Sludge Trap?

[BSA_54A10]

Yep,
Really big fan of left hand drills.
Clean up the punch / drill area with a Dremmel on the plug only.
Do not touch the crank. it has been butchers enough already.

Got a pile of grade 8 left hand bolts and nuts.
Drill hole with a left hand drill. usually this spins out broken bolts all by itself.
Follow up with a left hand tap then a left hand bolt with a couple of nuts on it.
Snug in down tight then screw it out, never failed.
Don't use easy outs any more.
To get the drill press to turn left hand get a double A belt and fit it figure 8 on one of the pulleys.

Because the belt will be rubbing across itself you do not want to use it like that all the time but once in a while to drill out a broken bolt is a really worth while investment.
Running the drill press backwards menas you can put a good amount of down pressure on the drill making it bite hard
Two or three increasing sized drills works even better as the enlarging drill really puts a lot of rotational force on the bolt ( plug )

[mugwump]

I'm no engineer so go easy on me if this is a daft question, but why use a left hand drill. Won't a left hand tap still cut well enough into a r/h drilled bore? But using a l/h bolt is a great idea.

[muskrat]

Sometimes the drill it's self will be enough to unscrew the plug/snapped off bolt. Tapping the hole might do it or screwing in the bolt. If it still hasn't budged a lock nut on the bolt and heave ho.
Cheers

[bsa-bill]

bought a set of left hand drills about four months ago from one of those shopping channels (yeah I know but I took a chance)
Within  a week or so I used one to remove a stud, worked a treat, (remember to have the drill going the right way though)

[chaterlea25]

Hi All,
I use the  LH drill mehod to remove broken studs quite a bit

Heres what SRM do with the the sludge trap plugs 
Drill a 3/8 hole in the plug and weld in a high tensile bolt (usually an old flywheel bolt)
The weld will expand the plug and when it cools it will unscrew easier

John

[a10 gf]

Lots of nice tips, experience and suggestions here. Excellent.

Now looking forward to TimK's choice of process(es) and the (great) result :O) Pictures please !

[TimK]

Thanks for all the advice, I'll try an incremental approach - centre drill to get the hole in the right place, LH drill (if I can find one locally), LH tap (again if I can find one locally), hex key, drill out completely. I'll let you know how many increments it takes to shift it.

[jjbsa]

I used to drill a line of 1/8" holes, close to each other, across the head of the plug, then Dremel them together into a slot, and use one of those 1/2" socket drive screwdriver bits (this came long ago from a jumble and has the MoD arrow to say it's a good'un) to fit the slot and undo the plug.  As several have said (the hailwood site mentioned has the most subtle description, I think) drilling out the centre punchings carefully makes things easier.

Nowadays I'm fortunate to have a Bridgeport mill, so with a bit of jiggery pokery I can get access to the plugs with a 1/8" end mill and make a slot for the screwdriver bit more easily.

Loctite do a viscous, treacly, thread sealant (number 577) which is gap-filling and is ace at locking replacement plugs in and preventing oil leaks down the threads (I've always found that when screwed in flush, the plugs still aren't that tight, so this sealant gives peace of mind).  HTH

[TimK]

Success!
After my good intentions for an incremental approach, my impatience and the lack of decent engineering suppliers in the local area forced me down a certain route. I couldn't get hold of a centre drill, LH drill or LH tap so I was stuck with what's already in my shed and the advice received in the replies to my original post. I lightly drilled out the centre punches on the plugs and drilled a pilot hole in the centre(ish) of the plug. This was expanded incrementally to 6.5mm which turned out to be a nice snug fit for a 6mm hex socket which was hammered in, a bit of effort on the socket handle and out they came. The plugs look as if they've been cut (by hand) from a bolt, they were so far in I suspect that the oil feed to the timing side main bush was partially blocked - which probably goes some way to explaining why the bush is knackered. Anyway, at least I can get on with the strip down and ordering the ever growing list of replacement parts. 

[muskrat]

Tim, anytime you need tools I'm just down the road (20 minutes). Only too happy to help.
Cheers

[mugwump]

Well done! and good luck.

[bsa-bill]

well done indeed, a certain satisfaction in such cases

[TimK]

Tim, anytime you need tools I'm just down the road (20 minutes). Only too happy to help.
Cheers

Thanks for the offer Muskrat, I'll give you a yell next time I'm stuck. Do you know of any local engineering suppliers which stock the slightly unusual stuff that we're likely to need? I know it's all available on the web, but it's often nice to see what you're buying before it arrives in the mail and isn't what you're expecting.

[RichardL]

I guess I'm not going to get my five bucks.

Richard L

[TimK]

I guess I'm not going to get my five bucks.

Richard L

Resorting to a punch was well down my list of options - the plugs were so deep that it would have been a real challenge to get any lateral force on to them with a punch. Maybe you should keep the bet open as "currently unproven" - I'm sure someone else will face a similar hurdle in the near future.