Seized Screws - Impact driver fail

[StPeter]

 
Removed the alternator cover this evening - well tried to! Yes, I've got my trusty impact driver but the lower two screws had obviously experienced previous abuse and there wasn't much left of the heads. These two aren't blind so the back end will be exposed to all manner of damp crap to aid electrolyitic corrosion. Quickly got to the drill-the-head-off point (man, those screws are harder than I remember).Cover off, two studs exposed. The mole grip will get them now that the tension is removed . . . . see, I've done it before. Unfortunately, not on a 37 year old. Got the back one out but the front one refused to move and the inevitable happened - it snapped off with about 8mm sticking out.
I think I know the answer - drill out and helicoil (if there's enough meat there) but has anyone got any other suggestions?

[kifer]

When removing cross heads that have been abused I usually tap lightly with small hammer then tap a torx into them very slight tighten then undo seems to work more often than not.  As for broken ones fit a nut on top and mig centre then use spanner.
These are what work for me but expect there are loads more ways, Good luck if you struggle go have a brew come back when cooled down  Tom.

[LesterPiglet]

I have in the past drilled broken screws out with a slightly smaller drill, then chipped away at the remainder with a hammer and a scribelike chisel, (something I knocked up with an angle grinder) and managed to save the threads. I think the heat from the drill helped break the corrosion a bit.

[StPeter]

Good thoughts, guys. Especially the thermal control effect of a brew! Unlike when I used to do this stuff before, I don't have to get it running to get to work in the morning. I'm doing it for fun. Remind me again how much I'm having!

[Bryanj]

Blowtorch of the type that plumbers use with disposable gas canister, warm up the alloy and douse liberaly with WD40 or similar.

ALWAYS hit the impact bit into the screw head before attaching the driver and trying to undo and remember that they ARE NOT pozidrive( and not exactly Phillips either)

[Spitfire]

I use a home made T bar, place it on the offending screw give it a sharp rap with a hammer and they tend to loosen off.

Cheers

Dennis

[z1100r]

I would grind whats left of screw flush with case, centre dot it and drill with  5mm drill. I would then heat it with a heat gun/blow torch until its real hot and let it cool down, heat it again and try an easy-out. I have hammered  small torx bits into the 5mm hole in the past. This sounds well stuck though and drilling out and helicoiling maybe  your only option.

[matthewmosse]

paste a big gob of weld on there with arc (stick) welder, whack on the mole grips and twist, - rarely fails but I have an exhaust stud on  my wifes 250 nighthawk that I've had up to white hot with the oxy acetalene, welded a 6mm sockett directly on there (one off a 5 quid / 200 pice sockett set, not a good one!) and still it will not budge, for this one I'm thinking of just welding some treaded bar to the broken off / protrudig stud and filing it to the correct dimentions.

[StPeter]

Thanks for your suggestions.
Bryan - I had forgotten that detail about the screw heads -  it's been a long time since I last did this stuff and my brain's filled up in the meantime. Thanks for the reminder.
I've managed to recut the thread on the stud and get an M6 nut on it. Stick welder will get an outing tomorrow (when I repair my mask - who left the batteries in?). That should get some serious heat into the threads and give me a flat-sided "gob of weld". It's marinating overnight in Plusgas at the moment!
If that fails, it's out with the drill bits.

[kifer]

Don't forget to strike up on some scrap first you know what these welders are like. Try a slight tightening pressure first was always told that as a lowly apprentice but it seems to work. Good luck Tom.

[StPeter]

Cheers, Tom.
Put off until the weekend - SWMBO's birthday today (the bike was her present!) best not to start after a couple of glasses of wine!
Helicoil kit arrived today - there is a plan C!

[StPeter]

Insufficient stud to weld to - I was worried that the crankcase was going to start dripping on to the garage floor!
Some delicate angle grinding to get it nearly flush to the crankcase. Put the cover back on and run a 6.5mm drill through the hole in the cover. This gives you a centralised (ish) mark in the stud. Run a 4.5mm drill bit through as square as you can get it. Follow up with a 5mm. I may have been lucky but using my favourite home-made tool (the bit of broken power hacksaw blade sharpened to a chisel point - more about which later) I was able to pick out the first half  turnof the original thread - enough to get a tap aligned. Plenty of lube and taking it very gently, I managed to recut the thread. I quit at that point - while I was ahead!

Going back to The Most Useful Tool In The World . . .
Get yourself a 1" power hacksaw blade. If you know some local machine shops you can probably scab some broken ones; if not buy a new one. Grind off the teeth on a bench grinder. Snap to length (wrap it in a rag while doing this in case a bit pings off). Grind the end square and put a bevel on one side (chisel stylee). You can use this for:
Anything you'd use a thin cold chisel for
Removing bricks from walls
Removing old pointing
Channelling cables in aerated blocks
Removing old gaskets
Cutting rivets and screws
Scraping old paint
Shaving wood - especially after burning paint off

In short, it takes an enormous amount of abuse; you can welt it with a hammer without it bending and you can get a good edge which can be resharpened in seconds. I have several of them of various lengths. I'd not be without them!

[Bryanj]

At least its out, now don't forget the antisieze on the new ones!!

[SteveD CB500K0]

A picture of the "tool of all tools" would be cool as I'm having trouble visualising your (otherwise excellent!) description.

[meerkat]

A picture of the "tool of all tools" would be cool as I'm having trouble visualising your (otherwise excellent!) description.

Hi Steve,
It's a modified one of these pictured below.
I have one somewhere in my collection of 'handy gear' that I used at work as a short straight edge, a weld chipping tool, scribing lines and lots of other things.