Home Tournaments Calendar Weather Merchandise Sponsors

Go Back   Spearboard.com - The World's Largest Spearfishing Diving Boating Social Media Forum > Spearfishing Gear > All About Pole Spears & Slings

All About Pole Spears & Slings What is it about that traditional method of the early hunter/gatherers under the water? These devices are indeed interesting and effective.

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-30-2016, 04:06 AM   #16
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

BANDS - FAT OR SLIM?
So, I have given some thoughts to bands today.

I have some Primeline Small ID in different sizes here and would like to rig the spear with just one band (not a loop).

From a quick test the other day, I figured out I could pull around 44 pounds. Let's call it 40 pounds for the sake of argument.
Now, the thing is, you can obviously set up bands in many different ways to get you to 40 pounds. Like a fatter band stretched less or a thinner band stretched more.

E.g. going by the Primeline force calculator I compared these two:
13mm small ID rubber stretched 400% = 41 pounds of force
14.5mm small ID rubber stretched 300% = 39 pounds of force

(I am using conventional stretch naming here. Not Aaron nor Primeline's own}

Let's call it an even 40 pounds for the two. Am I right in assuming that the thinner one stretched more would be advantageous? I am thinking that since it would be cut shorter, it will have more "efficient band stretch" and push the spear over a longer distance before it goes slack.

I guess the downside is that bands stretched more have a shorter life time, right? But then again 400% is just about what most people say are still ok. And anyways, a single band would cost less than 5-8 bucks to make.
Attached Thumbnails
Click image for larger version

Name:	PRIMELINE SMALL ID BAND FORCE.jpg
Views:	225
Size:	98.2 KB
ID:	230198  
Diving Gecko is offline   Reply With Quote
Old 12-15-2016, 11:52 AM   #17
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

So, I have drawn up some connectors in a CAD program.
Just two quick screen shots here:



This is an early sketch, I have added a few more glue channels since then.

I went forward with my idea of running an internal safety lanyard between the metal parts on the inside of the CF tube. Also, I am trying to run an o-ring under some pretty crazy compression to hopefully give a little bit of a friction lock to reduce to the risk of the connectors unscrewing themselves in the water. I am also undecided about whether I want/need tightening flanges on the connector for a slim wrench.

I looked up as many polespears and their weights as I could and it looks like I am very close in weight to the Gatku 8' but my polespear is two feet longer.
The Headhunter has some good reviews on this board. It is 765g/1.7lbs for about 9' so also a very light spear. In comparison to the Headhunter my spear is app 110g/4oz lighter and 8'' longer.

So, my spear is indeed a lightweight, though not for a Japanese style one. I haven't even tried to save weight on the connectors, except a little on the front one. I think I will stay with it as it is and may draw up a Modular Weight that I can insert between the tubes. A piece of 250mm/10'' long SS316 will give me 400g/14oz more punch. Since this will be my first spear, it might make sense to do this so I can try different setups out.

Buoyancy wise, the volume of my spear is 505cm3. In saltwater (with a density of 1.025g/cm3) my spear would be ((505cm3x1.025g/cm3) - 656g) = 138g/4.9oz negative.

If others are interested here is a list I compiled mostly by reading through old posts here, asking around and checking manufacturers' websites:
  • Linghunt (1/2’’), 6’______422g / 0.93lbs
  • Linghunt (1/2’’), 7’______507g / 1.12lbs
  • Gecko DIY (Mine), 9’8''____656g / 1.46lbs
  • Gatku, 8’_______________670g / 1.48lbs
  • Linghunt (5/8’’), 6’______708g / 1.56lbs (app)
  • Barret Rods, 8’7’’________740g / 1.64lbs
  • Headhunter Predathor, 9’__765g / 1.7lbs
  • Riffe, 10’_______________993g / 2.19lbs (incl. rubbers)
  • Crist, 6’_______________1045g / 2.3lbs
  • Ray Odor, 6’____________1270g / 2.8lbs
  • Manny Puig, 8’3’’________1475g / 3.25lbs
  • Neritic, 10’_____________1551g / 3.42lbs
  • Billfish, 10’_____________1590g / 3.5lbs ('Fast' version)
  • Crist, 9-10’_____________1700g / 3.75lbs
  • Billfish, 10’_____________2040g / 4.5lbs ('Punchy' version)
(I'm not exactly sure on the lengths as some quote lengths with tips, some without)

Last edited by Diving Gecko; 12-22-2016 at 04:34 AM.
Diving Gecko is offline   Reply With Quote
Old 12-18-2016, 09:29 PM   #18
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

A note on the weights compiled above and some personal thoughts on it (spurred on just a tiny bit by Linghunt, too).

