Dressing Up A Scratched Cylinder Rod???

[Wayne County Hose]

Doug,

1 psi, but what about flow restriction? I.D. doesn't restrict pressure, it restricts flow. You can equate pressure (psi) and flow (cfm) to volts and amps. Pressure is like volts, you need it to operate. Flow is like amps, the more you have, the more potent it is.

Before you go spending a bunch of money on a 1" gun that still may not take this off....... I use......... I mean...... I know a guy who uses a snap-on 3/4" breaker bar with an 8' pipe. It has never failed me.... no..... I meant...... it has never failed him yet.

 

[Dougster]

Doug, 1 psi, but what about flow restriction? I.D. doesn't restrict pressure, it restricts flow. You can equate pressure (psi) and flow (cfm) to volts and amps. Pressure is like volts, you need it to operate. Flow is like amps, the more you have, the more potent it is.

Now Andy, don't make me come down there! Nobody is reducing flow here. You may be the rich, successful hydraulics guy here... and Lord knows I am the one eating generic peanut butter on "firm" bread sandwiches while sitting here in my freezing house because I can't afford heating oil... but I am still the 33+ year mechanical engineer with an extensive fluid systems design and testing background and about 16 books on the very topic of compressible and non-compressible flow through systems, nozzles and orifices sitting right behind me (although I may need to burn some of them soon to stay warm). The insignificant pressure drop I quoted you was at nearly double the flow my air wrench takes. The actual flow capacity of those "worst case" (i.e., cheap Chinese junk) 1/4" couplings is more than 30 SCFM at 100 PSIG without a crazy substantial pressure drop (i.e., 9 to 10 PSI). For expensive, Parker premium quality couplings, you can go up to an amazing 70 SCFM for that same 9-10 PSI pressure drop. I wouldn't, but you can. Personally, I wouldn't jump up to 3/8" pneumatic couplings until I got to at least 20-25 SCFM. I am at 6.1 SCFM.

Before you go spending a bunch of money on a 1" gun that still may not take this off....... I use......... I mean...... I know a guy who uses a snap-on 3/4" breaker bar with an 8' pipe. It has never failed me.... no..... I meant...... it has never failed him yet.

Well, for me, it goes back to that Valvoline oil change kid I told you about. With the biggest breaker bar he had, and with everyone cheering him on, he still couldn't remove the oil change plug on my GF's car. I took it off in about 1 second with my small air wrench on low power. It is all about the dynamic advantages of impact... and the fact that you can never have too many nifty, shiny tools (especially air tools!!!).

Dougster

 

[Wayne County Hose]

but I am still the 33+ year mechanical engineer with an extensive fluid systems design and testing background and about 16 books on the very topic of compressible and non-compressible flow through systems, nozzles and orifices sitting right behind me (although I may need to burn some of them soon to stay warm).

Dougster

Ahhhhhh, okay. I see the light now. So, you are the guy to blame when all this hydraulic junk coming out of these factories gives me and everyone else on here fits. And we're helping you? We should be throwing rocks at you, some of this junk out here. He-hee.


Hey Doug, what do you call mechanic with an I.Q. of 65?
An engineer.

How many engineers does it take to grease a car?
One if you hit him right.

Did you hear about the latest trick the engineers wife does with her arse?
She sends him to work.

What do you call an engineer with no girlfriend?
homeless.

And, how do you keep an idiot engineer in suspense?
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I just did.

 

[Dougster]

I just did.

Cruel Andy... Cruel!!!

Dougster

 

[Wayne County Hose]

Sorry Doug, I had to. You know that I wouldn't do that unless I liked you.

Hey, why aren't you out working?

 

[gemini5362]

.

Trust me, this 3/4" is a brute and I have full confidence in its ability to break loose that nut. But if for any reason it isn't enough, I have no problem ordering up the 1" version and even a second air compressor if needed. Been shopping for a second air compressor anyway... purely for greater flexibility & convenience... and this would be a good excuse to finally go for it!

Dougster

UHHH could we go back to that part of the post where you are worried about the cost of a new rod ? and the cost of the nut ?

Exactly how much is a new 1 inch heavy duty impact wrench and the heavy duty high volume air compressor just to drive it ?

 

[Dougster]

Sorry Doug, I had to. You know that I wouldn't do that unless I liked you. Hey, why aren't you out working?

Okay, I forgive you.

I am not out working because I've got no paying work right now. It was always my intent to take a 2-week "maintenance, repairs & upgrades" outage after the rockscape job... but that is now looking more like 3 weeks (or longer) by the time every last task will be completed. Everything is taking me twice as long as expected... mainly due to long lead times and family-related distractions. In any case, with winter and snowplowing season fast approaching, I purposely haven't booked any more tractor work. There isn't much going on out there locally anyway.

Dougster

 

[SPYDERLK]

I'll bet you have a 1/4" connector on your air gun, which has an i.d. of .2". I hope that your air gun does take this nut off for you Doug, but if it doesn't, let me know how that hat tastes. Do yourself a favor, take the air q.d. off and plumb the hose directly into the airgun. This will give you much more flow. Even though pb-n-j sandwiches is not a healthy diet alone, I would hate to see you supplement it with a dirty old hat.

