Reducing spine weight

[JoJoDapyro]

It is raining really good here today. I can't shoot, and am just not feeling working on a bow, so I decided to spine out all of the bamboo shafts I have. Here is my problem: the spine of the shafts are between .070 and .303, all too heavy by far for the 2 bows I have made (54# and 65#). What can I do with these to decrease the spine? I know length and point weight will reduce the spine, but it seems that these are still just to stiff. Any information would be helpful. Thanks

Joe

[ajbruggink]

I'm new around here but I have a book by Nicholas Tomihama called The Dowel Arrow Handbook and he suggests that if your arrows are too stiff, a light sanding in the center can adjust the spine down. If you keep shooting them and adjusting and they're still too stiff, he suggests going down a shaft diameter. I have some 70-75# spined wooden shafts that I was going to try that to, or least get them down enough to use a reasonable weight point but I'm not sure if that'll work for bamboo, as he doesn't cover bamboo shafts in that book. I don't know how helpful that is but I'd thought I'd mention it. 

[JackCrafty]

Depends on what type of bamboo you have.  Tonkin has thick walls, so you can sand them down quite a bit.

Check the wall thickness by splitting one shaft down the middle the entire length.  This will be a sacrifice of one shaft but you will know how thick the walls are.

[JoJoDapyro]

It is Tonkin.

[JackCrafty]

Cool.  Sand one down to the correct spine and then bend it until it breaks.   If you are satisfied that it didn't break too easily, proceed to sand down the rest of the batch and then make some arrows. 

[bubbles]

Haha, don't want to end up with just nodes....

[Sockrablur]

Good question and great answer. Pictures would be fun if u r in the mood Joe...

[JoJoDapyro]

LOL, this may take awhile. remember the giant pencils they sell? I have a few of those, but 4 footers. 

[Grasshopper Mouse]

You may want to consider making a couple up as they are and trying them out. I've found bamboo to be a very forgiving material as far as spine goes.

Guy

[mullet]

The shafts you have are four feet long so it gives you plenty of room to move them back and forth on your spine tester.I shoot the same weights you are with the same shafts. My arrows are usually around 31-32" long with 125 grn heads.

[JoJoDapyro]

How do you make your nocks Mullet? These are the shafts I got from you. I usually use a nodule to make a self nock. It would make it easier if I could just use any position.

[JackCrafty]

I used to make the nocks where the nodes are but I don't any more.  Just cut the nock anywhere and then wrap thread or sinew above the nock.

[mullet]

Same as Patrick;

I just cut them on the Band saw, oriented to the stiff side of the shaft, file clean and wrap with sinew.

I don't have a spine tester. I usually cut the Tonkin where it is thick enough to cut a knock in. Then I cut it around 34" and start shooting it till it flies good. It doesen't take much to get Tonkin shooting good when you have 4' to work with.

Maybe you can get Danzinbear  to chime in. He makes some excellent arrows and has a lot of the same Tonkin.

[jeffp51]

Joe,

Here is my experience with bamboo--if you sand them down, you can sand smooth the nodes, but only after you straighten them.  I didn't know what I was doing when I started, so I just made a bunch and shot them to see which matched well with the bow I had.  I found that a wide variety of weights shot about the same, but the really stiff ones  didn't.  I also found a pretty good correlation between diameter and stiffness.  When you spine them, they will be differently stiff depending how you turn them, so put the stiff side of the arrow against the bow when you make your nock.  drill a hole where you want the nock and then cut down to it.  If you look on the how to at the top of this page, it works really well. Wrap at the base of the nock.  If I can do it, anyone can.

[Danzn Bar]

Good points Jeff....JoJo, if it is the same Tonkin that Mullet (Eddie) had at the last classic, yes I've made a lot of nice arrows out of it.  With a little work, I have reduced the spine on some of them by 10-15# by straighting them first as Jeff said, after I cut them to about 34".  Then I used a scrapper and scraped the rind off.  After that I put them in a drill and spin them,  take some 150 grit sand paper and concentrated on the nodes.  then dropped to 220 to finish the entire shaft.  take it slow you can remove too much quickly and make the shaft weak in spine and in strength as jackcrafty said.  I have a spine tester and use it as I am sanding the shafts.  Some final straighting is always needed afterwards and I stain an seal the shafts after final straighting with rub on poly, poly spray and I have used true oil.  I also would rather not have a node at the nock end.  The node is always the hardest point to get straight, therefore, I like to place my nocks in a long straight section and wrap.  Same at the point end.  Some of that Tonkin I got from Eddie at the classic I ended up having only 2 nodes in a 31" arrow.  Much different than my river cane arrows.

Eddie, I hoping you can bring some more of that stuff to the Classic this year.  I was just down the street a few  months at a fabricators shop from the boo place in Lakeland, was flying and didn't bring any back with me wish I had.......  

JoJo hope this helps,
DBar