Allen Keys or is there something better?

[Quandary]

I have a Volvo three blade folding prop. The pivot pins for the blades are kept in place by three socket headed stainless steel machine screws which are screwed in to the bronze boss. They are located in small recesses so only a socket headed bolt will do. When I take the prop apart each winter to grease the pivot pins I put them back with some threadlock. This year I can not get two of them out with an allen Key, The sockets are quite a loose fit for a 5mm. allen key but just too tight for a 5.5mm. one, so when I try to apply torque the key eventually skids out. I have tried using a key from a socket set to get a straight drive but they seem only to be available in 5mm or 6mm. sizes. and not that high quality, I have a set of imperial allen keys in intervals of 1/32 but can not find a tight fitting one there either. Part of the problem with ordinary keys is that it is very difficult to apply enough torque while keeping the things straight and they cut the hands off you. I am puzzled by the poor fit or do Volvo use a special key of their own size, the sockets in the heads are not damaged, yet!
I am sure real engineers have a solution for this but I have got away with ordinary keys until now.
Or is it a waste of time greasing the bearing surfaces and teeth on folding propellors, I presume the grease soon washes off anyway to be replaced by water lubrication?

 

[ksutton]

I am not familiar with this prop, (I have a Variprop). If you applied loctite that will be half your problem. Depending on which loctite it was, it may need heat applying to the screw and surrounding area to free it up. I would try a heat gun, probably 100c should be enough. Also get a steel flat ended punch or drift, similar diameter to the screw and give give it a firm knock to shock it.
A socket driven allen key is the best way to go but there are various qualities, might be worth investing a good quality one.

 

[Pinnacle]

We have the same prop. I have never used any thread lock before, but a couple of weeks ago I did buy some to use when the boat is next lifted in June.

Maybe I wont use any thread lock now.........................

 

[Dipper]

I have a Radice folding propeller on my Volvo saildrive and I think the grub screws are similar to yours. I had trouble in the past with the hexagonal socket disintegrating if any force was needed to remove the screw. I am fairly sure that the hexagonal part is a separate insert inside the head of the screw and is a weak point in the design.

A friend of mine with a lathe made me some grub screws from some stainless steel bolts. They have a nice deep slot in the top for a normal flat bladed screwdriver to fit and I haven't had any trouble since.

I think that using a thread lock on the screws makes the problem of removal worse. I've found that if the screws are below the level of the bronze boss, antifouling paint in the recess clogs the thread enough to stop the screws unthreading themselves. I can easily scrape the paint away when I need to remove them myself.

 

[Fr J Hackett]

I have a Volvo three blade folding prop. The pivot pins for the blades are kept in place by three socket headed stainless steel machine screws which are screwed in to the bronze boss. They are located in small recesses so only a socket headed bolt will do. When I take the prop apart each winter to grease the pivot pins I put them back with some threadlock. This year I can not get two of them out with an allen Key, The sockets are quite a loose fit for a 5mm. allen key but just too tight for a 5.5mm. one, so when I try to apply torque the key eventually skids out. I have tried using a key from a socket set to get a straight drive but they seem only to be available in 5mm or 6mm. sizes. and not that high quality, I have a set of imperial allen keys in intervals of 1/32 but can not find a tight fitting one there either. Part of the problem with ordinary keys is that it is very difficult to apply enough torque while keeping the things straight and they cut the hands off you. I am puzzled by the poor fit or do Volvo use a special key of their own size, the sockets in the heads are not damaged, yet!
I am sure real engineers have a solution for this but I have got away with ordinary keys until now.
Or is it a waste of time greasing the bearing surfaces and teeth on folding propellors, I presume the grease soon washes off anyway to be replaced by water lubrication?

Try an imperial allen key you will get a better fit if as you say it is between 5 an 5.5 mm but don't persist with the metric ones as you will destroy the allen screw head and then it will be a bugger of a job. As said earlier use some heat on the head it will have to travel down the screw but that will break down the loctite.

 

[VicMallows]

, The sockets are quite a loose fit for a 5mm. allen key but just too tight for a 5.5mm. one,

When I've got desperate trying to get one out I've resorted to grinding down the next sized key until I achieve a really tight fit. Then heat and a good sharp tap on the key

 

[colhel]

I've used the following method on bolts siezed in alluminium it may be worth a try in bronze.
Try TIGHTENING the bolt before trying to loosen it.
You can sometimes get torx drivers to fit allen key sockets, but I'd try the simple stuff first.

Regards

Colin

 

[savageseadog]

Always use a top quality make of Allen key, Allen keys are a no compromise tool, only the best will do. I use Bondhus but there are other makes. Use heat to help get the screw out, hot water then blowlamp. Use the right grade of Loctite, a removable type like 222.

 

[steve28]

carefull if you use the torx option, if they snap in the head your buggered, you cant drill them.

 

[VO5]

Allen Keys are a nuisance and a real pain.I do wish someone would come up with a holder so that the corner of the L could be ground away converting a whole set into screwdriver mode. Now that would be a plus. I have hunted high and low and never found anything.

 

[JKay]

Try an imperial allen key you will get a better fit if as you say it is between 5 an 5.5 mm but don't persist with the metric ones as you will destroy the allen screw head and then it will be a bugger of a job. As said earlier use some heat on the head it will have to travel down the screw but that will break down the loctite.

That's the way to do it(said in parrot type voice)

 

[macd]

Allen Keys are a nuisance and a real pain.I do wish someone would come up with a holder so that the corner of the L could be ground away converting a whole set into screwdriver mode. Now that would be a plus. I have hunted high and low and never found anything.

Maybe your hunt is over. Do you mean something like this?:
http://cgi.ebay.co.uk/Snap-set-Alle...t=UK_Hand_Tools_Equipment&hash=item4aa90cdc0a

They also come in "stubby" size with shorter keys, which reduce the springy "wind-up" which you sometimes encounter undoing stiff fasteners. Both types also made for 1/4" drive.

 

[grafozz]

Recently removed both folding and fixed Volvo props and always use an impact driver to break the seal on the set screws , so far 100 % success rate , also I use superglue as threadlocking agent and have done for years . it always " lets go "

 

[alan17]

Allen keys

Allen Keys are a nuisance and a real pain.I do wish someone would come up with a holder so that the corner of the L could be ground away converting a whole set into screwdriver mode. Now that would be a plus. I have hunted high and low and never found anything.

Look at decent quality tool manufacturers such as Snap on, Facom etc. They do allen keys usable with a socket set and also can supply replacement allen key bits with no angle in the shaft.

 

[macd]

Look at decent quality tool manufacturerssuch as Snap on, Facom etc. They do allen keys usable with a socket set and also can supply replacement allen key bits with no angle in the shaft.

...or cheaper via the link at post #12

 

[Playtime]

Maybe your hunt is over. Do you mean something like this?:
http://cgi.ebay.co.uk/Snap-set-Alle...t=UK_Hand_Tools_Equipment&hash=item4aa90cdc0a

Or maybe this?

 

[fisherman]

An engineer told me before he died to use Unbrako Allen keys.

 

[Bojangles]

You could try a shock freeze spray on the allen screws first, I havent used it myself but I know others who have and say it works well.

 

[Ergonomist]

If all else fails,( although I would favour a good quality torx socket as already suggested), place a 10mm or 12mm thread nut over the screw and carefully fill the centre with a MIG weld. Allow to cool and unscrew. I have used this method to extract broken studs and bolts on many occasions.

 

[Deleted member 36384]

Try these. Much closer fit by design. http://en.wikipedia.org/wiki/Torx