As we all know, Carbon Fiber is approximately one billion times better for anything. Actually, anything in the life. (And I should make a coffee mug and toilet seat in CF while I am at it).

But in this rarest of freak cases, the polespear, carbon fiber actually offers very little to no advantage, perhaps even a disadvantage. Yes, the very foundation of my world is shaking here, guys...
Thing is, as examplified in my own spear, when using even pretty thick CF tubes and stainless steel connectors the spear will still end up so light that you very likely need to add ballast to it later. (My spear is longer and lighter than most of the commercially available spears). So, unless you are setting out to do an ultralight, super long Japanese polespear, you could very well just stick to aluminum tubes with no other downside than you will have to spend less money. It is my own belief, that carbon fiber in polespears offer bling but not much more. (Hats of to bling, btw. I'll roll with that this time around).

I guess Aaron, John and the rest of the bunch are onto something with all that non-bling aluminum

BTW, if anyone have weights for more polespears I'd love to add them to the list. Ohara, Poseidon and the beefier Headhunter Piledriver would be good to have, too. I think not only DYIers but def also people looking to buy could benefit from such a list.

Last edited by Diving Gecko; 12-22-2016 at 10:53 PM.
Diving Gecko is offline   Reply With Quote
Old 12-22-2016, 04:28 AM   #19
Ren
Registered User
 
Ren's Avatar
 
Join Date: Jul 2015
Location: Carlsbad, CA Fri 6am-4pm, Sat 6am-2pm
Posts: 347
Re: Help Needed, DIY Jap Style Polespear

Quote:
Originally Posted by Diving Gecko View Post
BTW, if anyone have weights for more polespears I'd love to add them to the list. E.g. I haven't found any on the Riffe and the Neritic. Ohara, Poseidon and the beefier Headhunter would be good to have, too. I think not only DYIers but also people looking to buy could benefit from such a list.

Just weighed a Riffe CF 10ft spear with ice pick slip-tip, 12mm rubber (don't quote me), RSP Resting hook..

Came out approx 35oz or 2.19lbs (0.99 Kg ~> 1 Kg)



One thing I've noticed is that between a gatku nine'er and the riffe spear, both are ballasted differently and handle differently in the water. The riffe spear sinks slowly while the gatku drops fast (solid 1/2" aluminum rod and solid carbon reinforced fiberglass vs hollow plugged CF tube). That being said between a gatku and a riffe the default grip placement is different as well.


Linghunt Polespear Physics 101

Last edited by Ren; 12-22-2016 at 04:42 AM.
Ren is offline   Reply With Quote
Old 12-22-2016, 04:39 AM   #20
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

Quote:
Originally Posted by Ren View Post

Just weighed a Riffe CF 10ft spear with ice pick slip-tip, 12mm rubber (don't quote me), RSP Resting hook..

Came out approx 35oz or 2.19lbs (0.99 Kg ~> 1 Kg)



One thing I've noticed is that between a gatku nine'er and the riffe spear, both are ballasted differently and handle differently in the water. The riffe spear sinks slowly while the gatku drops fast (solid 1/2" aluminum rod and solid carbon reinforced fiberglass vs hollow plugged CF tube). That being said between a gatku and a riffe the default grip placement is different as well.
Ren, thanks a ton for that one - I just updated the list (which also has the new Neritic in there now).
Riffe is def a lightweight in that length, though I am sure it is still ballasted quite a bit as I think their CF tubes are thinner-walled than mine. Maybe their connectors are the ballast.
With the 400g ballast insert I am intending of having machined it puts me a tad above the Riffe in weight but well below the heavy hitters of Crist/Billfish/Neritic. I think that is actually quite good for my intended hunting grounds.

I am happy this list is coming together:-)
Diving Gecko is offline   Reply With Quote
Old 12-22-2016, 04:54 AM   #21
Ren
Registered User
 
Ren's Avatar
 
Join Date: Jul 2015
Location: Carlsbad, CA Fri 6am-4pm, Sat 6am-2pm
Posts: 347
Re: Help Needed, DIY Jap Style Polespear

From John's website (Linghunt Polespear Physics 101)
Attached Thumbnails
Click image for larger version

Name:	ling1.png
Views:	271
Size:	100.8 KB
ID:	230553   Click image for larger version

Name:	ling2.png
Views:	220
Size:	144.6 KB
ID:	230554  
Ren is offline   Reply With Quote
Old 12-22-2016, 05:00 AM   #22
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

Yup, it's easy doing volume calculations and mass and then figuring out buoyancy. I did that early on with mine. What I deducted, as my lightweight spear which is kinda in the middle in terms of diameter and it is not very negative, is that most spears will be quite negative in water. Put another way, they weigh 2-3 times as much as mine but doesn't have much more volume (sometimes less).
I don't know how that matters in real life - except a negative spear will help you shoot downwards and hurt you shooting up;-).
A neutral spear might help aiming a little.