Perfect! Dougster, you have what you need. The 3/4 if properly fed will do any tractor sized job and the mucho$ saved will keep your PB/J larder stocked for years. As suggested, plumb a short line from your accumulator tank to the gun. No connectors, largest fittings that will go in the hose. Use short bursts because the accumulator will drop quickly unless it really is a large tank. Even the little guns use 10CFM minimum - a 3/4 will use 30 or so.

Im not sure of your full setup - if you have workpiece fully restrained from turning a breaker bar will do it. If not, and the rod has enuf mass and rotational moment of inertia the gun will work by striking against its resistance to accelerate. Trouble is a rods axial moment is low and it willreactquickly to the impacts. In such case, a robust 1/2" may succeed where a 3/4 would fail because it gives quicker impacts at very comparable force at extremely low duration. So it doesnt spin up the rod as readily as the longer hard hits of the big gun. To realize the full benefit of the big gun it is more necessary to couple some hard mass to the rod as near as possible to the point you are impacting. When needed, I do this by boring a rod sized hole in a block of metal, and then cut it in half lengthwise. I then clamp it around the rod just snug in a vise with Loctite #638 retaining compound in the joint. Takes a bit of time to set strong but heat up to boiling can be used to speed it up and get near full strength w/i 24hrs. Then clamp the vise a little tighter and you have a vise well coupled to the rod to react against impact. A 2Dx2" joint should do about 4000Ft-lbs. After, the block can be split off easy. Loctite is strong in shear but not tension.
larry

 

[Dougster]

UHHH could we go back to that part of the post where you are worried about the cost of a new rod ? and the cost of the nut ? Exactly how much is a new 1 inch heavy duty impact wrench and the heavy duty high volume air compressor just to drive it ?

I can see that my business's budgeting system is confusing you. There are actually five separate line items in my Year Two budget for:

1) scheduled maintenance,
2) equipment upgrades,
3) equipment repairs,
4) capital spares, and,
5) tools.

The new rod is coming out of "repairs" while a new nut would have to come out of "capital spares"... not a good thing since that line item is very tightly funded this year for very specific items. Any and all tool purchases would come out of the "tools" line item" which already envisioned purchasing a new compressor and certain other new tools this coming year.

The new compressor I've been eyeing is a rebuilt and is only about $180.00... a real bargain. It's about the same capacity and specs as the one I own now, but it is better suited for jobsite work. I have no idea what a new 1" impact wrench would cost (along with a new 1" impact socket set). I'll cross that bridge if and when I come to it. Other tools I want would obviously have to be delayed.

Despite my good friend Andy's doubts, I think the 3/4" will work fine.

Dougster

 

[Dougster]

Perfect! Dougster, you have what you need. The 3/4 if properly fed will do any tractor sized job and the mucho$ saved will keep your PB/J larder stocked for years. As suggested, plumb a short line from your accumulator tank to the gun. No connectors, largest fittings that will go in the hose. Use short bursts because the accumulator will drop quickly unless it really is a large tank. Even the little guns use 10CFM minimum - a 3/4 will use 30 or so.

Actually, your numbers are raising a very good point here: We are talking apples and oranges. It appears you are talking instantaneous max flow (in SCFM I'm assuming) while I am talking average demand. Your numbers are clearly more relevant to hose size, coupling size and Andy's concerns. However, I can't honestly tell you that I know the maximum instantaneous flow specification for my 3/4".

And BTW, my remote accumulator is about two actual cubic feet (ACF) in capacity.

Im not sure of your full setup - if you have workpiece fully restrained from turning a breaker bar will do it. If not, and the rod has enuf mass and rotational moment of inertia the gun will work by striking against its resistance to accelerate. Trouble is a rods axial moment is low and it willreactquickly to the impacts. In such case, a robust 1/2" may succeed where a 3/4 would fail because it gives quicker impacts at very comparable force at extremely low duration. So it doesnt spin up the rod as readily as the longer hard hits of the big gun. To realize the full benefit of the big gun it is more necessary to couple some hard mass to the rod as near as possible to the point you are impacting. When needed, I do this by boring a rod sized hole in a block of metal, and then cut it in half lengthwise. I then clamp it around the rod just snug in a vise with Loctite #638 retaining compound in the joint. Takes a bit of time to set strong but heat up to boiling can be used to speed it up and get near full strength w/i 24hrs. Then clamp the vise a little tighter and you have a vise well coupled to the rod to react against impact. A 2Dx2" joint should do about 4000Ft-lbs. After, the block can be split off easy. Loctite is strong in shear but not tension.
larry

Let's pray it doesn't come down to this. I certainly understand your points, but my beloved little 1/2" impact wrench isn't going to do anything for this monster nut except waste time and compressed air. If the 3/4" won't do the job and do it well, perhaps it will be time to take it over to the expensive cylinder repair guy.

Dougster