Myford Vice for Vertical Slide

[Mick B1Participant @mickb1]

Posted by Michael Gilligan on 13/07/2019 22:46:49:

Posted by Mick B1 on 13/07/2019 22:12:21:

Posted by John Haine on 13/07/2019 20:54:23:

I assume (to repeat) it's there to avoid stress concentration.

I can't imagine how a plausible stress concentration would compromise accuracy more than the indeterminate datum Mike's suffering from.

.

I think John's point was that cracks start where stress is concentrated !!

MichaelG.

Anybody seen a vice cracked there, ever?!

I've seen some deeply abused vices, especially in subcontract machine shops, but never a crack at the base of the fixed jaw.

[JasonBModerator @jasonb]

Image from Here

[not done it yetParticipant @notdoneityet]

I don’t know how ‘original’ that vise might be. Could have been cast in some back yard in India. I would expect subcontract machine shops would have far better vises to start with – not a myford hobby exhibit.

Likely, too, that any hard-worked commercial vise has replaceable jaws?

I suspect it is not a vise from the 70s or before. Myford quality started(?) to go downhill when they imported from asia? Cheap and cheerful, I would suggest. Cheap casting, minimum machining and no replacable wearing parts. Give me an Abwood any day (probably now sourced from the far east but built robustly).

[John HaineParticipant @johnhaine32865]

QED.

[Mick B1Participant @mickb1]

Posted by JasonB on 14/07/2019 06:58:40:

Image from Here

Gordon Bennett – never seen owt like that before. Can't see either radius or undercut in that corner.

I still think a radius raises some 'fitness for purpose' issues. I've never noticed one on any vice I've used, and if I ever buy another, I'll make sure it's like my current one and allows datuming off a square-cornered flat located against fixed jaw and vice floor.

[Mick B1Participant @mickb1]

Posted by not done it yet on 14/07/2019 07:08:23:

I don’t know how ‘original’ that vise might be. Could have been cast in some back yard in India. I would expect subcontract machine shops would have far better vises to start with – not a myford hobby exhibit.

Likely, too, that any hard-worked commercial vise has replaceable jaws?

I suspect it is not a vise from the 70s or before. Myford quality started(?) to go downhill when they imported from asia? Cheap and cheerful, I would suggest. Cheap casting, minimum machining and no replacable wearing parts. Give me an Abwood any day (probably now sourced from the far east but built robustly).

They might have been better to start with, but some I've seen had had the handgrip hammered off the handle, and the 'replaceable' inserts – or for that matter the whole vice – looked as if they'd been chewed by a steel dog with carbide teeth. This was in the 70s – there were very many workshops being run hard on a shoestring with knackered kit even then.

[not done it yetParticipant @notdoneityet]

Back in the 70s? Unlikely that those items would have been cast in a back yard foundry like many are these days!

[Mike DonnerstagParticipant @mikedonnerstag]

Michael Gilligan: Mine has the engraving of the Myford name and part number too.

Jeff Dayman: The fixed jaw has no holes drilled at all, though there's nothing to stop me from drilling it for fitting false jaws, though I'm worried a little about the resulting accuracy.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mike Donnerstag on 14/07/2019 11:00:52:

Michael Gilligan: Mine has the engraving of the Myford name and part number too.

Jeff Dayman: The fixed jaw has no holes drilled at all, though there's nothing to stop me from drilling it for fitting false jaws, though I'm worried a little about the resulting accuracy.

.

Thanks for the confirmation, Mike

May I repeat my suggestion that you attach a false jaw [maybe made from gauge plate] with magnets.

MichaelG.

[Mick B1Participant @mickb1]

Posted by Mike Donnerstag on 14/07/2019 11:00:52:

Michael Gilligan: Mine has the engraving of the Myford name and part number too.

Jeff Dayman: The fixed jaw has no holes drilled at all, though there's nothing to stop me from drilling it for fitting false jaws, though I'm worried a little about the resulting accuracy.

If you use gauge plate as Michael suggests, that would probably solve the whole issue with no loss of accuracy – though my preference would be to avoid magnets and use socket head countersunk screws in the jaw insert, possibly with clearance holes in the fixed jaw, nutted onto a spotface on the outside. That way you can set the top edge of the gauge plate insert parallel to the floor of the vice and tighten it there – though you might have other ways to achieve the same result.

[Howard LewisParticipant @howardlewis46836]

An alternative daft suggestion, to retain the maximum jaw opening, and hopefully, avoid a stress raiser.

Clamp a sacrificial piece in the vice, (Radius the edge if you like, to match that on the fixed jaw ) and then drill a small hole through the intersection. The radius removes the "arris", and undercuts the jaw without making a stress raiser

There will be a minimal loss of strength, since metal has been removed, but probably not enough to cause real concern.

Howard

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mick B1 on 14/07/2019 09:13:06:

Gordon Bennett – never seen owt like that before. Can't see either radius or undercut in that corner.