I actually think that it is less of an issue and hard to do much about as buoyancy seems to be far down the ladder in terms of design parameters. Say you want the mass for punch and a spear that is not too thick (creates more drag) then you are bound to end up with a negative spear. Nothing you can do about it if you lock in the two first parameters.
Diving Gecko is offline   Reply With Quote
Old 12-22-2016, 07:33 AM   #23
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

Slight update.
I added flanges back to the connector parts but I am still undecided on the front adapter design for the injector rod. I might go for the shorter "bullpup" version in the first pic below. I think I will redesign it with a slightly more pointy front than it has now, though. I do like the other, slimmer version in the second pic a whole lot. It just looks a bit too much like a HH (though my shape is even prettier;-)).










O-ring Issues
John has been super helpful and he has pointed out that it's not easy using o-rings for friction locking. I have been thinking it over quite a bit - but sadly I can't do too much trial and error as I don't have a local machinist that I can do testers with - but I think John is right. To get an o-ring to work as a friction lot you have to have it compress to a fully square/rectangular cross section. If you don't, if there is not 100% compression on it, it will likely not offer enough friction. But to get that much compression means that the o-ring will "stick out" a whole lot from it's seat when in the relaxed position (when the pole sections are apart). The thing is, while rubber in all practicality is incompressible, it changes shape easily. And with an o-ring that protrudes way more than is normal you have a high risk of cutting/shredding the o-ring when you assemble the sections.

Perhaps moving the o-ring all the way down so it rests on the shoulder could be an option. And not using a traditional gland but rather a wedge shaped one, could possibly work. I will have to draw it up to help me visualize it and see if if it would help.

Otherwise, just teflon and wrenches;-)

Last edited by Diving Gecko; 12-22-2016 at 10:47 PM.
Diving Gecko is offline   Reply With Quote
Old 12-23-2016, 05:15 PM   #24
Linghunt
Registered User
 
Linghunt's Avatar
 
Join Date: Mar 2006
Location: Santa Rosa
Posts: 254
Send a message via Skype™ to Linghunt
Re: Help Needed, DIY Jap Style Polespear

Some pictures to help complete the Post threads concept, here is a joint I made for a Riffe pole back in early 2015 that was just a glue joint. He sent me the part so I could measure properly, i added picture of that part.

One trick since this was just a "1 of Part", I left the diameter of the part too big by .005" or so , last step was to assembly the part and then do a final pass on both sides to get proper diameter and also add to axial straightness. Matched the parts together as a set. Was this needed? probably not, but easy so why not.







Lots of different materials to select from for O-rings and styles, [ e.g. I use cross sectional CROSS O-rings on my Mares tirgger pins ]

Who says you have to use an O-rings...

There are many ways to do this thread locker feature, but the cost of complexity can be a factor.

Make the front to match the Headhunter Slip tip. I don't think they will care as long as you are buying their slip tip. I have made parts to match up to it per request, lots of divers just love that design and want nothing else. Drop a line to Brad or Rodney if you like. I've talked to Rodney a few times, super nice people there.

http://www.headhunterspearfishing.com/pages/contact-us
__________________
Later on -- keep your powder dry--

Last edited by Linghunt; 12-23-2016 at 05:18 PM. Reason: typos
Linghunt is offline   Reply With Quote
Old 12-28-2016, 01:02 AM   #25
azspearo
Spearboard Sponsor

 
Join Date: Aug 2005
Location: Mesa, AZ
Posts: 1,178
Re: Help Needed, DIY Jap Style Polespear

You can use a simple rubber plug stuck in the female end. Figure out the distance from the bottom of the female part to the end of the male stud after parts are joined. Add a couple thread lengths to the plug length and once screwed together the rubber plug will compress and add resistance.

Here is a set of adapters. The CF tubing failed on the male connector.
Attached Thumbnails
Click image for larger version

Name:	IMG_4228.JPG
Views:	224
Size:	131.8 KB
ID:	230653  
__________________
Aaron Crist
azspearo is offline   Reply With Quote
Old 12-28-2016, 01:12 AM   #26
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

Quote:
Originally Posted by azspearo View Post
You can use a simple rubber plug stuck in the female end. Figure out the distance from the bottom of the female part to the end of the male stud after parts are joined. Add a couple thread lengths to the plug length and once screwed together the rubber plug will compress and add resistance.

