mts0628
Contributor
- Messages
- 623
- Reaction score
- 6
I made a set of spring straps for my ScubaPro Jet fins today. I was going to buy a set for 50 USD but the shop that said that they could get them had a difficult time getting them in stock and more importantly for the timeline I wanted them. So, I did what I do best: improvise.
The tools used were a drill (I actually used a lathe but you can get by perfectly with a drill), a vise, drill bits of course, a pair of Irwin adjustable pipe pliers, needle nose pliers, a razor knife, a lighter, and some side cutters.
I used 4 sections of 3/4 inch diameter by one inch long Delrin rod. In each section I drilled 1/2 inch holes through the body on the x-axis to accommodate the spring, and a 7/64 inch hole on the y-axis to accommodate my 3/32 inch stainless steel welding rod. I also used McMaster Carr stainless steel springs, 1/2 inch diameter by 11 inches long. (I have XL fins and wear a size 9 Akona thick soled boot and the 11 inch spring was perfect!)
So after the Delrin rod was cut and drilled, I nipped the hooking ends off the springs. I then bent two coils down from each end. I did it like this because I didn't want the single preformed loop to become dislodged for whatever reason, but I also planned on running [safety spool] line through the spring so maybe I could have gotten away with it. I wanted the added security through.
With the welding rod I started with bending it to form an L. Then I bent the short L part down, to form an L on an L. It sounds confusing but the bottom line, after these two bends you're half way done with the side assembly. The hardest part was bending the wire rod to measurements. The bend lengths were 1/2, 1, 1, 1, 1/2- all inches. After the top part was bent, I inserted the spring with the line inside the Delrin and then threaded the rod through the assembly securing the spring and line to the Delrin rod. The first wire bends were on the bench vise but the latter bends were with brute force and pliers. I did put the assembly in the vise to square everything up and then rebent everything to final fit.
I added the nylon tubing to the spring and then repeated the above to finish the opposite side. It took me about an hour to do one spring strap mainly because I wanted to get everything perfect. Admittedly when I got everything to what I thought was perfect, I put the strap on the fin but the top and bottom bends were about an inch and a quarter so the Delrin was about 1/4 of an inch from resting in the groove of the fin. This not only looked ghetto but it made the fit ever so slightly loose. I removed the assembly and rebent the rod to a better fit.
Final comments: They look almost factory, aside from my bright yellow safety line which was extra from a spool that I removed it from. The estimated total cost was about 10 USD. The springs were about 6 USD (PN3932K54) and the Delrin was about 3 USD. I scored the 3/32 welding rod for free from a welding supply shop and the safety spool line I had laying around. I also had the tubular webbing around but you could get it from DiveRite or a climbing store on the cheap.
I drilled the 1/2 inch holes completely through the body to facilitate easy assembly. I had a set of Delrin slugs that was about half drilled and the spring and rod went together ok, but it was impossible for me to secure the safety line blindly. A through hole does not offer any disadvantages that I could think of but maybe someone can.
Good luck with your spring straps and feel free to email me if you have any questions.
And for those interested, I actually put spring straps on my Aqualung Blade II fins last year without issues. They have a different strap attaching assembly from the standard buckle- it uses the slot and T-post as OEM but the spring straps were easier to place than my ScubaPro ones. Anyway, happy building!
Nickel Rocket: take off!
The tools used were a drill (I actually used a lathe but you can get by perfectly with a drill), a vise, drill bits of course, a pair of Irwin adjustable pipe pliers, needle nose pliers, a razor knife, a lighter, and some side cutters.
I used 4 sections of 3/4 inch diameter by one inch long Delrin rod. In each section I drilled 1/2 inch holes through the body on the x-axis to accommodate the spring, and a 7/64 inch hole on the y-axis to accommodate my 3/32 inch stainless steel welding rod. I also used McMaster Carr stainless steel springs, 1/2 inch diameter by 11 inches long. (I have XL fins and wear a size 9 Akona thick soled boot and the 11 inch spring was perfect!)
So after the Delrin rod was cut and drilled, I nipped the hooking ends off the springs. I then bent two coils down from each end. I did it like this because I didn't want the single preformed loop to become dislodged for whatever reason, but I also planned on running [safety spool] line through the spring so maybe I could have gotten away with it. I wanted the added security through.
With the welding rod I started with bending it to form an L. Then I bent the short L part down, to form an L on an L. It sounds confusing but the bottom line, after these two bends you're half way done with the side assembly. The hardest part was bending the wire rod to measurements. The bend lengths were 1/2, 1, 1, 1, 1/2- all inches. After the top part was bent, I inserted the spring with the line inside the Delrin and then threaded the rod through the assembly securing the spring and line to the Delrin rod. The first wire bends were on the bench vise but the latter bends were with brute force and pliers. I did put the assembly in the vise to square everything up and then rebent everything to final fit.
I added the nylon tubing to the spring and then repeated the above to finish the opposite side. It took me about an hour to do one spring strap mainly because I wanted to get everything perfect. Admittedly when I got everything to what I thought was perfect, I put the strap on the fin but the top and bottom bends were about an inch and a quarter so the Delrin was about 1/4 of an inch from resting in the groove of the fin. This not only looked ghetto but it made the fit ever so slightly loose. I removed the assembly and rebent the rod to a better fit.
Final comments: They look almost factory, aside from my bright yellow safety line which was extra from a spool that I removed it from. The estimated total cost was about 10 USD. The springs were about 6 USD (PN3932K54) and the Delrin was about 3 USD. I scored the 3/32 welding rod for free from a welding supply shop and the safety spool line I had laying around. I also had the tubular webbing around but you could get it from DiveRite or a climbing store on the cheap.
I drilled the 1/2 inch holes completely through the body to facilitate easy assembly. I had a set of Delrin slugs that was about half drilled and the spring and rod went together ok, but it was impossible for me to secure the safety line blindly. A through hole does not offer any disadvantages that I could think of but maybe someone can.
Good luck with your spring straps and feel free to email me if you have any questions.
And for those interested, I actually put spring straps on my Aqualung Blade II fins last year without issues. They have a different strap attaching assembly from the standard buckle- it uses the slot and T-post as OEM but the spring straps were easier to place than my ScubaPro ones. Anyway, happy building!
Nickel Rocket: take off!
i doubt about the capability of the two bended sticks as it seem you are able to bend it easily with such perfect and straight. But I believe it just because you are having good skills to bend it perfectly. 
