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Main Boards => The Bowyer's Bench => Topic started by: Krasus on May 22, 2015, 10:33:00 AM

Title: why taper grind?
Post by: Krasus on May 22, 2015, 10:33:00 AM
Just what exactly does the taper grinding do? Other then lowering the poundage. I have been making my last couple of bows with 1 piece (72 inch?) Hickery lams and can't really notice a difference.

Thoughts?
Title: Re: why taper grind?
Post by: Bowjunkie on May 22, 2015, 10:48:00 AM
Do you mean thickness tapering of wood in the limbs? If so, it allows for even amonts of flexing/strain to be distributed along the length of the limb. Without tapering of thickness and/or width, a limb will do most of its bending near the handle, which can cause overstrain there, and possibly unnecessary handshock, set, chrysals, limb failure, delamination, etc.

The taper rate helps determine limb action. A slower taper rate bends more near the handle. A faster taper rate causes the limb to bend more out toward the outer limb. On board bows, backed bows, trilams and such, limb taper can be accurately done(ground) prior to tillering if one has the means. I grind them just like I grind tapered lams for glass/wood laminated bows... with my lam sled and thickness sander. It's not necessary, but it's very accurate and expedites the tillering process on such bows.

If that doesn't answer your question then I may have misunderstood what you meant, so please clarify.
Title: Re: why taper grind?
Post by: Krasus on May 22, 2015, 10:53:00 AM
No your spot on.  Just curious as I don't like making my lams with a splice and haven't figured out yet how to do my tapering on a full length lam.
Title: Re: why taper grind?
Post by: Bowjunkie on May 22, 2015, 11:14:00 AM
Oh, ok. Do you have the means to grind them? Lam sled and grinder or something similar?

If so, I grind tapers on full length pieces by feeding the limb tip/thinner end into the grinder first... with the other limb overhanging my 40" sled. When the sled exits the sander, the overhanging half of the blank is angled down and never touches the sanding drum. Then I flip it around, grind the other half, then close the gap on the sander and repeat.
Title: Re: why taper grind?
Post by: Roy from Pa on May 22, 2015, 12:00:00 PM
That's how I do it too...
Title: Re: why taper grind?
Post by: Krasus on May 22, 2015, 01:30:00 PM
Is the recommended taper grind .002? I heard some guys going up to .300
Title: Re: why taper grind?
Post by: Pago on May 22, 2015, 04:57:00 PM
Bowjunkie or Roy could you post a picture for us imaginationally challenged?
Title: Re: why taper grind?
Post by: macbow on May 23, 2015, 10:16:00 AM
Back when, I had KennyM build me a full length taper sled.
Center is thinner than the ends. .004 taper.
Title: Re: why taper grind?
Post by: fujimo on May 23, 2015, 04:18:00 PM
we can build you a full length- double taper sled when you come up here- unless you have already built one by then!!
Title: Re: why taper grind?
Post by: Krasus on May 24, 2015, 10:32:00 AM
Lol who knows I'm just about ready to make some lams so might "play with them  ;)
Title: Re: why taper grind?
Post by: kennym on May 24, 2015, 10:55:00 AM
Quick sled for dbl taper, spot tack with CA a pair of lams the right taper with thin ends to center on a 6' pc of stock(for forward taper), other way for reverse taper.
Title: Re: why taper grind?
Post by: fujimo on May 24, 2015, 01:12:00 PM
Kenny knows!   :thumbsup: