Spring Straps

[wetman]

I was just curious about the restrictor string that i'm sure we've all been made aware that is aboslutely necessary to put in the spring to keep it from over extending and becoming unsprung.

Has anyone actually tried that? I bought a bunch of springs last year and faithfully put my little restricto-string in there without a second thought.

However, i was just bored and put a pair of springs on a set of my backup fins for fun. I dont believe there is any way you could unspring the standard mcmaster-carr springs without doing it absolutely intentionally. Thos things are rock solid. I've got a single extra spring here that i clipped on something and pulled. It took a stretch of about 3 times the lenght of the spring before it was unsprung. That is not realistic in every day use. It got to the point where i was getting scared that it would give. I think that string is redundant. And if you pull it far enough to deform the spring, then you're abusing your gear.

Anyone else tried this?

steve

[el-ninio]

[However, i was just bored and put a pair of springs on a set of my backup fins for fun. I dont believe there is any way you could unspring the standard mcmaster-carr springs without doing it absolutely intentionally. Thos things are rock solid. I've got a single extra spring here that i clipped on something and pulled. It took a stretch of about 3 times the lenght of the spring before it was unsprung. That is not realistic in every day use. It got to the point where i was getting scared that it would give. I think that string is redundant. And if you pull it far enough to deform the spring, then you're abusing your gear.
]

I'm not convinced that the test was fair. when you actualy use the springs, you may pull just one side, or worse, you may pull a small part of one side, and then you hit deformation much, much faster.

if the spring still has a "good" part, you can try and deform it by pulling on just a part, and seeing what happens.

BTW, how did you connect the springs to the fins? I have a working prototype, from a thermoplastic material that will go soft in boiling water, and is still benable at aboout 40 deg C. it's grate for a prototyoe, but if you leave your fins in the car, the plastic may bend way out of shape.

[wetman]

Well, i put on some steel toes , stepped on the center of it and pulled very hard. The part under the boot wouldnt have moved, it was just the sides that stretched. And i'm pretty convinced that the amount of force it took would be enough to damage the connection before the spring itself. It was far more force than i would subject the fins to at any time for sure.

Connections - nothing fancy, and nothing fancy is needed. This is your 10 dollar spring strap solution. Nothing more nothing less.



steve

[hockeymulder]

Well, I don't know how, but my roomate managed to overstretch his spring straps even with the cave line inside.

[wetman]

Where did he get his springs? The ones i'm using are the ones at mcmaster-carr. No idea what they're made of steel-wise but maybe not all springs are created equal?

steve

[hockeymulder]

i'm not sure where he got them. he got them as a ready made spring strap setup. i believe they maybe from fifth dimension up in seattle. he's got size 13 feet in addition to DUI rock boots. i don't know if that contributed to it or not.

[Brutus23]

Hello Wetman,

Where did you get the clevis' for the composite fins in your picture? I have a set of quattros and like your idea for spring clips

Thanks,
Brutus

[wetman]

Those can be had at Canadian Tire or whatever your southern equivalent for a hardware store would be. Its a 3/16 shackle ( at least, thats the only measurement thats on the package for them.

It was actually mddolson (whos on this board) who came up with that one. Thought it was pretty ingenius. Especially for him :)

steve

[pcscuba]

You can also get those shackles at Lowes or Home Depot for 2-3 bucks

[mddolson]

wetman bubbled: "It was actually mddolson (whos on this board) who came up with that one. Thought it was pretty ingenius. Especially for him "


No, just clever!

Ingenious would have been finding a way to make em PINK!

By the way is that a pair of spring straps on your Vollos, Steve?

Mike D

[wetman]

They have been relegated to backup duty. Hopefully NEVER to have to use them but just in case i drop a turtle into the drink, i'll have the ability to go down and get my precious shelled beasts... :)

steve

[Birdman]

I am using 60# test tackle cable as a restrictor for my DIY spring straps. Working well so far. Heavier test causes the spring to kink.

[pcscuba]

I tried out my spring straps this weekend, total failure! I used the springs from Mcmaster-carr which worked fine but my method of attaching them didn't work at all. I got the idea from www.cisatlantic.com/trimix/newspring/schultzspring.htm
He used stainless split rings. It wasn't near strong enough. I am going to use small stainless shackles and see how that works.

[wetman]

Theres really no nead for either. If you take a look at my picture above, all you have to do is basicallly clip the ring end of the spwing around the shaft of the supplied attachment on turtles or the shackle on the mares fins. You'll notice on my turtles though its not quite as neat as i had to clip off about an inch of spring to make them tight enough and thus made my own loop in the spring.

If you're having a harder time of doing that a pair of needle nose pliers would likely help by letting you pull it out a bit. I dont see any advantage in adding the split rings at all.

steve

[kramynot2000]

to attach my springs to my jets as a test to see if I liked the spring strap setup and I didn't have any problem. However, I later got to thinking that the rings weren't needed at all if I bent a new loop in the springs like Steve did. On my other set of jets I'll probably just do that and ignore the split rings.

I wondered about the line inside the spring as well since the springs seem to be really tough but figured it wouldn't hurt to put them in anyway.

