Armor removal and armor screws

[Lauren Child]

To use it you apply pressure to seat the driver into the screw (with a second person guiding it if you need), then push the handles sharply forward. This spins the disc up which then whacks into the end delivering a forward rotary shock. You then grab the disc and pull back which rotates the driver, undoing the screw. You can click it into an alternate runner for doing back up (making sure that it's good and tight).

The book states it's for rusty tank screws and female war workers who may not have built the needed strength for such work. A nice and useful bit of history.

I don't know why they don't still make them.

[Mrs Vampire]

Now that looks very noice but very very hard to find one :?/

[Lauren Child]

Originally Posted by Gina Vampire

Now that looks very noice but very very hard to find one :?/

Unfortunately yes, but it gives you an idea of what to look for (or to try and replicate with modern tools). Basically you need a shock push and twist motion at the same time, with a bit that fits exactly into the slot (very little play).

[Mrs Vampire]

The results of my latest attempts at unscrewing the bolts.

I have managed to get all but ten of the large bolts out and have made good progress on the smaller ones.

I have made some , for me, startling discoveries. The penetrants I have use made virtually no penetration apart form some very slight surface intrusion.

All my theories about penetrants are out the window. My primary penetrant was WD-40 with Methyl Salicylate added to it. I have used methyl Salicylate straight, RP-7 , CRC, Reducteur H-72 and Wurst Rost Off plus. Not one of these made any penetration worth speaking of. Once I had the screws out a sixteenth they aided in further extraction but they played no part at all in helping with initial release.

I will experiment with phosphoric acid and see if that gets in. The next attempt will be to heat and cool using penetrant along the way .

The best helper yet has been a small rivet gun with a chisel end , my 1/2 inch drive rattle gun and the long handled T bar with my home made drag link.

The small rivet gun is not a big hitter but has a very high cycle. I tried my big hitter Rivet gun with a lower cycle rate without success. Likewise my 3/4 rattle gun is to hard to hold in place and hits to hard to control.

Photos are of extracted screws showing how nearly new some are , how little rust and how crummy the penetration...they are all dry.
Also a heap of removed bolts...just because I am so pleased to have them out... the very expensive penetrant that is useless the el-cheepo rivet gun that did the best work and the head of a screw showing the slight damage done in removing them.

Not one of these screws would move using a drag link with a four foot extension bar ( it broke the drag link) or using either rattle gun the little rivet gun moved them in seconds.

I checked the parts book and finally found the tool originally designated for Armour removal...it was a 1/2 inch drive drag link socket

[Steve Greenberg]

Gina,
Have you tried Kroil? I have used it before and it does seem to penetrate after it sits for a bit. http://www.kanolabs.com/
Steve

[maple_leaf_eh]

How about diesel fuel in a squirt bottle? I had to clean some minor rust and grease spots off a rifle barrel. Diesel and a scrub brush worked as good as any more expensive fluid.

BTW, I was told that Kroil is only sold business to business, and not to consumers.

[Mrs Vampire]

Terry Diesel is harder to get in than WD...I have had these bolts soaking for a couple of months now so its tough to get something down into an inch and a half of armour.

Steve I don't seem to be able to get that in Oz and they wont ship...except at exorbitant prices. I will try to hunt some out the reviews seem positive.

I got onto another couple of penetrants one is a Loctite product another a local Queensland mixture Inox. The Loctite is a freeze it idea Inox products seems to have MEK amongst other things in it.

I hit them with heat today and got one more big one out and a few more of the little 'uns .

The golf bag looks a bit like this now.

[Lynn Eades]

Gina, It is probably obvious to you, but may not be to some, so I will state the obvious;
The countersunk screw is (was) designed to be tightened (loosened) from the nut end. The taper is (was) supposed to sit cleanly in the countersink, and "bite into the taper. The purpose of the slot in the head is (was) to hold the screw from turning while it was still loose. I guess it can be likened to a taper on a shaft, when the two components are assembled nice and clean, they will come apart cleanly (easier than when rusted etc)
I would expect those heads to seal completely metal to metal and rust free between the faces. To me the best shot is to back the nuts off while the screws are still "stuck", and then pop them out.
I hope that helps somebody. It has worked for me, at least some times. (Carrier screws are a lot smaller)
Your various penetrants or rust removing compounds will have a better chance working in the threads of tensioned c/s screw.

