Author Topic: I think it moved! (Read 1979 times)

cannonmn · « **on:** September 09, 2009, 01:37:41 PM »

Here are some pix taken today during continuing restoration efforts on the Moffatt 12-pdr. breechloading howitzer. See attached slideshow, most should be self-explanatory. When it didn't open in the "open it" direction, I flipped it over and applied pressure in the opposite direction since getting any kind of movement is good in these situations. I think our total range of motion today was about 0.010 inches, so "I think it moved." The bad news is this range did not increase after a few such reversals, meaning possibly there's a solid steel blockage due to deformation and not just corrosion products.

I bought many cans of "PB Blaster" since that's the best rust-cutter currently available that I know of.

Fortunately I'm not in a big hurry, I spent two years (maybe 15 min. a day) to get the 3-pounder Whitworth open. Now I have better equipment and hopefully it will go faster. The press shown is 20-ton, air over hydraulic, and I probably took it from zero to 20 tons at least 50 times today. If there's some deformed steel in the breech mech., I don't think a 50 ton press will work any better, the deformed steel that's in an interference position will have to be removed.

http://s17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums44/?action=view&current=ae28bc6c.pbw

Double D · « **Reply #1 on:** September 09, 2009, 02:12:33 PM »

John,

PB Blaster is just barely better than WD-40. Try 50/50 Automatic transmission fluid and acetone.

I got this from www.nitroexpress.com and it came from some where else:

Machinist's Workshop Mag (tm)recently published some information on various penetrating oils that I found very interesting. Some of you might appreciate this. the magazine reports they tested penetrants for break out torque on rusted nuts. They are below, as forwarded by an ex-student and professional machinist. They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.

*Penetrating oil ..... Average load*
None ...................... 516 pounds
WD-40 ..................... 238 pounds
PB Blaster ................ 214 pounds
Liquid Wrench ............. 127 pounds
Kano Kroil ................ 106 pounds
ATF-Acetone mix..............53 pounds
The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Our local machinist group mixed up a batch and we all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price.
For further information:
http://forums.thecarlounge.net/zerothread?id=4547049

cannonmn · « **Reply #2 on:** September 09, 2009, 02:18:28 PM »

Thanks, I'll try the ATF/acetone.

jeeper1 · « **Reply #3 on:** September 09, 2009, 02:43:11 PM »

Is there anyway to slow or stop the slide show so I can see and study the pictures?

GGaskill · « **Reply #4 on:** September 09, 2009, 02:52:01 PM »

Putting the cursor in the image will cause reverse/stop/forward buttons to be displayed, at which point you should click the appropriate button.

KABAR2 · « **Reply #5 on:** September 09, 2009, 03:03:03 PM »

Cannonmn,

This may sound crazy but back when I was re-converting percussion conversions back to flint, I would plug the nipple and pour
tapping fluid down the bore and let it soak after a day or two I would put a wrench to the bolster and it would come off with out
any trouble, after 100 plus years of being there. if nothing else works you might give that a try.

subdjoe · « **Reply #6 on:** September 09, 2009, 03:46:18 PM »

You left Coke off your list.

KABAR2 · « **Reply #7 on:** September 09, 2009, 05:13:06 PM »

Cannonmn,

Can you get further back on the strap with the press? I think if you increase the length on the pivot point you will
increase your leverage. you might try moving back and forth it would increase the surface area you are effecting.

Allen <><

parmamoon · « **Reply #8 on:** September 09, 2009, 07:06:16 PM »

Cannonmn, what is the purpose of that pull ring on the bottom side of the breech? Could it possibly be a locking pin to keep the breech closed?

cannonmn · « **Reply #9 on:** September 09, 2009, 09:35:54 PM »

Quote

pull ring on the bottom side of the breech?

The ring you see is just the form the makers used for the head of the bolt on which the breech door is hinged. The actual breech plug is a truncated cone, according to what I've read. It sits on a bottom-hinged flap or door. The ring is the end of the hinge pin which enables the user to unscrew and remove it quickly with ordinary objects such as a sailor's marlinspike, so special wrenches aren't required.

Rickk · « **Reply #10 on:** September 10, 2009, 01:19:08 AM »

You might want to add "impulse" to the equation.

Get it in the press and then hit the steel plates that the press is pushing on with a 12# sledge hammer.

Impulse force rises theoretically upwards to infinity.

I remember trying to take apart the steering box in my Farmall tractor. We had been working on it for hours, using heat and a gear puller.

Eventually we managed to get it into a 10 ton press, with a 10 foot steel pipe added to the lever, and I was hanging from the end of the pipe (feet off the ground), and it still wouldn't budge. My buddy hit the top of the press (it wasn't hydraulic kind, but the kind with teeth and a gear, so the top of the pressing part is exposed) with a sledge hammer.

