Round V-Blocks

[IanTParticipant @iant]

I don’t think i’ve seen anything quite like this before.

An interesting idea?

Round V-Blocks

Regards,

 

IanT

 

[Michael GilliganParticipant @michaelgilligan61133]

Nifty !

MichaelG,

[Martin ConnellyParticipant @martinconnelly55370]

Since I have a couple of clamping sets I think I would just make some angled blocks from bar stock with a through hole for a stud and clamp them to the T slots with the standard T nuts, studs and flared nuts. Too lazy?

Martin C

[Nigel Graham 2Participant @nigelgraham2]

Interesting… indeed.

Not so sure about the “beginner” label – that was clearly a demonstration by a highly-experienced machinist on high-grade machines, and assuming a lot of audience know-how such as tool selection, setting-up, edge-locating, cutting rates and other details omitted.

I could not determine if a conventional or NC mill as the whole lot was focussed on the work-piece and tool. Nor could I decide what material he used, but the discoloured chips suggest a steel of some sort. Also, the speeded images give a misleading idea of the milling: I’m sure he was not really pushing the cutter through the material at Warp Factor 8!

 

As for the blocks themselves… Certainly an ingenious idea, though you could adapt it to suit conventional Vee-blocks, e.g. by tenons in their undersides.

The crucial point not made by the video – especially given the “Beginner’s” label – is that all four of those blocks and both link bars must be identical within fine limits on their heights, locating surfaces and fits to be any good. They should be fully interchangeable within the whole set; and ensuring that hangs very heavily on setting them for milling, and the milling itself.

I’d not try it – I know I’d not achieve such accuracy!

[jimmy bParticipant @jimmyb]

Interesting idea!

 

Jimb

[Graham MeekParticipant @grahammeek88282]

A very novel approach which will work fine with round stock. Square bar would not be so good as there is nothing to register the faces of the bar against.

Regards

Gray,

[renardiere7Participant @renardiere7]

Not dis-similar to the Rubert England ball bearing v-block sets.

[BazyleParticipant @bazyle]

Not sure how the round face helps. Might be easier to achieve the required identical faces for a flat faced version by making the tenons first and mounting to machine all together.

[Bazyle]

On Bazyle Said:

Not sure how the round face helps. […]

Bigger range of capacities for a given size of block [as claimed]
… basic geometry

MichaelG.

[BazyleParticipant @bazyle]

…,…but the splitting into two parts has increased the capacity enormously.

[Michael GilliganParticipant @michaelgilligan61133]

and not but [?]

[JasonBModerator @jasonb]

I’m not sure the curved faces make much of a difference to capacity. A circular item will still sit on the two top edges of a vee block just as well as the faces of the curved version. Not unlike using a tee slot to rest round work in.

Might even be tempted to say that the fact that the tops of the Vees are further apart makes for a more stable setup. Same would apply if using two half vees spaced out like the curved ones.

[old martParticipant @oldmart]

I always like to see something that I hadn’t thought of, but too hard for me to make, having already got vee blocks from 1/2″ to about 6″ at the museum.

[Neil LickfoldParticipant @neillickfold44316]

I have not seen those round Vee blocks before. But have seen pairs of dowel pins, with surface ground flats that were put inside of Vee blocks to position small parts for the shadow projector. They were a pair of 8mm dowels.

I like the way he puts them together on the common reference  making them all having the relative heights. Also like the modular aspect and how they can be attached to differing bases.

As an apprentice exercise, it would be their advanced milling and turning test.

I do like the 90deg Vee for square stock items, and when a feature requires a 90 alignment and can be left in it’s clamped position.

Not sure that I would make a set and use it, but useful to know about for when the occasion may arise.

[Nigel Graham 2Participant @nigelgraham2]

Certainly an interesting concept though not easy to make.

For milling moderately large diameters of reasonable length, I sometimes use a T-slot as “Vee-block”. Provided of course I don’t need cut a through-hole bigger than the width of the slot.

The first time I tried this, was the keyway on a length of inch-diameter stainless-steel bar to replace the lost mandrel for a Pallas horizontal mill. It worked, too. I tried to find more of those straight-flute, single-edge end-mills, but with no luck… I  learnt later I had unknowingly used a wood-working router-cutter.

[Bill PhinnParticipant @billphinn90025]

Does a round bar sit down as securely on convex-sided vees as it does in flat-sided ones, even if clamped down on to the vees, like this guy’s aren’t?*

I agree with Nigel that they’d have to be made very precisely to be useful and they’re not a beginner’s project.

*The still image at the start of a large diameter pipe shows it just resting on the vees and later footage shows the ends of a bar clamped (like they very typically never would be) in the vice jaws. How does he propose round bar is clamped in an x-axis orientation?

