Thread: Stuck Vicmarc Jaw Screw

That is pretty much the first thing you try to remove a stuck screw from any thing

I had one stuck in a long nose jaw a few years ago and rang Vicmarc , they told me to do it as per the video and it worked fine, although I needed to give it a more substantial wack than the video shows .
It is a big advantage being able to speak to the manufactures .
Ted

I take they were countersunk head screws.
It is not uncommon of this type of screw to lose its hex, most time it occurs after a couple of time the Allen has not been fully bedded into the hex hole. But at the end of the day, they will go eventually an old trick of toolmakers is to gently... gently pein the area around the damaged hex hole with a ball peen hammer.[ take your pick on the spelling both are right ] Then with care align the Allen key and drive into hex hole recreating the hex again. Now you should be able to remove the screw.

Ah the old one chuck per jaw set ...... the perils of luxury.

When the hex hole, in the Counter Sunk socket head machine screw, is showing signs of stripping another handy tip is to take a small centre punch (not the spring loaded auto type) and "mark" a centre in the head of the CS socket head machine screw beside each face of the hex socket. This deforms the metal in the head to crudely reform the hex socket enough to have a second go. Tip courtesy of Rob McKee.

Follow Marco's directions in the video (above) using a pin punch to tap the head of the socket head machine screw first though or you will be back where you started.

The big tip though - regularly loosen the machine screws and do some preventative maintenance - clean the crud that gets between the CS head and the jaw body then use some UBeaut Traditional Wax (or similar) to coat the CS faces then reassemble. Makes a huge difference in the future.

I strip down my chucks every six months or so and give them some TLC, it doesn't take long to do five or six chucks - well maybe he first time it does.

Often they don't really need it however the preventative maintenance of removing the jaws and socket head machine screws is but a fraction of the time wasted in butchering the head off one screw.

Oh and another tip consider the screws as consumables, regulary replace them - at least replace any showing signs of wear!

I use an engineers scribe tool to "scour" the crud that gets into the socket then blow it out before inserting a hex allen key. Doing this permits the allen key to be inserted to the full depth of the socket, which is really the cause of most of the issues & saves a lot of grief.

Suppliers like Konnect can supply a box of 100 Counter Sunk socket head machine screws ( & other styles for the Cole jaws etc) to suit Vicmarc chucks for less than $20 - that's 12 sets at less than $2 a set with 4 spares. So get a few mates together and split a box. Styles to suit Nova chucks aren't so easy to source though.

With a Vicmarc chuck, the supplied T bar Allen key does start to get slightly rounded with constant use. To rectify this, I present it at 90º to a grinding wheel for a poofteenth to square things up.

I second the buying of a 100 pack of those counter sunk socket head screws, one of the better things to have on hand for when a screw starts to get worn in the head department.

Mick.

What a timely thread!

My current 'shed' suffers from dampness, which has caused me serious grief in the past. Everything from siezed bearings on my thicknesser through to mouldy/warped wood stock.

Now I heartily endorse Mobyturns recommendation of servicing your chucks several times a year, a practise I follow, but for some reason this year has been a bad one. T'other day I was maintaining my other machinery (waxing, lubing, scrubbing off surface rust , etc.) and decided 'twas time to service the chucks.

Of five chucks, four had a stuck screw. The fifth had two!! Five screws were eventually removed using a drift but the sixth - one of the pair on the same SN2 chuck - was a nightmare as it was an 'outside' screw in a set of Nova Step Jaws, countersunk about 20mm or so.

Eventually I broke the chuck down and soaked the jaw slide/jaw assembly in a bath of diesel/kero for a while, before trying the pin punch method. It worked... eventually. That particular jaw screw is toast, however, as is the cheap chaiwanese pin punch I used. Luckily, I carry spares.

Needless to say, I spent more time trying to remove them than I'd spent servicing everything else.

The Allen CSK head screws are notorious for locking on the countersunk angle. One of the more common methods of persuading the screw to move is to shock it before starting. Using a drift or pin punch and a hammer being careful not to stuff the hex hole, generally, it will away easily after a few good whacks. But if it persists and the head is stuffed just drill the head off they are not hard. M6 screw use 6mm drill bit as soon as you're through the head it will fly off and you can undo the remaining part with your fingers. Rarely are they tight or will need much persuasion to come out after the head is gone.

The reason head variations is due to different standards in use.

Practical Maintenance » Blog Archive » Socket Head Cap Screws

Here the m5 csk has a head dia of 11.20mm


https://www.fullerfasteners.com/prod...rew-stainless/

here the m5 has a head dia of 10mm.


STS Industrial » Socket Flat Technical Data

here gives you an idea of what or why the variance occurs. In the diagram, it talks about or shows the theoretical dia and the minimum dia. .One head has a noticeable flat on the edge whereas the other has not.

Thanks for the post guys. I've got a VM120 that behaves in exactly the same way at times. Hope this makes it much easier.

Sent from my HTC U Ultra using Tapatalk

All good advice above. I am a believer of taking everything apart every 6 months or so and cleaning, lubricating, and adjusting. Spindle to chuck, and face plate to chuck;hand wheel to outboard spindle; banjo to bed; tail stock to bed; tail stock barrel; chuck and jaws; etc.

After this tune up, everything works better.