Bamboo backed Degame [lemonwood]
Posted: Sun May 17, 2015 3:02 pm
As the last test on Degame I decided to back the original flat bow with bamboo.
The unbacked bow drew 45# @ 28 inches but had a rather poor power stroke and didn’t build up much until the last third of the draw. The bow is 68” n to n; limbs 37mm at the widest point and 14mm at the string nocks.
Although the smaller than desired diameter bamboo pole yielded a higher crowned backing a bit of extra tillering corrected the issue but some poundage was lost.
As a result of the backing the power stroke comes in much earlier in the draw cycle and has a steady increase in weight to 28 inches. The bow settled in at 52 lbs. but may shed some weight with more usage.
The original bow had a degree of string follow but after being pulled into reflex for backing it only lost a little reflex from mid limb to tip, partly due to the ratio of bamboo to timber.
In all Degame has not shown any issues with compression fractures with the various limb cross sections or bamboo backing at this stage. Loosing a few thousand arrows may tell a different story.
For the beginning bowyer Degame is an excellent timber as it is easy to process with hand tools, exhibits consistency in its properties throughout the length of the board and grain orientation appears to be irrelevant.
One point to remember is that limb thickness needs to be quite a bit thicker to obtain similar draw weights as achieved when using rock maple or hickory.
Price has taken a big jump; original price estimate from the supplier for 145 x 45mm was $23.00 per lin/m, new price $63.00 per lin/m.
This new pricing places Degame in the hickory / hard rock maple price range, so I will probably go for the latter as they produce a ‘snappy’ bow when compared to Degame.
Irrespective of my findings it is up to the individual bowyer to make up their own mind.
Daryl.
The unbacked bow drew 45# @ 28 inches but had a rather poor power stroke and didn’t build up much until the last third of the draw. The bow is 68” n to n; limbs 37mm at the widest point and 14mm at the string nocks.
Although the smaller than desired diameter bamboo pole yielded a higher crowned backing a bit of extra tillering corrected the issue but some poundage was lost.
As a result of the backing the power stroke comes in much earlier in the draw cycle and has a steady increase in weight to 28 inches. The bow settled in at 52 lbs. but may shed some weight with more usage.
The original bow had a degree of string follow but after being pulled into reflex for backing it only lost a little reflex from mid limb to tip, partly due to the ratio of bamboo to timber.
- Bamboo Degame Flatbow.JPG (30.19 KiB) Viewed 2635 times
- Bamboo Degame Tip Overlay.JPG (31.84 KiB) Viewed 2635 times
For the beginning bowyer Degame is an excellent timber as it is easy to process with hand tools, exhibits consistency in its properties throughout the length of the board and grain orientation appears to be irrelevant.
One point to remember is that limb thickness needs to be quite a bit thicker to obtain similar draw weights as achieved when using rock maple or hickory.
Price has taken a big jump; original price estimate from the supplier for 145 x 45mm was $23.00 per lin/m, new price $63.00 per lin/m.
This new pricing places Degame in the hickory / hard rock maple price range, so I will probably go for the latter as they produce a ‘snappy’ bow when compared to Degame.
Irrespective of my findings it is up to the individual bowyer to make up their own mind.
Daryl.
Well done Daryl, another sweet looking Bow.
Are you building bows to order, or just for the enjoyment and discovery of working with the different materials. 