Allen driver needed

I have an expensive item that is manufactured from Billet Aluminum. It is assembled with 316 stainless steel csk hex head screws.
I need to disassemble and the screws are stuck fast.
The heads are 7/32" hex imperials (yep 100% sure - It's a US manufactured product)
I have tried encouraging Allen key with mallet - no good. Applied releasing oil - no good (happy to try a specific product if there is a particularly good one)
So far only one of the 8 have come out !
Now one way to approach this would be to use an impact driver ... I have a compressed air 1/2" square drive impact driver, and assorted sockets ... but would need a 7/32" hex insert ............ anybody know where I can get one ?
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wrote:

Heat or cold or combination of both , blowtorch, oxy torch applied carefully.
http://www.arco.co.uk/products/44C4013 Freeze and release , not tried myself but heard good things.
Mig welding nut on top of fastener, heat helps free it and gives good surface to grip with tool.
Spark erosion was invented to remove snapped taps out of aluminium radar guides, its the expensive but ultimate way for removing HT steel from alloy.
7/32 will have too much slop by time come down from 1/2" drive, 6mm drive T-bar would give more feel and torque would guess.
http://www.shop4fasteners.co.uk/acatalog/Wera_Professional_Hexagon_Hex_Drive_Screwdriver_Insert_Bits.asp
Cheers Adam
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On Thu, 08 Apr 2010 14:18:44 +0100, Rick Hughes wrote:

================================================ I think this is what you need:
http://www.machinemart.co.uk/shop/product/details/facom-jt-732-38-hexagon-bit-socket-732/path/screwdrivers-bits-hex-key-sets-2
You can buy them in sets - Halfords etc.
Cic.
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http://www.machinemart.co.uk/shop/product/details/facom-jt-732-38-hexagon-bit-socket-732/path/screwdrivers-bits-hex-key-sets-2
That is exactly what I want ... just tried Machine Mart ... they don't stock them, in store - special order only.
Halfords don't have them in imperial.
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Rick Hughes wrote:

Many years ago I made my own using some spare sockets, spare allen keys, araldite and an angle grinder (to cut a suitable length of hex from the keys) - they're still going strong!
Dave
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On Thu, 08 Apr 2010 15:46:00 +0100, Rick Hughes wrote:

=============================================== Not much help if you're in a hurry. Have a look at this set which contains a 7/32" bit:
http://www.machinemart.co.uk/shop/product/details/cht569-100pce-bit-set
You might need an Imperial 1/4" socket or ring spanner to drive it but the set does contain several adapters.
Cic.
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Thought final solution may be of use ...
Tried Allen key .. no good Tried Plus Gas & Hex bit in ratchet .. no good Tried off cut of Allen key in socket .. no good Tried heat ... no difference (could not go warmer than hand hot) Tried Plus Gas .. no good Bought proper Allen bit in socket ... no good
The problem is the screws being Stainless are reasonable soft .. and Allen key just chews out the hex head.
Solution .... hammered in a Torx T40 bit ... then using a ratchet & 3' extension bar the screws came out ... with hell of a crack ... kept expecting ratchet to break each time. First Torx bit remove screw but was ruined itself .... (was a bit from a multi part DeWalt set) ... went and bought a couple of WEARA bits ... they removed them with no damage to bits at all .... WERA bits really are worth the extra.
Once the parts come back from anodizing I will reassemble with stainless anti-seize paste.
If you were wondering what I was undoing .. it was this :
http://i771.photobucket.com/albums/xx351/Tafflad/red.jpg
well it will be that colour once anodized.
That makes up my my SkySki, which you use to have fun like this:

http://www.youtube.com/watch?v=ahKeh0e3EwA

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On Thu, 15 Apr 2010 20:44:31 +0100, Rick Hughes wrote:

'kinell Rick!
What's that being towed by? Looks like a line from the sky (hence the name I guess) but what's at the other (towing) end?
--
John Stumbles

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<Snip>
The screws could be fitted with thread locking compound. Suggest you use a Hot Air Gun.
From tds.loctite.com/tds5/docs/220-EN.PDF
For Disassembly
1. Remove with standard hand tools.
2. In rare instances where hand tools do not work because
of excessive engagement length, apply localized heat to
nut or bolt to approximately 250 C. Disassemble while
hot.
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No Thread lock used ... but guess dissimilar metals has caused the issue.
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Rick Hughes wrote:

You can get adaptors from various square drive heads to a hex bit holder, and then a standard hex bit of the required size would fit that.
e.g.
http://www.machinemart.co.uk/shop/product/details/facom-j-235-bit-holder-38-drive-14hex
I think my first approach would be a allen hex bit in my small cordless impact driver - it only develops about 20 Nm, but might shock it free. Failing that a full size cordless one before resorting to a full on 1/2" drive pneumatic impact driver
--
Cheers,

John.

