Spear Shaft Comparisons - Spring Steel VS 17-4 Steel
There are many ways to look at different spear shafts. You can compare different flopper styles, shaft length, manufacturers, or slip tips. In this post, we will be looking into differences in the type of metal used and the pros and cons of each. It should be noted that there are exceptions to every statement in this blog post. There are always options for custom work to be done, but most of it comes at a great expense, which comes as a result in having to change a mechanical production process in what is already a niche market.
17-4 Stainless Steel Spear Shafts
There are a wide range of options available for 17-4 Stainless Steel shafts. Probably the most common style, however, are the American notch shafts. These are a square notch shaft that fit into American style trigger mechanisms. You can also get these shafts as euro notched shafts. Euro shafts have a rounded groove that goes into European style spearguns. The third most common is the A.B. Biller Style spear shafts. Biller shafts only fit into A.B. Biller style spearguns. While that sounds limiting, there are a lot of those spearguns floating around in the world, as well as accessories for them.
Thickness and Thread
17-4 Shafts have a wider range of thread options and shaft thicknesses. Spear shaft threads can only be as thick as the shaft thickness. Standard thickness options for 17-4 shafts include 9/32” (7.1mm) and 5/16” (8mm). They can also be ordered in 11/32” and 3/8” for large spearguns. These thicker shafts are typically used for larger species, like large Tuna and Billfish. 9/32” spear shafts typically come with 6mm threads. 5/16” spear shafts typically are made with 5/16” threads, but the shafts can also be “necked down” to 6mm threads. This means these shafts can accommodate different slip tip options.
Flexibility
One of the big differences between 17-4 Stainless Steel Spear Shafts and Spring Steel shafts is that 17-4 is a much more flexible spear shaft. That means when a fish is struggling with a spear shaft it has been shot with, the shaft has more flex before it is bent permanently. The steel can take a shock or two from hitting a rock. The problem is that once the shaft is permanently bent, it is pretty much done. There are plenty of people that claim they can blend the shaft back, but the metal will always be weak in that place. The next big fish you shoot will bend that shaft right back again in the same spot.
Spring Steel Shafts
After 17-4 spear shafts, the next most common type is the Spring Steel Spear Shaft. Euro spearguns are really the only spearguns that accept these shafts. That means they have a rounded notch at the back of the spear shaft that only works with euro speargun trigger mechanisms.
Shaft Thickness
Most spring steel shafts only get manufactured in two thicknesses: 7mm and 7.5mm. As fas as slip tips go, pretty much every threaded euro shaft is just a 6mm thread. All slip tips that go with spring steel shafts have a slip tip base that fits 6mm threads. The only other difference is the size of the slide ring that goes onto the shaft. You need to buy the correct size slide ring. If the slide ring is too big, fish scales and flesh can cause the slide ring to not be able to slide on the spear shaft and cause the slip tip to not deploy effectively. If the slide ring is too large, it could pull right over the slip tip base.
Flexibility
One reason many divers love spring steel shafts is that they are rigid. These shafts do not want to bend. They are extraordinarily stiff for the thickness of the shaft. That means that a fish will have a harder time bending these shafts if it goes into structure. The issue with these shafts is that when they fail, they do not bend, they break. That is because these shafts are much more brittle than 17-4 spear shafts. It is unlikely that the shaft will snap, but it is possible and has happened to divers in the past. The worst part about gear failures is that they rarely happen on small fish. Failures occur most often when your gear is under maximum stress, usually with the fish of a lifetime on your spear.