SP owners will know that the adjustable counterweights that fit into the barrel shroud are retained by a top plate which is held in place by two small cap (machine) screws. These two screws must be removed in order to gain access to the counterweights and springs.
On my SPnew, these screws are of button-head style with hex socket. The hex socket requires a 2 mm hex key (Allen wrench) which is supplied with the tools that come with the gun.
When I first got the gun, I tested its operation with the springs placed in front of and then behind the counterweights. I settled on a configuration and snugged up the button-head screws with the hex key (not really tight, its a small hex key).
Now, several months later, I am unable to loosen the screws!
I live in a dry climate and the gun has not been exposed to moisture or condensation, so I don't expect that the screws have rusted. Never-the-less, I've soaked the barrel and shroud assembly in penetrating oil (Kroil) overnight.
I've cooled the assembly by placing it in the freezer for an hour.
I've heated the screws with the tip of a soldering iron.
All to no avail. I can not budge those screws. I've twisted the hex key so hard that the tip of the key has rounded off and the key spins in the socket. I've reground the key to give a square (hex) tip and tried again - no success.
The socket in the screw head still looks good (undeformed) - the screw is harder than the key, it seems.
Any suggestions for getting those screws out?
Mike T.
Looking for help with Pardini SPnew
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Ernie Rodriguez
- Posts: 344
- Joined: Fri Apr 15, 2005 1:50 pm
- Location: Tennessee
Pardini Issue
Perhaps you can get an E-Z out and fit it into the tight screw-after a drop of penetrating oil ,of course. Ernie.
Last edited by Ernie Rodriguez on Thu Jun 01, 2006 4:31 am, edited 2 times in total.
Re: Looking for help with Pardini SPnew
Mike-Mike T. wrote: I've heated the screws with the tip of a soldering iron.
Mike T.
My answer is strictly from a theoretical standpoint, but theoretically you should be able to loosen them by heating the entire shroud (especially around the screws). This should cause the shroud to expand, which should loosen the screws. By heating just the screws, you are causing the screws to expand, which will only make them tighter. Maybe remove the shroud assembly and somehow place it in contact with a stove burner under heat low enough to not scorch the finish but hot enought to cause the needed expansion?
Good luck!
Ted
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Guest
Buy a top quality allen wrench from an engineers supply store.
Soak the area again in penetrating oil.
Remove as much oil as possible from the screw hex before trying again.
A little lapping paste on the end of the wrench.
Use some sort of extension on the wrench to apply a good positive pressure.
Don't let the wrench slip out of the screw when applying pressure.
If this fails, drill the heads off the screws and buy new ones.
Soak the area again in penetrating oil.
Remove as much oil as possible from the screw hex before trying again.
A little lapping paste on the end of the wrench.
Use some sort of extension on the wrench to apply a good positive pressure.
Don't let the wrench slip out of the screw when applying pressure.
If this fails, drill the heads off the screws and buy new ones.
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Fred
Mike,
I have had to deal with this problem a couple of times recently, and it isn't easy. There was a piece in a recent American Rifleman that dealt with the problem (April 2006, p.52). Do not use an L-shaped Allen wrench/hex key. You want to keep the torque centered on the center of the screw, and the hex key shifts torque to one side. Use a good quality hex bit - good quality is especially important for small sizes like 2mm (I just broke two poor quality 2mm bits so I know!). If the screw recess gets rounded, you can sometimes save the situation by using a Torx bit. For more, I'd advise reading the article, which is directly applicable to your problem.
HTH and good luck,
FredB
I have had to deal with this problem a couple of times recently, and it isn't easy. There was a piece in a recent American Rifleman that dealt with the problem (April 2006, p.52). Do not use an L-shaped Allen wrench/hex key. You want to keep the torque centered on the center of the screw, and the hex key shifts torque to one side. Use a good quality hex bit - good quality is especially important for small sizes like 2mm (I just broke two poor quality 2mm bits so I know!). If the screw recess gets rounded, you can sometimes save the situation by using a Torx bit. For more, I'd advise reading the article, which is directly applicable to your problem.
HTH and good luck,
FredB
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F. Paul in Denver
Just out of curiosity Mike, what did you learn from your experimentation with the positioning of the weights and springs?? What did you finally settle on and why??
I have been meaning to do this for two years now and have never gotten around to it.
Thanks in advance for sharing youIr observations.
F. Paul in Denver
I have been meaning to do this for two years now and have never gotten around to it.
Thanks in advance for sharing youIr observations.
