Best penetrant?

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JayC

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I know this pops up from time to time regarding unscrewable screws. What is the best penetrant with which to soak a stubborn screw? I cannot remove the trigger spring screw on my Pietta Remington New Army. I have heated it on the Warm setting of the oven while covered with Ballistol, then let it cool after another shot of Ballistol. I have tried the same procedure using Militec-1 Weapons & Machine Shop Grade I had hoped that the heating/cooling cycle would draw lubricant down into the threads and allow me to get the screw out, but so far no luck. I did this three or four days in a row. The gun has been apart since last Saturday.

I have read some reference to heating, but I don't know whether this involves an open flame, and if so, at what is it directed?

It seems that I may have to take every new Italian gun to a smith and have him remove all the screws one time so I can do so in the future. I always get only so far in the disassembly process and hit one screw that I either damage or am afraid I am about to. I figure that if a smith damages a screw, he will replace it.
 
Heat is usually applied to an old screw driver and then applied to the screw. That way you do not ruin the temper of the screw driver or ruin the finish on the gun. As for lube, Kroil is good for penetration but it smells bad, PB Blaster cuts through rust well and penetrates good also. As for the screw, use a proper set of screw drivers. Grace makes some good ones. About $30 for a set from Numrich or Sarco Inc. Also by the piece or set at Brownells.
 
Jay you must be talking about a new gun ..I just bought a new Pietta Remington last month and I can tell ya they must have hired Mongo to tighten the screw you are haveing trouble with , same problem with mine ..I have a good set of gun smithing screwdrivers ...found the one that best fit the slot , gritten my teeth , bit my tounge , held my breath , pharted twice and finally it broke loose .
 
I've learned by watching the boilermakers and other trades that Kroil is the chosen penetrating oil to use. I've used it for years especially on my old car parts. Heard and tried PB Blaster but didnt see as good of reaction from it as Kroil. To me, PB stinks but I dont like the smell of mothballs and thats what it smells like to me. If it worked I'd use it anyhow but Kroil seems to be best.
 
Sometimes it's a matter of penatrating oil, and sometimes it isn't. If it isn't, then no amount of soaking will make any difference. Sometimes it's just a matter of using enough torque, which means having the right driver and the right technique. If you've buggered the slot already, you have a real problem-- a slot file can sometimes be used to fix a slot, but that particular screw is in a recessed cavity...

If the head snaps off, you know it was stuck threads (you don't know that right now-- it could be the head stuck against the spring). If the head pops off, you have to try a small easy-out, or drill out the screw and maybe even retap to a larger thread diameter. My guess, based on experience with my own Pietta, is that you may just need more torque and the thing'll come right out.

I've been working on stuck screws for 30 years on musical instruments, and in only a minority of cases do penatrants make any difference. The right driver and the right application of muscle usually works. On rare occasions an impact driver is needed.
 
If it's a new gun the likelihood of corrosion binding the threads is not very high, so a penetrant is probably not going to help much. In that case the best solution is sundance's: get some good (not inexpensive) gunsmith's screwdrivers (while you're at it, buy a couple of sets of replacement screws too - they're cheap and you'll save on shipping if you get the screwdrivers at the same time). Carefully select the best fitting screwdriver and apply the torque just as carefully, making sure the driver is straight up and down.

Application of heat also depends on what the cause of the problem is. If it's corrosion, heating the penetrant is best, so heating both the frame and the screw is called for. If it's not corrosion, heating the frame is the best choice, so it will expand away from the screw threads. This is, however, of minimal help as the heat will transfer to the screw threads pretty quickly, expanding them also. But, you won't need much differential expansion.

I my experience the best penetrant is Kroil, but it's not a great deal better than WD-40 or the others.
 
Do you have access to a drill press? If so, pad the vise well, then clamp the gun in. Chuck a short stubby screwdriver blade (of the right size for the slot) into the chuck. [DO NOT turn on the power!] Bring the driver down onto the screw, lining up the slot. With the blade in the slot, use the drill press handle to hold the blade down and keep it from jumping out. Turn the chuck. The screw will come out.

Jim
 
Best penetrant. Impact driver. I took mine filed down one of the bits and it works like a charm. place some rags under the frame on a firm surface. put the bit in the driver. Turn the setting. put the bit in place. Then it the driver hard with a hammer. Thats it. after that put a screwdriver on it and unscrew it. Here is one from harbor freight. the one i have i got in a metal box from an autoparts store about 20 years ago.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=37530
 
Thanks for all the comments and suggestions.

I have used the gun to shoot 6 CAS matches over the last two years, plus have shot it informally a few times. I had never taken it down beyond removing the grips, cylinder, and ram assembly. I decided it was time to go further, and found much crud under the trigger guard. I have used 777 for virtually every shot.

I have a Brownell's set and believe I have selected the correct bit, but got the least little bit of slot damage the last time I tried to break it free. I don't have a vise yet (although I am being given one in the near future). Because this particular screw is on the underside of the gun, not the side, it is all I can manage to keep everything lined up just with a screwdriver. I was aware of the hammer trick, but didn't think it would be a good idea without a vise to stabilize things.

I don't know whether it is crud or just overtightening at the factory, but I guess I should try Kroil. Where is that sold, hardware, autoparts, or some other type store?

Thanks again.
 
"Break Free" is accurate

No luck fingding Kroil around here, but each time I would ask what the best penetrant in the store was. The last guy suggested Break Free among two or three, so I dug out a bottle that I had squirreled away 25 years ago or so. Two cycles of heating and cooling, applying a few drops before and after the heat, and the screw finally let loose!

I guess "Break Free" is accurate.
 
> ...Impact driver...

My vote, too. It is the best tool to use after a soak in Kroil. If the screw can be loosened, an impact driver will do it every time without damaging the screw head.
 
I've had good luck with Kroil, both plain Kroil in the can, and Aerokroil with silicone in the spray can. It smells, but I deal with it.

I've read good things about PB Blaster but have not tried it myself.
 
I've tried both PB Blaster and Kroil. Of the two, Kroil seemed better.

As far as penetrating oil goes, "Thrust" is the best I've seen. A product of a company named
"Castle Products". At least for my uses(I use this stuff daily at work), Thrust makes PB Blaster and Kroil look like WD 40!

Thrust is also a pretty decent gun oil and protectant. I don't know if the stuff is widely available, but it is the spray/penetrating oil of choice for many in my area.
 
PB Blaster is one of those that the last store recommended, but since I already had Break Free, I figured I'd try it before buying anything.

Regarding impact drivers, is that a tool powered by air or electricity, or by a hammer?
 
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