The box came apart first hit.

Rick

cannonmn · « **Reply #11 on:** September 10, 2009, 02:25:40 AM »

Quote

You might want to add "impulse" to the equation.

Thanks, yes you are correct impact is important. In the slideshow maybe later in it than you wanted to watch, you see a small sledgehammer and a hand and a block of zinc. I have hit the block of zinc maybe 500 times so far. Pretty soon I'll substitute a much heavier hammer and try that. Then you have to have protection over any part of the cannon that might get hit by a missed blow, or you'll damage it, which complicates things a bit. I tend to like to use a 50 lb. lead block as a hammer since if it hits in the wrong place on a steel cannon, it won't damage anything but the paint.

The worst feeling there is: Working to restore a valuable antique that has survived without damage for well over 100 years, and permanently damaging something on it. As Richard says, "bindere, dundat."

cannonmn · « **Reply #12 on:** September 10, 2009, 05:52:35 AM »

Hopefully it is permissible to ask this since it relates to BP cannons, specifically the one this thread is about.

Am thinking about upgrading presses to a 35T item, maybe the extra force will be what the doctor ordered, who knows. Am happy with the present 20T item, but need more force for some projects, especially current one.

Has anyone bought or used one of this particular HF model shown at link below? I like the idea of it, but frankly the vertical supports look a bit spindly to handle 35T unless they are other than mild steel. I suppose it wll work and not come apart or I dont' think HF would be selling it, but sometimes you just never know for sure. Whatever I get it has to be air over hydraulic, which takes about 5 sec. to go from zero to max pressure, the hand-pumped kind takes forever and wears you out as well.

http://ww2.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=95865

Double D · « **Reply #13 on:** September 10, 2009, 07:22:07 AM »

Slower is some times better, faster sometime passes the push stage and gets to the break stage real fast.

belt fed frog · « **Reply #14 on:** September 10, 2009, 07:33:11 AM »

have you tried leaving it at full press pressure for a while ? or packing the barrel with dry ice to get it to shrink the shoulder lugs a bit ?

back in the day i used to work Gov contract shop and at one time we were building APC torsion suspension assemblies that required the idler shafts be pressed in with high interference fit so we would run the air over Hyd press up to max and let it sit for a while and PUCHUNK the spindle would go in a bit , top out the press again and wait PUCHUNK it would go a bit further in until they were fully seated ,use of heat was verboten by spec.

GGaskill · « **Reply #15 on:** September 10, 2009, 12:44:30 PM »

Have you personally inspected that HF press? Besides the usual disclaimers, you really can't tell much from the ad. What is the thickness of the material?

I am not a doctrinaire anti-HF person, I buy stuff from them frequently and Chinese stuff is getting better almost every day, but I buy it in person so I can examine before purchase. Too bad there isn't a store near Alexandria.

KABAR2 · « **Reply #16 on:** September 10, 2009, 12:57:34 PM »

Their press's are not too bad, you might consider having another hefty chunk of steel welded to the cross piece

to stiffen it and keep it from bending. you may need to reinforce other welds here and there. I would do this either way

as the tool will last longer corner gussets welded in would greatly reinforce the top plate.

cannonmn · « **Reply #17 on:** September 10, 2009, 02:19:05 PM »

I know it moved today! The breech is now free of the strap-see slideshow.

I still like PB Blaster, note the dissolved rust pools in the slideshow, that was only from a short time of squirting today, of course, but it is a good idea to put down witness plates, I had one of wood and one of steel that was already in the rig. If a penetrant just penetrates and does not dissolve rust, it won't help with situations like this. PB dissolves rust, so the compressed rust that was keeping this thing from moving at all, ran out gradually until it was able to move under 20T. force.

The other thing to do when freeing anything up is to find an indicator spot, with the two surfaces which will change clearance when it starts moving. Find one where you can get repeatable measurements. That's what my pix yesterday showing the caliper used as depth gage were all about. If you take readings after doing a particular thing (hammering let's say) and you find a tiny movement, then hammering is productive, keep it up. Today after 1 hour the reading had changed 0.020, twice what it changed all day yesterday. In the next 30 min, it changed o.040 in., so I knew I was doing productive things by pressing, taking pressure off, squirt PB, press again, hammer it a few times, then repeat pressure cycles. The objective of the pressing and hammering is really to work penetrant down into the rust. Heating can help too, particularly heating and cooling, where penetrant is added right after heating, so the cooling sucks the penetrant into the crevices.

Now I have to get the breech door open, and it feels like it is welded to the barrel at this point, no movement at all.

http://s17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums44/?action=view&current=e32d3c7a.pbw

KABAR2 · « **Reply #18 on:** September 10, 2009, 02:39:13 PM »

Congratulations! on getting it off, what about an aluminum rod 2" dia down the barrel and some tapping ?

