Linghunt - Flopper Wing Install and Removal

Topics concerning flopper wings and pins installation, repair, replacement and tuning.

There are many different practices available concerning replacing or adding a flopper wing to a new shaft or tip. This section is for assisting divers with a basic understanding of the process with "How To" information.

A flopper wing will have many battles of fish, rocks, and just getting kicked around in use. Dealing with it is just part of the game. The tuning and performance of a flopper wing is SUPER important. I corrolate this to the fly fisherman who is always adding a new edge to his hook. The dangling sharpening stone on his vest is a hint of a fisherman on the TOP of his game.

Forming the pin properly in assembly and tuning the wing properly gets lost in the shuffle by many and overlooked unimportant as long as it doesn't fall off.

Others are adjusting the wings with precision, or at the least verifying it's doing its job correctly. These are the types that sharpen a fish hook that is sharp.

Properly tuned wings will provide improved results.

---------------------------------------------------------------------------

Orbital Cold Forming Basics:

This is what you are attempting to do when you are beating on the pin with your hammer in formal terms. Your understanding of this process will help you mount your flopper with your limited tools.

The goal in this process is to roll the edges of the pin over so the wing can't fall off. Some say it's super easy and just get a hammer. The same can be said for pounding nails. But to those of you that are framers (Pre-nailgun days) that it's a touch more than just hitting the nail on the head.

Here is a cross sectional picture as to what you are trying to do.

That's half the battle, note the rolled over edges of the pin that will prevent the wing from fall off. Some call this shape a mushroom.

Orbital cold forming, doesn't really sound the same as get a hammer and just hitting it.

Courtsey of "Handbook of Jig and Fixture Design" - 1989 - SME

Orbital cold forming is a line of contact process with low pressure (LIGHT Hammer strokes). There is an incline angle of 3-6 degrees where the tool axis intersects the axis of the pin. This process has an inportant advantage over other methods for it provides high quality results for strength and close tolerancing and a nice finish to boot. Negative aspect is it takes time to do. In an automated machine this could take a 3 - 5 seconds. By hand plan on 2 - 3 minutes.

LIGHT pressure, lots of little hammer strokes. I can't say this enough times.

Flopper pin forming vs riveting: Same processes going on here, but there is one big difference.

Installing a rivet in most applications, you are looking to hold the stock materials close together (Think of the rivets on a boat).

For the flopper wing you want the wing loose to move around. You want the pin to just hold the wing on the shaft. Some out there use the pin as part of the tuning process and install the wing tightly to the shaft preventing it from being free to float, I advice against that approach.

Installing a new pin with flopper:

Gather tools and parts at your anvil. Don't have an anvil? It's a low cost item that comes in handy for many jobs, might be worth it. A chunk of carbon steel from scrap yard is a great option. A piece of Railroad Track is a sweet pounding surface.
Verify the cross hole is properly deburred, a drill bit can be used to do this. you don't want a metal burr hanging up in the hole or on the wing.
Put the parts together and verify you got a LOOSE fit and wing opens up properly.
Set the head of the pin on the anvil. If you have round headed pins, you should drill a small hole in the anvil to act like a cup to hold the pin. A round nosed endmill is perferred tool for making a cup.
What you want to do is to lightly tap on the edges of the pin and keep doing it as you move around in circles with your small hammer. If you have a peening tool use that and the hammer.
HAMMER MODIFICATION: Take that hammer and grind the bevel off the edge of the hammer head. If you have a sharp edge to the head, you have more room to work the edge of the pin without hitting the wing. This modication will make your hammer more likely to chip a metal fragment off in normal use. Save this hammer for just doing pins and don't use it for other jobs. Hammer shards flying off can be DANGEROUS.
Think light strokes and plan on 200 or more of them to complete the job.
One big heavy SLAM is just going to bend the pin to the side wedge the wing so it's stuck and then your time will be spent getting the bent pin out of there to start all over.
The flopper wing should be loose to flop around still. The pin just holds the wing on the shaft.

Tuning a Flopper:

GOAL: When done, the flopper should be loose when it is next to the shaft. When the flopper is engaged OPEN [at 60 -80 degree angle to shaft], the wing needs to be STUCK in this position. If the fish moves down the shaft and then back to the wing, you don't want the wing to falling to the spearshaft so your fish can fall off the end.
There are edges to the flopper wing. Tap with hammer, use a punch, or use plyers to bend the wings edge. The edge to bend is next to the pin hole. This area that is in contact with the shaft in the OPEN Position.
This bent edge will not contact the shaft in axial CLOSED position. ( flopper loose )
When the flopper rotates to the engaged position this little bend will be on top of the shaft providing friction to hold the wing open.
CENTER PUNCH: dependent on which wing you have, but you can use a center punch to add an indent to the wing. Place the indent so it doesn't contact the shaft with wing closed and then it's in contact when wing is open. Open the wing to 80% or so and then add indent to wing on top of shaft for location.

