Topic: Broken cylinder case bolt failed drilling attempt.

[Korven]

Was taking my case apart and was removing the cylinder case bolts. I had 3 bolts that didnt feel like comin loose. i was at them for week. heating up, lettin cool. Hammering on the stud here and there. using diffrent solvents. using a double nut with wrenches on both nuts. two of them came off and the last sucker was left. had a friend use a plummers wrench at near the bottom but then it broke off. What i was left with was 2cm sticking up over the engine case. Got a nut welded on by a guy in the garage next door. that didnt work either. He consulted with his friend and he told me that it should be drilled out and that his friend had alot of good quality drills, left threaded ones and some other good tools for extracting broken bolts. Sounded good as i was told that he had experience with drilling in aluminium before. I have never done anthing like this myself either. A few weeks later i got it back with a 4mm drill broken off in the bottom. Claming that the weld hardened the bolt to the point that its undrillable and it just kept breaking off. its 14mm deep and the other ones seem to be 28mm or so. it doesnt seem to be center either. Not sure what the next move is from here.

[spotty]

theres a process called spark erosion that eats the unwanted bits one spark at a time, obviously this is done by an expert with the special equipment.
i'd be thinking they eat away a nice perfectly round hole and the tap and helicoil a new thread of the correct size into the hole

anyone who knows more about this should now jump in and correct and or expand on this explanation

heres a nice youtube man to show you more

[beemerbum]

The process is called "Electric Discharge Machining". A lot of information on the net

[pjlogue]

I would consult a reputable machine shop and see what they say.  If the drill that broke off is high speed steel they might be able to mill it out with a carbide end mill.  Perhaps a coring drill if they make one that size.  Core it out and then helicoil it.  In either case the case needs to be clamped and set up properly.

I don't know if spark erosion would work in this case as the heat generated may melt the aluminum casting. 

Good luck! 

-P. 

[flybox1]

time and energy....
unless this is a sandcast, a new set of feebay case halves woulda been here yesterday.
save these for a rainy day.

[Darren Jakal]

There was once a pretty funny video of a guy called AvE using alum (potassium aluminum sulfate) to dissolve a ferrous bolt out of aluminum.

Can't find the video, but came across this thread:

http://forums.sohc4.net/index.php?topic=73735.0

by a member called    fantino.

good luck, Darren

Found this video from AvE. Might help.

[Medyo Bastos]

Ball breakers work on broken drill bits too!


Sent from my iPhone using Tapatalk

[754]

 4 problems with the machine shop.
 1 it's pricey
 2 it's expensive
3 it's not easy... you need a tilt table, or a bar to fit across bearing bores, then they can shim it up. So paying for them to figure out How to hold it costs

 Bring the cylinder and dowels in, they can level the case, pick up stud hole, with great  accuracy, pull cylinder off, then go to work.

Best bet EDM or spark erosion, gets thru and hard broken off stuff, if they have it clocked in they can burn out the hole to tap drill size, then whats left will almost fall out. If there is nothing broken off in there, they burn a hex shaped hole and use an Allen wrench.

 These studs at are tricky, tough to get the heat to threads easily because they only start about 8 mm down in the hole.and they are deep.
 I still got 3 stuck in my F case, no luck welding,  (kept breaking off)wrong  settings, no one that I wanted to pull off work in the shop I was using. They were trying to help me heat it with a torch, but I said no thanks.. I want to sell it not melt it..
I think my best bet bet is to pile up the weld, and get the heat in that way.. way safer.

[disco]

I feel for you Korven! I remember taking out the old cylinder studs to replace with APE HD studs. It was very much a "sphincter clenching" experience I can tell you!  . I was $hi!ting bricks until I had them all out. Some of them took a lot of time & slow persuasion. Hopefully you'll have it all sorted soon!

[kblackburn]

Hi,

I had the same problem with my daughters bike, we had a cylinder stud that broke off, I used very good quality stud extractor, that snapped off,
in situ.
I tried all different methods to get it out, I finally found the Rescuebit on you tube video. there very expensive, but absolutely brilliant.

I have attached the youtube link.

worked perfectly for me.

kevin

[Remcod]

theres a process called spark erosion that eats the unwanted bits one spark at a time, obviously this is done by an expert with the special equipment.
i'd be thinking they eat away a nice perfectly round hole and the tap and helicoil a new thread of the correct size into the hole

anyone who knows more about this should now jump in and correct and or expand on this explanation

heres a nice youtube man to show you more

+1 on this one, this is how I got the broken stud removed from my cb350 engine. Cost me around 150usd but the case was saved. It actually turns the metal in plasma that is then washed away, or something like that. I could just bold in a new stud after.

[MessnerMoto]

Carbid (WIDIA) drill will drill/remove broken stud with broken drill. Use 5mm/6mm drill...Like I said WIDIA drill  Drill table can help. But I did something similar with quality WIDIA drill and ordinary hand held driller... use helicoil to repair thread... there is plenty of alu around the hole so don't worry  No need for some fancy methods.

