Stubborn Grub Screws in SRB Aluminium Suspension

[bugman]

Recently stripped a couple of SRB chassis down and have encountered the Stubborn Grub Screw Scenario! After rounding two allen keys, it occurred to me to introduce some WD40 into the equation - too late thougth the holes are now nicely rounded. So I took to one with a drill bit, thinking they would be easy to drill out. You get quite an impressive puff of somoke and a bright red glow as the drill bit loses all interest in procedings - what do they make these screws out of?? So I'm very open to suggestions.

[Bluefoot]

You need a set of screw extractors. They look a bit like a screw but with the thread in the opposite direction (anticlockwise)like this:

http://www.tamiyaclub.com/getuserimage.asp...004100418_2.jpg

You put the appropriate size extractor in your drill, set it in reverse, put the pointy end in the nice round hole in your grub screw and SLOWLY wind it out. If you have already got the thing red-hot you may have some problems with the screw being welded in though.

I would lend you mine but it's a long drive to Auckland.

[GPZ1000RX]

I know its too late for these particular grubscrews, but what you need is the correct size precision ground high speed steel bit allen drivers.

I use the Associated ones but many others are available.

Using these stops the cycle of rounded key = rounded socket = rounded key etc etc, because they are the CORRECT size and double hard!

Be careful with sizes tho, for example 2.5mm is only 0.005" larger than 3/32in and the difference DOES matter.

[jozza]

Take 1 old bendy rubbish allen driver from a kit or cheap DIY shop. This should be a loose fit in the grub screw. Apply a dab of expoy glue (Araldite or similar) to the allen driver, then pop it into the grub screw, support it with some tape/string or anything else which comes to hand. Leave for 24 hours for the glue to set, then simply undo it, and chuck away the allen key and what remains of the screw. Make sure you use extra strong epoxy and not the 10 minute quick set stuff (Halfords car spares shops in the UK sell a range of different strengths/cure times, the strongest/slowest setting would be the best to use)

I've done this a few times in the past with success, and it doesn't cost much, plus there is no danger of damaging the thread into which the screw is screwed.

[pleiku68(2)]

I will give a tip for the next time...I have spent the last year rebuiling all kinds of SRB's..with some real nasty grub screws...What I do is put the parts in boiling hot soapy water for five minutes..Aluminum expands at a greater rate than steel..The grubs come out effortlessly..even rounded over ones if you can get any kind of a bite..works for the shocks as well to remove the brass ends without scratching the aluminum..God had to revise this could not believe my spelling...is there a spell check for this forum..????

quote:Originally posted by bugman

Recently stripped a couple of SRB chassis down and have encountered the Stubborn Grub Screw Scenario! After rounding two allen keys, it occurred to me to introduce some WD40 into the equation - too late thougth the holes are now nicely rounded. So I took to one with a drill bit, thinking they would be easy to drill out. You get quite an impressive puff of somoke and a bright red glow as the drill bit loses all interest in procedings - what do they make these screws out of?? So I'm very open to suggestions.

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[bugman]

Guys, thank you.[^] some great ideas to try out here! I really appreciate you coming up with these different aproaches.[] The parts are currently simmering nicely and I'll be trying to hold some red hot aluminium in a mo! [] I'll keep you posted as to the success I enjoy. Next chassis will be completly imersed and only the highest quality allen key/drivers to be used!

[jozza]

Good quality allen drivers are worth every penny they cost, the only problem I sometimes find is that the imperial ones are so close to the metric sizes, you have to be careful to use the correct one. But they don't round off like the cheap ones. I bought a set over a year ago and they are still perfect, they get a lot of use too..

[Shodog]

Jerry, that is a great Idea. I have a set of arms that I can't get the suspension pins out off. I am going to give it a try

Jim

[bugman]

Umm! Aluminium gets quite hot when immersed in boiling water! So does skin when in contact with said aluminium![:I] Sadly the keys and the screws were too far gone to succeed, so on to Plan C. Next stop Bunnings (Local major hardware franchise) for some really really strong glue. Does anyone know if superglue would be strong enough or (work at all) in this scenario?id="Arial">

[Shodog]

Okay guys I gave Jerry's idea a try and I am pleased with the results. I have an SRB front end on my scratch built Rough Rider that had the pins seized into the arms. Since they are CRP aftermarket ones I wanted to save them to reuse them in a nylon set of arms I want to install. so I boiled a pot of water

I took a 2X4 piece of wood and drilled some holes so the shafts could slide down in them.

I boiled the parts for about 5 minutes. These suckers were Scorching hot (Pun intended)so I used a set of tongs to position them in the block of wood. I then used a hammer and a allen driver to knock the pins out.

Tada! all done. Heating the part definetly helped get the pins out. I found that the previous owner of these parts applied a liberal coating of loc-tite around the pins which is why they wouldn't budge on previous attempt to remove them.

[usapirap(2)]

Boiling water works wonders on a lot of things. Check out this thread:

http://www.tamiyaclub.com/xforum/topic.asp?TOPIC_ID=14355

[Lordcroker]

Brave man, using a pot to boil car parts and workshop tools in the Kitchen....my girlfriend would kill me![]

[Shodog]

quote:Originally posted by Lordcroker

Brave man, using a pot to boil car parts and workshop tools in the Kitchen....my girlfriend would kill me![]

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It's all good as long as I clean my mess up. The post is an old one. My wife would kill me if she caught me using our Calphalon pots for these projects

As for pounding, the wood took most of the brunt. The countertops are 3cm thick manmade granite. They are very strong. Once I accidently dropped a pot on the corner of the counter top. I thought for sure it would chip it. Instead it put a dent in the pot