Big Hooks

[PatM]

  Piking increases draw weight.   A better question would be how did the F/D curve change by reducing the tips.

As far as the big hooks increasing early draw weight, picture if the hooks were made so that they could be quickly manipulated without changing any other factors. 

 If you could wind them a little tighter or back them off a bit with the bow strung, the string tension would certainly change, no?

[Selfbowman]

Hmmmmm. I would say extra mass on ends will effect speed and shock. Always a trade off it seems to me. The only real thing we can count on is gravity. I like both recurves and long bows. The most efficient bow design I like is a mix of both. That's just a Texans point of view though. Arvin

[aaron]

I understand that shortening increases draw, and that lengthening would decrease it, but I thought this would only apply to areas of the limb that are not in contact with the string. In the drawing below, would bow 2 and 3 have the same FD curve? It seems to me they would. Would the bow with the very curly tips have a lower draw weight at any point than the bow with the more normally recurved ends? I don't see how it would.

If you could wind recurves tighter while keeping the bow strung, brace would increase and you would be shortening the distance between the contact points of the string at brace, so the draw weight would go up. Likewise if DC took the bow pictured at the beginning and steam bent the recurves back to a lesser curve, draw weight would decrease.  This seems different to what we are discussing because if DC were to cut off his recurve tips, he would also shorten the string and maintain equal brace height (I assume).

[DC]

 If you could wind them a little tighter or back them off a bit with the bow strung, the string tension would certainly change, no?

If I'm following correctly that would change the brace height, yes?? I would be shortening the string so the brace height would be the same. I've been meaning to build a jig for my tree to aid making F/D curves so I'll do that. Is taking a measurement every 2" accurate enough? Coffee first, I just got up

[gfugal]

  Piking increases draw weight.   A better question would be how did the F/D curve change by reducing the tips.

As far as the big hooks increasing early draw weight, picture if the hooks were made so that they could be quickly manipulated without changing any other factors. 

 If you could wind them a little tighter or back them off a bit with the bow strung, the string tension would certainly change, no?

But the string length doesn't change in those examples. So yes the extra length would theoretically pull the bow further, just like putting a string of similar length on a longer bow increases brace height. But if you pike it, and make a new string that effect shouldn't apply anymore.

[DC]

OK the before 38#@27"
7"- 0
9"- 5
11"- 10
13"- 15
15"- 18
17"- 22
19"- 25
21"- 28
23"- 32
25"- 35
27"- 38

Chrono 173,176,185,179,179,183,179,190?,170?,183,175,178,178 Avg 178.9. I left out the two question marks

Now I'll cut the tips off.

After. I cut 3/4" off the tips and used a shorter string. For some reason when I got to the last hole in the pegboard I made to ensure consistent results I was only at  26 " draw so you'll have to keep that in mind. I haven't figured out what I did. I left the columns the same for consistency but remember they skew a bit and actually end at 26 not 27. crap.

After 37.5#@ 26
7"- 0
9"- 6
11"- 11
13"- 15
15"- 19
17"- 22
19"- 26
21"- 28
23"- 31.5
25"- 34
27"- 37.5

Chrono after 176,181,178,178,211?,177,180,184,178,186,183,175,174 Avg 179.1 Left out the iffy one again.

So I don't think I accomplished much. .2 fps doesn't mean squat. I wish I hadn't screwed up the FD but I can't go back. It didn't get worse though.

[aaron]

Looks to me like any changes were within a small margin of error. Bow stayed essentially the same.  Thanks DC for taking the time. PatM does this match your expectations? You seemed  to be hinting that it would  raise draw weight and possibly lower early  draw
Edited to change the word improve to lower in last sentence

[PatM]

I don't think the bow was changed enough to give us a meaningful comparison. I was under the impression that the beyond string contact point would be much larger and thus be a dramatic  enough difference to really highlight any changes.  As it is the results are kind of erratic.
      Can we see pics of the actual bow?

[aaron]

Im not sure I understand what you were expecting and why, PatM. Can you explain what you thought would happen (or what you think would happen if the hooks were even bigger (like in my sketch above with the super curly tips)?

[DC]

I found out what was causing my error as to draw length. When I built my peg board for doing FD curves I didn't remember that the scale gets longer as you pull it. As my peg board is below the scale it skews the numbers by close to an inch by the time I reach 40#. I have a fix in mind. Anyway I guess I didn't notice the draw length when I was doing the first run. So the end result is that the numbers should be directly comparable unless a there was a slight change in brace height caused by the new string . They are both slightly low as you get toward the full draw. So piking the bow in this case did slightly raise the early draw weight but it lowered the late draw weight. It looks like it didn't make a lot of difference though as the speed numbers show. I may have to build a machine for that.
Here's some pictures. The tiller is quite a bit off and there's a hinge on the right limb. I was hoping to gain a bit of weight to give me some working room. Like I said before this one really fought me. It may go in the corner of shame.

[PatM]

Im not sure I understand what you were expecting and why, PatM. Can you explain what you thought would happen (or what you think would happen if the hooks were even bigger (like in my sketch above with the super curly tips)?

 I would expect higher early draw weight with big hooks.  I don't care to speculate on your clockspring hooks.  That's too much exaggeration.

[DC]

Can we define big hooks? I'm thinking a big hook is one with a larger radius and a 90 degree bend. A larger radius will "shorten" the bow more at brace and that will increase the early draw weight. It will also "lengthen" the bow more at full draw which gives you more leverage which will lower the full draw weight. I put quotes there because it kind of depends which direction you're thinking from. Smaller radius lessens both of these. The angle of the bend controls lift off. I still think that anything past string lift off at full draw is wasted

[joachimM]

As long as the angle between string and nock is zero degrees at full draw, you have excess wood on your tips. This extra wood is not giving you any leverage, only excess mass.
So on your first drawing, you didn't remove enough wood.
And 2 fps means a lot in flight shooting, that's 5 m extra with a 10 gpp arrow.