[pcscuba]

I did bend new loops in my springs but to attach them to my jets, I would have to thread the spring through the existing hardware. I just don't know if that would be the best way to do that. I bought some stainless 5/32" shackles and attached them that way. It worked great but to each is own. :)

[Waterborne]

Here's a pic of my jets after my buddy used them last weekend. I told him there was no way they would fit his vulcanized rubber drysuit boots. He told me he was diving wet anyway. Then he brought them back and told me they didn't fit his drysuit boots. That is the standard McMastercarr spring and the cave line inside somehow broke. Anyway, I now have to replace the spring as it's too big to fit over my boots, not to mention it's deformed.

[el-ninio]

SCORE ResQ once bubbled...
Anyway, I now have to replace the spring as it's too big to fit over my boots, not to mention it's deformed.

untill you get the new spring, you could shorten the existing spring, and bend a new loop at the end. if the spring is not too deformed (and it's hard to see from your picture), it should work just as well.

[ifukuda]

I've recent purchased a pre-made spring strap kit for my jet fins. The C-shaped wire attachments really suck. I've bent the wires completely out of shape before I was able to get the straps to fit right.

There's got to be a way to attach these straps which does not involve bending a piece of hard wire with a pair of pliers. I searched around for squared u-bolts, but I couldn't find any that were thin enough to fit the machined aluminum end pieces (1/8" I believe). I'm trying to find a dive shop to order me 6 buckle JetFin assemblies, but I cannot find a ScubaPro dealer willing to go through the trouble for such a small order...

If any of you have come up with better (cleaner, less painful) ways of attaching this straps, please share.

[wetman]

Can you post a pic of what you currently have? Might help us see the issue.

steve

[el-ninio]

ifukuda once bubbled...
I'm trying to find a dive shop to order me 6 buckle JetFin assemblies, but I cannot find a ScubaPro dealer willing to go through the trouble for such a small order...

If any of you have come up with better (cleaner, less painful) ways of attaching this straps, please share.

You don't bave to get it from scuba-pro. they charge an arm and a leg for each such buckle. you can get identical ones for about a seventh opf the price from other companyes./ search google for DIY spring strups and you will see the catalogic number for the buckles avalable from some company called somthing like "Global". about 1$ a piece i think

[rstark]

Anyone have a McMaster part number for those shacles to fit the Quattros or Vollos? Also, did you have to bend them to get them over the knub?

[notabob]

You can also use stainless s-hooks instead of shackles. Your neighborhood Lowe's (or whatever home improvement chain you have in LA) should have them - that's where I got mine. Worked great on my Volos. Also, you will also have to file down the little nub on the inside surface of the strap post, but you already knew that :) Just don't think I saw anybody mention that in the thread so far.

-Roman.

[Scubaroo]

I have the part number, but I'm not posting it - they don't work well. You can easily twist the anchor shackle off the post on the fin, and then your "unbreakable" spring strap has come off. Kind of makes it pointless.

That was on a Cressi Space Frog, with a 1/2" stem with 3/4" button on the post, which is the standard dimension for this type of attachment AFAIK.

I tried the 3/16" shackle, which was the smallest SS they had.

[ifukuda]

el-nino,

The part number of the Global's JetFin buckle assembly is 53030. Unfortunately, the shops in my area didn't carry these either.

But, I did find out that Trident makes the same buckle assembly (for the Rockets). And for some reason, the dive shop seemed much less resistant to order from Trident than Global.

Until I get my buckle assemblies, I am using 1" eye-straps and 6/32" diameter bolts (purchased at local boating shop) to hold my fins together. So far, my makeshift strap attachements appear to be working well. But, I hope to change them ASAP because I do not like the fact that there are so many parts to this assembly (too many possible failure points).

[mddolson]

Scubaroo bubbled:" they don't work well. You can easily twist the anchor shackle off the post on the fin"


The secret is to clinch the shackle to close the "C" shape tightly around the T post. So it can't come off.

I went a step farther. Having a Tap and die set I threaded the shanks further so would fully tighten up. Then I deformed the protruding thread so the shank could not come loose.

Here's a picture of wetman's Volo's with the spring straps inplace.

He and I used the "Canadian Tire " 3/16 SS shackle.

Mike D

[Scubaroo]

mddolson once bubbled...
The secret is to clinch the shackle to close the "C" shape tightly around the T post. So it can't come off.Now why didn't I think of that? :)

Will have to give that a go. My first thought was that if you did this, the pin would no longer go through the smooth hole and mate up correctly with the threads, because it's been bent out of shape, but hey, you've got a photo to prove it works!

Now if only I hadn't screwed up and only ordered 2 anchor shackles instead of 4, I'd put them back on my fins!

[Allen42]

Can someone please point me to a set of detailed instructions for building some spring straps for my Quattros?

Some specific questions:

Which part number to order from McMaster-Carr? The only part number I find referenced is now obsolete, so what is the proper replacement?

I couldn't find the shackles referenced above at HD or Lowes... can anyone provide a brand & part # for these, or tell where in the store to look?

How long do I order the springs? Or will I have to size them to my feet/boot? If so, how much tension should the spring be under when in place?

