Armor removal and armor screws

[Mrs Vampire]

Hi I am up to removing the armor from my Stuart.

I have done this before many years ago on on other Stuarts with less than happy outcomes for the armor screws.

I have so far done the full flush with oil of wintergreen etc mixtures to get as much penetration as possible. I have whacked them with a 1 inch drive rattle gun . My next trick will be to heat them and cool them try to get a bit of penetrant into then when they are warm .

Heating stuff up is always a trick with all the accumulated oil etc around.

I cant find any reference to special screwdrivers for armor in my parts/reference books. The screws are a pain as they have very narrow slots given their size. Every screw I stuff up means a screw I have to make.

Any clues would be gratefully received.

[Andrew]

Im not firmillar with what kind of bolts it has, are they like american halftrack bolts? Countersunk flat head bolts?

Andy

[Mrs Vampire]

Yes just about the same.

The large armor bolts are about 1/2 inch I think the biggest on a half track is 3/8

there are about twenty at 1/2 inch and thirty at 3/8

[Wayne Henderson]

Hi Gina,
Same problem here with the Staghound turret, the front plate has 1"
countersunk screws with locknuts on the inside.
I made an 1 1/8" Screwdriver out of an old leaf spring because I couldn't find a big long driver to fit. Then I made a bar to fit horizontal to the screw driver to control the twist. CRC, heat and swearing also help.
Two person job to undo each bolt.
Wayne

[Andrew Rowe]

Another cunning trick is to mig a reasonable size tack on each side of a hex nut, then use a standard socket while it is still warm. You have to relinish the top of the screw when finished , but at least you achieve the job. Just make sure the tack welds don't cover the slot area of the screw.

[Mrs Vampire]

OK thanks for the great tips...will organize a bit of leaf spring and a Mig and give it a go....

Wayne any recommendations most effective words re the swearing.... ???

[Lynn Eades]

I'm guessing its a spur of the moment personal inspiration thing.

[Wayne Henderson]

I find it is best to start alpabetically, screws come out around words begining with c or d.

[motto]

What I ended up doing with the White M3A1 armour screws was to split the nuts with a chisel. Saves time and angst. No damage to the screw heads and nuts are not expensive or difficult to get. Any damage to the thread on the screw can be easily fixed by running them through a die.

David

[Andrew]

Gina, here is a tool on ebay right now. Its expensive but you can get ideas to make one yourself. on my halftrack I just heated nut up and used a flat head ended socket for my 3/8 drive ratchet, although the t handle would be better i would think

www.ebay.com/itm/like/231269007868

Andy

[Mrs Vampire]

Hi Motto

Most the rear nuts are captive...the others way way back inside the engine compartment .

If I can get the rear armor off then maybe I can reach in and split the nuts on the top deck...its a good suggestion.

Hey Andy ...you are right I can make one of those....what a great gadget!!!

as to the swearing...I was looking to vocabulary extension....

[Robin Craig]

Just a word about slot screw heads and modern screw driver type tools.

The tips on modern screwdrivers are tapered and the old type screwdrivers used by armourers have parralel tips.

The difference is that the tapered screwdrivers will naturally try and climb out of the slot head, that is why they round off and are so hated. An armourer type friend taught me this.

My 2 penny worth

R

[maple_leaf_eh]

Originally Posted by Robin Craig

Just a word about slot screw heads and modern screw driver type tools.

The tips on modern screwdrivers are tapered and the old type screwdrivers used by armourers have parallel tips.

The difference is that the tapered screwdrivers will naturally try and climb out of the slot head, that is why they round off and are so hated. An armourer type friend taught me this.

My 2 penny worth

R

Good point Robin.

This question reminds me of other posts, but I forget the answers. Surely this isn't the only forum on the net for armour restorers?

[David Herbert]

Looking at the ebay item in Andrew's post #10 it seems to be ordinary screwdriver bits and adaptors off a market stall and a 1/2" to 3/8" adaptor welded to a piece of pipe and painted white. I don't understand how this is any advantage over a normal T bar handle except you can put a really long piece of pipe into it and destroy the bit with less effort.

In my experience the driver bits shown are useless when confronted with "oval head bolts" (the correct term for them, from the parts lists) and I favour the use of a piece of leaf spring, carefully ground to a suitable shape, without getting it hot, and turned with the aid of a big adjustable spanner. Heating the bolt up to red hot and then letting it cool before trying helps too. Splitting the nuts is a good plan but usually the ones that won't undo are the ones that you can't get to the back of.

