Myford Vice for Vertical Slide

[Mike DonnerstagParticipant @mikedonnerstag]

I have an original Myford small vice for the vertical milling slide. I wondered whether anyone else has had a problem with the fact that the base of the fixed jaw has not been machined square but instead has an arris that pushes any square-edged material out of the vice slightly when the jaws are tightened. I was hoping to use the base of the vice as a reference surface. Am I wrong to expect to be able to do this?

Does anyone have an easy solution to this? Am I missing something?

Many thanks,

Mike

[Mike DonnerstagParticipant @mikedonnerstag]

[Mick B1Participant @mickb1]

Don't really know what you mean by 'arris', and internet definitions don't really help.

My vice (which I *think* is a Myford) does seem to hold material square with in a thou or two on my double-swivel vertical slide.

If it didn't, I don't really see why I shouldn't skim it square with a decent carbide endmill – it's machinable. The finish wouldn't be as perfect as I'd like, but it'd be better than an out-of-square jaw.

If yours is not machinable, I'd say that's a good enough reason to spend not too much money on one that is – occasionally you might need to cut a special location.

[John HaineParticipant @johnhaine32865]

Do you mean the small radius? I think it's there to prevent a stress build up if the corner was sharp. I've got used to putting a bit of packing in under the work.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mick B1 on 12/07/2019 21:47:03:

Don't really know what you mean by 'arris', and internet definitions don't really help..

.

The definition given by Collins is good [well at least it equates to my previous understanding], but I'm afraid it is almost exactly opposite to Mike's usage: **LINK**

https://www.collinsdictionary.com/dictionary/english/arris

I'm almost sure that Mike is referring to a small radius at the internal corner, between two faces.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mike Donnerstag on 12/07/2019 20:20:18:

Does anyone have an easy solution to this?

.

An easy solution might be to add a packing-piece to the fixed jaw, perhaps secured with little neodymium magnets.

MichaelG.

[BertyParticipant @berty]

I have heard of Arris Rail as in fencing. (A length of wood cut diagonally to form a triangular shaped end cross section). If the bottom jaw had this shape, in a much reduced form of course, then as Mike says, it would push the work out of the jaws.

Berty

[John BaguleyParticipant @johnbaguley78655]

Hello Mike,

I'm not sure without looking in the workshop but on mine I think I just machined the corner square with an endmill for the reason you state.

It doesn't really get used nowadays as all my milling is done in the milling machines.

John

[Andrew Moyes 1Participant @andrewmoyes1]

I've checked mine and for all practical purposes it's a square corner. Put it this way, it's never been an issue with the radius on any workpiece. Perhaps the milling cutter had become worn when yours was made. There is a 1/16" X 1/16" undercut on the moving jaw that ensures the jaws close tightly. I think you would be justified in cleaning out the corner or undercutting but the problem will be avoiding spoiling the sliding surface. Perhaps go in at a slight angle with a dovetail cutter? It would raise the stress as has been pointed out but I'd have thought there is enough in hand in the design.

[Michael GilliganParticipant @michaelgilligan61133]

Mike,

A picture of the problem area might be useful

… worth a thousand words, they say.

MichaelG.

[Mike DonnerstagParticipant @mikedonnerstag]

Apologies to all, I had obviously misunderstood the word 'arris'. Next time I'll stop trying to be clever and use common English!

The photo below shows the radius at the base of the fixed jaw. I have been using packing, though I have no accurate parallels, so I expect the accuracy of the setup will be compromised. Would it be a good idea to run a narrow slitting saw at 45deg into the corner to remove the radiused section? Using a radius gauge, I found that the radius at base of the jaw is about 1/16". I'm surprised that Myford did not machine this truly square, or is this a common occurrence on machine vices?

[JourneymanParticipant @journeyman]

The small radius in the corner is probably for stress relief, I would call it a fillet! You could fix a secondary jaw in place if you can drill a couple of holes through the fixed jaw (or even glue it) permanent packing. Many vices have replaceable jaws, you could even make a set with horizontal and vertical grooves for holding round stock.

