Primitive Archer

Main Discussion Area => Bows => Topic started by: JWMALONE on March 10, 2018, 04:41:28 pm

Title: BBI r/d design help.
Post by: JWMALONE on March 10, 2018, 04:41:28 pm

Yea I know its me again, thanks guys for all your help so far.
 Now I need to make another boo backed ipe. This time a r/d going for #50, 72 inches long for ease of tillering and ive always wanted a really long bow. I have the boo profiled to one inch wide parallel to mid limb to .5 tips. And a 12 inch riser.
Question is were to place the clamp and block that pulls it down into deflex? Half way? Also how much should I put in there?

Title: Re: BBI r/d design help.
Post by: Springbuck on March 10, 2018, 09:24:09 pm

  Closer to the tips than the handle, but not way out there.

It's a good idea to do some tapering or other tillering so the bow's components WANT to go into the profile you intend.

Title: Re: BBI r/d design help.
Post by: JWMALONE on March 11, 2018, 06:41:33 pm

How much should I glue in there? tips even with the handle then mid post 2 inches lower?

Title: Re: BBI r/d design help.
Post by: Badger on March 11, 2018, 06:53:47 pm

  At 72" long you really don't need any deflex. Just a nice gentle sweep of the limb into about 2" reflex will give you a very sweet shooting bow.

Title: Re: BBI r/d design help.
Post by: JWMALONE on March 11, 2018, 06:56:26 pm

Thanks Badger.

Title: Re: BBI r/d design help.
Post by: PEARL DRUMS on March 11, 2018, 07:23:40 pm

I agree, at 72" you wont gain the RD advantage until you pull it 30", unless you do pull 30?. If not, Make it about 1" wide and make the boo very thin. Keep as much ipe depth as you can. It will hold nearly all your glued in reflex and be super smooth drawing and zippy. Leave the last 10" or so stiff if you draw under 28". Just my opinion on the subject.

Title: Re: BBI r/d design help.
Post by: JWMALONE on March 11, 2018, 07:34:03 pm

Thanks guys, sounds good.

Title: Re: BBI r/d design help.
Post by: JWMALONE on March 12, 2018, 11:13:49 am

I decided to go with 66 inches. I tapered the thickness some more to account for the shorter length but as I was cranking down the midlimb post she went CRACK. Next time with ipe ill use two lams instead of one.

Title: Re: BBI r/d design help.
Post by: PEARL DRUMS on March 12, 2018, 11:25:33 am

If you were squeezing the clamps hard enough to break the core then you were also squeezing all the glue out.

Title: Re: BBI r/d design help.
Post by: Badger on March 12, 2018, 12:08:43 pm

  She probably went crack because you didn't have sufficient taper to allow for smooth transitions. If you put a curve mid limb they are a night mare to tiller out. I has to be a gradual curve all the way to the tip, you get his by pretillering the bow to take on this shape when being pressed down on the posts.

Title: Re: BBI r/d design help.
Post by: DC on March 12, 2018, 12:20:32 pm

Should the shape of an unbraced RD be roughly the reverse of a partially drawn straight bow? If you understand that gibberish :D

Title: Re: BBI r/d design help.
Post by: JWMALONE on March 13, 2018, 09:13:20 am

Ok guys, I'm only posting this to keep myself humble. After examining my form this morning I discovered my bonehead mistake. When I made the midlimb post I cut them 2 3/4 tall, they were 2 inches wide. When I screwed them to the base I put em the wrong way, they were 2 inches tall. So when I cranked it down I noticed it was stiffer but I figured it was the glue or something. Needless to say I was trying to crank em down 3/4 of an inch further than what I had tapered them to do, so crack.

Title: Re: BBI r/d design help.
Post by: JWMALONE on March 13, 2018, 09:29:20 am

Another question guys. Going to try again this time its only 64 inches (that's what I got) should I still place the midlimb post midway between the end of fade and the tip? Or should I move it in closer?