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Old 08-12-2019, 02:04 PM   #1
Hpwatson
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Neptonics UHMW Enclosed Track inserts

Anybody ever used these?

https://neptonics.com/product/uhmw-enclosed-track/

Feels pretty expensive but just thinking about the installation process for one of these inserts vs. the process of pouring an epoxy track, I wonder if it's worth it. Just doing one pass on the router with a dovetail bit then installing the track sounds like a nice change from the multiple passes required for an epoxy poured track. My process for an epoxy track is usually to do an oversize pass, fill with epoxy in 3-4 pours to avoid bubbling, then do a keyway for the ball bit's shank, then another pass with the ball bit. That's a lot of opportunities for a mistake, and I've had to refill the track a few times before when I was a bit off-center or something else went a bit off. Just doing one full-length pass on the router as opposed to 3 sounds nice but for $60 I'm still not sure it's worth it. I estimate an epoxy poured track uses probably $15-20 worth of epoxy.

Just thinking through it it seems like there are some advantages to using these UHMW inserts. The material is likely more durable than an epoxy track. I've experienced some of my epoxy tracks chipping at the end when the shaft gets bumped, I bet UHMW will hold up much better. I also wonder how it looks if it isn't a perfectly tight fit though. If there were a gap or something I bet it would be very noticeable.

I'd be interested to hear from anyone who's installed these before. Is it worth the money?
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Old 08-12-2019, 04:01 PM   #2
popgun pete
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Re: Neptonics UHMW Enclosed Track inserts

Enclosed tracks are shaft whip suppressors so they cost you some energy by the guns being less efficient. The bending shaft rubs on the track which serves as a sort of dynamic splint. To gain something you give up something, so if you need a small diameter shaft flying at high velocity over a longer distance then they are worth it.
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Old 08-12-2019, 04:39 PM   #3
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Re: Neptonics UHMW Enclosed Track inserts

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Originally Posted by popgun pete View Post
Enclosed tracks are shaft whip suppressors so they cost you some energy by the guns being less efficient. The bending shaft rubs on the track which serves as a sort of dynamic splint. To gain something you give up something, so if you need a small diameter shaft flying at high velocity over a longer distance then they are worth it.

Yes I know that
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Old 08-14-2019, 11:51 AM   #4
Wood Guy
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Re: Neptonics UHMW Enclosed Track inserts

In my opinion, installing a prefabricated track should be done with at least 2 passes: the first is a straight cut the width of the narrowest dimension of the dovetail or a little smaller, then the dovetail part. Removing too much at one time can cause chattering of the cutter, making the cut oversized. On a dovetail this can be bad news since the angle makes any inaccuracy in the cut result in a loose fit because of the angle.

You might want to consider this: https://www.makospearguns.com/Enclos...ns-p/metws.htm

Developed by Tin Man and me, it is cheaper and much friendlier to install. It uses a straight cutter, which you already have if you're installing poured tracks, and a "T" track cutter, which is available from Mako. Since the cuts are all straight cuts, it is much less sensitive to slight inaccuracies in the cut. An additional advantage over a poured track is that, since it's easily removable, you can cut a slot under the track for trim and ballasting weights. That lets you adjust trim for lights, cameras, or reels right in the boat.

I made and used several of these during development, and stopped using the dovetails after I tried the first one. I realize I'm biased because Tin Man and I developed it, but it's so much better than a dovetailed track, you should give it a look.
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Old 08-14-2019, 12:56 PM   #5
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Re: Neptonics UHMW Enclosed Track inserts

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Originally Posted by Wood Guy View Post
In my opinion, installing a prefabricated track should be done with at least 2 passes: the first is a straight cut the width of the narrowest dimension of the dovetail or a little smaller, then the dovetail part. Removing too much at one time can cause chattering of the cutter, making the cut oversized. On a dovetail this can be bad news since the angle makes any inaccuracy in the cut result in a loose fit because of the angle.

You might want to consider this: https://www.makospearguns.com/Enclos...ns-p/metws.htm

Developed by Tin Man and me, it is cheaper and much friendlier to install. It uses a straight cutter, which you already have if you're installing poured tracks, and a "T" track cutter, which is available from Mako. Since the cuts are all straight cuts, it is much less sensitive to slight inaccuracies in the cut. An additional advantage over a poured track is that, since it's easily removable, you can cut a slot under the track for trim and ballasting weights. That lets you adjust trim for lights, cameras, or reels right in the boat.

