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How to get coupler out of nose cone (big FWFG cone).

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How do I get this coupler out (in a hurry)?

  • Try to tap it out gently with a hammer.

  • Use the claw end of a hammer and/or a crow bar and try to jerk it out.

  • Try to get a piece of wood in there and try to tap it out.

  • Heat it? Freeze it? Some combination of both?

  • Have someone hold the cone while I pull and twist (may be too tight for that).

  • Other?


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Bat-mite

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I really screwed up. Not going to go into it, but I am now worried that my Formula 200 will not be ready for LDRS, even though I have been working on it since July. :facepalm:

My major worry right now is that I have to get the coupler out of the nose cone. It has been in there for months, and it is EXTREMELY tight. No glue, just friction.

Check a box, or chime in with other ideas. Thanks.
 

Banzai88

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I did that with a formula 54. I put the assembly in the freezer and left it for a while. Once it was full frozen, I filled the sink with water as hot as I could stand it. Out of the freezer, nose ONLY into the hot water held by the coupler. It loosened just enough to pull like a mule and came unstuck. Next time around it went together with rocketpoxy for life.Good luck.
 

Bat-mite

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This is WAY to big for a freezer, but it is below freezing outside at night right now. Not sure how I would get enough hot water to stick it in. Bathtub, perhaps. Thanks.

Keep 'em coming!
 

djkingsley

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John,

Using the claws on a hammer of pry bar is going to put an uneven force that will likely make the problem worse. I have a gear puller that I can flip the hooks to the outside that might work. I would put a heavy centering ring in the nose cone to push off of.

This is a 2 jaw version of the gear puller I have, you just unscrew the jaws and flip them to get external lips.

2-jaws-gear-puller-3-.jpg

here is a sketch of what it would look like, the gear pullers are about $30 and you would need one that is pretty wide.

Puller.png
 
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patelldp

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Hold cone under non-dominant arm, then using dominant arm pull at a single point on the cone. Work your way around in 15-20 degree steps. Won't feel like you're doing anything, but eventually you'll feel the movement.
 

rms

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Perhaps a slide hammer with a flat "panel hook" to catch the furtherest inside coupler edge. Don't try to get it all at once but work your way around the coupler. Probably better done with two people.
 

Bat-mite

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Perhaps a slide hammer with a flat "panel hook" to catch the furtherest inside coupler edge. Don't try to get it all at once but work your way around the coupler. Probably better done with two people.
I have no idea what a slide hammer or a panel hook are. Got a picture or a link?
 

rms

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link to an image of a panel hook wouldn't work :eyeroll:
 

ActingLikeAKid

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Not necessarily cheap, but might work:
1. Acquire a chunk of tubing that fits the OD of the coupler. (Theoretically, you could do this with the airframe if you were careful and patched the holes. Or just pre-drill the vent holes....)
2. Put the tubing on the coupler.
3. Drill at least 3 holes through the tubing and the coupler; the bigger the better (a large diameter hole will spread the force better)
4. Install soft bolts (e.g. plastic) or dowels into the holes.
5. Get a wooden stake that's longer than the whole assembly. Bang the stake into the ground.
6. Put something soft on the top of the stake (like a blanket) to protect the nose cone.
7. Slide the nose cone, coupler, and tube assembly onto the stake.
8. Holding the tube, GENTLY tap the whole thing down so the top of the wooden stake bonks against the inside of the nose cone.

Variation 1: Depending on how much coupler is sticking out of the nose cone, you could try doing this by just holding onto the coupler.

Note: If the coupler is COMPLETELY inside the nose cone, you could do this with a piece of tubing that fits the ID of the coupler, you'd need to epoxy it though.
 

ActingLikeAKid

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Another idea: If you don't care about losing the coupler, go in with a Dremel and grind away in a line until you've gone all the way through the coupler. Then you can squeeze the coupler with a clamp and it could slide out.
 

