Tillering my bow

[Jason/Woody]

Ok, I am making a short string for my bow, and I want to get something cleared up for when I start to do the tillering on that.  As was shown in my first thread, I added the reflexed tips to my oak board.  Should the bend in the bow transition to a flat spot where the reflex starts and then curve back out?  Or should it make one smooth curve when drawn?

It seems to me that I would have to remove a lot more material in order to get that part to bend like the lower part of the limbs.

Also, for these string jigs.  I have found 2 different schools of thought on them.  I downloaded the CAD drawing of a jig layout on here, but it didn't tell whether to follow the numbers according to bow length, NtN length, or final string length.

If my bow is 70" and 68 NtN, do I put the string on the 70" spot, the 68" spot, or do I need to go to 65" for the string length?

TIA

[John Scifres]

The last 6" or so of the bow won't bend.

Make your string 3" shorter than your NtN length.

[Jason/Woody]

Ok, thanks.

You say to make it 3" shorter, but does that mean I would need to loop it to 65" on the jig, or is the 3" built into it and I loop it at 68"

[John Scifres]

I don't know.  Make one.  If it's not 3" shorter, adjust your starting point.

[Badwithabow]

id almost swear that the length on the plans for the jig are "Bow length"

[Jason/Woody]

Yeah, so I made one.  I need to make it shorter.

I also think I made the loops too big.  The string popped off twice once I got out to about 30#.

It was my first string that I have made, so now I know I need to make those loops smaller for sure.  That would be the main cause of the string coming off, right?  My nocks are deep enough to hold the string, but on the belly the loops come down a good 3/4" or better on the small loop.  Too much?

[John Scifres]

You can untwist the loops and try again.

[Jason/Woody]

Ok, I shortened the string a bit, and got it on low brace with no slips so far!!  I am pulling 39#@25".  I have somewhere to be, so I can't go any further right now.  Does this mean I still have quite a bit of material to take off?  I figured once I went to full brace it is going to increase the poundage considerably, or am I wrong?

[Shakes.602]

Howdy Jason/Woody!!   Can I Ask How Much Total Poundage Your Working at, and the Drawlength??

[John Scifres]

Assume 3 pounds per inch of draw.  So at 28", you would be around 48#.  You'll lose a couple in shooting it in and finishing.  So 45# is a safe bet assuming tiller is good now and holds the rest of the way.

[Roy from Pa]

Every string jig and string maker, "You", is slightly  different. All depends on how you build the strings, how long a section you start out with to begin your loops, I use 8 inches, but 9 would shorten the string, 7 would make it longer, how tight you twist, etc. You will soon learn your own jig and compensate for future strings. It's all fun and games. Just enjoy it.

[Jason/Woody]

@Shakes - I'm not working for any poundage because this is my first bow, and I would just like it to be successful     The draw length will be around 29" though.

@John - Thanks, I thought it was something like that (the 3# thing).  I wasn't aware I would lose 3# with shooting and final sanding stuff.  I am seriously worried about pulling it all the way because it feels damn tight lol.  If I exercise it 20-30x per inch, I should be able to draw it down to 28" huh?

@Roy - I am starting to figure it out some.  At first it was difficult to handle the string in my hands, but I am getting the hang of it now.


My real issue wasn't addressed though.  Will the draw significantly shorten once I go to the full brace string length?  

I have some pictures of it that I will get on here shortly for reference.  Thanks guys

[Jason/Woody]

Ok, here are some pics.

The first is my old large loop.  I made it half the size, and the small loop about 3/4 the size it was.  Too big, huh?

 

Here is one of the tiller on the low brace string.

 

Now for the new large and small loops.  Are they still too big?

 

An at rest picture of the shorter string.

 

And finally, here is the 39#@25" on the string I have now.

 


How does the tiller look on that?  From looking at the picture for the first time, it kind of seems to me that the first 1/3 of the right hand limb is stiffer than the left hand.  The bow is completely level at this point, and I think, in my uneducated experience, that the tiller looks pretty good.  Any suggestions on where to take material off, if anywhere?

[Jason/Woody]

Alright, on the same string as is used in the pictures I worked it down to 29" draw.  It registered 44# at 29" on that string.  It looks like the limb on the right at that level is about 1" above level when compared to the left limb.  Is that too much, or would that be a good candidate for the bottom limb?

Tomorrow I will go and have a string made for the bow because I don't have any dacron yet anyhow.  The string on it now is stripped out paracord threads.  It works, but I think the dacron stuff is much better.  Anyhow, this way I will know the first string is spot on for where it needs to be    

Then I'll put that sucker on and finish the tiller, add the osage nock overlays and carve those out, carve the handle and finish this baby!

I was so excited to get it to my full draw length on this string.  Now I can't wait to move forward since I let that cat out of the bag    :D

[Jason/Woody]

Wow, nobody with any suggestions?

[TheBronzeAge]

Suggestion: build one of these, use it to check the tiller:
 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=001047
I'm not going to eyeball your bow because I'm still at the stage where I post pics for others to help me with, but this device has done a nice job keeping my bow even.  Not perfect (user error, I think) but my second bow is coming out much nicer than my first.

[vanillabear?]

[Dublin Joe]

Your second loops look better, for sure.  If you twist a string with only one loop and use a timber hitch on the other, the hitch can stay on the bow and the loop can be just big enough to slide down the limb until you string it up again.

I wish I had an answer about whether you'll lose draw length with the short string.  My understanding is that you shouldn't really measure draw length until you're on the short string anyway, so get it on and tiller patiently to the 29" you're after.

Good pics, and I like the curves you got.

Joel

[John Scifres]

You will gain weight the shorter you make the string.  Don't weight the bow until you brace it.

[Jason/Woody]

Ahh, I seem to have been confused I guess.  I thought if I strung it with a low brace then that would be the next step to getting to full brace.  I ordered some B-50 today.  I just looked online, and it appears that 3Rivers is only about 90 minutes away.  That might come in handy in the future...

Thanks for the input guys.  As soon as I get my string and get the final string on, I will hopefully only post one more picture before I post a completed set    

As some of you may have noticed, I like to be thorough, but I do appreciate the patience in answering questions that have likely been answered countless times.  I know the feeling......