Self Centering Vice

[VicParticipant @vic]

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

[VicParticipant @vic]

[IanTParticipant @iant]

I have a small one Vic – it's a good solid small vice and seems well made but frankly I've never used the self-centring aspect of it as such, although it might be useful.

For instance my small Taig head has a ER16 collet (max 10mm). So in theory I could hold a 10mm rod in the collet, grip it in the vice, then bolt the vice in position and then place (say) a 30mm piece in the vice and it would be 'automatically' centred.

I'm not sure how accurate this would be in practice though. Probably in the "near enough" category for most things I would think but I don't know for sure. I guess I'll have to test it now…

Regards,

IanT

[DalboyParticipant @dalboy]

Having seen self centering vices there seems more moving parts so therefore I would not use them for accurate work.

[VicParticipant @vic]

Posted by IanT on 12/02/2021 14:52:14:I

I'm not sure how accurate this would be in practice though. Probably in the "near enough" category for most things I would think but I don't know for sure. I guess I'll have to test it now…

Regards,

IanT

let me know if you do …

[Martin KyteParticipant @martinkyte99762]

I don't see it would help at all unless I'm missing something. For a start you lose the benifit of a reference jaw you get with a standard milling vice. With a clocked Jaw corner and a DRO you can quickly reference a workpiece and Drill or machine wherever you choose.

As I said please tell me if I have missed something.

regards Martin

[Anonymous]

Presumably you get a reference centre instead of an edge which I, for one, would find useful in some circumstances. There are several ways to do any job. Everyone has their own preference(s) but it's usually worth keeping an open mind.

I've looked at self-centering vices and – like others I suppose – wondered just how accurate they are. It would be nice to have a feel for that.

[VicParticipant @vic]

If a job needs the accuracy then I work off the fixed jaw. Some jobs though are “near enough” in this case if I want for example to centre drill a 12mm rod I’ll put a 12mm piece of short stock in the Chuck and then move the vice until it just touches the bar. I can then replace the bar with a drill bit and drill the hole. This is pretty quick and pretty accurate. Sometimes though the piece to be drilled is not a size, often too big, that I can put in the Chuck. If the SCV is reasonably well made (I’m not sure it necessarily would be) then it could come in handy for any size up to its max capacity.

[Anonymous]

The jaw positions are controlled by LH-thread and RH-thread leadscrews. As far as I can see, the positional/centring accuracy is determined wholly by the accuracy of those threads. Other accuracy/precision determinants (jaw-alignment; parallelism etc) would be as for any other vice I suppose.

Edited By Peter Greene on 13/02/2021 01:55:24

[JasonBModerator @jasonb]

The CNC boys love them, Ideal if machining all around a rough block, if it's size varies you still take equal amounts off both sides. As with everything what you pay is what you get and the CNC ones come out more expensive than say the Warco offering.

Unless there is a need to machine a varying range of parts centrally without disturbing the vice I don't see much use for them otherwise.

[colin hawesParticipant @colinhawes85982]

I always prefer measuring and working from one known datum edge in x and y axes. A vice with both jaws moving would not satisfy this condition. Colin

[VicParticipant @vic]

Bit outside my price range …

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[old martParticipant @oldmart]

They can be very useful for repetitive work with a drill press, but not so much with a milling machine.

[VicParticipant @vic]

I found it quite surprising how little of the blank is actually gripped in this video. The mill was taking some sizeable cuts as well.

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[Michael GilliganParticipant @michaelgilligan61133]

Posted by Vic on 13/02/2021 17:41:55:

I found it quite surprising how little of the blank is actually gripped in this video. The mill was taking some sizeable cuts as well.

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Astonishing !

… Don’t try this at home folks.

MichaelG.

[JasonBModerator @jasonb]

The hardened jaws have small "teeth" that actually bite into the work or another option is to pre machine a small dovetail along two sides of the blank. Once all 4 sides and the top have been machined the part will then often go into a second vice with custom nesting jaws that grip the machined shape of the part which is then decked to remove the waste from the bottom and do any other machining on that side which removes the jaw marks from the second operation.

You can buy replacement jaws for your "Kurt" clone type vice that will take the hardend serrated jaws if you can't stretch to a full blown CNC vice.

Also worth noting the vices are quiet tall which is to allow all round access when using a 5 axis machine.

[VicParticipant @vic]

Posted by old mart on 13/02/2021 16:42:13:

They can be very useful for repetitive work with a drill press, but not so much with a milling machine.

Which vice do you have?

[old martParticipant @oldmart]

I don't have a self centring vise, I don't have a use for one.

[VicParticipant @vic]

Posted by old mart on 13/02/2021 20:19:54:

I don't have a self centring vise, I don't have a use for one.

I see, so you don’t have one but you say:

“They can be very useful for repetitive work with a drill press, but not so much with a milling machine”

[DMBParticipant @dmb]

They come under the heading of gimmicks as far as I'm concerned since you can't beat a fixed jaw to ref to in all 3 axis, then you know where you are. As said above, heavily dependent on the accuracy of not one but two leadscrew threads, two moving jaws with the possibility of both rising up (probably by varying amounts) as the are tightened. Good idea at first sight but fails on many points. Even if made to 'aero' tolerances, wear would soon put paid to manufacturing accuracy. Not got one, dont want one, not even free gift. Likely to be more trouble than it's worth and I'm too long in the tooth therefore lacking strength to loose my rag and chuck it over the hedge!

[Anonymous]

Can't imagine they'll sell many of these then.

Edited By Peter Greene on 13/02/2021 23:06:33

[DMBParticipant @dmb]

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.

[Anonymous]

Posted by DMB on 13/02/2021 23:49:11:

Kurt supposed to be one of the better makes……………..

I really like my Kurt vice.

Andrew

[JasonBModerator @jasonb]

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.

[Martin KyteParticipant @martinkyte99762]

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

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