Is cave line still the right answer for the restraint? If so, where do I buy just a bit of line? Is sometihng available from HD or Lowes for this? How long should the line be?

I love the idea, and am pretty handy.... I just need a few pointers.

Thanks,
-Allen

[Waterborne]

Allen42 once bubbled...
Can someone please point me to a set of detailed instructions for building some spring straps for my Quattros?

Some specific questions:

Which part number to order from McMaster-Carr? The only part number I find referenced is now obsolete, so what is the proper replacement?

I couldn't find the shackles referenced above at HD or Lowes... can anyone provide a brand & part # for these, or tell where in the store to look?

How long do I order the springs? Or will I have to size them to my feet/boot? If so, how much tension should the spring be under when in place?

Is cave line still the right answer for the restraint? If so, where do I buy just a bit of line? Is sometihng available from HD or Lowes for this? How long should the line be?

I love the idea, and am pretty handy.... I just need a few pointers.

Thanks,
-Allen


Allen, I just ordered some new springs from McMaster-Carr on Monday. The new part number is 3932K54. I got them today and they are indeed the same spring.

I made a set of spring straps for my Tusa Imprex fins using the same springs and a set of SS S-hooks from Home Depot. They have held up great although I primarily use my Jets for everthing now. I followed Ben's spring strap page for my straps. Excellent directions with enlargable pics as well.
Here's the link
http://www.giddins.net/scuba/spring_straps/

You can use either vinyl tubing or tubular webbing to cover the springs or what ever you like instead. I have done both and can't really tell the difference in the water, only cosmetically.

The springs from McMaster-Carr come in packs of three and they are eleven inches long. You will need to size them to your foot yourself.

Now for the cave line, yes it's definaltely a good idea. You can use use any decent strength braided nylon line. That's all that cave line is anyway. It should be available at HD or Lowes. I found out after taking my Jets apart to fix them, my cave line inside was not secured at one end like I thought it was. Hence the spring overstretching and the need for replacement. ( reffer to previous post in this thread for a picture) All you need is another inch or so of line past what it takes to stretch them over your boots to put them on. That works good for the other fins that I have done (and are secured at both ends :D) without overstretching the springs.

[Allen42]

Man, that was fast! The S-hooks look good. Anyone have thoughts on s-hooks vs. shackles?

[Waterborne]

The only thoughts I would have on S-hooks vs. shackles is that the S-hooks are easier to work with and replace. Also they were only 79 cents a piece at HD.

[ENikS]

Well after looking at all the posts here I thought I'll put my few cents too.
I've got the general idea and all the part numbers from Alex and Olga's page:
http://www.cyber-strategy.org/pers/FinStraps.html
They recommend 0.062" spring but I find it a bit too strong. Instead I've used 0.057". I didn't like how they attach spring to the fin so I kept looking. I wonted field replaceable solution and when I came across this thread I really liked the idea to use shackles.
http://www.scubaboard.com/attachment.php?s=&postid=311935

I've bent my shackles little bit more to get better grip around the attachment post and to reduce gap between screw holes. Made bolts out of shackle pins, but you can use any SS bolts of appropriate size. Little heat shrink tubing and here you go...

[ENikS]

Few more views

[ENikS]

Few more views

[wetman]

That heat shrinking gives that an excellent finished look. What diameter tubing is that ans where did you pick it up?

steve

[ENikS]

Home depot sells assortment of heat shrink tubes with 1/2 inch and I think 3/4 inch. The 1/2 inch tube fits perfectly over the spring. Another benefit of their tubes they are much tougher then electrical tubing. This photo is after about 30 - 35 dives. As you can see it can take abuse pretty well.
I think McMaster-Carr has them too but I don't know part numbers.

Eugene

[Kevin R]

I tried out my spring straps this weekend, total failure! I used the springs from Mcmaster-carr which worked fine but my method of attaching them didn't work at all. I got the idea from www.cisatlantic.com/trimix/newspring/schultzspring.htm

Steve's split rings seemed to attract line when he used them on our Tech I course. :) As will most other designs that have multiple line traps built in.

You need a bushing over the point where the spring attaches to the fin. Try this. Take a piece of 1/2" dia brass or delrin rod, lay it on its side and drill a hole the same size as the OD of the spring in the center looking down from the top. Now stand the rod on its end and drill a 1/8" hole through the center from end to end. Bend the last two coils in your spring 30 deg., and put it in the hole in the rod. Take a piece of 1/8" SS wire and run it through the rod and through the two bent coils. Bend the wire over each end of the rod and again into the holes in the fin where the factory pin was so that the wire forms a rectangle with the opening in the center of the hole in the fin. It will take some effort to get the wire to go into the fin. Now you have a bushing that won't trap line as easily and still holds the spring in place. I used clear plastic tubing that barely fits outside the spring in the heel area. Put this on before you install the other end.

I don't know how to do this with anything except Jetfins since I don't dive with anything else.

I havn't been able to pull apart my Mcmaster Carr springs and I don't have cave line in them. I have also never pulled out the attachment point. One other member of my dive team also uses this design without any problems.

Kevin