To cut a long story short - bike carbs have a stud snapped in. Its the end one on the side where air flter attaches. Not fixing it could result in air being sucked in past the o-ring.

I drilled it with small drill bit (stud actually moved a bit while drilling so i dont think the its seized in) but managed to snap the drill!!!
I was convinced an easy out was going to removed the offending stud but now there is a drill bit (approx 1.7mm which is a bugger as i was going to use that one to drill the jets out with!!!!) in the way im stuck.

The bit is just a std HSS.

Any ideas what to do next.

The stud holds the air filter plate down so id rather get it fixed. Ive already thought of smearing a bit of silicon aroung the o-ring first so that end seals. But would prefer a proper fix. i dont want to give the RR operator any excuses when the time comes (also piece of mind etc).

stud extractor should do it

If it's not siezed you might be able to tap it undone with a pin punch if you can get access.

Carefully drill it and the broken drill bit out with a tungsten tipped drill bit. Or for a sure fire fix get it spark erroded out by an engineering firm offering this service. Or is there enough room to drill another hole for a stud in a slightly different place?

[Edited on 11/7/07 by Phil.J]

IMO I would not use a Stud Extractor... we did that on our exhaust port block and split the casting.

Safest way to do it is to drill it out as far as you can, then grind it using a Dremel (or suchlike) then re-weld, drill and tap again.

Steve

I'm assuming that the stud and drill have necked off flush, so there's nothing to grip on to with mole grips or similar?

A stud extractor is no use until you can get the drill out, so your best option will be to use a carbide bit in a Dremel, with a very steady hand! Have a look her e, though you can get them a lot cheaper than this....

If you're uncertain, and don't want to mess up the item, then I agree with Phil.J - strip it down as far as possible, then take it to a local engineering shop.

If it's ready for the machine then all they have to do is to line it up, press the green button and go and do something else for an hour. Very little man-hours, so shouldn't cost to much. In my case, I paid a cash contribution to their tea fund, as it didn't interfere with the firm's 'proper work'.

Just be aware that the piece will be immersed in some cooling fluid, so any rubber bits should be removed.

HTH
David

Im comfortable to do the repair just couldnt think what to use.

Both the stud and bit are sub flush so unfortunately nothing to get hold of. I have tried to tap it round but cant get the angle on it.
I tried to drill a hole down the side but its only M4 so tiny.

Thanks Coose for the suggestion. I have one of those Aldi dremel kits with all sort of bits inside - i keep forgetting to look in there!!!! That might just be the solution. At least ill be able to grind out the stud a little at a time and re-tap it. The fixing doesnt have to be torqued up silly - just enought to seal down on the o-ring. Alittle sealing compound will also help when the time comes.



Thanks for the suggestions.

Get some new tungsten bits and drill 'em out. Don't whatever you do use a stud extractor. They work when the stud is flush with the surface but loose.... but when the stud is seized in place it'll just snap off the stud extractor (guess how I know)....

Go slowly with new bits and you should be fine. One you've drilled it all out apart from a 1mm rim of old stud at the very edges you should be able to collapse the stud in on itself (pry it with a v small screwdriver) and pull it out. The drilling will take a while but it should work fine.... Obviously be careful when you're drilling that you don't go too deep and drill past the stud into something important. Measure the depth from some of the other holes and put pieces of gaffer tape or masking tape around the drill bits at that depth to use as a depth gauge....

Drilling out drill bits sounds like it shouldn't work (the drill bit is only as hard as the thing it's drilling) but it does.... It just takes time and a fair bit of cooling lube....

Enjoy

Ive managed to get a 4mm cobalt drill to drill out the stud / snapped bit - will this do the job?

Get it to someone with a tig welder. they can build up a weld onto the top of the stud and then weld a piece of steel big enough to get some grips onto. The added heat from the weld should help with shifting it.
The last resort is spark erosion.

[Edited on 11/7/2007 by nitram38]

that may well do it, just don't go over 650-700 rpm. Once removed retap and insert a Helicoil wire coil insert to suit. You shoudn't need special tools to insert one about that size, I've done it with a parallel punch with a slot cut in the end with a hacksaw.

Best of luck