Cat Whisperer · « **Reply #19 on:** September 10, 2009, 02:47:22 PM »

PB Blaster is highly respected by most of the industrial maintenance folks I know.

Different things get disolved by different solvents, so it's good to have an arsenal.

Took me a while to recognize the zinc!

cannonmn · « **Reply #20 on:** September 10, 2009, 02:50:50 PM »

Quote

Different things get disolved by different solvents

One we haven't discussed is Break Free. I've had pretty good luck with that also. You have to look around to find it, only place I could find that carried it was WalMart.

cannonmn · « **Reply #21 on:** September 10, 2009, 03:00:26 PM »

Quote

what about an aluminum rod 2" dia down the barrel and some tapping ?

I'm thinking along the lines of some kind of shaft about a foot longer than the bore. Then I pick up the tube with forks and straps, by the breech so muzzle is down, with shaft entering the bore. Then drop it far enough so end of shaft whacks the inside of breech plug, but don't let go of it. Repeat as many times as needed. That's the same as a 1000 lb. hammer dropped from a few feet. Have to think a little more about the quick release-cutting a rope is a traditional way but of course primitive, I think I have an aircraft bomb shackle around somewhere that would work, since its job is to cut loose of a heavy load instantaneously.

Double D · « **Reply #22 on:** September 10, 2009, 03:11:26 PM »

It doesn't appear that you pentrants did much penetratrating. The "smoke", is that from dry ice? If so that's what broke it free.

Rickk · « **Reply #23 on:** September 10, 2009, 03:23:44 PM »

Only bad thing that I can think of that might happen doing it that way is that the breech might get expanded like a rivet and get tighter rather than looser. Aluminum as KABAR2 suggests would probably be OK as opposed to a steel shaft. Maybe with steel a block of wood or lead in between the shaft and the breech might be wise to use, at least at first, until it is obvious that more extreme measures are in order.

Thinking about penetrating oil, if you added oil and then hammered in a tight fitting ram rod of sorts, you may be able to gather enough hydraulic pressure to make the oil go into the problem area. Of course, some of it may squirt out into your face in the process as well.

While I am rambling, here is a radical thought... what if you closed the strap again and fired a few blank loads from it? At the very least it might drive any oil you have dumped in there deeper into the breech to bore interface.

If any of you drive a dually pickup and hate convincing the rear wheels to come off (they instantly rust themselves tightly onto the axle, just like the breech plug is rusted into the barrel), THAT I actually CAN help you with, as I do have a surefire technique for dealing with that

cannonmn · « **Reply #24 on:** September 10, 2009, 03:48:40 PM »

Quote

The "smoke", is that from dry ice?

That's where I've heated the breech area then squirted PB onto it, so it can get into cracks easier. Heat, squirt PB, let cool somewhat, then repeat about 3 times. Then do something else.

Double D · « **Reply #25 on:** September 10, 2009, 04:49:32 PM »

Then the heat did it on the same fashion that dry ice would.

gary michie · « **Reply #26 on:** September 10, 2009, 04:54:05 PM »

Hi

Ok up here we say if all else fails BLAST put a light charge in with a some wet ragges and lite it
gary

cannonmn · « **Reply #27 on:** September 10, 2009, 05:04:22 PM »

Quote

the heat did it on the same fashion that dry ice would.

Must be a problem with the sequence of photos, not sure, but today the only heating I did was after the barrel got free of the strap. I heated the hinge joint that holds the breech door on, since nothing in that area will move yet. I'd like to unscrew that pin with the ring on the end, but it won't move yet.

The cannon was made with tolerances/clearances between adjacent parts that seem way too tight. There isn't even room for oil or grease to go in, but water can seep in, cause rust, and lock it all up tight like it is now.

Double D · « **Reply #28 on:** September 10, 2009, 05:26:42 PM »

Not seepage, condensation, the same way it gets in inclusions in things like welded seamed tubing. It only need a molecule wide gap

cannonmn · « **Reply #29 on:** September 12, 2009, 12:59:43 PM »

Continued work today, remounting the barrel for the next operation. It was put on a stand that holds muzzle elevated somewhat. An aluminum plate in a small cylindrical positioning fixture was put on the inside of the breech in contact with the breech plug, as an anvil for striking with harder things. Wires led from both sides of this out the muzzle to make retrieval easy. A 4.5" OD PVC pipe one inch longer than bore was inserted to the breech, to protect the bore surface. A 10-foot by 2" dia steel shaft weighing about 100 lbs, or so it seems, was inserted and then used as a battering ram against the aluminum plate. Then some heating and cooling cycles, and of course, squirt penetrant wherever it might do good. No apparent movement of breech plug today.

Sorry no pix today, got too dirty and oily and didn't want to touch the nice camera. Maybe tomorrow.