Topic: cost of removing a broken cylinder stud

[drumstyx]

I dropped off my crankcase with a broken stud (~2mm above the surface) at the local motorcycle machinist 2 or 3 months ago now, and now that he's finally ready to work on it, he says I'm looking at about 2 hours -- $180. Does this sound right? I think he was referring to if he needed to put in a helicoil, but even still, that sounds steep.

[drumstyx]

I avoided the idea of the drill because my biggest worry is drilling off-angle, especially with the fact that it's not straight on, and I don't have a drill press. I'm considering it at this point though

[camelman]

The left hand drill bit can work, but I really recommend welding another bolt onto whatever is left of the stud. The heat of welding will break the broken piece free, and then you can just unscrew it. Since you have 2mm left above the surface, it'll be an easy job. If you try to drill it out with a left-hand bit, or God forbid an EZ-out, then you could destroy the metal available for welding and ruin your chance at an easy repair.

The steel bolt will not weld itself to the aluminum, and any competent welder can weld a bolt to the remaining stud without damaging the aluminum. Make sure to lay down a towel over any bearing surfaces that might be exposed to protect them from weld splatter.

FYI, I've done this on 14 bolts now, and I've only had one bolt that I couldn't remove. I've NEVER had any damage to the surrounding aluminum.

[camelman]

BTW, even a wire EDM removal shouldn't take two hours. Your mechanic/machinist doesn't seem to know many tricks of the trade.

[drumstyx]

I don't mind paying to get it done at all, so I wouldn't mind having to take it to a welder, I just thought $180 is kind of outrageous, glad to know I was right. I'll take them back tomorrow then, he said he couldn't get to them until monday anyway.

Also, why TIG specifically? My dad's got a MIG welder if that works.

[camelman]

Cal and I have different opinions on this, but I think a couple mm are plenty to work with. The welders I go to have actually welded to studs that are broken off below the surface of the parent material!!  Anyway, your choice. If your welder thinks he can do it, then give it a try. If not, then try heat and a left-hand drill bit.

[Powderman]

If you can get the nut on what's left at all and fill the hole with weld it will come right out. 10 minutes at the most to fix it.

[camelman]

Hmm, I just realized we're approaching this differently. I haven't welded a nut onto the stud before as it seems Powderman and Cal are suggesting. However, that sounds like a great option if there's enough material left from the original bolt.

I've always just used the original bolt piece that broke off, but filed it down to a rounded point. The rounded point makes it easy to weld to the remaining piece of bolt that's still in the threaded hole.

Sounds like you have some good options available. Just don't pay $180 for it!!! 

Camelman

[drumstyx]

Interesting...I still have the broken bit, so that could be an option, but I was thinking that if I'm welding something anyway. Might as well be something I can hit with an impact gun

I had a peek at eBay and I could get a whole new crankcase set -- year matched, for less than that. Bet I could get a whole engine for that at the wreckers

[mystic_1]

Use a nut that's large enough to just slip over the OD of the stud (drill out the nut if necessary) and then push it onto the stub so that it's almost flush with the case.  Plug weld through the center of the nut onto the end of the stud.  Should spin right out with a ratchet after that.

mystic_1

[slikwilli420]

How about a chemical option? I have read about this a few times. No effect on aluminum but effective on steel.

http://hackaday.com/2015/08/03/dissolve-steel-drill-bits-in-alum-from-the-grocery/

[Garage_guy_chris]

#$%* your only maybe 20 mins from me. Im in East Scarborough.  I did the "weld a nut to it" method on a couple of mine. I would / could do it for ya for a lot less. I probably also have some decent used studs to replace the busted ones. Let me know via PM if i can be of assistance

[AshimotoK0]

I got a below the surface 750K0 stud out using the weld method but no success with a nut, even though I removed all zinc plating. In the end I  simply welded a blob to the stud remains and kept building it up with MIG weld until there was a large blob that I could file two flats on and then whilst really hot from the final weld it came out easily with vice grips. The MIG is a really good way of getting loads of localized heating in there (TIG too if you have it)

[CycleRanger]

[strynboen]

he is burning the main bearings aut of that drill machine...if it pulls all the power through the spindel..

[CycleRanger]

he is burning the main bearings aut of that drill machine...if it pulls all the power through the spindel..

I dunno, the guy seems to know his business!

[strynboen]

yes he is vearing a Harley cap...so absolut a specialist...or maskinist..

[Powderman]

Says he's been doing it for a living for 40 years, I'd say he is qualified.

[drumstyx]

#$%* your only maybe 20 mins from me. Im in East Scarborough.  I did the "weld a nut to it" method on a couple of mine. I would / could do it for ya for a lot less. I probably also have some decent used studs to replace the busted ones. Let me know via PM if i can be of assistance

PM sent!

[Airborne 82nd]

he is burning the main bearings aut of that drill machine...if it pulls all the power through the spindel..

Would need to know where the ground is before knowing that This is not his first rodeo cap or not.

[strynboen]

he put the ground at the metal part..( he said it vas the gruond konnektion)..so the metal konstruktion vas groundet
my vorryes vas the elektrode(did not see a vire for the elektrode part(so think it powered through the vertikal moved spindel..(the mashine used for this Work is a standart vertikal moveded drill head)..so to get povered up the elektrode a separat vire is needet to move the pover direkt to the elektrode..not through the drill bearings..so a duppel isolated elektrode holder is the right vay to make this..i just not see one..