Help! Need Ideas - Coupler Conundrum

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TheTank

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Ill all went wrong when i was using my Nosecone and coupler/shoulder for weight to keep my booster balanced in the stand. I stupidly had the rocket pitched up when I went to remove the nose cone and coupler slid out of the nosecone and down inside the booster and is stuck (friction stuck… no glue).

I’ve tried the “gravity” method of putting the rocket upside down and bouncing it off the floor/plywood/foam…no .

I’ve inverted the rocket and tapped around it outside with a rubber mallet hoping to get it to straighten and drop…. No movement…

Motor mount is installed and it slid past the end of the motor mount so i cant try to tap it out from the back side… i also dont think there is room to get a puller in there (more than a single hook) with the motor mount there…

This isnt my first rodeo but im running out if ideas… Before i leave it in there and get another coupler… any ideas to try?

Thinking of flushing water down in there to see if it will help (parts were washed so there should be minimal dust as it is) but not sure if that would do anything. Coupler was a loose fit before it slid and got stuck.

Details: Booster - 6” x 50”
Coupler: 12” long
Coupler is 27” down from the top of the booster…
 

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Kelly

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Can you bend little hooks on the ends of a couple pieces of coat-hanger wire (or similar), thread these down between the coupler and MMT, and pull it out?
You might try some heat on the tube as well, applied from the outside (hair dryer?), to get a bit of thermal expansion.
 

TheTank

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Can you bend little hooks on the ends of a couple pieces of coat-hanger wire (or similar), thread these down between the coupler and MMT, and pull it out?
You might try some heat on the tube as well, applied from the outside (hair dryer?), to get a bit of thermal expansion.
I havent tried wire hooks but i pinched a washer between two nuts at the end of a piece of all thread and was able to pull on the back lip with no success. That said, the piece of all thread I had was only long enough where i had to put my whole arm in the tube. Im going to grab two full length pieces today to make two “hooks” to not have my arm in the tube and be able to pull on two sides while maybe having someone tap the outside of the tube with a rubber mallet. May try a hair dryer for some expansion too per your recommendation above also. May have to wait until after the weekend as I need to prep tonight and leave for NARAM tomorrow. Cant believe how locked in this is from gently sliding down the tube. While I hate to buy another coupler if I cant get this out… it wont cause any harm where it is and the added weight would be minimal as this thing will be 50lbs on the pad…. But i would like to try everything i can think of at least.

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Kelly

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I havent tried wire hooks but i pinched a washer between two nuts at the end of a piece of all thread
Oh now we're getting somewhere. Get TWO lengths of all thread (or more, if you can). To pull on the allthread, use another nut and washer bearing against the open end of the tube, and tighten the external nuts gradually, going back and forth. (Maybe this is what you were already doing?) You should be able to exert as much force as you need. If this doesn't get it, it's not coming out.
 

G_T

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Place a plate of plywood on the end of the tube. Hit that plate solidly with a dead blow hammer. Have a helper catch the launched tube. Repeat until the coupler creeps out (of the tube, silly). You'll get much higher acceleration on the tube this way than banging on the floor where you have to be more gentle.
 

G_T

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Or if you want to be lazy, put strips of duct tape on opposite sides on the inside of the coupler. Rub down for a solid grip. Have them long so they come off on a shallow angle. Pull on those evenly. If that isn't strong enough, use fiberglass reinforced strapping tape. Get lots of adhesive contact area, and put a balsa stringer across to keep the tape against the tube at the top end of the coupler so it won't pull off readily.
 

TheTank

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Oh now we're getting somewhere. Get TWO lengths of all thread (or more, if you can). To pull on the allthread, use another nut and washer bearing against the open end of the tube, and tighten the external nuts gradually, going back and forth. (Maybe this is what you were already doing?) You should be able to exert as much force as you need. If this doesn't get it, it's not coming out.
Great minds think alike. I was going to do exactly this with 3/4 pieces of all thread and a ply plate up top to tighten down with wing nuts and washers. That said, i think 36” 1/4-20 all thread is long as I can get locally that I know of… not sure if that will reach long enough to come up and out of the body tube.
 

les

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not sure if that will reach long enough to come up and out of the body tube.
You can buy couplers for the 1/4-20 all thread. That will allow you to connect 2 pieces together (72" total length)
 

TheTank

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Got all the items I need to build a custom pulling system... but trying will have to wait as I am off to NARAM for the weekend. Fingers crossed that it works when I get back!
 

TheTank

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Happy to report…. custom puller worked flawlessly! Couple turns on the wing nuts was enough to pop it free. I then laid the rocket down and pulled it the rest of the way out easily as I pulled the puller out so the coupler didnt fall back in!

Used 1/4-20 all-thread with couplers to make 4’ lengths (since all I could find was 3’, 2’, and 1’ lengths). 1/4” ply “cap that i rough cut on the band saw after marking the tube diameter. I marked and drilled 3 1/4” holes 120 degrees out, inset 5/8” to account for tube thickness and washer diameter. Dropped the rods in roughly aligned with the fins, slid the cap on. Dropped washers on and ran down the wingnuts until they got close, the pulled the rod up until the washer engaged the coupler and snugged it just enough to hold it in place then repeated for the other two rods.

Once all snugged, 1/2 turn on each wing nut at at time, changing the sequence up until it popped. I changed the tightening sequence assuming the tube was mis-aligned causing it to get stuck, so i wanted to vary which rod had the pressure on to possibly straighten it.

10 minutes to build the rig… 5 minutes to install and pop the coupler out. Hopefully this helps others down the road.

Thanks for the help fellas.

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