Screw extractors

[AlanT]

Several times on here i have recommended the use of "parallel-fluted" extractors.

 

One of my friends just posted a video showing these in use.

 

Scroll to 4:20 mins because he talks too much!

Edited November 13, 2014 by AlanT

[peejay4A]

I'm convinced.

[RogerH]

The logic is sound. With the usual lefthanded spiral extractor there is a limited point contact because it is tapered.

Although it tries to bite in further upon turning it is still a point contact.

 

The parallel fluted version starts off with a larger contact area so may stand a greater chance of success.

 

The video clip displays its functionality but does not really compare to a rusted and aged screw/bolt.

 

However I'm also convinced.

 

Roger

[Lebro]

Yep,, must get some

[Motorsport Mickey]

It's a shame it doesn't show it working upon a stud sheared above the surface and using the centralising bushes supplied to drill the stud but I endorse that using it like that works also. You can apply the torque with a torque wrench set to a nominal setting for dia for a stud of that size and ease off it gets frightening, they've always shifted before for me.

 

Mick Richards

Edited November 13, 2014 by Motorsport Mickey

[AlanT]

I got two broken head studs out with this. Broken just below the surface like the demo.

 

Just wound out the same. No torque required really. The drilling and hammering loosens them up.

[Lebro]

A quick look on eBay has shown several used sets with broken extractors - so they are not infallable - new ones seem quite expensive

[RobH]

There is a set on Amazon at a not too unreasonable price:

 

http://www.amazon.co.uk/gp/product/B00EON429O?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

[Motorsport Mickey]

As I said above if using them on "Titanic" grade seized bolts or studs apply the pressure with a torque wrench set at a torque commensurate with the dias of the extractor being used then you won't brake them, any tool can be broken if used uncaringly.

Their advantage is in not having any stress raiser on them as Roger points out there is on the accursed "easy outs," which is where the thread is formed upon the shank. The parallel flutes allow good torque to be applied in a controlled manner where the easy outs by virtue of their self tightening left hand thread configuration has the torque applied exponentially and rapidly such that they literally explode.

 

Mick Richards

[Ur1328]

Let's see him using them on forty year old exhaust studs,only then will I be convinced!! ( from a man who's extracted thousands of broken studs the only way how- The HARD Way!!!!!)

[Lebro]

Amazon ones are not "Snap-On" does this mean they are inferior ?

 

Bob.

[Motorsport Mickey]

Only if you think that Snap on tools are automatically superior !

 

Mine are Neilson and work fine, there's not too much in the way of technical knowhow needed for this sort of tool, as long as the fluted rods are of the correct grade there's only a fluted nut that slides onto them and the your wrench turns it, simple.

 

Mick Richards

[Guest ntc]

I have done that many times with a good Torx set

[stillp]

I was a little surprised that Al's friend started drilling by using a smaller twist drill to make a pilot hole. I've found in the past that this technique can lead to an off-centre hole, since a) the smaller drill is more likely to bend than a larger one, and if the point of a twist drill is unsupported it is more likely to run off line. I'd have preferred to see him use a centre drill to start.

Any thoughts Alan?

[RogerH]

It looked like it went straight to the tapping drill - quite big(ish).

It was only a gash hole anyway. Just to get a screw in to break off.

 

Roger

[stillp]

Sorry Roger, I thought he took 2 drills from the screw extractor pack, and started with the smaller one.

[AlanT]

Americans seem to get away with doing stuff that would crash if I did it.

 

They use end-mills in collets. If I do this they mine in.

They don't use taper and plug taps and they just screw them in with a machine.

 

Part of the reason is they use much larger and heavier machinery.

 

Remember he did this in a milling machine.

These have much superior axial retention of the spindle than a drilling machine.

 

Tom is a master-craftsmen in metalwork, lives in a converted munition store in a decommisioned arsenal and met his wife when they were on a welding course.

[stillp]

Hmm. Maybe their twist drills are stiffer too.

 

I did think that using a milling machine to drill the holes was 'cheating' a little.

 

I think the most stubborn fasteners on my 4A were the body to chassis mounting bolts, which had been trapped under, and in some cases welded to, the 16 swg patches the PO had welded to the inner sills and floors. To get those out I had to arc-weld a 1/2" bolt to their head, then put a socket on the 1/2" bolt and wind them both out while red-hot. Not sure if these extractors would have helped at all.