F. Paul in Denver
Looking for help for Pardini
Hi,
I know a number of people here in Oz that have a similar gun, and they have found it works very well.
However many of them have been told to leave the gun as it is - as it came from the manufacturer, and use it for at least a year before you make any changes.
My suggestion to remove the screw is to tap the top of the screw - to break the seal that has happened - and use a drill to ease to out.
You have most probably already damaged the top of the screw, so no tool will be able to be used. I expect you have crossed a thread.
I suggest you don't look for trouble in future, and don't go investigating!!!! :))
Hope you can get it fixed.
Alex L.
I know a number of people here in Oz that have a similar gun, and they have found it works very well.
However many of them have been told to leave the gun as it is - as it came from the manufacturer, and use it for at least a year before you make any changes.
My suggestion to remove the screw is to tap the top of the screw - to break the seal that has happened - and use a drill to ease to out.
You have most probably already damaged the top of the screw, so no tool will be able to be used. I expect you have crossed a thread.
I suggest you don't look for trouble in future, and don't go investigating!!!! :))
Hope you can get it fixed.
Alex L.
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Guest
Re: Looking for help for Pardini
I don't believe he has crossed a thread. He is detailed in his description and would have realised it happening.Alex L wrote: I expect you have crossed a thread.
I suggest you don't look for trouble in future, and don't go investigating!!!! :))
Alex L.
There is also nothing wrong with trying different things as long as you have a commonsence approach to what you are doing.
Otherwise we'd still be living in caves.
weight position
These recoil systems are designed to have the springs at the front. From a physics stand point if you put the springs into the gun first it will increase the amount of felt recoil and muzzle flip. The adjustability in these guns is whether to have 2, 4 or 6 weights in there, and what their distribution would be. If you have put the springs in first, this has caused your problem as when the gun fires the weights are forced onto the front plate probably causing the thread to become damaged. If you do get the plate off I think you need to put the weights in first and then the springs. It is due to the laws of inertia.
Phillip
Phillip
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Fred
Since we're speculating on why the screws locked up, I'd like to suggest another possibility. I have seen on some Pardini models (I've never examined an SP) the use of steel screws mating into aluminum threads. There can be a reaction between the dissimilar metals that basically freezes the screw in place. Maybe that's the case here?
FredB
FredB
SPnew frozen screws
Thanks for all the comments and suggestions, fellows. Let me address them:
Ernie suggested an E-Z Out and that will be an option if I can find one small enough to fit the tiny (2 mm) hex socket of the screw. However, short of drilling out the screw, that will be my last option.
I've been reluctant to heat the shroud because it is aluminum (alloy) and I worry about causing distortion if I overheat it (also concern about causing a change in temper of the steel barrel). I heated the screws because I thought the expansion (and subsequent contraction on cooling) might break the threads loose. I also thought the heat might loosen any thread-locking compound (although I had not used any on the screws).
I have obtained a good quality T-handle hex wrench and it is definitely far better than the L-shape hex key for getting a good purchase on the screw. I haven't tried lapping paste but I can push very straight and firmly with the T-handle wrench. Still, the screws have not budged.
Fred, thanks for the reference to the American Rifleman article. Good information there, some of it echoed in other messages here.
Paul, about 10 months ago I experimented with the weights and springs. I shot slightly better sustained-fire scores with the springs behind the weights, but the scores were not good, so I concluded I was having an "off" day and put the assembly back to its "as received" configuration - with the weights behind the springs.
Earlier this week, my friend tried some Rapid Fire (8, 6, and 4 seconds) with his GSP and then with my SPnew. He found the muzzle flip on the SPnew to be about as bad as that with the GSP. I suggested I switch the springs and weights and he try the gun again. That's when I discovered I could not loosen the screws to remove the cover plate over the weights!
As Fred B. noted, the steel screws are threaded into the aluminum alloy barrel housing. If not corrosion, then certainly galling between the dissimilar metals is a very likely scenario.
My next step is to try a Torx bit with light hammering while I twist the bit. If that fails, then an impact tool - the kind that translates a heavy linear blow into a rotary motion.
Drilling out the screw would be a final resort because the threads in the barrel housing will then likely need to be re-tapped to a larger size. I'll postpone that for a while, I expect, because I can use the pistol as it is for everything except Rapid Fire - and I'm staying away from RF until I've regained some measure of discipline with the trigger (smooooth).
Mike T.
