V track instead of U ?

[Will Read]

Have been debating cutting a V shaped speartrack for my next gun , but then I thought there must be a reason why manufacturers don't use V tracks and opt for U shaped spear tracks. To me surely it would offer less contact area with the shaft so less resistance/speed of shot?? Thoughts any one.

 

[CCspearo]

Hi Will
I used an 80cm gun with a v groove for about 20 years. Only because I had a v router bit and didn't see any advantage in buying a U bit for a 1 off job. I did notice that the groove had distinctive wear marks on the sides, the varnish had worn off and the groove had started to take on a U shape after 20 years of use. I eventually cut the gun down to a 5ocm rollergun and turned the groove into a U groove using a steel tent peg wrapped in heavy sand paper . I now use 2 pack epoxy on my guns instead of marine varnish so I can't really compare the wear, but my theory is that if the shaft bears on a smaller area the force applied to that area will be greater than if the shaft is fully supported hence greater wear. I hope this helps
Cheers Mal

 

[foxfish]

I also think the spear glides on a film of water in a U shape, or at least that is a theory I have read about!

 

[CCspearo]

I should have wrote Track instead of Groove , my excuse is it was 2.30 am here in Oz when I wrote that post. Or maybe I am still living in the 70s, groovy man! I thought it was my great epoxy work that was reducing the wear but I can see how the close proximity of the spear to the track would cause the spear to float on a film of water. thanks foxfish