.

Perhaps the radiused corner was 'cleaned-up' by some well-intentioned 'previous owner'

MichaelG.

[Swarf, Mostly!Participant @swarfmostly]

My vice is a genuine (Beeston) Myford item, I bought it in the early 1970s. It has the radius at the foot of the fixed jaw.

I use it with a packing piece, a length of 5/16" diameter rod with a flat machined along its length, but a bit of flat strip would do. I usually grip a steel rule in the jaws, on the packing piece, and offer the rule up to the face-plate (fitted temporarily) before tightening the securing bolts that attach the vertical slide to the cross-slide. It works for me.

Best regards,

Swarf, Mostly!

[Neil WyattModerator @neilwyatt]

I've had two vices have the fixed jaw pop off. One was a cheap angle vice which had a massive blowhole in the casting, the other was a middle-quality vice, but its lever-camlock design allowed far too much force to be put through it.

Neil

[Mike DonnerstagParticipant @mikedonnerstag]

Another view of my vice, showing the part number:

[Mick B1Participant @mickb1]

Looking at that pic, I'd want to make up two strips of steel flat with suitable holes spaced for those mounting slots. I think washers would force the t-bolts too far out for comfort.

Ah, I see Alan Vos suggested something similar…

Edited By Mick B1 on 15/07/2019 16:42:40

[Mike DonnerstagParticipant @mikedonnerstag]

Does anyone use a swivel vice with the Myford vertical milling slide such as this one:

[Mick B1Participant @mickb1]

Posted by Mike Donnerstag on 15/07/2019 18:35:14:

Does anyone use a swivel vice with the Myford vertical milling slide such as this one:

I don't know if you could mount it straightforwardly, but even if you could I reckon you'd just aggravate the already apparent rigidity issues. Might work for plastics, woods and other light materials.

I use a double-swivel Myford vertical slide a lot of the time, with a vice t-bolted straight to its face, and that's springy enough to be quite limiting on milling cuts to steel. I very rarely use the swivel in the vertical plane, but quite often in the horizontal. And that will bring in a further issue of crossslide space and travel – I think it might be difficult or impossible to actually make use of the supposed versatility of such a vice, and still be able to get the tool to reach the job without colliding with some other part of the machine.

[not done it yetParticipant @notdoneityet]

No myford and don’t use a milling attachment on a lathe, but firstly I don’t use the swivelling base on my machines. Secondly, I agree with Mick – holding items close to the slide can be challenging enough, without introducing extra distance between slide and workpiece.

It may be satisfactory for some materials, but….

[David Standing 1Participant @davidstanding1]

Posted by JasonB on 14/07/2019 06:58:40:

Image from Here

I am willing to bet good money that that vice fractured solely because of the local point loading of the way it was clamped down. I cannot imagine any reason whatsoever why I would ever want to clamp a vice in that fashion!

[Howard LewisParticipant @howardlewis46836]

Very occasionally, I use a three way vice like the one above, for milling. But only when there is no alternative. The jaws are so far above the base as to "wave around in the breeze" unless you are gentle.

They have their uses, but at the expense of rigidity.

With regard to Jason's broken vice, the fracture was probably caused by excessive clamping force against the fixed jaw, rather than how it was clamped to the machine. Tightening the moving jaw against the workpiece, and the fixed jaw, imposed a tensile load on the base, greater than the material could withstand.. Cast iron is not elastic, like steel, being strong in compression, but not in tension.

Howard

[Mick B1Participant @mickb1]

Posted by Howard Lewis on 16/07/2019 15:49:15:

…

With regard to Jason's broken vice, the fracture was probably caused by excessive clamping force against the fixed jaw, rather than how it was clamped to the machine. Tightening the moving jaw against the workpiece, and the fixed jaw, imposed a tensile load on the base, greater than the material could withstand.. Cast iron is not elastic, like steel, being strong in compression, but not in tension.

Howard

I thought that too, but what amazes me is that any tommy bar that could fit through the 'ole in the 'andle could be strong enough to deliver it!

Edited By Mick B1 on 16/07/2019 17:38:51

[Howard LewisParticipant @howardlewis46836]

A screw thread can deliver enormous loads. The mechanical advantage is a very high number. Think how little real effort is needed to jack up a car.

You can crack cast iron quire easily with a 1/4 BSF thread., using just an ordinary spanner, without recourse to tubular extensions. It wasn't the Tee slot that cracked, it was the Cross Slide.

Take my word for it! I wanted a long Cross Slide anyway

Howard

Edited By Howard Lewis on 17/07/2019 18:25:51

[Mike DonnerstagParticipant @mikedonnerstag]

If any of you were to buy a machine vice for the Myford milling slide from ArcEuro (I have a 10% discount code), which one and what size would you buy?

Many thanks,

Mike

[Mick B1Participant @mickb1]

(deleted)

Edited By Mick B1 on 22/09/2019 18:06:43

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