Ernie suggested an E-Z Out and that will be an option if I can find one small enough to fit the tiny (2 mm) hex socket of the screw. However, short of drilling out the screw, that will be my last option.
I've been reluctant to heat the shroud because it is aluminum (alloy) and I worry about causing distortion if I overheat it (also concern about causing a change in temper of the steel barrel). I heated the screws because I thought the expansion (and subsequent contraction on cooling) might break the threads loose. I also thought the heat might loosen any thread-locking compound (although I had not used any on the screws).
I have obtained a good quality T-handle hex wrench and it is definitely far better than the L-shape hex key for getting a good purchase on the screw. I haven't tried lapping paste but I can push very straight and firmly with the T-handle wrench. Still, the screws have not budged.
Fred, thanks for the reference to the American Rifleman article. Good information there, some of it echoed in other messages here.
Paul, about 10 months ago I experimented with the weights and springs. I shot slightly better sustained-fire scores with the springs behind the weights, but the scores were not good, so I concluded I was having an "off" day and put the assembly back to its "as received" configuration - with the weights behind the springs.
Earlier this week, my friend tried some Rapid Fire (8, 6, and 4 seconds) with his GSP and then with my SPnew. He found the muzzle flip on the SPnew to be about as bad as that with the GSP. I suggested I switch the springs and weights and he try the gun again. That's when I discovered I could not loosen the screws to remove the cover plate over the weights!
As Fred B. noted, the steel screws are threaded into the aluminum alloy barrel housing. If not corrosion, then certainly galling between the dissimilar metals is a very likely scenario.
My next step is to try a Torx bit with light hammering while I twist the bit. If that fails, then an impact tool - the kind that translates a heavy linear blow into a rotary motion.
Drilling out the screw would be a final resort because the threads in the barrel housing will then likely need to be re-tapped to a larger size. I'll postpone that for a while, I expect, because I can use the pistol as it is for everything except Rapid Fire - and I'm staying away from RF until I've regained some measure of discipline with the trigger (smooooth).
Mike T.
You might try a "Chapman" set. This is a kit with a series of very short bits, and I believe they have metric hex bits. Here's a place that sells them, but they don't indicate which kits have which size bits:
http://precisionreloading.com/screwdrivers.htm
Because the bits are short (and high quality), I've found I can apply a lot more torque that with regular wrenches. Using the ratchet arm, I would be very surprised if you can get enough torque to take the head off the screw, so be careful. If the heads come off, that may relieve enough of the tension to allow what's left to come out easily. It's tough with so small a screw, but if you try to drill it out, use a left hand drill bit.
Good luck.
http://precisionreloading.com/screwdrivers.htm
Because the bits are short (and high quality), I've found I can apply a lot more torque that with regular wrenches. Using the ratchet arm, I would be very surprised if you can get enough torque to take the head off the screw, so be careful. If the heads come off, that may relieve enough of the tension to allow what's left to come out easily. It's tough with so small a screw, but if you try to drill it out, use a left hand drill bit.
Good luck.
Hex bits
Thanks for the lead to the short hex bits by Chapman. I intend to get a set.
Left hand drill bit? Here I thought I was pretty familiar with tools, but that is a new one for me. Makes sense, though. Learn something new every day. (Now I am good for two days!)
Regards,
Mike T.
Left hand drill bit? Here I thought I was pretty familiar with tools, but that is a new one for me. Makes sense, though. Learn something new every day. (Now I am good for two days!)
Regards,
Mike T.
Mike T,
You might want to try the following: Sacrafice a short section of hex key, say 10mm long, insert it in the offending screw and give it a sharp rap, axially, with a small (4 to 6 oz.) hammer. Remove the section of hex key and retry removal with a standard hex key. I have found this procedure to work well. The axial shock load will set the screwhead back and break the bond of the screw to base metal. P.S. be carful with the hammer so as not to damage anything.
Gort
You might want to try the following: Sacrafice a short section of hex key, say 10mm long, insert it in the offending screw and give it a sharp rap, axially, with a small (4 to 6 oz.) hammer. Remove the section of hex key and retry removal with a standard hex key. I have found this procedure to work well. The axial shock load will set the screwhead back and break the bond of the screw to base metal. P.S. be carful with the hammer so as not to damage anything.
