HEAD STUD EXTRACTOR.

[Rpm]

Morning Guys, I currently have my engine on the bench, and whilst I have the opportunity would like to change some or all the head studs. What I don't want to do is open a can of worms and wish I hadn't decided to start due to fracture of a stud although that cant is eliminated even when using the proper tool.
So, can someone recommend a stud extractor that will do the job and also what size will be required? I watched Geoff Halstead Utube piece on stud removal A7 head and the extractor he used almost covered the stud and perfect job, however, he didn't mention the tool used.
Your thoughts and views are always appreciated.
Regards Rob

["Slack Alice" Simon]

4PC STUD EXTRACTOR 3/8 AND 1/2" DRIVE IN CASE


Above is copied from A****n, these look like the one I use, which I have had for 40 years or so.   It has three vertical rods inside which grip the stud, it works very well -IF the stud is willing to move at all.

You have to get the right one for the diameter of the stud, I couldn't tell from the above ad. if one of these would do, but a bit of research should sort that.

But - snapped studs are almost guaranteed when working on a Seven, and looking at yours I think you need to cater for that.

Which means a good centre punch, a selection of nice new good quality drill bits increasing in size, a set of taps for 5/16" BSF  and another for 3/8" when it goes a bit wrong.

Something to guide the drill, though I usually do mine by hand, and something sharp and pointy to pick the threads out of the grooves if you get the drilling right.

And standard and stepped studs as required - or a Helicoil kit if you want to stay standard.

I try heating the block (oven), heating the stud a bit more (blowlamp) and seeing if it moves.   Repeat, adding a penetrating fluid as appropriate.

If that doesn't work, sometimes a freezing spray on the stud will do it.


But the most important bit of kit is your being cool with a broken stud .....


Good luck.

[Rick F]

Good advice from Simon....

I always use copious amounts of Diesel as penetrating oil

[Colin Wilks]

Koken 5/16" stud extractor.
Consolidated Tools 01617987964
About £25 delivered.
First Austin Seven specific tools I bought myself and I haven't regretted the price.
PS As others have said, 8mm is within a gnats of 5/16". I went imperial as I bought a 1/4" one at the same time. I don't know if others have managed to use a 6mm metric one on 1/4" studs? I would have thought it would be tight.

[Robert Leigh]

I find that an 8mm stud extractor is near enough to grip the stud properly, and is widely available where imperial sizes are no longer so. To get a centre for drilling out a broken stud you can drop the head back on the remaining studs and use a 5/16" or possibly a fractionally larger (metric?) bit which is a good clearance fit for the hole in the head. Only use it enough to create a centre in the top of the broken stud, then remove the head to check that it is nicely centred. If not you may need to do some careful work with your centre punch. If the centre is right it can be useful to pop the head back as a guide for keeping your drill vertical, at least until you have gone right through the brken stump. With care you can work slowly up to tapping size, and if you are lucky you can wind the old thread out with a scriber. If unfortunately you finish up slightly off centre things can be recovered using a mousetail file. In my experience techniques required vary a bit with how stubborn the stud or how lucky or unlucky you are.
Robert Leigh

[Renaud]

Hi Robert,
About imperial re metric, indeed 5/32" is 7,94 mm so very close to 8 mm.
Also 7/16" is 11,11 mm but 11 mm is not very often found.
15/32 would be 11,91 mm as 12 mm studs are usual.
This is very useful to remind in my workshop when one unusual shape of imperial wrench is required!

[AustinWood]

I always hit the stud hard with a hammer, straight down from above. This can help loosen the threads. Apply penetrating fluid as well.

[Ian McGowan]

If the worst should occur and one finds one's self drilling out broken studs, I have found a selection of appropriate sizes building up to the clearance size LEFT HAND drill bits advantageous. Frequently, before you are down to the clearance drill bit size, the LH bits will bring out the remains of the broken section of the stud.

[Tony Betts]

If you are unsure.

Let an expert do it.

I use the same tool for removing studs, and can confidently say studs will still regularly break. After removing thousands.

Two words of wisdom.

1. Don't just swing on a long bar, best way to put force into the rotation. Is to hold one hand on top of the bar and tool, and turn that hand as much as the other hand on the end of the bar? Sorry my explanation is not the best.

2. Often slightly tightening, before loosening. Can help.

But they still break.

Tony.

[Chris Garner]

My number one tool for stud removal is a " Blue Point ". This has never failed me and has worked every time on normal studs, ie those which are not severally " waisted ". 
It's an expensive purchase but worth the money. Laser and Sealey do similar but I cannot vouch for their efficacy.