Main Discussion Area > Bows
Bows by mass
Dan Perry:
Steve,
I feel this is a very usable model. I also feel that this forum is lucky to have such a dedicated bow building researcher such as yourself
sharing good info like this. There are several bowyers on this site that serve the sport this way.
This idea has met with some resistance by many of the Icons of the trade. I was never sure why, becuase if you push the width to its limmit, the mass relationships are pretty easy to see.
Do you know why it works? What is happening?
I am writing about it, and saw this post. I was thinking of making it's own post on PA, rather than making people wait for the book,
but since this is a related topic, I think your post will help people to understand.
Dan
marvin:
Steve,
I asked David to share his tillering approach to lead people to the next step so to speak. It's my opinion that your mass theory cannot be fully realized or seperated from a very carefull tillering methodology.
Dan,
Good to see you here. Did you see my post on the fight archery site about the message board?
Dan Perry:
Marvin,
I replied to it today.
I feel that what Steve is doing is different and sepperate from Tillering. Although Steve uses it as a tillering aid, it is really a design technique. It can also bedesign on the fly tillering if the bow is being narrowed.
I believe it is important to understand what Steve is showing us here.
It is also impotant to understand why. It has puzzled me that the "why" has never been addressed. I have seen bowyers walk all around the "why" when writing about the affects, in books, whithout ever standing squarely on the real issue and explaining it.
Dan
tom sawyer:
Steve has said that you need a cetain amount of wood to do a certain amount of work. If the bow is under the target mass it will probably degrade. Any more mass and you have essentially an overbuilt bow, not the worst possible situation but not as good from a performance perspective. I like Steve's tillering method of reducing width until you see a bit of set, then proceeding on thickness. I think it gets you to this target quite efficiently, and takes into account the properties of each piece of wood that is being worked.
Didn't mean to speak for Steve, I'm sure he'll add to this. But I wanted him to see I've been paying attention.
Badger:
One thing that I suspect dan would agree with along with many other experienced bowyers is that we are often doing things unconciously because we know they work, When it comes to time to explain the how's and why's we tend to overlook what we consider the obvious. Dan has been posting his semi pyramid bows for years, The mass theory when used on a stiff handle bow will almost force you to build that same design. The biggest part of the theory is just basic stuff, mass placement, put the mass where it does the least harm, near the handle, Maintaining the force draw curve, keeping the tips stiff and a minimum of set on a straight bow will do a pretty good job of this with no further ado. The " why" probably the most important part is simple but not easy and will still challenge the best of bowyers to their highest level of skill on every bow, and that is to minimize wood deformation, even the softening of the wood that takes place before set becomes visually evident. In my entire life I could count the bows on one hand that I was able to complete with no perceptable wood defoprmation, 3 of those were somewhat overbuilt. perfection is the goal but not neccessarily the expectation. Getting back to another of Dan's posts where he talks about the relationship of working limb to draw length I believe. This is a very key and very important element of design. It has a major effect not only on performance and speed but also smotthness of draw and handshock. learnign how to manipulate the center area of your bow by using various degrees of stiffness to control not only the working mass but also the force draw curve and the amount of wood deformation. The tillering tecniques used to control mass will monitor these things and tell you when to take your tillering toward the handle or toward the tip. More than you cna really cover in 1 thread, but general ideas can be conveyed. Steve
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