Gort
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Mark Briggs
- Posts: 583
- Joined: Mon Mar 01, 2004 8:35 am
- Location: The Frigid North - Ottawa, Canada
Mike,
Sorry to hear your SP is giving you heartache. I've been down that road with mine and have concluded that it's a problem pretty much unique to the SP design. These guns have short barrels which result in lots of gunk blowing back over the front of the gun. This blowback "gunk" is somewhat corrosive, and I found the screws in the nose of my SP1 to be pretty sticky after leaving the gun uncleaned for a couple of weeks.
If you can't get Champman screwdriver hex bits, you may want to run down to your local UAP/NAPA store, or a store that caters to machine shops. If you can find hex keys sold under the brand name "UnBrako" you'll find they live up to their name. Also, the application of impact force to the head of the screw will indeed loosen things up. When this whole mess is sorted out you'll find that a little lithium grease under the head of the screw (not the threads) will help prevent recurrance.
Also, of note, I just started the transfer of my 2nd MG-2 today from J. Langlois. He'll be stocking some parts for these too so we should have a couple of in-country sources of parts.
See you at the Nationals!
Sorry to hear your SP is giving you heartache. I've been down that road with mine and have concluded that it's a problem pretty much unique to the SP design. These guns have short barrels which result in lots of gunk blowing back over the front of the gun. This blowback "gunk" is somewhat corrosive, and I found the screws in the nose of my SP1 to be pretty sticky after leaving the gun uncleaned for a couple of weeks.
If you can't get Champman screwdriver hex bits, you may want to run down to your local UAP/NAPA store, or a store that caters to machine shops. If you can find hex keys sold under the brand name "UnBrako" you'll find they live up to their name. Also, the application of impact force to the head of the screw will indeed loosen things up. When this whole mess is sorted out you'll find that a little lithium grease under the head of the screw (not the threads) will help prevent recurrance.
Also, of note, I just started the transfer of my 2nd MG-2 today from J. Langlois. He'll be stocking some parts for these too so we should have a couple of in-country sources of parts.
See you at the Nationals!
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Guest
Re: SPnew frozen screws
You wont need to drill the whole screw out . Use about 0.5 mm oversize and drill till the head breaks free and relieves the tension.Mike T. wrote:Drilling out the screw would be a final resort because the threads in the barrel housing will then likely need to be re-tapped to a larger size. Mike T.
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R.M.
- Posts: 156
- Joined: Mon Mar 01, 2004 8:35 am
- Location: On top of a mountain west of Golden Colorado
Mike,
I agree with drilling the heads off. By relieving the tension, it could very well loosen things up. If not, maybe you could get a pair of visegrips on the stubs, after getting some penetrating oil at the threads.
Hope you get it without much more trouble. Sorry to hear about your MG2. I pick mine up tomorrow.
See you in Edmonton.
R.M.
I agree with drilling the heads off. By relieving the tension, it could very well loosen things up. If not, maybe you could get a pair of visegrips on the stubs, after getting some penetrating oil at the threads.
Hope you get it without much more trouble. Sorry to hear about your MG2. I pick mine up tomorrow.
See you in Edmonton.
R.M.
Thoughts on drilling the screws
Thanks to all who suggest drilling the screws. However, if I drill the head of the screw off, then I'm left with just the threaded body of the screw in the tapped hole. It is the threaded body of the screw that is frozen in the tapped hole. I really doubt that any significant portion of the body will protrude above the barrel housing. The cover plate that the screws are retaining is less than a millimeter in thickness. At best, there will be less than a millimeter protruding and that portion will be weakened by the countersink portion created by the tip of the drill, no? This is only an M3 screw after all. If I drill the screw head off, I really expect I will have to drill out the body of the screw, too.
For the moment, I'm giving up on removing the screws and consequently abandoning experimenting with the weights and springs. I can still shoot the gun as it is.
Mike T.
For the moment, I'm giving up on removing the screws and consequently abandoning experimenting with the weights and springs. I can still shoot the gun as it is.
Mike T.
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Guest
Mike,
I think you will find that the head of the screw is supplying all the resistance to the removal of the screw.
The screw head can be safely drilled off with no damage at all to the parent material.
As you are a little concerned about doing this, a specialist machine shop would be the best bet.
They will be able to centralise on the screw and feed slowly to ensure no damage to the shroud.
There will be clearance between the two at the start of the threaded portion.
I think you will find that the head of the screw is supplying all the resistance to the removal of the screw.
The screw head can be safely drilled off with no damage at all to the parent material.
As you are a little concerned about doing this, a specialist machine shop would be the best bet.
They will be able to centralise on the screw and feed slowly to ensure no damage to the shroud.
There will be clearance between the two at the start of the threaded portion.