Author Topic: MOLLY THICKNESS TAPER  (Read 3761 times)

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Offline OTDEAN

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MOLLY THICKNESS TAPER
« on: November 27, 2014, 07:19:15 am »
Hi,

I have just carved out my molly bow with levers.  The working limbs are parallel width taper.  Do I tiller this with an even thickness taper and go for a circular tiller profile with the aim of getting as much bend in the reduced working limb as possible or should I tiller this with a gradual thickness tiper from handle fade to lever fade?  I am guessing even thickness taper and circular tiller profile over gradual thickness taper and elliptical tiller? 


Your thoughts folks
Dean

Offline arachnid

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Re: MOLLY THICKNESS TAPER
« Reply #1 on: November 27, 2014, 09:13:47 am »
Boarrior bows has a great molly build along on his you tube channel. You should check it out.

Offline Pat B

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Re: MOLLY THICKNESS TAPER
« Reply #2 on: November 27, 2014, 09:33:44 am »
Theoretically if the back profile is even than the thickness needs to be tapered. If the back profile is tapered the thickness should be even.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline huisme

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  • I'm Marc, but not that Marc.
Re: MOLLY THICKNESS TAPER
« Reply #3 on: November 27, 2014, 12:33:42 pm »
A more authentic molle has no width taper and is tillered in thickness.
50#@26"
Black locust. Black locust everywhere.
Mollegabets all day long.
Might as well make them short, save some wood to keep warm.

Offline Springbuck

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Re: MOLLY THICKNESS TAPER
« Reply #4 on: November 27, 2014, 02:34:31 pm »
  Anything that tapers in thickness should not really have a circular tiller, although the levers do mess thst rule up a bit.  The whole idea of circular tiller in a pyramid bow is that the whole limb is evenly strained.  The strain is exactly the same because it all is the same thickness and bends the same amount.

   Basically, if you have parallel sides and circular tiller, the thick end is bending more than it should (which is where set comes from, which is bad close to the handle), and the thin end is bending less than it could so it weighs more than it needs to.  So, even in a molly, keep thickness consistent and accept that the sides will taper some, or tiller in thickness, and accept that the bend will be pretty close to, but not exactly, circular.

 The good thing is that because of the stiff outer limbs, just a very little of either or both will get a good tiller.  In spite of what Huisme says, my mollies usually width taper just BARELY, maybe 1/4-3/8" over 60% of the limb length-ish, and then I touch up tiller with a little thickness scraping.

Offline huisme

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Re: MOLLY THICKNESS TAPER
« Reply #5 on: November 27, 2014, 03:03:04 pm »
I didn't mean to say width taper isn't good or useful, but the artifact didnt taper until the outer fades. I made a completely side-tillered molle for a friend, shot beautifully.
50#@26"
Black locust. Black locust everywhere.
Mollegabets all day long.
Might as well make them short, save some wood to keep warm.

Offline JonW

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Re: MOLLY THICKNESS TAPER
« Reply #6 on: November 27, 2014, 04:41:14 pm »
If you have parallel working limbs make it bend by reducing thickness. Like Marco said the artifact is parallel working limbs. The thing with making your own though is that you can do what you want. A Molly tiller is something in between circular and elliptical because of the short working limb and stiff levers. You have to remember that the bend is only in the WORKING area.

Offline OTDEAN

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Re: MOLLY THICKNESS TAPER
« Reply #7 on: November 27, 2014, 05:55:53 pm »
Thanks, thought it would be thickness taper with parallel width limbs, just read an article by someone online who wrote about keeping the thickness the same and that through me.  I will stick with what my experience tells me works and stop reading stupid crap on the net!

mikekeswick

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Re: MOLLY THICKNESS TAPER
« Reply #8 on: November 28, 2014, 03:30:34 am »
Come on Dean  ;)
Don't you remember all those lessons where I tried to drum that tiller logic in!?!
Thickness determines bend.
Thickness taper - Parallel width = Elliptical tiller
No thickness taper - Pyramid taper = Circular tiller.
Don't be tricked into thinking 'oh my working limb is cut in half, must bend more than usual somewhere'. Follow all the same rules as a 'normal' bow. DO NOT make it bend a bunch out of the fades unless you don't like your teeth! Also blend the outers in well and don't make it abruptly stop bending. All the copies i've made following the originals dimensions have had a shade of bend in the outers. In one of the TBB's there is a picture of a holmguaard made by a very nice chap I once met called Juri - that's what mine look like.
Anyway I hope it works for you.  :)

Offline OTDEAN

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Re: MOLLY THICKNESS TAPER
« Reply #9 on: November 28, 2014, 04:07:46 am »
I do remember the hours of you showing me which way was up on a ruler! ;D 

I might get this sucker finished for Spring. 

Dean