Really underground garage
Join Date: Aug 2010
Location: mnts of Va
First of all,welcome.
Second,I hope you know how bloomin special it is that you have a "working" relationship with your papa!IMO,this needs to be cultivated to the umpteenth degree.More opinion.........never blow smoke up his,you know.Learn everthing you can from him.If ya'll are havin "creative" differences....step back and chill just a little.Artestry with wood,as with other crafts are such a personal thing that ego's can get in the way pretty quick if left unchecked.So work on win/win scenerios.
I like the word pendantic,look it up...its a doosey.Your question about a straight line ain't a simple one.Straight?But what are you referencing to?
One way is if you had for instance a dead flat(google surface plates used in machine shops,luthier work)plane and you laid a bow on its side you could reference off surface plate and "scribe" a cntr line.......it would be as straight as the SP(surface plate).Whether or not thats the true cntr line of the bow is open for discussion.....a topic that can be beat to death with a cpl interesting tangents.
In fast fwd,gotta get this bow finished or we don't get paid sort of way......a "sheared",straight pce of sheet metal is used more often than not.In use it bends to follow limb and is marked accordingly.But in the world of metrology,everybody has an opinion.The discussion of this sheet metal "trick" can go off the deep end as well.
Then theres another way that can be just as accurate,albeit dependant on how well you can "grind" a limb.It basically involves getting a scrap string on asap.Just get a cpl grooves filed/machined onto limb tips.....A reference line transcribed from bow form(if applicable)really speeds this up.......once string is on,and this is a tough process to describe,you look at the way the limb wants to go.Viewing it from every conceivable angle.The limbs get ground on the side to get everything in alignment.Kinda like a chiropractor in its ambiguous'ness.IOW's if you trace a sheet metal pattern on limb,that'll only get you so far.........Theory vs the Practical.It IS a wood based limb(assumption here),so sometimes the practical solutions aren't always in alignment(haha)with accepted metrology practice.
JMO here......on a longbow,the skinnier the limbs the easier it is to get it tuned.On a recurve,the skinnier the limbs the harder to get the alignment.And on the latter,the more Hi-perf(think tight radius limb tips)the limb design the harder to accomplish.Its a case where how much % of total limb width is required to remove to move tip in desired direction.......further,on laminated limbs......your total taper per inch much influences this tuning.Which explains why manuf. stick to rather "soft" tapers of 1 or 2 thousandths per inch.Go to .004 and variable tapers and it gets real complicated real fast.
Good luck,take notes........and don't be afraid to mess some stuff up.........its all part of the process,BW
Those who say it cannot be done shouldn't interrupt the people doing it.
Last edited by BWSmith; 07-12-2011 at 07:46 AM.