354 replies to this topic

[utahnerf]

Does anyone know the best way to get a good, square hole drilled in the nylon rods? I'm having trouble with it and need some advice.

[Hipponater]

utahnerf, on Jun 23 2010, 08:51 PM, said:

Does anyone know the best way to get a good, square hole drilled in the nylon rods? I'm having trouble with it and need some advice.

For a square as in centered hole, I took a block of wood, drilled a 1/2" hole with a forstner bit, which gave a smaller centered hole. Pop the nylon rod into the 1/2" hole and use the one from the tip of the forstner bit hole to center yours.

Edit: A spade bit would work too, just go slow so as not to tear out the back.

Edited by Hipponater, 23 June 2010 - 08:46 PM.

[Lt Stefan]

Put it in you drill press vice and use a carpenter's square to make sure it is vertical. Then you line up the table with the center of the drill bit by centering the bit with the rod from at least two viewpoints around the rod. Then clamp/tighten the table/vice down and drill.

-EDIT-

Hipp beat me to it. I actually like his way better... I will have to try that haha. I imagine a spade bit would work as well?

Edited by Lt. Stefan, 23 June 2010 - 07:59 PM.

[Lucian]

Because my +Bow handle hurt my hand and gave it a good amount of blisters


I decided to do something about it, which ended up involving felt washers for a very easy fix:




If your grip has ever cut your hand, consider this option defiantly.

[Lt Stefan]

Not only does that look much cleaner than wrapping it in e-tape, but it works even better IMO.

[CaptainSlug]

That's why it's a good idea to sand or file all of those edges down.

[TantumBull]

I've been researching seal types on Mcmaster lately, and although I'm not a +bow user/builder myself, I found something you guys may find of use: 9691K56

They're known as "U-Cup Seals" and are used in low pressure pistons (which is basically what a nerf springer is). The durometer hardness is listed as A70, so I'm not sure if stiffness will be an issue or not.

Anyway, the real reason that they look promising is the price. At $4.67 for 5, they're a steal relative to what skirts will run you.

Edit: My apologies Slug, thought it might be useful for anyone who wanted to try it out.

Edited by TantumBull, 07 August 2010 - 09:22 PM.

[Merzlin]

Skirt seals bought of Mcmaster-Carr have a durometer rating of A85, so these are very similiar in hardness. I'll lob these onto my purchases to see how well they do. Thanks for the find, TB.

[CaptainSlug]

TantumBull, on Aug 7 2010, 05:35 PM, said:

I've been researching seal types on Mcmaster lately, and although I'm not a +bow user/builder myself

Then you really shouldn't post in this thread. Unless you have tried something (successfully or not) then there's not a whole lot of reason to report on it here.

Also, that part number is for a seal size that may not actually fit in the plunger tube correctly since that's the width of the base.

[Lt Stefan]

Thanks to TonyStark in the IRC for this idea.

A new way to mount the bushing:



Packing tape. Not only is it thinner and clear, but it is wider and less stretchy than e-tape so it makes the bushing perfectly straight. The bad thing is, it is a bitch to get on straight since you can stretch it.

Edited by Lt. Stefan, 30 August 2010 - 06:40 PM.

[utahnerf]

Can anyone tell me how well UHMW would work for a +bow? Is it strong enough? Is it better than polycarbonate? Does it machine well? I was wondering because Split used it on his pumpbows. Also, my scroll saw isn't shitty, so it may machine better in mine. It's a DeWalt.

Edited by utahnerf, 09 September 2010 - 05:22 PM.

[BustaNinja]

utahnerf, on Sep 9 2010, 03:20 PM, said:

Can anyone tell me how well UHMW would work for a +bow? Is it strong enough? Is it better than polycarbonate? Does it machine well? I was wondering because Split used it on his pumpbows. Also, my scroll saw isn't shitty, so it may machine better in mine. It's a DeWalt.

Well, Split used it for the Pumpbow, so you can machine it. It seems to work well for that, and its super strong. If polycarb works, this should too. Although I would honestly just stick with Polycarb. Its cheaper.

[Doom]

As with all material choices, "better" is relative. What do you want?

UHMW-PE is weak (has a relatively low tensile strength) and bendy (has a modulus of elasticity that is about 1/3 that of PC), but can absorb a very high amount of energy in impacts. That is the reason to use UHMW-PE. It's very difficult to fracture UHMW-PE. So if you don't want your side panels to fracture, UHMW-PE is one option. Note, however, that this is not the most elegant option.

