Author Topic: steel stud/bolt stuck in aluminium (home-brewed drill-guide)  (Read 2721 times)

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Offline Foy(notFox)

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Re: steel stud/bolt stuck in aluminium (remove with battery!?)
« Reply #15 on: December 23, 2017, 11:07:17 PM »
Yes I've done that a good few times over the years with fasteners stuck in steel components Ridgy but not sure if you can get an earth on an alloy head. Suppose you can just earth the mig to the stud tho.

Also worried that I'll weld nut on and shear the stud anyway.

This video suggest the battery current is actually breaking the bond the threads have inside the component.

I once tackled an aluminium scaffold leg where the adjusting ring had seized to the (very coarse) thread on the leg. There were no access problems. Got plenty heat on it. dipped it in all sorts of fluids. Much less fragile than an 8mm stud. You could hammer on the ears of the ring until they broke off and still the thing wouldn't budge so ended up cutting a slot in the ring which got it moving.

When it was free and revealed the amount of white corrosion that had been between the components it was quite a shock. Nothing would have shifted it but it does show you how deep electrolytic corrosion can set-in 
« Last Edit: June 19, 2018, 07:58:17 PM by Foy(notFox) »
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Offline Foy(notFox)

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Re: steel stud/bolt stuck in aluminium (remove with battery!?)
« Reply #16 on: December 24, 2017, 09:56:58 PM »
Surely you can clamp earth onto one of the other exhaust studs while you weld a nut or blob on, but the bolt may snap even shorter, I am sure an induction heater would do it too if you have enough bolt to grip, you should be able to hire one.

I've seen them used on Wheeler Dealers. Ed China says they're about £600! but I didn't think about hiring one. I like the battery trick tbh.

Here's the link

https://www.youtube.com/watch?v=cUlJ5f2-FcQ
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Offline Foy(notFox)

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Re: steel stud/bolt stuck in aluminium (remove with battery acid)
« Reply #17 on: January 06, 2018, 11:38:49 PM »
Don't know if I mentioned it but whilst I was trying to dissolve a steel component with Alum I was also trying to do one with battery acid.

The difference here is that you don't need any heat so theoretically you could dissolve broken studs out of full engines without stripping them down. he shortcoming of the Alum procedure was that without heat it doesn't work.

So as a test piece I got a spare Honda 50cc head and tried to dissolve an M6 bolt out of the exhaust-stud hole. It wasn't a seized one. I just put a bolt in the hole and stuck a plastic lid over the hole with Sika sealer then filled the cap with battery acid from one of the ready-mixed tubs you get with a new battery.

Problems I encountered were that the process seemed slow and it was difficult to get a totally secure seal with the sealer so you'd get a little acid trickling onto the alloy.

I was thinking perhaps you need neat acid, not the diluted stuff for battery and also need to improve the sealing operation. It was kinda forgotten about over Christmas but I found it the other day with no traces of the bolt in it and quite a bit of nasty-looking staining. So great news re the bolt but not so good re the damage to the alloy



there was a bolt in here a couple of weeks ago







ouch! nasty staining from acid where it trickled over the alloy   


So I took the part up the road and rinsed it in a solution of hot water and baking soda then clean water then dried it off and cleaned up all the bad areas with a brass-bristled brush and it looks like the damage is superficial. There are certainly worse marks on the part from before I got it.

Also the threaded where the bolt was seems remarkably clean so mb the acid doesn't really harm the alloy. It seems someone has tapped a wider thread at the top of the hole (M8?) at some time but not went in very far as the original M6 thread still exist for most of the length of the bore.




alloy looks ok after cleaning



as does hole where bolt was

So a big success then and inspiration to try it out on real projects? - like the exhaust-studs on the XJR1300

Well perhaps not as maybe the bolt wasn't in there. I'll report back once the area has been forensically-swept
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Offline Foy(notFox)

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Re: steel stud/bolt stuck in aluminium (remove with battery acid)
« Reply #18 on: February 03, 2018, 01:23:58 AM »
Ok so as I suspected the bolt wasn't in the head but I chucked it in a cup with an inch or so of battery acid (ie diluted) and it is disappearing. To get it to do that on an engine in-situ would be very difficult. What about neat battery acid? Well tbh you hear so many incidents of this heinous crime of ppl throwing it in other ppl's faces that I'm surprised it's even available to buy unchecked.

Anyway the point of this post is that I got two of the XJR studs out tonight and they got a taste of Freeze Yer Nuts Off spray and a mix of acetone/brake fluid.

I've no idea if the above chemicals helped but one of the studs had had quite a bit of time lavished on it the other week. I welded a little blob on the side and tried to tap it free with a chisel but it didn't seem to budge. Tonight I gave it a little of the acetone/brake fluid mix and put some vise-grips on it and it turned straight away  :-\

I then moved to next one and tried similar approach minus the welding and it didn't budge. Then moved to other end of the cylinder head and that one backed-out with two nuts locked on it. The interesting thing is how clean the hidden threads were. It's given me the enthusiasm to tackle the others. One or two have been replaced in the past so I only really need to get 4 more out.

