welding a broken head bolt - aluminium head

[Jim Davey]

For The Win

FTFW you can guess

FTMFW you can guess again

 

[steveo3002]

ffs

 

[Woody.v8]

FTFMFW

 

[doubleboost]

Weld a washer then a nut
The heat of welding makes a massive difference
If you do drill it make sure you drill all the way through it

 

[Jim Davey]

Potty mouth, two Fs is just excessive.

 

[dai]

Wow. Overwhelmed by all the responses. Thanks all.

So, last night I built a blu-tack dam around the hole, and sprayed a pool of PlusGas in there. It will be soaking for about a week, as I will only get time to tackle it the weekend after next. PlusGas it appears is simple kerosene.

My next plan is to fab a (300mm long) 25 x 5 steel flat bar with a 40mm long offcut of solid round-bar (32mm diameter) welded to the centre. Then a hole either side of the flatbar corresponding to the head-bolt holes either side of the offending one.

I've bought a set of titanium coated HSS left hand thread bits, 3,4,5,6,7,8mm... and will drill the centre of the round bar on my drill press at 3mm, then bolt to head and drill offending headbolt at 3mm, remove and go to drill press and move up to 5mm, back to head... rinse and repeat till about 8mm. This little tool should work as a really nice drill guide - provided I get it 100% accurate to the centre of the broken bolt. Lots of plusgas sprayed whilst drilling and taking it slow.

If I am lucky it will come out with the left-hand bit, if not, at least there is no chance of the drill driving the bolt further down and putting pressure on the weak aluminium threads.

If the LH bits don't remove it... then I will mig-weld all the way down from the bottom of the now hollow bolt right to the top, and weld a nut on top.... with all the heat it should come out.

If that fails, grind flat, drill out, and helicoil or timesert - hoping it wont get to this stage, not really thought through plan C!!!

I'll send updates and pics on how it goes.

Oh and thanks for finding the link to the other thread on this subject - I read it with great interest.

acetone (your womans nail varnish remover) is a good penetrating liquid

 

[HMB]

Acetone/atf 50-50 mix never fails

 

[doubleboost]

Acetyline /Oxygen mix
Always works

 

[Jim Davey]

An arc set is cheaper than bottle rental though my Northern friend.

 

[Jim Davey]

I love broken bolt removal Top Trumps.

 

[Kram]

If the head is off, you should get it accurately drilled out. Im guessing your drill press is too small to clamp the head down? A small lathe or mill will do this easily if you can find somone local.

If you do try drilling, dont use plain HSS drills for this.. they will be HT bolts and cobalt drills are much better.

 

[Woody.v8]

If the head is off, you should get it accurately drilled out. Im guessing your drill press is too small to clamp the head down? A small lathe or mill will do this easily if you can find somone local.

If you do try drilling, dont use plain HSS drills for this.. they will be HT bolts and cobalt drills are much better.

The broken bolt is in the block

 

[Franknstein]

Have you thought about how to get it 100% accurate with your drill press? Gonna be tricky!

Are you in SE London? If so, pop the 32mm bar over to me and I'll drill you the first hole on the lathe - it will work out more accurate than on the drill press

I don't think I will need accuracy drilling the centre of the 32mm round stock, as I'll be reaming the corresponding holes in the flat bar, allowing for a bit of adjustment for the drill guide jig. An initial 3mm hole through the jig, pin punch the centre of the head bolt by eye, then shine a torch through the jig hole and align, and tighten the bolts up... well thats the plan!

About the HSS bits, I wanted to buy cobalt LH bits, but they seem to only be available in USA. So lots of lube, slow speeds should do it... Cobalt is no harder than HSS, but it can withstand sustained heat for longer (so I've read).

 

[Kram]

Ah. well you could make up a fixture to drill it in place... Easy as you can weld if not use a large angle plate and bolt together.

LH drills are available www.ebay.co.uk/itm/252083846055

 

[Franknstein]

Weld a washer then a nut
The heat of welding makes a massive difference
If you do drill it make sure you drill all the way through it

Just curious why you say to drill all the way through?

 

[doubleboost]

If you snap something in the stud .you can always "hammer it through"

 

[Franknstein]

Well. A real anti climax here. I thought before I start drilling or anything I would try an old trick first. I removed the blue tack dam from around the bolt and noticed about 1/2 of the plusgas (kerosene) had soaked in over the 3 days.

Dried it off. Then grabbed a cold chisel and a hammer and gently tapped anti clockwise on the protruding nib from where the bolt sheared. Turned instantly. Continued with this until it protruded enough for me to unscrew by hand.

I guess all the tension was holding the head down. Once that was released it was a non issue. No corrosion on threads. I think it was my lack of finesse removing the bolt which snapped it.

Anyone want to buy left handed hss bits

 

[rich r]

Just goes to show that trying PlusGas first often does the trick before having to move on to more brutal methods

 

[Kent]

Time it takes time for any penetration lube to get were it's needed.
So often people leave stuff 20 mins not 20 hours or even 20 days before they get brutal and resort to desperate measures

 

[mike 109444]

Well. A real anti climax here. I thought before I start drilling or anything I would try an old trick first. I removed the blue tack dam from around the bolt and noticed about 1/2 of the plusgas (kerosene) had soaked in over the 3 days.

Dried it off. Then grabbed a cold chisel and a hammer and gently tapped anti clockwise on the protruding nib from where the bolt sheared. Turned instantly. Continued with this until it protruded enough for me to unscrew by hand.

I guess all the tension was holding the head down. Once that was released it was a non issue. No corrosion on threads. I think it was my lack of finesse removing the bolt which snapped it.

Anyone want to buy left handed hss bits

No, you put them on the shelf of your shed/garage then in a year or two when you need them you will spend about half a day looking for them and give up (cursing)