John

[Grindstone CowboyParticipant @grindstonecowboy]

I guess that's an internal arris

I'd go with the slitting saw idea, I can't imagine there would be a problem with stress unless you're really overtightening the vice. If it's a worry then wouldn't a very small round nosed cutter (at 45 degrees) make a nicely rounded clearance cut?

[Mike DonnerstagParticipant @mikedonnerstag]

I like the idea of the round nosed cutter, which I assume would 'spread out' any stresses in the corner. I also like the idea of the replaceable jaws, though it would reduce the capacity of the vice. Does anyone have any photos of their own modified Myford vice? Or perhaps a better alternative vice that fits the standard-sized milling stand.

I also have a Groz 3-way swivelling vice, something like this:

However, the centres for the bolt holes won't fit the standard milling stand. Does anyone have any thoughts on this? Is it simply too big to be used for milling on the Myford?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Journeyman on 13/07/2019 10:48:06:

… You could fix a secondary jaw in place if you can drill a couple of holes through the fixed jaw (or even glue it) permanent packing. Many vices have replaceable jaws, you could even make a set with horizontal and vertical grooves for holding round stock.

.

Much as I suggested last evening … 'though I thought that magnets might be attractive.

< all groan >

MichaelG.

[Alan VosParticipant @alanvos39612]

Posted by Mike Donnerstag on 13/07/2019 10:34:17:

The photo below shows the radius at the base of the fixed jaw.

As an aside, I suggest using washers with a larger outside diameter to secure the vice. The washer under the top bolt is tipped into the slot. To work properly, the washers need to bridge the slot, plus a bit. There is probably a formula. You may need to put a flat on the side of larger washers. Or drill two holes in a strip of metal. Or whatever arrangement takes your fancy.

[Mike DonnerstagParticipant @mikedonnerstag]

Alan Vos: You're right – I hadn't noticed that! I will find or make more appropriate washers for the vice. Many thanks.

[Mick B1Participant @mickb1]

Seeing that radius at the base of your fixed jaw – from a firm like Myford – surprises me.

Here's mine:-

I now don't think it's Myford as it has no name on it. It was clearly designed to fit Myford slides, though, from the screwhole spacing. It came in a blue plastic box – long since lost in house moves – and I bought it at the Olympia show in 2003 for about 20 quid, and it's served me well since.

I thought all small milling vices were undercut like this to clear dirt and debris and ensure the location faces were definitive – to me, the radiused design looks like a bit of a rookie error.

Edited By Mick B1 on 13/07/2019 20:18:50

[Mike DonnerstagParticipant @mikedonnerstag]

That looks far more like what I would expect of a milling vice! Comparing the photos also serves to illustrate that I need better lighting in my workshop!!

[Martyn DuncumbParticipant @martynduncumb88863]

Mike, I too have a Myford vice, purchased 40+ years ago, which is the same as yours with a radius at the bottom of the fixed jaw. I always assumed they were all made like this. Have no idea why though.

Martyn

[John HaineParticipant @johnhaine32865]

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

[Michael GilliganParticipant @michaelgilligan61133]

If it's any help … the one illustrated here seems to be the real deal: **LINK**

It's engraved with name and part number on the top of the fixed jaw [pause video at 0:16]

Of course, the usual caveat will apply [continuous product development, blah, blah]

MichaelG.

[Mick B1Participant @mickb1]

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.

[Michael GilliganParticipant @michaelgilligan61133]

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.

[Jeff DaymanParticipant @jeffdayman43397]

Mike Donnerstag – just curious – are there any tapped holes or through holes in the fixed jaw with the radius? f there were, maybe the vise was supposed to have a ground jaw insert plate wider than the jaw base radius. This would allow the vise to have a stress relief radius but still hold work square / not rise up so much. The radius on your vise is unusual – I have only seen it on vises from the far east made with low strength iron. Hope this is not the case with yours. Clamp up some steel and take a good heavy cut, and see!

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