[Mrs Vampire]

Lynn

All of the screws that hold the Armor on the Stuart and Grant are captive. ( the nuts are welded in place) 'twould be but a simple task were it otherwise. Likewise that theory would not work on aeroplanes where nearly every screw is into an anchor nut countersunk or otherwise. The P-40 gave me many interesting hours drilling the rusted ones out and replacing anchor nuts. ( though many were reid and prince type screws there were a good many slot types..)

I'll check out the half track but I think the same applies there.

[Lynn Eades]

Gina, fair enough! I thought that I'd read that you preferred not to attack them from the other side, because of the risk of fire. I didn't go back and check.
Now I understand.

[colin jones]

I'm curious Gina! are you heating the bolt or the welded nut underneath. If you are heating the bolt then I can understand why you're having trouble. I personally would heat the nut underneath red hot, not cooling it down and undo it while the nut is still hot. Can I ask why you want to remove the panel. Are you wanting to pull the engine.
Colin.

[Mrs Vampire]

Hi Colin

I am heating the bolt. The nut and the thread in the nut is not a problem. Once I get them moving they come out reasonable easily.

Hoping the photo below clarifies the problem. It shows the thread quite shiny but the four centimeters above the thread , that part of the bolt that passes through the armour as quite rusty/dirty.
The rust dirt residue around the part of the bolt that passes through the armour and the rust under the head is the thing that is making it tough to get out. It just wont let the bolt turn.
Heating it expands the bolt and shrinks the hole, hopefully compressing and pulverising the rust and dirt. it also lengthens the bolt giving me a bit of a gap under the head to get some penetrant into . Those I have cooked so far show the rust/dirt burnt and blackened and good penetration of the Inox.

As soon as I get the slightest movement the bolt comes out with the small rattle gun by backwards and forwardsing for a few minutes and using plenty of penetrant.
The thread and nut are inside the engine compartment...its a continental W-670 so they are and always have been liberally lubricated by the total loss oil system radial engines have ( you know the one " it it ain't leaking oil then your oil tank is empty" ) and is a reason I am cautious about heat on that side of the bolt. I have water and fire extinguisher to hand all the time I use heat because of the real danger all that accumulated oil and grease in the engine bay will catch on fire.
I am removing the armour to clean out the engine bay, change/clean the plugs do the timing check compressions and leak by and give the W-670 a good going over. Change the rubber hoses and a couple of gaskets that are notorious leakers as well ....the engine exudes oil all over the place when I run it but doesn't smoke much past start up the rocker cover hoses are practically fossilized.
I am unsure about how many engine hours it has on it but from what I have discovered from the unit histories I think it may be close to its overhaul life of
500 hours. If it checks out OK I will continue to run the Stuart with this engine , if not I will use one of my spares and pull this one for overhaul.
So far as I can tell its the original engine from manufacture so for me there is a certain authentic sweetness in keeping it in the Tank.

Only Nine to go to get rear armour off

Photo (a) unheated bolt showing clean thread and depth of rust on shank and head. (b) heated bolt showing blackened rust/dirt and penetration of Inox.

[Mrs Vampire]

The job from the underside.

I removed a couple more bolts today. They are getting harder to shift and when they are out are very rust wasted between the thread and the head.

The rust is very fine like dirt. In the photos you can see the thread in the nut is is shiny like new.

[Mrs Vampire]

A final say on removing the armor bolts.

I now have them all out. The solution turned out to be.

1 heat with Oxy until just under dark cherry red.
2 with a very close fitting driver in the slot strike heavily with a mash hammer
3 using a T bar and pipe extension over the handles one person levering one person holding the t bar down and striking it with a hammer push until it moves a bit
4 apply penatrant then tighten and loosen until it comes out.
we lost but a single bolt of the sixty or so removed.

[motto]

It's sure been a labour intensive, time consuming job. One of those rare jobs that will be quicker to assemble than it was to dismantle.
Good going.

David

[Dianaa]

I'm sure it will be going back on with liberal amounts of neverseize!

I just want to see the two Stuarts running together!

[Mrs Vampire]

Too True Motto and Diana.

Reassembly will include Never-seize on the threads and Ardrox 3322 or equivalent thixatropic wax on all joints .

[Dianaa]

Hijack transferred to AAVA forum

[Mrs Vampire]

possible to see a photo ???