I made and used several of these during development, and stopped using the dovetails after I tried the first one. I realize I'm biased because Tin Man and I developed it, but it's so much better than a dovetailed track, you should give it a look.

That's cool, I agree about the design advantages over a dovetail. What size is the track? Will it be snug on a 7mm shaft? I've also looked into buying some UHMW bars and cutting my track into that, then just epoxying that into the gun. I bet epoxy doesn't get a great grip on UHMW or delrin though even if you sand it first. And I'm not a fan of gorilla glue even though its specified for those materials.

I'll definitely think about the track you designed i think it's a cool alternative. Wish it didn't stick above the gun so far but that's just a cosmetic thing. Thanks for the input!
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Old 08-14-2019, 03:02 PM   #6
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Re: Neptonics UHMW Enclosed Track inserts

It's made for a 7.0 and a 7.5 mm track.

I machined the tracks out of delrin during the development stages, and while it can be done, it's not easy to hold the small size of the track. I tried using a table saw, router, and milling machine, and ended up using the milling machine because I could build a matching jig to hold the delrin. For the price of the track, it's not worth the effort, and the price of the plastic (not counting "do-overs"), can easily equal the cost of the track, unless you just want to prove you can.

You can set the track any depth you want- you just set the depth of the router bit at that depth. I usually like the top of the track to be about 1/16" above the gun just to help keep the wishbones off the top of the gun, and it also seems to help in pointing the gun (like a raised rib on a shotgun), but that's just personal preference.

I wouldn't recommend trying to glue it into the gun. It needs to be able to expand and contract in length, so I would anchor it with a small screw near the trigger mech and let the other end float. That also makes it easy to put a slot under the track for weights and adjust trim and ballast for cameras, lights, and reels.
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Old 08-14-2019, 08:26 PM   #7
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Re: Neptonics UHMW Enclosed Track inserts

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Originally Posted by Wood Guy View Post
It's made for a 7.0 and a 7.5 mm track.

I machined the tracks out of delrin during the development stages, and while it can be done, it's not easy to hold the small size of the track. I tried using a table saw, router, and milling machine, and ended up using the milling machine because I could build a matching jig to hold the delrin. For the price of the track, it's not worth the effort, and the price of the plastic (not counting "do-overs"), can easily equal the cost of the track, unless you just want to prove you can.

You can set the track any depth you want- you just set the depth of the router bit at that depth. I usually like the top of the track to be about 1/16" above the gun just to help keep the wishbones off the top of the gun, and it also seems to help in pointing the gun (like a raised rib on a shotgun), but that's just personal preference.

I wouldn't recommend trying to glue it into the gun. It needs to be able to expand and contract in length, so I would anchor it with a small screw near the trigger mech and let the other end float. That also makes it easy to put a slot under the track for weights and adjust trim and ballast for cameras, lights, and reels.

Awesome, I think I'm going to give that a try sometime. I like the sound of it. Epoxy tracks look nice but they're a lot of work and not very durable.
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Old 08-15-2019, 03:38 AM   #8
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Re: Neptonics UHMW Enclosed Track inserts

I think UHMW tracks actually have a better friction coefficient than epoxy track. But installing them has to be done correctly. The track should be on loosely so that you should be easily able to move it forward and backwards … then you pin the track with one screw and the other side should be kept free floating. The reason being that the wood and plastic material have different expansion rates and if you don't prevent the plastic from expanding it might "bulb" up in some areas and constrict the track and cause a lot of friction that would severely drop your shaft velocity. Also be aware that any slight micro warpage of the wood can also constrict the track and cause velocity robbing friction. So IMHO it is best to keep the track very loose where the UHMW can easily and freely move around once you remove the pinning screw. You certainly don't want a track that is tight fitting as in an epoxy poured track.
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Old 08-15-2019, 08:19 PM   #9
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Re: Neptonics UHMW Enclosed Track inserts