Bat-mite

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Another idea: If you don't care about losing the coupler, go in with a Dremel and grind away in a line until you've gone all the way through the coupler. Then you can squeeze the coupler with a clamp and it could slide out.
Definitely want to keep the coupler!
 

rstaff3

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Not necessarily cheap, but might work:
1. Acquire a chunk of tubing that fits the OD of the coupler. (Theoretically, you could do this with the airframe if you were careful and patched the holes. Or just pre-drill the vent holes....)
2. Put the tubing on the coupler.
3. Drill at least 3 holes through the tubing and the coupler; the bigger the better (a large diameter hole will spread the force better)
4. Install soft bolts (e.g. plastic) or dowels into the holes.
5. Get a wooden stake that's longer than the whole assembly. Bang the stake into the ground.
6. Put something soft on the top of the stake (like a blanket) to protect the nose cone.
7. Slide the nose cone, coupler, and tube assembly onto the stake.
8. Holding the tube, GENTLY tap the whole thing down so the top of the wooden stake bonks against the inside of the nose cone.

Variation 1: Depending on how much coupler is sticking out of the nose cone, you could try doing this by just holding onto the coupler.

Note: If the coupler is COMPLETELY inside the nose cone, you could do this with a piece of tubing that fits the ID of the coupler, you'd need to epoxy it though.
This is a better variation of what I was going to say and it what I'd have done....at least before I asked.
 

mpitfield

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I did that with a formula 54. I put the assembly in the freezer and left it for a while. Once it was full frozen, I filled the sink with water as hot as I could stand it. Out of the freezer, nose ONLY into the hot water held by the coupler. It loosened just enough to pull like a mule and came unstuck. Next time around it went together with rocketpoxy for life.Good luck.
Hold cone under non-dominant arm, then using dominant arm pull at a single point on the cone. Work your way around in 15-20 degree steps. Won't feel like you're doing anything, but eventually you'll feel the movement.
My initial thought before getting too exotic and or investing in tools would be trying one of the two techniques listed above. If you don't have a freezer big enough, maybe a friend or neighbour has one or you might be able to approach either a restaurant or local grocery store to use the walk in and you just bring a tub to fill with hot water.

I have never had a coupler stuck to the point where I needed to do anything more than the techniques pateldp mentioned. Possibly if it has a removable nosecone tip then you could get a dowel down there and bang it down from the top walking around the edge using the same process.

Good luck
 

Bat-mite

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My initial thought before getting too exotic and or investing in tools would be trying one of the two techniques listed above. If you don't have a freezer big enough, maybe a friend or neighbour has one or you might be able to approach either a restaurant or local grocery store to use the walk in and you just bring a tub to fill with hot water.

I have never had a coupler stuck to the point where I needed to do anything more than the techniques pateldp mentioned. Possibly if it has a removable nosecone tip then you could get a dowel down there and bang it down from the top walking around the edge using the same process.

Good luck
Dan's technique will be my number one. Number two will be to try to pull on it while my wife holds the other end. Number three will be to freeze it.
 

ActingLikeAKid

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A related laugh, one of my favorite bits from Car Talk:

Caller says the glove box in her BMW won't open. The guys start making the basic suggestions like whacking the lock mechanism and in the background you hear "Tried that...."
"Who's that?"
"Oh, that's Larry. I asked him for help too."
...they suggest the other usual suspects (liquid wrench, reaching underneath, etc) and "Larry" says he's tried all of it. So their final suggestion....
"OK, try this one, and if Larry's tried this, we don't know what to tell you. Go to your local BMW dealership. Tell them you have some special Bosch spark plugs that you ordered from Germany that you need them to install for you. Tell them the spark plugs are in the glove box. They will never admit that there was a problem. When they call you to tell you the plugs aren't there, apologize profusely, pick up the car, slip them a 20 for their trouble, and tell them you'll come back when you find the plugs."
 

cavecentral

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I've hung parts from ceiling of my garage and pulled down before. Easier than tug of war with someone.
 

nh4clo4

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Is it a metal tip?

I had a similar issue once and was able to insert a dowel from the top of the nose cone and tap on the shoulder of the coupler to push it out.

edit: Oops. Just realized someone else suggested that already...
 

