Rounded off hex head screws.

Hi,

I just had a bit of a problem today with my insert MEGHR parting tool, The tip was positively blunt and needed replacing, the tension that keeps it in it's seat is held by a hex head screw, the hex had rounded off and it was far too tight to undo. The screw is countersunk into the body so you can't grip it. 

There isn't really alot of options to removing stuck screws but luckily i've found the most decent solution is to heat the offending area til it glows a little bit, transfer it to a bench vice and find a point on the hex screw, with your hex key where it still bites, and gently release it.

I would've been totally stuck if i hadn't managed to get it out! anyone else know of any other solutions to stuck bolts (in metal)?

After the fiasco i obviously chucked out the old screw and replaced it with a much better conditioned one. 

(My father had suggested using a scrappy allen key the same size and supergluing it into place, but i doubted it if it could stand up to such tension) 

Michael W

Edited By Michael Walters on 12/07/2016 16:11:34

Edited By Michael Walters on 12/07/2016 16:12:48

Drill or grind head off the bolt - usually works if just head damaged, not so successful when the thread itself is corroded as it doesn't leave much to turn the bolt shank with when removing it.

A bit of Never Seize/Copper Coat on screws often helps to prevent these sort of misfortunes.

Dave
The Emerald Isle

David J,

As OP stated countersunk, no room for grinder. All my inserts are held with Torque screws though

One of the metric shoulder bolts/screws in my knurling tool has become rounded (soft cheap metal), it's also a hex head. I can tighten and loosen it with an imperial allen key as there's enough space left in the corners for the key to engage into.

Ed.

.

KWIL ... do you mean Torx ?

MichaelG.

Depends how big the grinder is...

Dental bit / Dremel burr etc. would potentially tackle countersunk head.

The question asked was about bolts in metal, even though example given was countersunk head.

CheeHi Michael

Sounds like you did the right thing. Heat is the game changer normally.

I've employed various tricks over the years on old cars et al, including your trick with the centre punch.

Welding on a nut through the bore with a stick welder works nicely if big enough - it's a double whammy; heat and torque. (That's torque michael G not Torx ) 😀

Also, heating the centre of the screw head to red and belting in a screw driver or over size allen key ... or Torx driver tends to work well.

Also drilled off the heads and applied mole grips to the stud when desparate, if countersunk and not too hard.

Cheers Will

we have hex heads at work and keep a load of torx bits we hammer in usually works.

But .........

The one thing that has NEVER been successful for me is those damn near useless screw extractors.

Never, not even once have I got those to work !!!!!

Wouldn't like to use a screw extractor on an M3 or M3.5.

Just drill head off as David said never fails. Just go up in size until head departs from stud, easy.

.

I have an interesting "opportunity" which I keep putting off.

When I bought the ML7R, it came with a Myford-Dickson QCTP ... One of the toolholders has stud for the adjusting screw sheared-off, just under flush.

One day ... When I'm in the right frame of mind ...

MichaelG.

That sounds tricky Michael ..... Perhaps you'd like to borrow my extractors ? They are in good nick ( hardly used ).

Seriously though, I bet those studs are hard or at least tough as old boots. Probably better to bin it and buy a replacement !!

Cheers Will

... It does make quite a good paperweight, Will

MichaelG.

I have been quite succesfull with rounded allen bolts using a piece of flattened solid copper wire placed in the allen socket and tapping an allen key in. Take a bit of 2.5mm about 4" long, flatten the end, and put it in the hole, then tap in the key.Usually works first go!

.

If I had a Spark Eroder that would do that, on [I think] a 4BA stud, I would enjoy trying.

... Meanwhile; I do have a 'plan' [but don't hold your breath]

MichaelG.

Hi Michael, it depends on what diameter the stud is, but if you have a TIG setup and can do some delicate building up, you can place a washer with a slightly smaller hole than the threaded hole, over the stud and build the end of the stud up enough to get a pair of grips onto it or weld a nut on, the washer will help, depending on the skill level, melting into the thread. This same method can be used for countersunk screws. A little patience is a bonus for this method, but with a good skill level, or finding someone who has the skill level, it is doable. I have done it with a 6mm broken stud and down to 10mm using MIG or stick.

If your QCTP is no use as is, then what is there to loose, it would still work as a paper weight

Regards Nick.

If you must use screw extractors, the one I have are probably the best (they are the most expensive), the are made by Snap On Tools, the set has about 6 sizes the extactor is a steel pin with 6 sharp ribs down the length. There is a drill guide for each size, and a drill bit, and a hex collar for each pin. I think 10 32/3/16", or 5 mm is as small as it will do. You just hammer the pin in the drilled stud, put on the collar, and 9 x out of 10, probably better the stud screws out. The tapered easy out seems to expand the broken stud in the hole, and if the worst happens and the extractor breaks, you have a hard bit of steel right where you don't want it!!

Ian S C

One way of loosening 'seized' or similar screws is to use impact, but scientifically. Find a short bit that fits, or chop off a short length of new, sharp, allen key (etc). Then hold it in place with long-nose pliers and smack it firmly into the reluctant screw. This should have two results:

1. The thread is jolted from the tight side to the loose side, crumbling any rust, etc.

2. The metal forming the bearing face of the screw, or the part, or both, is distorted - knocked down, giving a tiny clearance.

With any luck this will allow you to turn the screw. Impact drivers do this, and apply a torque at the same time, but finding the right size of insert is not easy (except for the Phillips screws that were the most trouble on 1970 era motor bicycles).

I have seen the same trick used to smack the head of a too-tight filler plug, too. One good hit was enough.

Hope this helps.

Regards, Tim