 'up' with by a known amount. These seemed good enough for this use...and I didn't mind sticking them in the vice either...

With the dial zero'd on 3/8th (0.375) I added a 5/8th (0.625) and took a reading, then added a 1/2" block before adding finally going to 2". The vice can fully open to about 2.2" .

I then reversed the process, taking readings as I removed blocks. In all cases the vice was slightly 'over-opened' and then tightened back up on the packing, such that any backlash was taken up.

This is what I found:

Packing Reading-Up Reading-Back Calculated

0.375 0.00 -0.0008 0

1.000 0.3115 0.3105 0.3125

1.500 0.5605 0.5605 0.5625

2.000 0.8128 0.8128 0.8125

To explain, the readings are referenced to the zero setting, so are off-set from the centre by 0.1875 initially (half of 0.375). Taking half of the packing size and subtracting 0.1875 will give the 'calculated' number. There are clearly all sorts of things that can effect the readings taken (and note that the dial did not return to zero) but for a relatively inexpensive vice, I don't think it is too bad. Certainly in the "near enough" class for most things I'd use it for I think... which doesn't include CNC by the way.

So I hope that's useful Vic. I'm sure I've screwed something up (or forgotten something key) - I usually do but bear with me, I'm trying my best...

Regards,

IanT

PS The Vice is the 2" HBM branded one, commonly available from your favourite UK Supplier with a rotary base but my base had gone AWOL before it came to me in "used" condition - although it seems it's previous owner was kind to it.

Edited By IanT on 14/02/2021 17:47:38

Thanks very much for taking the time Ian, very kind of you. Yes, it does appear to be good enough for non critical jobs. It could save a lot of time for drilling and machining shafts etc.

No problem Vic, I was curious too and I was happy to help

Regards,

IanT