NOTE the OPEN angle: 60 - 70 degrees as shown in the picture above

----------------------------------------------------------------------------------------------------------------------

Wing Tuning GONE BAD

NOTE: Tuning has nothing to do with the pin friction on a wing hole. It's important to rememder that pins ONLY Job is to hold the wing on the shaft.... the end is rolled/formed to prevent it from falling off.

The use of a hammer and screwdriver for tuning can be done at LAST resort, not your 1st option.

If you are needing a screwdriver to loosen a wing, odds are you bent the pin to the side or over pinged the pin and it's not a rivet vs a pin. Tuning a wing with a bent pin and distorted wing hole will drive you crazy on the process.

Why this is called a "best practice method", I have no clue. It is a common practice and promoted by some in this industry.

------------------------------------------------------------------------------------------------------

Wing Tuning Done Correctl

Here is a video of a properly tuned wing on a speargun shaft.

Courtesy of SpearDiver / Spearfishing World -- What a tuned flopper looks like -- Thread --

Courtesy of SpearDiver / Spearfishing World -- Tuning floppers -- Thread --

Ron Allen shows a nice concise video of how to tune. Note he doesn't use a screwdriver on the wing and a hammer on the pin. He deflects the shape of the wing near the pin hole.

A bent pin, REPLACE don't tune with a bent pin.

Flopper and pin REMOVAL for speargun shaft or spear tip:

Use a Grinder or file to remove the peened side of the pin. Try not to grind into the flopper wing if you are hoping to re-use it.
Try to remove the little metal burrs on the side of the pin post grinding/filing so the pin can just fall through the cross hole.
Flipping the shaft over and using the hammer on the head of the pin will push the pin out a little bit so you can clear edges easier.
A touch of oil or WD-40 can help.
Use a punch and try to knock it out if it's stuck. Clamping the shaft in a vice makes a good working platform. If the pin is just not moving, you can try to center punch to dimple the center of the pin for a drilling operation.
Slow and Easy, don't be in a big hurry. all you need to do is get the pin partially removed then you can get a grip on the head of the pin with plyers or other tools.
If you are having HELL, odds are the pin is bent in the hole and wedged in tight.
If you made a total mess of it, consider drilling a new hole for the flopper wing.

Miscellanous Information on pins and flopper wings

Cold and Hot forming operations produce different results.
TIG welding the ends of the Pin reduces the strength, Same for torches using hot forming methods. It's easier to do but you get a different grain structure. Just "Food for Thought".
Remember not all metal forming operations are the same. Peening, swaging and crimping are all different processes, thusly different names.
Over peening the pin and having to try to loosen it up is a Pain. Go slow with the hammer and take your time, 100's of tiny hits. If you are tuning your wing with a screwdriver, you are off the road into the ditch.
Removing a pin can be really tough at times. If the pin is bent in the hole and all FUBAR-ed on the end from attempted removal efforts. Your just going to have to get a drill to remove it. Proper alignment of drill and different types of drills comes into play.
Drilling holes is not hard if you have correct drill type, proper rpm, coolant and feedrate. There are many charts and guides for this. Doing it wrong and work hardening the work can make this a nightmare. See other section on cross hole drilling.
Non solid pins [hole drilled into them] out there might look easy, but without the poper peening tool you can have a weak connection.
Shooting into Sand: the sand can prevent the flopper from proper deployment and it can also wedge the flopper. Consider keeping the tip in the sand until you get control over the fish. Assuming it will not deploy with give you a better chance at not losing the fish.
Drilling an over sized hole in the shaft will increase your chances of having a BENT pin. This bent pin can make tuning difficult.

Tools:

Better tools the easier the job. Amount of tools in your box is mostly driven by how much you are willing to spend on them. Here are some of the common tools used out there.

Hammer, Anvil, Punches, Plyers, Chisels, Screw driver, Peening hardware, drill bits, Hand drills and Drill presses, Files, Holding fixtures, Vices, TIG welders, Oxygen-Acetylene torches, MAP Gas hand torches, and Safety Glasses.

A seasoned machinist model maker once told me, " Don't be scared to modify a tool to do the job you are working on." Grind that hammer or screwdriver. You can buy another one and use the modified tool for this purpose only. Modifing your purchased tools is less common than you might think. This doesn't mean to grind the end off your "Snap On" wrench, but buy a low cost wrench and flip the grinder on.

Safety Glasses always a good idea.	Specialized hammer with different heads
Ball Peen Hammer	Avils come in many sizes, It's nice to have something to pound on for many applications
Just a forming fixture with different dies	Everyone should have one of these
Lots of different punches out there	A fixture to hold Dies Misc forming hand tools
Some Peening tools for different applications	Typical Plyers
Forming / Peening tools	Forming Tool Head for Pins with centerholes