張 – 張[る] – to stretch
台 – stand.
Hari-dai – 張り台 –> “stretching stand”.
In essence that’s what it is – as wooden stand that is used to bend the bow in controlled manner, to distribute the tension evenly, and to generate the correct curves on the bow.
Some are carved from one tree trunk, some are made of planks.
Why it is even needed for making a bow?
- My main reference – ecoecoman+Shibata Sensei:
Step 9 – right after untying the bow / removing wedges.
“You can adjust the strength of the bow made by using Haridai. ”
- Asahi Archery bow maintenance has a short description of bow making process; it says that one day after glueing the bow should be stretched to the final shape, stringed and then left to dry:
“9． Stringing the Bow
After removing the wedges and the rope, cut the ends of the Sekiita
so that they are able to hold the string. Place bow on the shaping
mount and leave for a half day. String the bow and check the shape;
tune the bow by pushing the lower or the upper part. This determines
a good or bad bow.”
“10． Finishing the Bow
Keep the bow on the shaping mount for 10 days. After the shape
becomes settled down, whittle away its sides and the Sekiita and
finish with sandpaper. In order to protect the surface, lacquer the
sides of the bow and the Sekiita.”
It is also used to correcting the shape of the bow that get’s “flat” after shooting, so it will be useful to have it in the long run as well.
I got a nice reference website from kuroken for how hari-dai should look like:
There are images of him making the hari-dai:
There are also two videos showing the hari-dai:
Still, the proportions / actual dimensions are not set.
As I have a glass yumi which already has the right shape I took it as the reference and marked its shape on the wood:
Then I cut out the planks with the hand saw and put it all together with screws:
This shape now was suited for the big curve, but it was still missing the small curve and the legs:
So how is it used?
First insert the un-stringed bow:
Then bend it to the correct shape and string it:
Same for shaping the small curve:
Few photos for reference of how it is put together:
There will be some significant forces applied to it so I used bolts instead of screws.
I used 4 8x120mm bolts for the thickest part, 9 6x80mm for the “body”, and 10 6x50mm for legs.
It is a simple construction so it only took two afternoons (and no accidents) to complete.