You can drill out broken WIDIA piece with WIDIA drill just be slow on drilling process

Machine shop should not take more than 1h to drill it out

[DaveBarbier]

I’m with Fly, look for a good set of case halves on eBay. Hell, I got an entire 650 for under $300 just for the motor. Why pay a machine shop over $200 for them to try and drill it out? These case halves have sentimental value?

[madmtnmotors]

I use these with a Dremel for removing remnants of broken bits/extractors:

https://www.harborfreight.com/diamond-point-rotary-bit-set-20-pc-69653.html

For the price you can run through several sets of these without breaking the bank. Once the broken bit is ground away you can continue using these to grind away the remnants of the broken bolt too, stopping short of grinding out the threads. I can usually pick the treads out at this point. Once the hole is cleared then you can assess the damage to threads, if any. If the threads are damaged then you can work on the repair, either Helicoil or Timesert.

[Prospect]

Hi,

I had the same problem with my daughters bike, we had a cylinder stud that broke off, I used very good quality stud extractor, that snapped off,
in situ.
I tried all different methods to get it out, I finally found the Rescuebit on you tube video. there very expensive, but absolutely brilliant.

I have attached the youtube link.

worked perfectly for me.

kevin

I think this would be the most economical method of extracting the bit. After you extract the bit you would have to weld the hole up and tap new threads. 

[madmtnmotors]

$100 for two bits? What would you use to remove the remnants of a broken "Rescuebit"? I'm a cheap SOB and can buy 12 sets (240 bits total) of the diamond rotary stones for the same price. If you can't get a broken bit removed with just 4 or 5 diamond rotary grinding bits you might want to seek additional professional help...

[Korven]

Ive looked into the alum stuff and bought some today. poured some in a cup with a piece of a drill. the reaction is steady but kind of slow. im not sure how long it will take to dissolve something if its not submerged from all sides. the next problem would be keepin the case heated up for the duration. i guess you could heat it with a heatgun but thats not something you could leave unattended over the night.

Sure i could get a new set of cases but not very keen on removing those studs again. one of several of them could leave me in this ol situation again.


heres a better picture of the case.

[Darren Jakal]

The original AvE video showed him using a light bulb to keep it heated. Can't remember what watt it was. It took a few days I believe and then the centre chunk fell out. He built a little dam with an old tin can and some putty and filled it up with the alum solution and taped the light bulb to the can. Wish the video was still around, it was funny.

Good luck, dj

[madmtnmotors]

The original AvE video showed him using a light bulb to keep it heated. Can't remember what watt it was. It took a few days I believe and then the centre chunk fell out. He built a little dam with an old tin can and some putty and filled it up with the alum solution and taped the light bulb to the can. Wish the video was still around, it was funny.

Good luck, dj

I was thinking the same thing about using putty as a dam if trying to dissolve in solution. Regardless of the method, I have found patience to be key to any of the methods used. 

[754]

Not sure if it's good, i would try modeling clay, build a dam.
Try a light bulb in the hole where the cylinder goes, then put a piece of metal over to cover most of the hole.
Dont use wood, it can char..

[Korven]

Update. The bolt is out! New threads are in.

The sucker was hard getting out. Used alot of drills but they all became blunted on the second of contact. Ended up using one of those expensive drill remover bits that we had laying around. It also got partly broken but seems to still cut. It was only afterwards that we both had been looking at the wrong drill size in the box of helicoils. We now had a 9mm hole. Doooh.

Was either ordering a big-sert kit or a new case... After some thinking and calculating the big-sert would only leave 1.5mm of aluminium in an 180degree angle apposed to 5m or so in the normal case.

We ended up purchasing something called "alutite" welding the hole. Heating the block up gave it a nice brown color that made soda blasting easier to spot. Drilling it up  took quite a few bits since the weld is alot harder than ordinary cast Alu. This only cost about 30$ (excluding the drill bits) Bolted the cases together and seemed to work fine. Also used this to repair some broken off fins.

[754]

How did you indicate the hole to drill it ?
 I would try to mount it so you slide cylinder on it, and dialing the hole.
 Then pull cylinder off and drill it.

[Korven]

Drilling the bit out we measured out the x axis from another hole. Drilling the new Alu we used the cylinder and one those punches same size as hole. We didnt secure it enough while drilling so it moved causing a oval hole. We ended up eyeing it up since we didn't wanna weld it again but worked out fine.

It wasn't just as important being spot on now since we had no old threads being careful of and there is 1mm or so flex while mounting in either direction.

[Prospect]

Where did you buy this stuff because it seems only available from the Netherlands and the website is in Dutch. 

Wow.  That alulite stuff looks very good and has versatile use.  I'm definitely going to keep it in mind for fixing threads on heads etc. 

Glad it worked out for you.

[slikwilli420]

All of that aluminum soldering stuff is junk. I wouldnt use it to fix anything I needed to say fixed. Your best bet would be to use a thread insert or weld the hole up properly and drill/tap. That huge aluminum case will pull heat away too quickly to get the type of heat he was able to manage in the video. Either way, I have used this stuff and its crap.