String blocks

[ridley]

Hey, first time posting here!  So I built my first bow following instructions online, but I'm a bit unsure about the string knocks.  Instead of filing string grooves in, the guy glued and lashed some blocks of wood to the end of the bow (like permanent tillering blocks).  Is this a good idea? I've never seen it done anywhere else.  It doesn't boost my confidence that the he says blocks still creeped when he strung the bow...

[Pat B]

Welcome to the Bench, Ridley.  I've never done that but I have seen it done. I think I'd glue them too but i think I'll stick with the old fashioned string nocks.

[Mad Max]

String nocks are groves

[Roy from Pa]

I would not do that.

[ridley]

Thanks for the replies guys, that's kinda what I figured.  Followup question, is a groove on the back necessary, or can I just do the sides.  The bow is only about a half inch square where the string loop lies in the picture, so I'm a bit nervous about making it any thinner.

[ridley]

Oh, and I do realize the picture labeled back is in fact the belly.

[Noah70]

Why not simply remove the lashing, slide the block out to the tip of the limb, and glue it in place, then trim it down and cut your string grooves?  It won’t affect your draw weight or tiller to any great degree.

[mmattockx]

Why not simply remove the lashing, slide the block out to the tip of the limb, and glue it in place, then trim it down and cut your string grooves?  It won’t affect your draw weight or tiller to any great degree.

+1. Just glue them on as tip overlays and then you can shape the groove with no problems.


Mark

[Pat B]

You can just cut grooves in the sides of the limbs but be sure to round the edges to protect the string from abrasion.  You should not cut a groove across the back unless you have a tip overlay.

[ridley]

I guess I'll stick the overlays on it then.  I was hoping to avoid that, since I really like the way it looks without them, but function over form I suppose.  The draw ended up pretty low (~25# if I remember, I'll have to find my scale) if that makes a difference. One other question, if I stick overlays on, how far from the tips should the string grooves be?

[Mad Max]

3/16"  thick is all they need to be and 1-1/2" long
something like this

[ridley]

Ok, 3/16ths isn't that bad I guess.  What material is that, horn?

[Noah70]

The groove across the back of the tip overlay should be approximately 3/4” from the very tip of the limb, or somewhere around that.

[Mad Max]

Ok, 3/16ths isn't that bad I guess.  What material is that, horn?

yes horn

[Longcruise]

I'd go ahead with the string blocks.  You can find more about it in one of Tim Baker's TBB chapters.  He talks about fine tuning tiller or adjusting tiller with them.   Might be fun to play around with.

[ridley]

TBB, that's the bowyers bible, right? I need to pick up a copy of that.  Also, Noah70, if you don't mind me asking, what is that top layer on your overlays?  That's an interesting pattern.  Hope I'm not asking too many questions!

[Noah70]

Also, Noah70, if you don't mind me asking, what is that top layer on your overlays?  That's an interesting pattern.  Hope I'm not asking too many questions!

Ridley - when I cut the sight window out of the riser, I square it up and slice it on the bandsaw, then keep them on file for the top layer of the tip overlays for any limbs built for that riser. Keeps the limb and riser matched.

[Kirkll]

There are a lot of different techniques used for tip notches. Your safest technique is using phenolic or G-10 laminations on the back of the limb first so you can use fast flight string with no damage to the limbs. Using hardwood only can be done too, but they are not as durable.

Here are a few tips to look at.

https://goo.gl/photos/pSoJGRPiqC5cW1h4A

I also have a you tube video showing the whole procedure if you are interested....    Kirk

[Mad Max]

Horn is good too

[Kirkll]

Horn is good too

It’s important to distinguish the difference between horn tip overlays and antler tip overlays.  Antler tip overlays can be a nightmare sometimes. The porous nature of antler material make using a standard super glue ineffective in many cases. I’ve had a lot of antler tip overlays pop off until I figured out how to seal them with epoxy before gluing them to anything. I won’t put antler material directly on glass ever again…..

but horn material is different stuff and is easier to work with because it flexes…. Antler is very brittle.    Kirk