Quite a good way to measure the size of a problem like this is to count the number of beers that you must consume before the answer becomes obvious. A large vocabulary helps too.

David

[Steve Greenberg]

Gina,
Do you have drag link sockets like these listed on ebay? I think Snap ON makes an impact socket.

http://www.ebay.com/itm/Walden-Worce...item2c88e0df3c

Steve

[Mrs Vampire]

Hi Steve.

I have used those drag link sockets and they break of at around the second hit with my impact wrench. maybe I should be using snap on
I guess I could use them when the bolts are loose enough ...

My current driver is a ground down Allen head impact drive socket.

I get ones that are big enough to provide a good screw driver head when ground. I am careful not to over heat in the grinding process and the length gives me lots of room for extra grinds when the driver gets rounded or bent.

The problem with blade drives and impact wrenches is keeping the driver in the slot, it jumps out as soon as it gets going on account of the physics of it all.

All that said ...the inch drive rattle gun makes not the slightest difference to most of the bolts.

I will make up a leaf spring driver as suggested as well as the modified pipe wrench thingy ....being able to put a substantially long bar through it makes it far more powerful than a T bar but i suspect as advised earlier I will need a couple of friends to help with it.

I think getting things low and close to the job is also important so the leaf spring idea has the advantage of me being able to make the thing right down close to the job.....all the sockets etc mean the leverage is a couple of inches of the armor so keeping the thing vertical while straining against the bolt becomes an issue.

Terry ...if there are other forums that tackle removing armor bolts I have been unable to find them...in fact when it comes to practical help MLU is the best around as far as I have found ...that said if anyone knows of another source i would be most grateful for links.

many many thanks for all of your combined wisdomes

[motto]

I understand the issues now with the nuts being captive or inaccessible you only have the head of the screw to work on.
The most effective tool I encountered for undoing screws on aircraft (sometimes by the hundred) was a rivet gun with tip adaptor and handle. The principle was that the shock load was applied completely independent of any radial force unlike an impact driver. Of course the screws in that case were 3/16" or 1/4" diameter.
To translate the principle to what you are attempting would require a jack-hammer or pavement breaker fitted with an appropriate tip and a handle to apply rotational force to it.
Maybe just fantasy but who knows what people have laying about the place.

David

[chris vickery]

There is also a tool which is hand impact driver of sorts, typically used on things like auto door hinge screws etc.
Look up Lisle 29200 on the internet to see what I'm talking about. Other companies such as Proto, SnapOn etc make them as well.
If you opt to purchase one, buy a good one.
It works like this;
You have a handle which has a striking surface at one end and a hex driver on the other. There are some mechanics inside which allows it to be used for driving in or loosening out screws by twisting the shaft one way or the other to change drive direction.
They usually come in a kit with various types of bits including the parallel ground type slotted bits.
You place the appropriate bit in the driver, place it into the screw and strike the end of the handle with a large hammer. I am sure if the bolt were heated it would help. I have used it in the past and it worked great.
I have often found as well that it benefits to try tightening rusted bolts a bit before trying to loosen them.

[Richard Farrant]

Originally Posted by motto

I understand the issues now with the nuts being captive or inaccessible you only have the head of the screw to work on.
The most effective tool I encountered for undoing screws on aircraft (sometimes by the hundred) was a rivet gun with tip adaptor and handle. The principle was that the shock load was applied completely independent of any radial force unlike an impact driver. Of course the screws in that case were 3/16" or 1/4" diameter.
To translate the principle to what you are attempting would require a jack-hammer or pavement breaker fitted with an appropriate tip and a handle to apply rotational force to it.
Maybe just fantasy but who knows what people have laying about the place.

David

David,
You have given me an idea here, an air needle gun or descaling tool. Remove the needles and make an adaptor to fit on of the screwdriver ends in to.

I have gone through the pain of these countersink screws on wartime British armour although they have deeper heads the slot is shallow and narrow. The head being more pronounced allows a flat drift to be used to knock the head sideways a fraction to break rust seal and allow penetrating fluid in.

[Peter Walsh]

I understand the issues now with the nuts being captive or inaccessible you only have the head of the screw to work on.
The most effective tool I encountered for undoing screws on aircraft (sometimes by the hundred) was a rivet gun with tip adaptor and handle. The principle was that the shock load was applied completely independent of any radial force unlike an impact driver. Of course the screws in that case were 3/16" or 1/4" diameter.
To translate the principle to what you are attempting would require a jack-hammer or pavement breaker fitted with an appropriate tip and a handle to apply rotational force to it.
Maybe just fantasy but who knows what people have laying about the place.

