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General control line discussion => Open Forum => Topic started by: bob whitney on July 16, 2015, 09:59:29 PM
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one of my Buddy's brought me an LA46 that had been in the woods for three months in an RC ship trying to get it apart ,he got one Phillips .
head screw out and messed up the other three
i got out my trusty hand impact that we used to use to get Phillip screws from Japanese motor cycles before replacing with Allen screws . it has a 3/8 end which i added a reducer to 1/4 in then put a 1/4 in socket on it then found a Phillips bit that fit the screws set the engine in a vise under the luggs one good tap with a medium hammer and the first two screws were loose . the third
screw was beyond using the bit so i took a small chisel ground to a sharp point and gave the screw a couple of good hits then took a small regular bit and tapped it into the slot ,then put the impact on it and with one good hit it was loose .the whole thing took less than ten minutes
a cheap impact can be had From harbor freight for next to nothing . it can also be used with Allen screws . the bits can be gotten at harbor also.
using this on good screws would all but eliminate stripped screw heads .use a regular screw driver for re-installing .
this is long but i hope it helps
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You know the the japanese screws that look like phillips, aren't phillips, right? They're JIS
(http://www.webbikeworld.com/motorcycle-tools/jis-screwdrivers/vessel-jis-screwdrivers/jis-vs-phillips-screwdrivers.jpg)
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PB Blaster is your friend, also. It really works, and this is coming from someone assigned to a 27 year old aluminum crew boat (with many SS fasteners).
Glad you got it apart.
R,
Chris
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Craftsman makes the best screwdriver for the jis screws
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I changed to allen cap screws as soon as I take the engine out of the box.
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I have some drivers in the shop just for those foreign screws. I replace them also with socket head screws.
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Here is what I have done.
Plug the exhaust and venturi with tissue.
Take a drill bit just a fraction more diameter than the threaded shank of the head bolt and holding the engine firmly in one hand gently using a drill press, slowly drill into the head bolt. The stripped hole centers the drill bit. When you reach the interface of the head and the shank the head will be cut loose. Remember to go slowly so that you do not go past the interface.
Do this for all the stuck head bolts and then simply pull the head off. The remaining part of the shank will now be exposed and can be removed using lock pliers if required. Usually once the pressure is off the bolts they thread out easily.
John McFayden
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that is deff plan B
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Just on the off chance that it hasn't been said enough already: Cross-head screws (Phillips, JIS, etc.) only really work well if you're using a driver that fits -- otherwise you just munge up the screws, and often the driver. If you do use the right driver, they work beautifully.
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I've used a dremmel tool cut off wheel to make a slot in the head for a regular screw driver.
MM
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The first time a screwdriver bit slips (and you don't have a better bit) apply a little bit of valve grinding compound to the tip. It increases the tips "bite" tremendously. Old-school aircraft mechanics used Comet but that's corrosive to aluminum. Permatex valve grinding compound can be bought in a small tube from just about any auto parts store for a couple bucks.
Impact screwdrivers are very effective and I have one I used on cars and motorcycles. On aircraft they dent/damage aluminum structures so a very effective method is to put the bit in a bit holder and attach it to a speed handle, 3/8" or 1/2" drive is best. Apply pressure to the end of the speed handle and just pop the "U" in the handle in the direction of removal. This may not sound like much but I have removed hundreds of screws this way. In one memorable occasion, another sheetmetal guy had been tasked with removing about 50 screws from an underwing panel on a 767 after the mechanic had stripped several. After an hour he still only had about 10 out. With the 1/2" speedhandle trick with some EZ Grip on it (valve grinding compound in a thick oil), all the screws were out in 10 minutes.
Last tip: Left hand screw removal or drill bits. I have a collection of left hand drill bits. Most of the time, as soon as a left hand bit starts to grab, it backs the screw
out. These days, left hand removal bits are common place even in hardware stores because of the widespread availability and use of cordless, reversible electric drills.
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You have a cut and paste issue above Bill.
R,
Chris
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You have a cut and paste issue above Bill.
R,
Chris
Thanks, Chris.
That's what happens when I'm typing on a laptop with a touch pad. Stuff end up all over the place!