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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.

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Old 12-06-2017, 04:57 PM   #1
HurricaneBK
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Polespear Build - Titanium?

A friend and I have been toying around with the idea of putting together a couple polespears for use in the Bahamas. Looking at the cost of some of the high end spears on the market, and the fact that he has access to a very extensive machine shop at his job building a couple sounds like a fun challenge.

Jokingly I said we should just use a solid titanium rod and mount the injector to that and call it a day. Doing a search through Spearboard it looks like someone used to make/sell a titanium polespear but most of the links and pictures I found to it are over a decade old and dead. Have any builders made one recently out of titanium or incorporated it into the build as say a front section?

Something like a 1/2" solid rod like this

http://www.onlinemetals.com/merchant...7&top_cat=1353

Then have male and female threads machined into it - probably two 4' sections with a separate stainless butt and head section for the band and then the injector rod. Clearly a pricey build but when some of the high end polespears are retailing for $400 it might be fun to make a one of a kind one that's different.

Realistically we'll probably go with aluminum or cf, just something fun to think about and curious if anyone has experience making a polespear out of Ti.
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Old 12-24-2017, 05:50 AM   #2
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Re: Polespear Build - Titanium?

Titanium has some qualities that are interesting to put it mildly, but raw stock cost is pretty high.

In machining Ti, it's really hard on cutting tools, I'd rather cut 17-4 all day than this stuff.

Have your friend do his research on inserts and proper cutting angles for tool wear.

Good luck with build. I stay away from it myself.
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Old 12-29-2017, 01:35 PM   #3
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Re: Polespear Build - Titanium?

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Originally Posted by Linghunt View Post
Titanium has some qualities that are interesting to put it mildly, but raw stock cost is pretty high.

In machining Ti, it's really hard on cutting tools, I'd rather cut 17-4 all day than this stuff.

Have your friend do his research on inserts and proper cutting angles for tool wear.

Good luck with build. I stay away from it myself.
My thinking has kind of been in line with yours in that machining would be the hardest part. Any thoughts on just using an 8' rod (1/2") and just machining male threads at each end to screw on a butt and an injector mount to?

I like the idea of not having segments, it would fit under the gunnels with the gaffs so storage aboard isn't an issue, it would definitely be a pricey build.

I think the other more practical option if I really want to incorporate Ti is a cf build with a front length of Ti say 3 or 4 feet that's OD matches the ID of the cf tubing. Probably wise to get a few CF or Aluminum builds under our belts before working with Ti though.

Really love your site, you have a lot of cool builds and parts.
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Old 01-20-2018, 05:12 AM   #4
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Re: Polespear Build - Titanium?

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Originally Posted by HurricaneBK View Post
My thinking has kind of been in line with yours in that machining would be the hardest part. Any thoughts on just using an 8' rod (1/2") and just machining male threads at each end to screw on a butt and an injector mount to?

I like the idea of not having segments, it would fit under the gunnels with the gaffs so storage aboard isn't an issue, it would definitely be a pricey build.

I think the other more practical option if I really want to incorporate Ti is a cf build with a front length of Ti say 3 or 4 feet that's OD matches the ID of the cf tubing. Probably wise to get a few CF or Aluminum builds under our belts before working with Ti though.

Really love your site, you have a lot of cool builds and parts.

Just spotted your post. 2018 is flying by. Lots of ways to skin a cat as you know.

Go back a step or two, figure out what you really want for mass , length, balance. Type of band and stretch length. Don't have to be perfect but gets you down a path. Economics is added factor along with tools on hand.

Don't forget about water displacement of the volume of pole. This is a hang up for my bamboo pole I'm working on.

Thanks for compliments on site, still so many banks and holes in it, I make too many parts not to mention all of the NON spearing parts. Been making Race car parts and tooling for them of late. Got a new job I'm quoting, It's in the drone market place. Titanium is one of the materials, Going to have to jump into cutting this stuff. I'll let you know what I learn, if I price it right.
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Old 01-20-2018, 08:52 AM   #5
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Re: Polespear Build - Titanium?

I bought a titanium rod years ago to use as a sling shaft. When it arrived, I felt like it was too light weight to have enough punch. Might have been good for hogfish or smaller fish, but I didn't feel it had the beef for a grouper. Never prosecuted the idea. I think I still have the shaft lying around somewhere.

With a polespear, the extra length and diameter might give you just the weight you need.

I started with pole spears and have tested several of the new ones on the market, but for the Bahamas, I just prefer a sling.

Sounds interesting and good luck!
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Old 01-23-2018, 12:44 PM   #6
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Re: Polespear Build - Titanium?

Quote:
Originally Posted by Linghunt View Post
Just spotted your post. 2018 is flying by. Lots of ways to skin a cat as you know.

Go back a step or two, figure out what you really want for mass , length, balance. Type of band and stretch length. Don't have to be perfect but gets you down a path. Economics is added factor along with tools on hand.

Don't forget about water displacement of the volume of pole. This is a hang up for my bamboo pole I'm working on.
This is kind of what lead me to inquire about using Ti.

Assuming I'm building a 10' pole Ti seemingly offers a nice mass/volume ratio with the added bonus of likely not snapping or breaking should a nice grouper take it into his lair.

Figure an 8' long rod with a .5" diameter of Ti. You're looking at a weight close to 3lbs in a relatively narrow rod which should reduce drag through the water. Add to that a butt piece and an injector rod and attachment and it would likely be around 3.5lbs in a fairly sleek pole. Could add a little mass if desired by making the stainless injector rod attachment longer as well.

I guess a related question. When balancing a polespear do you find adding mass close to where your hand is to be beneficial or would you rather have that mass spread throughout the length of the spear. For instance with your bamboo spears you might add a bit of lead near where you'd plan to hold it if you wanted a little more punch so to speak.
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Old 01-24-2018, 10:59 PM   #7
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Re: Polespear Build - Titanium?

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Originally Posted by HurricaneBK View Post
I guess a related question. When balancing a polespear do you find adding mass close to where your hand is to be beneficial or would you rather have that mass spread throughout the length of the spear. For instance with your bamboo spears you might add a bit of lead near where you'd plan to hold it if you wanted a little more punch so to speak.
I see your weight at 3 lbs and take off like 11 oz for buoyancy.

Ti is like 60% more dense that Aluminum , but twice as strong based on which alloy you got.

You got the Center of gravity already determined from your original design. Think about inertia to decide the added mass in a length or point.

You want the CG in the front area of the pole, If it's in the back not going to work as well, This is why the boys with open ended poles that flood with water plug them.

Go outside with a broom and a cardboard box. Play caveman and toss the broom at the box. Brush in front and behind. Draw a picture of a Tiger on the box for realism

Bamboo pole is more than just that. It's not just bamboo but anyway, you don't want the backside to float up during the shot time. A pole that sinks horizontally is one thought. Granted the shot time is small so not that critical. Your hand guiding the pole , the rubber hanging off the back. etc.

Play with it. Thinking that lead wire used for sinkers in fishing might be useful. Not seen it around in a while. I would cut it into like 3 inch length and stick it in a rubber tube.
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