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First off you might want to read this.
http://www.pumaracing.co.uk/ToolUse.htm
Countersunk fittings do tend to lock on very tight because of the angle and area of the underside of the head. You need to shock these loose with something other than an unmodified right angled allen key which can't really be hit directly on the end very easily. A small brass or bronze drift is ideal, especially if you can machine a pip on the end in a lathe to keep it centred inside the allen screw so it doesn't jump about and mangle the aluminium around it. Or just cut a bit off an old 5.5mm allen key and hammer that. By mallet I assume you mean a wooden one. You *must* use a steel hammer to get a proper shock loading on the drift. Hitting something with wood will achieve three fifths of FA. If they still won't come out hit them harder! You won't hurt anything. It's like training a dog. Once it really knows who's boss it'll give in and stop dicking about.
To use an allen key in your impact driver simply cut a length off the long end with an angle grinder disc and use it in a 7/32" socket.
Absolutely no point using releasing oil. The joint will be fluid tight.
You also must tighten back up each screw you loosen to take the load off the others and when all are free remove them one at a time.
If the screws are loctited in then applying heat for a while will soften it.
Car engine oil pumps are often held together with csk allen screws and I've had to remove god knows how many ultra tight ones over the years but nothing has ever failed to succumb to the right technique.
I'll bet you a pound to a pint if you cut a bit off an old 5.5mm allen key, belt that firmly with a claw hammer a few times and then just use a good tight fitting 7/32" key they'll pop out as easy as anything.
--
Dave Baker



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Tried some heat ... no difference (don't want to apply too much)
Bought new set of metric Allen keys to make sure it's a good fit ... still no go.
I have now ordered a socket driven allen key .... I'll give that a go with my pneumatic impact wrench .. on lowest setting and low air pressure.
My worry is it it rounded off the screws .... be a major issue to solve.
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Not really. You just drill the heads off and you're left with a bunch of easily removeable threaded stubs after the cover is removed. Just use a drill a gnat's bigger than the screw shank and drill until the head spins off.
--
Dave Baker



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CSK hex head are about the easiest screws to drill out.
--
*One tequila, two tequila, three tequila, floor.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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London SW

My worry would be damaging the Aluminum .... hope it does not come to this.
I have ordered a Hex socket bit .... I'll try walloping it a few times to seat it well, and hopefully loosen the fit. Contacted the manufacturer - he said this is very common ... suggests using a Torx bit and driving that in ... so it cuts itself in, plus the driving in will loosen .. and then it should come out.
He did add a standard 90 degree bend allen key is no use, needs a socketed driver.
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You drill using a size slightly less than the thread diameter. You'll get a pretty good centre using the hex. A tap with a mallet on the back of the top part should then break the head off. If the top part can then be removed, a pair of grips on the thread should remove that. Perhaps soaked in penetrating oil overnight if corroded. Happens all the time with BMW disc brakes. ;-)

Yes - the torx trick can work.

Indeed.
--
*You never really learn to swear until you learn to drive *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On Fri, 09 Apr 2010 01:11:18 +0100, Rick Hughes wrote:

=============================================== I would suggest that you start by using the new hex bit normally at first - either T-bar or ratchet with steady pressure. There's no point in risking damage from a violent assault before you need to.
Cic.
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My experience with impact drivers says they are less likely to break things than steady pressure. Although a very powerful impact driver could be different.
--
*Laugh alone and the world thinks you're an idiot.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On Fri, 09 Apr 2010 10:15:21 +0100, Dave Plowman (News) wrote:

================================================ Given the comparative rarity of impact drivers it's obvious that the primary use of the type of tool which the OP has is as a hand tool. Few people routinely reach for an impact wrench for every tight nut, bolt and screw. I hardly ever use mine and of course there is often no access for an impact wrench, so it makes sense to try basic conventional methods first as I suggested.
Cic.
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