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Impact Driver & Stuck Screws


Andy Joyce
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Having had to revert to the use of a Dremel disc cutter on several head screws recently is a small impact driver a suitable tool to use on stuck engine screws? 

Sure OS must have used an obscure Philips head screw type as none of my screwdrivers seemed to match so don't wish to damage any further engines as the Dremel did mark the head cooling fins.  Will be fitting hex head screws as a replacement but interested to know how others remove screws stuck in with baked on caster oil.

 

 

 

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Maybe OS use 

Japanese Industry Standard.

http://www.motorcycle.com/blog/wp-content/uploads/2017/10/101617-japanese-screwdrivers-JIS-vs-Phillips-633x490.jpg

Looking at a JIS tool next to a regular Phillips screwdriver, most people are hard-pressed to tell the differences, but they are definitely there. Ninety-percent of the time, a regular Phillips will work on a JIS screw; but it’s that other 10% that gets us swearing, then throwing things – those tight screws holding on your carburetor float bowls being particularly devilish once they’re past about two decades of non-removal. That’s when the right tool can make all the difference. The right tool is a JIS screwdriver, which just fits better in a JIS screwhead and is designed to let you apply more torque than a Phillips driver.

 

I use heat and WD40 to help get "difficult" sews out. And I never use fuel containing castor oil!

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      Not always possible because of plastic/rubber parts but heat is often the answer to removing stuck items. Pencell flame torch or even holding a 100w soldering iron on the screw until castor bubbles.

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The simplest way to free off and dismantle an engine that is gummed up with castor oil is to warm it in the oven as the hardened castor will soften and screws and bolts will move out easily. I'd not let any kind of impact driver near the fastenings on a model engine.

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I always wince when someone suggests taking a flame to an engine. It will quickly cause one part to become much hotter than the surrounding area and could easily cause some permanent distortion of the metal. A hot air gun is a much gentler way of heating engine parts as it's not so concentrated.

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Hi first check theat the hex recess in the screw is clear of hardened castor . They can fill with old castor and this stop an allen key from fitting properly. If unsure  dig out with a sharp tool first. Only use decent HSS allen drivers  for these screws as the cheapo allen keys that often come with engines are  generally rubbish and will round off and in the process will round the socket in the screw . Heat is a friend when it comes to stuck theads . An oven . hot air gun or if you know what your doing a blowlamp can be used . For stubborn screws fit  a HSS allen driver and give it a sharp tap with a small hammer .

 

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14 minutes ago, Engine Doctor said:

Hi first check theat the hex recess in the screw is clear of hardened castor . They can fill with old castor and this stop an allen key from fitting properly. If unsure  dig out with a sharp tool first. Only use decent HSS allen drivers  for these screws as the cheapo allen keys that often come with engines are  generally rubbish and will round off and in the process will round the socket in the screw . Heat is a friend when it comes to stuck theads . An oven . hot air gun or if you know what your doing a blowlamp can be used . For stubborn screws fit  a HSS allen driver and give it a sharp tap with a small hammer .

 

I thought it was established that the problem screws were JIS not Phillips & definitely not Allen head Or have I missed something ? 

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It’s often useful to give the head of the fastener a sharp hammer tap via a punch or other drift to break any bond of corrosion. 
 

I’ve also used “Screw Grab” to assist where worn or damaged fixings have been encountered - a paste containing diamond or similar dust which improves the grip of the (correct!) tool.  Useful stuff to keep in the tool box…

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JIS screw X heads can also get filled with castor goooo...

 

Is the picture from a honda superslug carb, air cut off/economy diaphragm/power diaphragm ?

 

I use a good soak in petrol to clean off castor goooo using great care due to the fire risk.

 

Baked on castor goooo and the baked on other lubricant residue can be quite difficult to remove...

 

I also tend to use a saucepan to heat sufficient car engine oil to allow the model engine in question to be submerged...again with fire and burn precautions....

 

The petrol soak and hot oil treatment takes place outside in suitable weather. Hot oil and rain do not mix well, you seen a chip pan fire !

 

Heavy handed techniques on a model engine is a bad idea...

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32 minutes ago, Rich Griff said:

JIS screw X heads can also get filled with castor goooo...

 

Is the picture from a honda superslug carb, air cut off/economy diaphragm/power diaphragm ?

 

I use a good soak in petrol to clean off castor goooo using great care due to the fire risk.

 

Baked on castor goooo and the baked on other lubricant residue can be quite difficult to remove...

 

I also tend to use a saucepan to heat sufficient car engine oil to allow the model engine in question to be submerged...again with fire and burn precautions....

 

The petrol soak and hot oil treatment takes place outside in suitable weather. Hot oil and rain do not mix well, you seen a chip pan fire !

 

Heavy handed techniques on a model engine is a bad idea...

Petrol isn't a solvent of castor, it must be the heat or something else that's shifting the goo, unless the goo is actualy from some mineral oil.  

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Modern petrol contains ethanol these days ?

 

Anyways petrol seems to clean off my engines when soaked. You can see the goo floating about in the Petrol that's in the jar the engine is in submerged.

 

I tend to Filter the petrol for a second go, or for another engine.

 

Works for me apart from the really baked on stuff. Even that ( d1000 and mt gn15, 5 percent and straight castor ) given time comes off.

 

Meths works but not as well as petrol in my experience.

 

Even though petrol has gone up in price it seems the best compromise cleaning ability versus price etc..

 

Heavy hail stones at the moment in Snowdonia !

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22 hours ago, PatMc said:

I thought it was established that the problem screws were JIS not Phillips & definitely not Allen head Or have I missed something ? 

Your correct . I missed that . 

Basic principles still apply ie decent tools , remove congealed oil,heat etc.

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Once you have acquired a set of JIS screwdrivers, you’ll be surprised how much of the fixings we all use appear to be JIS.   Take servo arm screws for example, plus many self tappers, machine screws etc sourced from the Far East, including Taiwan.   There are subtle but distinct differences between Phillips, Pozi and JIS and I generally try all three on an unknown head until I find a tight fit.   Wera do a set of three inc. Pozi 2 and PH 2 with 300mm shafts which get a lot of use as the extra length helps keep them square on and a lot more pressure can be put on a stubborn fixing.

BTC

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On 25/06/2022 at 07:16, David Ovenden said:

Maybe OS use 

Japanese Industry Standard

 

I'm almost certain that they do, where they use pozi style screw heads. Otherwise metric hex drive.

 

On 25/06/2022 at 10:18, Andy Stephenson said:

I always wince when someone suggests taking a flame to an engine. It will quickly cause one part to become much hotter than the surrounding area and could easily cause some permanent distortion of the metal.

 

Agreed.

 

Dare I say it, wait for the oven to become vacant and pop it in there for a few minutes.

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I got my JIS screwdriver set from the USA a few years back and after delivery was informed that Halfords carry them, just typical.

 

ANyway, just checked their website and yes Halfords still carry a set of four drivers from just under £16. Search on "JIS screwdrivers"

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