[Bill Phinn]

On Bill Phinn Said:

Does a round bar sit down as securely on convex-sided vees as it does in flat-sided ones, […]

In a world of kinematic perfection, Yes

either option gives ‘line contact’

MichaelG.

.

Background Reading for the curious:

https://farside.ph.utexas.edu/Books/Euclid/Elements.pdf

[Neil LickfoldParticipant @neillickfold44316]

Thanks for the Geometry info. I was thinking it’s all Greek to me, but the translation is awesome.  The mathematical minds before the modern way of calculating still fascinates me.

The important aspect is the face being true to the recut diameter, and then the parts being parallel. Thickness is not required to be the same.

The 1/4’s could be located with precision dowels and a central screw for example.  Many precise reference parts are fitted with 1 very close fitting dowel in  around hole with an air vent, and the other end sits in a slot for example to allow for expansion.

While not an absolute beginners thing to make, it should not be outside the scope of a fitter turner apprentice to be making.

I would think that time wise, a matched pair of these, would be no less work than making a matched pair of Vee blocks.

Making multiple matched pairs of the round blocks is where for most it gets to be tricky. But if you have access to a really good wire edm machine, they would be very easy to make.

[SillyOldDufferModerator @sillyoldduffer]

Asking myself if round blocks had any advantages over v-blocks, I came up with this table.  It’s based what my books say about production grinding, the video, your comments, and Jason’s drawing – the maths are too hard for me!

The performance of the two types are similar.   The advantage of round blocks seems to be that they can be precisely made with a mill and lathe in an ordinary workshop, and could be bespoke to fit a particular milling table.  The level of skill needed is moot – doesn’t seem that advanced to me, but much depends on the required precision.

Best to put figures on precision and accuracy, so we’re all on the same page.  Using rough methods I often knock up parts that only need to be within 0.1mm, and though that keeps me happy, it’s not always acceptable!  So instead of allowing speculation about what I mean by accuracy here,  all dimensions and parallels must be ±0.005mm, a requirement that disqualifies rough blocks satisfactory for ordinary work-holding.

How easy are blocks to make?  I have several DIY V-blocks, all approximately milled within near my usual ±0.02mm range.  I can certainly stretch to ±0.01mm, and might get  ±0.005mm at the cost of several rejects!  Therefore, I suggest precision V-Blocks are significantly harder to make in a basic workshop than precision round blocks.   Opposite is true in a factory where accurate V-Blocks are easily made by grinding.  And in a factory many economies are possible, for example by using stock with a pre-rolled V, or roughing out with a big horizontal mill.  Mass-production by grinding is quick and cheap and  fundamentally more accurate than turning or milling.  In contrast, round blocks require more operations, so I guess they’d be a shade more expensive to mass-produce, to no particular advantage.

So I buy off-the-shelf commercial v-blocks and mill bigger home-made V’s as necessary, ‘good enough’ rather than accurate. A caveat: though I work with pipe, it’s usually bendy plastic, not metal, so accuracy is limited by the material.  So I won’t rush to make any round blocks – unless there’s a need, they’re a waste of time.  But if I need to accurately mill a 4″ metal pipe, I shall remember they’re an option.

Of course my analysis could be wrong, or inappropriate to your needs.  Perhaps I’ve missed something!  Anyone decided to make a set of round blocks?  If so, what for?

Dave

 

 

[John HaineParticipant @johnhaine32865]

One benefit of circular by the look of them is that they look as if they can accommodate round stock much bigger than an equivalently sized standard vee.  I’ve got 2 sets of vee blocks, one small bought from an ME supplier when I got started. the other a nice bigger set of Mitutoyo bought cheap off my favourite market tool stall.  I can’t remember ever having used either!  A bit like rotary tables and adjustable angle plates.

[John Haine]

On John Haine Said:

One benefit of circular by the look of them is that they look as if they can accommodate round stock much bigger than an equivalently sized standard vee.  I’ve got 2 sets of vee blocks, one small bought from an ME supplier when I got started. the other a nice bigger set of Mitutoyo bought cheap off my favourite market tool stall.  I can’t remember ever having used either!  A bit like rotary tables and adjustable angle plates.

When you haven’t got the piece of kit you need it and when you have it you never need it again. I’m sure it somebody’s law.😅

[John Haine]

On John Haine Said:

One benefit of circular by the look of them is that they look as if they can accommodate round stock much bigger than an equivalently sized standard vee.

My image would tend to show there is no difference in what either can accomodate, Vee supports over a wider distance so a bit more stable. Round are probably a bit kinder to holding softer of finished materails

And my Vee blocks do get used fairly often

[Author]

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