Am thinking with the really thin one I'll bulk it up with weld then tackle it.


weld-blob for chiselling-on didn't work the other week but tonight stud came out easily


1 down. 7, or less, to go



another one came out easily but I suspect that one came out easily before
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Offline Foy(notFox)

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Re: steel stud/bolt stuck in aluminium (carnage)
« Reply #19 on: February 05, 2018, 02:36:34 PM »
So like a naive fool I approached the XJR on Saturday night expecting another two or more studs to wind out. They weren't moving with grips on them so I moved it up a gear. I figured that as the hidden threads of the the two removed were clean as a whistle it was safe to mutilate the outside bits by welding nuts on as they were sure to come out.

Wrong. The one on LHS wouldn't budge and now it has no thread on it as the nuts welded on rubbed them away when they were wound off. Don't know what the studs are made off but the MIG welder isn't penetrating them at all. So on the LHS we have the full stud but no thread to speak of.

Moving to the RHS I upped the ante with more weld and more force. The thing was red hot at the end with blobs of glowing weld dripping off it. The studs just snapped and interestingly the casting was still stone cold. I was right when I said that putting heat on the stud won't help as it doesn't ecxpand the casting. Only thing that might expand is the end of the stud.

So am royaly f&*("d  now  >:(

Got someone else's property in worse nick than when they handed it over to me.

Back on it today. There might have been an miracle and they'll have came loose since I last attacked them (this is what seemed to happen with the first one to yield) but now I think I'll need to weld bolts/studs on to the remains of the original studs. Total bodge job but at least I can them get the exhausts c/w new gaskets on and see if it runs properly.

I had a look at the Haynes manual regarding removing the cylinder-head to get the studs drilled out but it seems the camshaft and camshaft caps are made of chocolate and will break if you disturb them. Don't think I could face more carnage  :(


futility


no useable thread on this one now


   
disaster


shambles


Forgot to say I also tried to make a small hole, at the interface of the stud and head, with a multi-tool and carbide burr to get some fluid into the hidden thread but the tool was useless and I'm not going out to buy a decent brand (Dremel for example) to try again
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Offline Foy(notFox)

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Re: steel stud/bolt stuck in aluminium (home-brewed drill-guide)
« Reply #20 on: June 18, 2018, 10:57:17 PM »
So I've missed a bit out here where I repaired the broken stud by welding on part of a new one (iirc). On that port therefore I've now got two useable studs but I'm not happy with it. Want all eight to be new.


outer exhaust port has now had semi-respectable repair to broken stud



Been thinking for ages about some sort of concentric-tube system to drill hole bang in centre of old stud then widen it out. Usually these schemes result in disappointment but I had no other option and spent around £15 on steel tube and cobalt bits.


my kit: original stud (M8); 12mm OD x 8mm ID tube; 7.94mm OD x 4mm ID tube; 4mm cobalt drill bit



bigger tube slides onto original stud



smaller tube is snug fit inside



peek after 1st contact looks promising



a little more



and more




but pushed too hard and broke 4mm bit this far in



so stepped-up to 5mm which seemed to cut much better



and finally 6mm




despite best efforts hole still off-centre

So all in all it went to plan. Am not too concerned about the hole going slightly off as I was trying to drill right through a full stud. On a shorter length - ie the bit in block - it will be less pronounced. Also notice that if drill bit breaks it still comes out of the stud easily unlike a tap or easy-out.

So I think I'll try again on another stud then move too the engine for real. Might actually need to take the engine out to get in at the inner studs. We'll see     
« Last Edit: June 18, 2018, 11:35:37 PM by Foy(notFox) »
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Offline Alvin Sparklug

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Re: steel stud/bolt stuck in aluminium (home-brewed drill-guide)
« Reply #21 on: June 19, 2018, 10:04:48 AM »
great reading this,
why not continue with the 4mm then when you get so far, cut off a piece of the stud at the top this may stop it going off ctr a bit, sort of.    :'(
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Offline Foy(notFox)

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Re: steel stud/bolt stuck in aluminium (home-brewed drill-guide)
« Reply #22 on: June 19, 2018, 08:04:21 PM »
That's a good idea Alvin S' but you're a bit limited by having to keep the stud long enough to have something to put the guide-tubes on.

Also once a hole has went squint you can't really straighten it up. You may notice this if you ever try to widen a drilled hole by pushing drill sideways. I never works lol.

I guess once you've made the initial hole the tubes could be done away with but after thinking of this scheme and determined that they have a purpose and are guiding that drill-bit home  ;D

NB are you related to Mr A Stardust;)
« Last Edit: June 19, 2018, 08:05:59 PM by Foy(notFox) »
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