Bat-mite

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Is it a metal tip?

I had a similar issue once and was able to insert a dowel from the top of the nose cone and tap on the shoulder of the coupler to push it out.

edit: Oops. Just realized someone else suggested that already...
It is. I'll consider that.
 

crossfire

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Call Wildman Tim he will have the answer to help you out.
 

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I've had success using canned air for keyboards. Turn the can upside down and frost the inside of the coupler only, it should contract away from the warmer nose cone.
 

patelldp

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Dan's technique will be my number one. Number two will be to try to pull on it while my wife holds the other end. Number three will be to freeze it.
Also consider friction fitting your payload tube onto the coupler tightly and 3/4 of the way engaged, then adhere it further with some duct tape to the exposed coupler. Use that extra length for better mechanical advantage.
 

Bat-mite

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Also consider friction fitting your payload tube onto the coupler tightly and 3/4 of the way engaged, then adhere it further with some duct tape to the exposed coupler. Use that extra length for better mechanical advantage.
Me like. Will let you all know something tomorrow.
 

michigander

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Is it a metal tip?

I had a similar issue once and was able to insert a dowel from the top of the nose cone and tap on the shoulder of the coupler to push it out.

edit: Oops. Just realized someone else suggested that already...
+2 been there done that , tap around edge
 

Bat-mite

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Well, I tried everything I was willing to try last night, and that sucker would not budge under any circumstances. So, I am starting a new thread on where to go from here. Look for my new thread entitled "What should I do now?" in the Techniques forum. Thanks.
 

redleder

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What about liquid nitrogen touching the tip of it?


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3stoogesrocketry

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Well, I tried everything I was willing to try last night, and that sucker would not budge under any circumstances. So, I am starting a new thread on where to go from here. Look for my new thread entitled "What should I do now?" in the Techniques forum. Thanks.
John I have your solution . This will sound kinda weird but it works . Unscrew your metal tip and insert a eye bolt sticking out of the end of the nose . You will then want to insert a bulkhead with a hole in it the diameter of your eye bolt and secure the eye bolt with a nut . Find a hard point to secure the cone to , I wrap a section of 1/2 tubular kevlar around a tree , something solid . Then using either rope or gorilla tape , secure two ratchet straps 180 degrees apart around you couple . Then find another hard point , around another tree , and tighten up the straps . Once you get everything tight , use a small rubber hammer and tap the outside of the nose cone covering the coupler . I've had couplers so stuck that there is enough force to pull each part several feet in each direction after they slid apart . This will work .

Eric
 

Bat-mite

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John I have your solution . This will sound kinda weird but it works . Unscrew your metal tip and insert a eye bolt sticking out of the end of the nose . You will then want to insert a bulkhead with a hole in it the diameter of your eye bolt and secure the eye bolt with a nut . Find a hard point to secure the cone to , I wrap a section of 1/2 tubular kevlar around a tree , something solid . Then using either rope or gorilla tape , secure two ratchet straps 180 degrees apart around you couple . Then find another hard point , around another tree , and tighten up the straps . Once you get everything tight , use a small rubber hammer and tap the outside of the nose cone covering the coupler . I've had couplers so stuck that there is enough force to pull each part several feet in each direction after they slid apart . This will work .

Eric
This sounds really promising. But I have some questions.

I'm not following you about securing the ratchet straps to the coupler. I assume you mean the outside of the coupler? I can't imagine any kind of tape holding them on with the amount of force that will be required to separate the pieces. And I can't picture how you would do it with rope.

Also, the eyebolt. Wouldn't it have to be really long, like three feet? Do they even make a 1/4-20 eyebolt three feet long?

If you see my other thread, you'll note that there is a lot of epoxy gunking up the inside of the coupler, and I can't slide the bulk plate in very far.

Do you have a picture or can you provide more details? Thanks.
 

blackbrandt

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You could use a thread coupler and a piece of all thread to extend the eyebolt.
 
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