Hello,
a friend from my archery club has recently completed making his 1st Take down recurve. (And only his 2nd made bow)
He was asking me about whether the tiller of his bow looked correct and I suggested rather than me giving him incorrect information I'd post it here.
Below is a a picture of my friend and his bow at draw.
Any comments welcome
Cheers,
Andy,
Advice on this homemade T/D recurve
Moderator: Moderators
Advice on this homemade T/D recurve
Common sense; so rare it should be considered a superpower.
-
- Posts: 1776
- Joined: Sun Sep 07, 2003 10:56 pm
- Location: Tocumwal, NSW. Australia
Re: Advice on this homemade T/D recurve
Andy,
It is pretty hard to judge the quality of the tiller in a picture of a drawn bow, but here is how I do it. I downloaded your picture and opened it in Photoshop. I then draw a line from string nock to the end of the riser. Then I compare the area under the limbs and above the line. Because it is difficult to see in your original picture, I have overdrawn the upper limb for clarity.
You can see in this redrawn picture that there appears to be a greater gap between the lower limb and the line than in the upper limb. This may indicate either of two things -
Firstly, that you have tillered the bow with too weak a lower limb, or
Secondly and the more likely from looking at this picture, that the shooter is 'heeling' the bow and causing the lower limb to 'belly' out a bit.
Heeling is the term used when too much pressure is being put against the grip of the bow by the lower part of the bow hand. On a recurved bow, the drawing pressure should come against the web of the bowhand or at worst no lower than the thenar prominence (ball of the thumb) so the bow is in balance when drawn.
Being in balance when drawn means that there is equal bending of the limbs at full draw which indicates that there is equal drawing force on each limb and therefore they will accelerate at the same speed to drive the arrow. The stored energy in the bent limbs will be applied to the arrow most efficiently that way. If there is more pressure against one limb compared to its mate, then they will accelerate at different speeds and the stored energy from the limb with the greatest bend will do most of the pushing and the slower limb will come to a stop fractionally later than the other resulting in some recoil in the bow limbs felt as vibration after the arrow has left the bow.
This may or may not be happening. It is a matter of degree of difference in the amount of bend between each limb. But, I would suggest from your picture that you try to get the young bloke in the picture to try lifting his lower hand a bit more off the grip and taking the pressure more into the web of his bow hand, THEN have a look at the tiller. If he is not sure about the security of his grip, get him to wrap only his thumb and index finger aroung the throat of the grip and open the rest of his fingers. This will bring the drawing pressure against the correct part of his bowhand for a recurved bow. This type of grip is called a 'high wrist' grip.
It is pretty hard to judge the quality of the tiller in a picture of a drawn bow, but here is how I do it. I downloaded your picture and opened it in Photoshop. I then draw a line from string nock to the end of the riser. Then I compare the area under the limbs and above the line. Because it is difficult to see in your original picture, I have overdrawn the upper limb for clarity.
You can see in this redrawn picture that there appears to be a greater gap between the lower limb and the line than in the upper limb. This may indicate either of two things -
Firstly, that you have tillered the bow with too weak a lower limb, or
Secondly and the more likely from looking at this picture, that the shooter is 'heeling' the bow and causing the lower limb to 'belly' out a bit.
Heeling is the term used when too much pressure is being put against the grip of the bow by the lower part of the bow hand. On a recurved bow, the drawing pressure should come against the web of the bowhand or at worst no lower than the thenar prominence (ball of the thumb) so the bow is in balance when drawn.
Being in balance when drawn means that there is equal bending of the limbs at full draw which indicates that there is equal drawing force on each limb and therefore they will accelerate at the same speed to drive the arrow. The stored energy in the bent limbs will be applied to the arrow most efficiently that way. If there is more pressure against one limb compared to its mate, then they will accelerate at different speeds and the stored energy from the limb with the greatest bend will do most of the pushing and the slower limb will come to a stop fractionally later than the other resulting in some recoil in the bow limbs felt as vibration after the arrow has left the bow.
