QUESTION: How do I determine the thickness of my limb kit (lamination stack)?
ANSWER: The thickness of your limb kit directly determines the poundage of the bow. In a recurve bow, a change of .001 of an inch may roughly translate to a 1 pound change in draw weight. In a longbow, .003 of an inch change may translate to a 1 pound change in draw weight. It is a very exact science, and we recommend you measure your limb thickness with a micrometer. Digital calipers are made for measuring round stock where a micrometer is made for measuring flat stock. You can find the Bingham Bow Draw Weight Chart here, which will provide you with a good starting place.
For our 1 piece recurves and t.d. recurves, the limb thickness is composed of 2 pieces of Bo-tuff, 1 parallel, and 1 taper (.002”). The total limb thickness is the sum of all four layers, the taper being measured at the butt (thick) end. For the take-down recurve, the wedge isn’t included in the limb thickness.
For our 1 piece longbows and our shallow t.d. longbow, the limb thickness is composed of 2 pieces of Bo-tuff, 3 parallels, and 1 taper (.002”). The total limb thickness is the sum of all six layers, the taper being measured at the butt (thick) end.
For our pronounced t.d. longbow, the limb thickness is composed of 2 pieces of Bo-tuff, 1 regular taper (.002”), 1 parallel, and 1 reverse taper (.002”). The reverse taper is simply a taper that is reversed so that the thin end of the taper is at the butt end of the limb. The total limb thickness is the sum of all five layers, the regular taper being measured at the butt (thick) end and the reverse taper being measured at the thin end. In the case of the t.d. bows, the wedge is never considered part of the limb thickness. Additionally, please note that this chart is accurate for Bingham Bows and designs only. We are happy to offer advice if you are using your own design, but we cannot guarantee an accurate limb thickness for different designs.
If you are ordering a limb lamination kit from us and plan on following one of the Bingham Bow designs you do not need to figure out your limb thickness. Please just state your desired weight, width, length, and draw length and we will figure out the rest for you.