David

In the workshop where I work we use a snap-on el brutus screw removal tool which is similar to this tool:

http://www.aetools.co.uk/product-ape...ractor-300.php

It is a smaller version a locally made tool referred to as a "gutbuster" that we used in the RAAF on the F111 aircraft for removing stubborn panel screws. It works on leverage to hold the screwdriver tip down while you turn it with a rachet or speedbrace. It has an anchor point at one end and a handle at the other end. In the middle is a 3/8" male/female square drive for the tip holder and rachet that can slide along the lever to reach the screwhead you are trying to undo. The closer the tip is to the anchor point, the more leverage you have. The lever and handle were up to 3 feet long. We broke a lot of tips and some even ended up with a nice twist like decorative wrought iron.

You have to remove a screw or bolt (not necessarily the same size/type as you are trying to remove) close to the screw you want to remove and use that screw or bolt to secure the anchor point of the gutbuster to the assembly you are working on. The anchor point had a round metal plate with holes of different sizes to take screws/bolts of various sizes. The gutbuster was a two person job where el brutus can be used by one person easily. In the workshop, we used to chew out up to half of the screws trying to remove them before we started using el brutus. If any, we only chew out the first screw for the first anchor point now. Absolute magic.

As a last resort you could probably make a version of the gutbuster and use heat and penetrant.

[colin jones]

Hi Gina, my wife said that she uses the gut buster on the F18s and said there is nothing like them. I don't think it would be hard to make a tool of similar design. I will be making one when I start mine.
Colin.

[Mrs Vampire]

Interesting gadget...but very expensive .

https://www.youtube.com/watch?v=yktPX2jVSTk

[universalgrl]

As I was a master aircraft technician I learned the correct way to extract frozen screws.
I saved ALL the screws on my carriers front plate including the 4 1/4 inch screws for the log book holder.
Use a penetrant of your choice (over several days) I use wd-40. Use a dremel with a fibre wheel to clean out the screw slot and remove burrs, make sure the sides of the slot are parallel to each other.
Make sure your tool bits are sharp and don't show any signs of twisting, the bits can cam out otherwise wrecking the screw slot.
Impact hammer with the extractor and appropriate bit or hand held impact and a zero bounce hammer.
If all else fails MIG a tack weld on the screw and attack the fastener on the other side, nuts are cheap.

[motto]

Lots of ideas to choose from here Gina. You can mix and match from dead blow hammers to blue tongue spanners, from shouting a curse to emptying your purse.
No golfer plays with only one club, they have a bag of them.

David

[Mrs Vampire]

The "No golfer plays with a single club" rule is spot on.

3/4 drive drag links hard to get so have one on back order from the states. ( snap on as advised by Steve)

In the meantime ground down a hex drive and now have thirteen of the 5/8 screws undone and only one of the 3/8.

A T bar with a couple of lengths of water pipe to give extra leverage has done the best so far.

The rattle gun is impossible to keep in for more than a few hits and it damages the slot dreadfully. I will take my Big Hitter rivet gun with a slot snap and give them all a good rattle.

I will also hit them with some heat. Heating is a bit of a hazard given the amount of oil , grease etc built up in the engine compartment and the risk of fire.

So far bit over half of the big screws on the rear armor. First time out since 1942 so far as I can tell.

Below reground home made drag link ( about five grinds for ten screws) I use grinding paste in the slot to assist with keeping the blade engaged. The screw has been polished to colour parade colour standard :/

[Lauren Child]

They were probably made to be used with an inertia wrench.

If you've not seen one it has a large rotating disc like a dumbbell weight that you spin down the length of the driver, building up inertia, and then it suddenly grips and transfers the inertia at the end.

[Mrs Vampire]

Ahhhh another club for the bag do you have a link to a photo??

[Lauren Child]

Originally Posted by Gina Vampire

Ahhhh another club for the bag do you have a link to a photo??

Here you go. This is an Atherton type Inertia wrench. Theres a 18" ruler for scale. It's a heavy lump which broke my other half's toe, hence not popular in our household... (a timely reminder to be careful with your tools)

[Lauren Child]

It comes with a kit of tools including a strap to go around you neck (to brace against your chest) and a stand for working on lower bolts.

[Lauren Child]

It has a 3/4 inch female square drive socket on the end for adaptors. This is one for 1/2" square drive socket and one for the kit of flat head and allen hex screwdriver ends, which are a special type (presumably hardened - it cautions you against losing them or making your own replacements). Hope that helps