Vicmarc VM120 Jaw Screw size?

[As]

Hello everybody,

Greetings
This is my first message, so here goes.
I have a Vicmarc VM120, it's my only chuck. I went to change the jaws and one of the screws was tight and I've messed up the hex hole.
I've looked up some ways to sort it out and will get round to that in time.
When that time comes I am going to want at least 1 new screw. I've tried looking up what size screw but found no conclusive details.
Simon Hope has them for sale at about £10 for 8, but I read somewhere about buying lots more for much cheaper.
I would like to hear your opinion on what course might be a good one to take.

Cheers,

As

[Valkrider]

A Google search shows them to be M6x12 you should be able to get some from Amazon / eBay or a local supplier.

[As]

Thanks, ordered a pack of 20.
Cheers

[Bill21]

Sometimes chuck screws don’t have normal countersunk heads. The ones on the Simon Hope site look fairly standard though so you should be ok.  Maybe let us know when you get them as it may help someone else.

[As]

I purchased A pack of 20 M6x12mm from ebay for £2.12. https://www.ebay.co.uk/itm/284006064396?var=585472467059
They seem to fit well, and tighten and loosen well too.
Cheers

[Bill21]

Glad you’re sorted.

I’m not a fan of countersunk screws as they can self tighten in use. To make things worse the hex key for them is a size smaller than for a cap head. You generally have to use what the chuck manufacturers intended though. My Axminster SK100 uses Cap Head screws and although my RP chuck came with countersunk screws I’ve found I can use Cap Heads with it instead.

[RichardS]

Some Chuck makers recommend that the screws are High Tensile Steel type.

I prefer to use Torx type screws as they have a better fitting key than the Allen Key type.

Richard

[Bill21]

Metric High Tensile screws should have a number of the grade marked on them.

[John D Smith]

 Hi Bill 21,
              That is very useful information thanks.

                                                  John

[yew turn]

Just for more info regarding the tensile strengths of fasteners:-

  8.8 grade -  hexagon high tensile setscrews
10.9 grade - socket countersunk screws
12.9 grade - socket cap screws

Hope this helps.

[Bill21]

Just for more info regarding the tensile strengths of fasteners:-

  8.8 grade -  hexagon high tensile setscrews
10.9 grade - socket countersunk screws
12.9 grade - socket cap screws

Hope this helps.

Tensile strength doesn’t seem to be fastener shape dependent.
C/S for example are available in 10.9, 12.9 and possibly others?

[Bill21]

Dragging up an old thread (pun intended) I know but I’ve recently seen some jaws screws that appear to be made from stainless steel. Stainless fasteners are commonly made in A2 or A4 steel and I suspect the shear strength of an M6 screw in either of these materials would be more than strong enough for our use? I’ve also noticed some of the screws supplied for my jaws don’t have grade markings on them. 

[Goldfinger234]

Just an addition to the stainless post. Stainless steel is soft, hence it’s easy to round stainless wood screws with an impact driver, much easier than normal screws. Also, the main drawback of stainless is it galls, or seizes in place, so it’s a must to use something like copper slip unless the bolts are being removed regularly. When they stick, you inevitably snap them with the force required to move them, or round them off. Unless your chuck is to be used underwater, I’d stay clear of stainless bolts, just like the manufacturers do.