30 replies to this topic

[Y-Brik]

Get a 1" PVC endcap, lop off the part that connects to the pipe (so you have a flat-ish surface), and use that. It's way simple yo, and more durable-Yay PVC!

[Meaker VI]

Fome, on Nov 16 2010, 11:24 PM, said:

I have my doubts about all the wood in the construction, especially in the plunger shaft, i'm not sure it has the elasticity to withstand the abuse of a [k26] but I suppose time can only tell. The wooden catch ramp is pretty cool, I'm sure if the wood is hard enough it wouldn't have any durability problems...

Y-Brik, on Nov 29 2010, 11:54 PM, said:

...It's way simple yo, and more durable-Yay PVC!

As a note to all the wood-noobs, not all wood is created equal in terms of 'strength'; in terms of hardness (despite it being classified as "hardwood" or "softwood"), bending strength, rot-resistance, flammability, and most other characteristics. For example, this hardwood (commonly called "Ipe") has the same fire-resistance rating as concrete, and takes 3,684 pounds-force to dent with a .44 caliber ball (Janka Hardness test). Douglass fir, on the other hand, is what we in the US typically build houses out of and is highly flammable, has takes 660 pounds-force to do the same thing. The hardness does have an effect on the bending strength, but to get a better idea of 'strength' of any material, looking at something called a "Modulus of Elasticity " is much better.

Now, while I'm not going to explain Modulus of Elasticity (E) to you, I do have examples; like steel, which has an E of 29,000,000. Carbon fiber is something like 22,000,000; Aluminum is 10,000,000; Concrete (under compression- it does not take tension the same way as compression) is 4,350,000; Ipe is 3,140,000; Oak is 1,600,000 - Pine 1,300,000 (with wood it's important to orient the grain properly, those are the long way); Nylon, which I've seen used for rods, has an E of only around 400,000. Polycarbonate is similar. Other plastics vary, but hopefully you get the idea. And while woods need a certain orientation, plastics and metals need a vary specific temperature range - steel looses something like 50% of it's strength at around 800 degrees F, most plastics melt above 400, Wood does not (It does ignite, however, but will remain as strong as the cross-section of whatever hasn't ignited).

The long and short version: Woods vary tremendously by type- many woods are superior to plastics in terms of raw strength.

[utahnerf]

Damn, I love wood. Looks great, probably functions amazingly. I built one of the MkV revised snapbows, and I love it. I have to try this out, thanks for the design!

P.S. ..... Fuck all the haterz

Edited by utahnerf, 17 December 2010 - 09:38 PM.

[Y-Brik]

I forgot to mention my Snap also uses a wood dowel plunger rod (It's 5/8" Oak from Home Depot- there was 2 types of wood, I opted for the heavier one). Works great but be good to it- use a long-ish wood screw (1"+ into the wood), as well as a deep fit on the priming handle- I bored out the tee so the dowel slid in further before adding my screw. Gotta say, I like this better than cpvc for the plunger rod- no fighting with that endcap on the plunger head.

[dizzyduck]

I've been using a 1/2" oak dowel on all of my SNAPs and so far after 200+ shots of each of them, I can't see any wear on them.

It's worth noting that if you use an Ace 62 spring on a 1/2" wooden dowel, you run the risk of getting tiny slivers of wood shaved off of the dowel as you prime it, resulting in splinters.

[NerfGeek416]

Wood is also great for bow plunger rods. Because you don't need a catch, you can simply screw the washer sandwich right to the dowel. You can also make the dowel as thin as you want, since it isn't under stress.

Edited by NerfGeek416, 13 December 2010 - 08:08 PM.