However, you should take into account the lower strength and lower elastic modulus. When converting from PC to UHMW-PE, use thicker pieces of UHMW-PE. I'm using a 3/8" thick piece in FANG 4.

Also, due (probably) to the long polymer chains in this material, when machining you may find your cuts won't be as clean as they might be with a different material. The polymer chains will hang off the edges, giving a ragged look to the material. This can be cleaned up with sandpaper and/or a file.

Additionally, UHMW-PE is among the worst materials for a plunger rod because of the low tensile strength. If you use UHMW-PE as a plunger rod (with typical dimensions) the rod will creep (i.e. slowly and permanently stretch), assuming that the rod can handle the force and the tapped threads hold.

Edited by Doom, 09 September 2010 - 07:29 PM.

[Draconis]

Just my personal experience here.... I made a couple of really snazzy looking plunger rods from Polyethylene (though they were HD-PE, not quite as strong as UHMW) and the first unit snapped right at the catch point. I think for plunger rods, we really should stick with nylon. For other structural components, though, I think PE works fine. It machines pretty easily, and comes in all sorts of colors that we just can't get with nylon, delrin, or polycarb. Which reminds me.... If anyone finds green, let me know!

[utahnerf]

Draconis, do you think it would be fine then to replace the front and back side plates on my +bow with UHMW?

[Draconis]

utahnerf, on Sep 10 2010, 12:56 PM, said:

Draconis, do you think it would be fine then to replace the front and back side plates on my +bow with UHMW?

Certainly. The compression and impact strength is excellent. Only the tensile (stretching) strength is poor.

[utahnerf]

Ok, thanks for the info. I'll post pics when I finish.

[nerf22]

Hello. I have just started my +bow and have a question. Is one of the rear side plates suppossed to be bigger than the other, in length.

[Lt Stefan]

nerf22, on Oct 24 2010, 06:22 AM, said:

Hello. I have just started my +bow and have a question. Is one of the rear side plates suppossed to be bigger than the other, in length.

If by side plates you mean the 1/8" thick pieces that are screwed into the side of the gun, then there should be four of them total and there are two pairs of congruent pieces (pardon my geometry terminology).

The ones with the rail holes are identical and the ones with the + are identical.

[Ice Nine]

nerf22, on Oct 24 2010, 07:22 AM, said:

Hello. I have just started my +bow and have a question. Is one of the rear side plates suppossed to be bigger than the other, in length.

I believe what Lt. Stefan means to say is that if these two rear plates were used to construct the fundamental group ∏_1 then the two groups would be equivalent, up to isomorphism.

I'm sorry, I should be more clear. I mean to say that there is a bijective function between the two that ALSO satisfies the homomorphism principle.

Edited by Ice Nine, 25 October 2010 - 09:26 PM.

[thedom21]

Alright I have a question about my +bow, Does anyone have Templates for single piece sideplates? also Is there a materiel I could use for the sideplates so they wouldn't crack?

[TantumBull]

'thedom21', on 26 Jul 2011 - 6:44 PM, said:

also Is there a materiel I could use for the sideplates so they wouldn't crack?

'Doom', on 09 Sept 2010 - 11:57 PM, said:

UHMW-PE is weak (has a relatively low tensile strength) and bendy (has a modulus of elasticity that is about 1/3 that of PC), but can absorb a very high amount of energy in impacts. That is the reason to use UHMW-PE. It's very difficult to fracture UHMW-PE. So if you don't want your side panels to fracture, UHMW-PE is one option. Note, however, that this is not the most elegant option.

Reading is useful.

Edited by TantumBull, 26 July 2011 - 02:25 PM.

[Shrapnel]

Hey guys I'm about to start my plusbow, and I am wondering. I am in Australia and the materials over here are different and scarce, I don't know if i can get the parts for the plunger tube and the plunger, but i can do everything else, also with the Rev2 templates, do you have to scale any parts up? They look rather small.

[ChaosPropel]

'Shrapnel', on 29 Nov 2011 - 10:35 PM, said:

Hey guys I'm about to start my plusbow, and I am wondering. I am in Australia and the materials over here are different and scarce, I don't know if i can get the parts for the plunger tube and the plunger, but i can do everything else, also with the Rev2 templates, do you have to scale any parts up? They look rather small.

No, you do not. You can just use the templates as they are.

[Shrapnel]

'ChaosPropel', on 29 Nov 2011 - 10:48 PM, said:

No, you do not. You can just use the templates as they are.

Thanks buddy