Here is a set of adapters. The CF tubing failed on the male connector.
Yeah, like a small disk sitting in the bottom of the female connector, right? I thought about that, too and should be a lot easier to do.
Diving Gecko is offline   Reply With Quote
Old 12-28-2016, 01:13 AM   #27
azspearo
Spearboard Sponsor

 
Join Date: Aug 2005
Location: Mesa, AZ
Posts: 1,178
Re: Help Needed, DIY Jap Style Polespear

Yep, you got it.
__________________
Aaron Crist
azspearo is offline   Reply With Quote
Old 06-11-2017, 01:59 AM   #28
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

Hey guys,
So... life, work, travels and all that jazz happened and this whole project took a backseat for a good while. But now I am back on it and my drawings are, supposedly, being looked over and coded for the CNC machine these days. Hopefully I will get some parts soon and assemble it all in time for my Okinawa trip in a month's time.

Shaft or No Shaft for Paralyzer?
My main goal is to make the spear very modular and flexible in setup, so I can try out different things. I will probably have a slip tip on it as my main setup, but for a shorter setup, I have a paralyzer I'd like to try out.
Now, obviously, the slip tip will be on a shaft but what about the paralyzer? Should I use a shaft or not for a paralyzer? Most of the pics I have come across have it right on the pole itself. Maybe because many of those spears are cheap and simple fiberglass poles.

My feeling is that I might put a relatively short shaft on it just to allow a little bit of flex and not have all the leverage go straight into the carbon pole as it would if the paralyzer was attached right to the pole itself. Something like a 7x200mm (9/32'' x 7.8'') shaft is what I have in mind now.
Sounds OK?

Last edited by Diving Gecko; 06-11-2017 at 03:08 AM.
Diving Gecko is offline   Reply With Quote
Old 06-11-2017, 02:08 AM   #29
Diving Gecko
Shooter & Shooter
 
Join Date: Nov 2014
Posts: 637
Re: Help Needed, DIY Jap Style Polespear

Changed To a Different CAD Software (still free)
As an aside, I think I may have mentioned the awesome free, powerful Onshape CAD software that I used for the designs and renderings above. Well, Onshape changed their minds and now their free version is almost useless as it is very restricted how many design files you are allowed to keep. Pretty annoying and a lot of people on various forums feel they got a shitty deal (though free...) having spent good time learning the program, recommending it to others and helping them learn it.
But Fusion 360 from Autodesk picks up the mantle beautifully and is now definitely the software to get. As a startup biz, it is free for at least a year. Very powerful and cloud based, too but I feel it is faster than Onshape. Perhaps the UI is slightly less modern than Onshape's but it is not far behind. It is made by Autodesk so tons of support behind it and there are already many tutorials on Youtube and elsewhere.

Remember, I have zero background in CAD or engineering and the only fancy software I am good in is Photoshop, so I don't think I had a leg up on anyone when getting into this. I am slowly learning and still have to watch a lot of tutorials, but it is all good fun and I can highly recommend anyone to give it a go.
I was able to import the files from Onshape in Fusion 360, too which was cool, so here are just a few more renderings - this time from Fusion. The carbon poles are shorter in the renderings - in real life, they will be about 4 feet each:





Here's a 310g (11 Oz) Weight Module in stainless steel for extra punch, with machined grooves for added grip:


Yeah, I still think I should move the o-ring seat down to the shoulder but for now, I will go with this and perhaps a small piece of rubber in the bottom of the female threads to work as a "compression friction lock".

I should have the parts in a 1-2 weeks and as long as the connectors thread together nicely, then I will be happy:-)

Last edited by Diving Gecko; 06-11-2017 at 03:13 AM.
Diving Gecko is offline   Reply With Quote
Old 06-12-2017, 02:22 PM   #30
Linghunt
Registered User
 
Linghunt's Avatar
 
Join Date: Mar 2006
Location: Santa Rosa
Posts: 254
Send a message via Skype™ to Linghunt
Re: Help Needed, DIY Jap Style Polespear

That new software produces a super nice tool finish. I was thinking about what tool radius you selected.

What diameter did you select? You calculated for water displacement in the design? I see the 11 oz counterweight.
__________________
Later on -- keep your powder dry--
Linghunt is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 08:24 AM.


The World's Largest Spearfishing Diving Social Media Forum Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright ©2002 - 2014 Spearboard.com