matt_the_blat Posted October 28, 2009 Report Share Posted October 28, 2009 Hi All, Like the title says really - I was going to replace the stock paddock stand bobbins on the Mille with some nice R&G ones but one of the original bolts is seized (salt corrosion). I tried all the usual remedies to no avail so now I'm faced with no other option but to drill it out (roughly 5mm dia.). I got some new metal drill bits from Wickes - I wasn't expecting miracles and I kinda half knew this already, but they went blunt without making much impression. On that basis (and because there's no sign of rust) I would assume the bolt is stainless steel of some sort and threaded into an aluminium swingarm. So, any tips from the seasoned pros? If it's *that* seized I'm thinking Easy-Outs might be a bad idea in case they snap in the hole. Is it simply a case of getting hold of some drill bits more suited to the task and gradually increasing the diameter (and potentially then having to re-tap the hole and/or use a bigger bolt for the new bobbins)? Any particular recommendations on drill bits? Obviously it's not a critical component anyway and 9/10 time I use an Abba stand so it isn't urgent but I'd like to get it sorted. Thanks in advance, Matt Link to comment Share on other sites More sharing options...
will#224 Posted October 28, 2009 Report Share Posted October 28, 2009 Have you used any heat on it? Have you tried plus gas over night? Is it an allen head fitting? How much have you swung on it? If your final option is drilling it out i'd exhaust all the other options first, if you've rounded the head sometimes a torx bit hammered into whats left of it gives you another chance. I'd have a look for some cobalt drills, they'll make stainless easier. HSS will struggle, imho the Ti coated drills are crap. Link to comment Share on other sites More sharing options...
deviant Posted October 28, 2009 Report Share Posted October 28, 2009 If it is a steel bolt in an ally swingarm then it will loosen up with heat. How much have you got left to try and turn it with? One trick I've used with recalcitrant exhaust studs is to weld an offcut of steel plate to the stud - you get something you can twist it with, and it puts a burst of heat into the local area, helping to free it off. Link to comment Share on other sites More sharing options...
vfr4 Posted October 28, 2009 Report Share Posted October 28, 2009 Heat is the answer, if you have or can get a shot of an oxy acetalene torch use that carefully. Failing that, you could weld a nut onto the bolt head. Dont bother with those plumbers torch things they give no heat at all. Link to comment Share on other sites More sharing options...
spacemonkey Posted October 28, 2009 Report Share Posted October 28, 2009 Heat is the answer, if you have or can get a shot of an oxy acetalene torch use that carefully. Failing that, you could weld a nut onto the bolt head. Dont bother with those plumbers torch things they give no heat at all. +1, Once the bobbin is off, use any kind of welder to stick a nut to the head of the bolt. The amazing heat shock will help to break the corrosion up and once the heat gets into the alumimium it'll expand more than the steel, get looser... Then you have a nice, big hex to get hold of! Link to comment Share on other sites More sharing options...
alexp5 Posted October 28, 2009 Report Share Posted October 28, 2009 I've had to do this before on an RGV swingarm. Arse pain of the highest order! Ended up removing swingarm and using a cobalt bit on a slow speed in a floor mounted pedestal drill. Use plenty of cutting fluid, not WD or suchlike, but Tallow or motor oil will do. Vinegar absolutely pisses on WD40 for rusted in fasteners, BTW. Centre punch the remains of the stud, the shock can help break it's grip. Heat is always good too. If all else fails, your gonna have to look up 'spark erosion' in the Yellow Pages. Link to comment Share on other sites More sharing options...
matt_the_blat Posted October 28, 2009 Author Report Share Posted October 28, 2009 Thanks all for the tips so far - Only about 5mm of stud sticking out so not much to get onto now - I cut it off short so there would be less to drill. Prior to that I did try a couple of bolts wound onto the stud together but it just tore the thread. Will try some decent penetrating oil though. Zak - Easy-outs best avoided then eh Drill, slow speed, lots of oil - gotcha. Will - All other options have been explored and exhausted. Cobalt drills you say? Righto Deviant/vfr/SM - thanks, will try some heat then see if it will shift with some vice-grips (heat then oil or oil then heat? ) Like I say, it's not keeping me off the road so no bother there, but it'd be nice to have it sorted properly. Cheers, Matt Link to comment Share on other sites More sharing options...
matt_the_blat Posted October 28, 2009 Author Report Share Posted October 28, 2009 Good quality HSS bits will do as long as you keep the speed low and use loads of cutting oil, but cobalt are better. Dont bother with spark erosion.......if it all goes pear-shaped then cut the bugger off the swingarm. Any ally welder could re-weld on a threaded boss in about 10 minutes flat. On the subject of keeping the speed low - would a cordless drill be better from that point of view than a power drill? Link to comment Share on other sites More sharing options...
DAMO666 Posted October 28, 2009 Report Share Posted October 28, 2009 Another method is to repeatedly hit the bolt towards it's edge with a nice sharp centre punch until you make a decent sized indentation then angle the punch so you are hitting the punch in an anti-clockwise direction to drive the bolt round. The combination of impact and torque usually free them off. Link to comment Share on other sites More sharing options...
blow_away Posted October 28, 2009 Report Share Posted October 28, 2009 If it's a stainless steel screw, get yourself some Presto "Hi Nox" drills I can only find them listed in sets, but they are available separately. They are on page 6. http://www.presto-tools.co.uk/files/Sets.pdf A stainless screw will sometimes be marked "A2" on the head Link to comment Share on other sites More sharing options...
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