This may or may not be happening. It is a matter of degree of difference in the amount of bend between each limb. But, I would suggest from your picture that you try to get the young bloke in the picture to try lifting his lower hand a bit more off the grip and taking the pressure more into the web of his bow hand, THEN have a look at the tiller. If he is not sure about the security of his grip, get him to wrap only his thumb and index finger aroung the throat of the grip and open the rest of his fingers. This will bring the drawing pressure against the correct part of his bowhand for a recurved bow. This type of grip is called a 'high wrist' grip.
- Attachments
-
- img00095201010171157.jpg (126.54 KiB) Viewed 1132 times
Dennis La Varénne
Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.
QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8
What is the difference between free enterprise capitalism and organised crime?
HOMO LVPVS HOMINIS - Man is his own predator.
Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.
QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8
What is the difference between free enterprise capitalism and organised crime?
HOMO LVPVS HOMINIS - Man is his own predator.
Re: Advice on this homemade T/D recurve
Hello Dennis,
Thank you for going to the time and trouble to fix my poor photo and share your knowledge.
I have printed this off and will take it along Sunday to share.
Thank you for your time, it is very appreciated.
Cheers,
Thank you for going to the time and trouble to fix my poor photo and share your knowledge.
I have printed this off and will take it along Sunday to share.
Thank you for your time, it is very appreciated.
Cheers,
Common sense; so rare it should be considered a superpower.
- Stickbow Hunter
- Supporter
- Posts: 11637
- Joined: Sat Jul 26, 2003 8:33 pm
- Location: Maryborough Queensland
Re: Advice on this homemade T/D recurve
I don't really have anything to add to what Dennis had said but do congratulate your mate on making the bow - good stuff!!! Perhaps get him to join Ozbow as well.
Jeff
Jeff
Re: Advice on this homemade T/D recurve
Hey Jeff,
I think he has joined - or may be lurking.
I'll encourage him to join..... or he won't be able to trust me when he goes down to collect his arrows each end....
I think he has joined - or may be lurking.
I'll encourage him to join..... or he won't be able to trust me when he goes down to collect his arrows each end....
Common sense; so rare it should be considered a superpower.
- Stickbow Hunter
- Supporter
- Posts: 11637
- Joined: Sat Jul 26, 2003 8:33 pm
- Location: Maryborough Queensland
Re: Advice on this homemade T/D recurve
Arrr ok.AndyD wrote:I'll encourage him to join..... or he won't be able to trust me when he goes down to collect his arrows each end....
Jeff
Re: Advice on this homemade T/D recurve
Hi Andy,
Dennis gave a good analysis of your friends shooting style and I would recommend that he tries the style as suggested by Dennis.
If the bow shoots well and does not exhibit any nasty characteristics I would suggest leaving the bow as is.
A couple of other points to consider;
The photo shows the bow being drawn three fingers under, try two fingers under and split fingers.
Is the arrow shelf/elevated rest equidistant from the upper and lower string nocks?
When the bow is braced is it in positive/negative or zero tiller, if plus or minus by how much?
Are the angles on the handle where the limbs are attached identical? Fine adjustments can be made by using tapered shims between the handle and limbs to find a tiller that suits the bow.
If possible swap the limbs top to bottom and see what happens.
Daryl.
Dennis gave a good analysis of your friends shooting style and I would recommend that he tries the style as suggested by Dennis.
If the bow shoots well and does not exhibit any nasty characteristics I would suggest leaving the bow as is.
A couple of other points to consider;
The photo shows the bow being drawn three fingers under, try two fingers under and split fingers.
Is the arrow shelf/elevated rest equidistant from the upper and lower string nocks?
When the bow is braced is it in positive/negative or zero tiller, if plus or minus by how much?
Are the angles on the handle where the limbs are attached identical? Fine adjustments can be made by using tapered shims between the handle and limbs to find a tiller that suits the bow.
If possible swap the limbs top to bottom and see what happens.
Daryl.
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken. [Ascham]
“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]
I am old enough to make my own decisions....Just not young enough to remember what I decided!....
For a good bow twice paid for, is better than an ill bow once broken. [Ascham]
“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]
I am old enough to make my own decisions....Just not young enough to remember what I decided!....