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Originally Posted by spearq8 View Post
I think UHMW tracks actually have a better friction coefficient than epoxy track. But installing them has to be done correctly. The track should be on loosely so that you should be easily able to move it forward and backwards then you pin the track with one screw and the other side should be kept free floating. The reason being that the wood and plastic material have different expansion rates and if you don't prevent the plastic from expanding it might "bulb" up in some areas and constrict the track and cause a lot of friction that would severely drop your shaft velocity. Also be aware that any slight micro warpage of the wood can also constrict the track and cause velocity robbing friction. So IMHO it is best to keep the track very loose where the UHMW can easily and freely move around once you remove the pinning screw. You certainly don't want a track that is tight fitting as in an epoxy poured track.
Great input thanks. Yeah the guy I'm building this gun for likes a snug fitting track for some reason. I told him there's really not much point in a close fitting track as long as it prevents shaft whip but he just hates it when the shaft can move around in there. I think Im going to give one of those track inserts a try next time and see how I like it
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Old 08-16-2019, 03:30 AM   #10
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Re: Neptonics UHMW Enclosed Track inserts

By the way, I really think that there are very few reasons to have an enclosed track today. It simply is not necessary for the many reasons ET were used before. Maybe if you like to free shaft, or simply like to rig your gun without line over shaft setup or are just used to loading the gun quickly with ET … it simply is not necessary. All you have to do is design the gun properly. This means bringing up the handle as high as possible into the Center of Gravity of the gun and shaping your handle so that it bring recoil into your palm rather than your thumb. I have been able to get even 170cm @ 6.75mm shafts to go at full power without shaft whip by simply design changes to the gun. Previously I would get shaft whip with the same diameter shaft even at 130cm.
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Old 08-16-2019, 06:27 AM   #11
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Re: Neptonics UHMW Enclosed Track inserts

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Originally Posted by spearq8 View Post
By the way, I really think that there are very few reasons to have an enclosed track today. It simply is not necessary for the many reasons ET were used before. Maybe if you like to free shaft, or simply like to rig your gun without line over shaft setup or are just used to loading the gun quickly with ET it simply is not necessary. All you have to do is design the gun properly. This means bringing up the handle as high as possible into the Center of Gravity of the gun and shaping your handle so that it bring recoil into your palm rather than your thumb. I have been able to get even 170cm @ 6.75mm shafts to go at full power without shaft whip by simply design changes to the gun. Previously I would get shaft whip with the same diameter shaft even at 130cm.
I totally agree. In this particular case I'm building a little gun for a guy's little kid and he wants an ET so the kid can avoid the line wrap on the muzzle. But I tell people the same thing all the time and a lot of them still want enclosed tracks for some reason. They're a pain to build.
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Old 08-16-2019, 02:51 PM   #12
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Re: Neptonics UHMW Enclosed Track inserts

If you want to eliminate the line wrap muzzle then just use a muzzle hoop. That used to be the norm before pin wrap muzzles ever came on the scene. An open track and a muzzle hoop work OK, in fact the Riffe standard guns used to have an optional metal hoop muzzle.
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Old 08-16-2019, 03:22 PM   #13
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Re: Neptonics UHMW Enclosed Track inserts

Quote:
Originally Posted by spearq8 View Post
By the way, I really think that there are very few reasons to have an enclosed track today. It simply is not necessary for the many reasons ET were used before. Maybe if you like to free shaft, or simply like to rig your gun without line over shaft setup or are just used to loading the gun quickly with ET it simply is not necessary. All you have to do is design the gun properly. This means bringing up the handle as high as possible into the Center of Gravity of the gun and shaping your handle so that it bring recoil into your palm rather than your thumb. I have been able to get even 170cm @ 6.75mm shafts to go at full power without shaft whip by simply design changes to the gun. Previously I would get shaft whip with the same diameter shaft even at 130cm.
I agree about enclosed track. The perceived upside of enclosed track simply does not offset the many downsides IMO. Unfortunately, many folks who buy an enclosed track gun were not made aware or did not do enough research on the many downsides but soon find out after using it. I guess that accounts for why you see so many being sold on the used market.
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Old 08-16-2019, 04:14 PM   #14
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Re: Neptonics UHMW Enclosed Track inserts

Yes, the enclosed track is really for multi-band monsters that are mid-handle ballasted logs with six or more fat bands blasting 8 and 9 mm shafts out to long range. Not your average general purpose speargun and usually with a Delrin track, otherwise you would not hit anything.
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Old 08-16-2019, 04:57 PM   #15
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Re: Neptonics UHMW Enclosed Track inserts

Yeah I have one big gun that I like having the enclosed track on. I think it's a good fit. Otherwise I really don't get it.
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