I just need to make sure that I am doing this correctly. Is it as simple as just stacking up the plank of woods?
Or is there a more complex way of going about it? Do the planks need to be of certain thicknesses? Do I need to boil the woods? Is Red Oak good enough? How would you go about creating a 350 lbs Wooden Leaf Spring?
Thank you
jkekoni
Is it as simple as just stacking up the plank of woods?
Yes. You make the the longest to outter surface. Then gradually make them shorter.
Add bindings, such as cable ties to near the ends. Only make nocs to the ending one. Do not glue them.
Like 80cm,60cm,40cm and 20cm.
NOTE Adding one with 30cm between the 20 and 40 would
make the tiller elliptic. All with same thickness.
Do the planks need to be of certain thicknesses?
Too thick and they cannot be bent and too thin and you will need
a million of them and the thing will be heavy.
Do I need to boil the woods?
No. Boiling can be used to heat bend. You do not need to heat bend.
Is Red Oak good enough?
Yes.
How would you go about creating a 350 lbs Wooden Leaf Spring?
You can make wonderfull bundles with a planer. My attempt have not required any tillering corrections ( !! ).
I have made 40# "flatbow" and 28# longbow from Aspen <populous tremula> (Read poplar if you do not know aspen.
I'll send some pictures.
Can you tell me the draw length and I'll calculate you some measurements, you may try?
I would rather use diffuse porous woods such as mapple, since
i am more convinient that they would have tiller-thickness ratio more
exact than ring porous wood. Probably does not matted since you need a lot of leafs.
(NOTE: probably not resonable caution...)
TheAzn
jkekoni wrote:
Is it as simple as just stacking up the plank of woods?
Yes. You make the the longest to outter surface. Then gradually make them shorter.
Add bindings, such as cable ties to near the ends. Only make nocs to the ending one. Do not glue them.
Like 80cm,60cm,40cm and 20cm.
NOTE Adding one with 30cm between the 20 and 40 would
make the tiller elliptic. All with same thickness.
Do the planks need to be of certain thicknesses?
Too thick and they cannot be bent and too thin and you will need
a million of them and the thing will be heavy.
Do I need to boil the woods?
No. Boiling can be used to heat bend. You do not need to heat bend.
Is Red Oak good enough?
Yes.
How would you go about creating a 350 lbs Wooden Leaf Spring?
You can make wonderfull bundles with a planer. My attempt have not required any tillering corrections ( !! ).
I have made 40# "flatbow" and 28# longbow from Aspen <populous tremula> (Read poplar if you do not know aspen.
I'll send some pictures.
Can you tell me the draw length and I'll calculate you some measurements, you may try?
I would rather use diffuse porous woods such as mapple, since
i am more convinient that they would have tiller-thickness ratio more
exact than ring porous wood. Probably does not matted since you need a lot of leafs.
(NOTE: probably not resonable caution...)
The draw-length would be 23-26 inches.
Thanks jkekoni for helping me.
Stephen Selby
Like this?
jkekoni
Red oak
350# bundle bow
Thickness: 14.0 mm
Draw: 68 cm (26,6")
Virtual width of bundle: 31cm (divided as bundle below.)
Bundle mass 2.8kg
(Sum of widths is more, since i have added some wood
to make it elliptic and to make the spacing of the
last bundle member less. This is based on XP
with that member taking most set.)
Brace <=12.5cm
(if you increase brace you should decrease draw weight about 1.5cm for each cm.)
NOTE: This has been calculated using self bow calculator and some common sence used to make it bundle.
I have only made light weight bundles from aspen, so any calculation
error(=data error) unless decade magnitude is less likely to be notised by me.
You should use board with good grain, but perfect grain is not needed.
Wood must be free from knots.
Take the best grain boards to the one closest to enemy. round the corners but otherwise keep the bundle members flat.
I can count you also shorter or longer arc, if you desire one.
I'll post pictures of my bundle self bows, when I have time&energy.
jkekoni
Do you have scale and tools for drawing such a monster?
If you build that please post pictures and tell us how did it go?
NOTE:
Please cut the wood so that the defects are going to be scattered so the same part of original board are not next to each other.
Please make the boards taper like, and make the bundle tilted a little
down, so that the string will putt less pressure to Xbow stock.
Arrow this side
____________
...................../
__________/
Stephen Selby
Anther leaf spring crossbow:
jkekoni
It just popped to my mind that 12cm is not enough for reasonable brace, since the arc is 10cm thick. This would mean only 2cm brace.
Also popped to my mind that this is for Xbow, so it will be kept at full draw longer than hand bow, so I should perhaps make a little less agressive measurements. (They were not agressive, but anyhow.)
I'll post a new set of measurements.
Alex S.
Stephen Selby wrote:
Anther leaf spring crossbow:
Do you know the length of prod for this crossbow?
Stephen Selby
I think you're looking at about 1.1 metres. By the way, note that in this Ming illustration, the prod seems to me mounted parallel to the stock. I would say that was almost certainly an error. It should point downward at a slight angle, otherwise the quarrel will not fly true.
Alex S.
Stephen Selby wrote:
By the way, note that in this Ming illustration, the prod seems to me mounted parallel to the stock. I would say that was almost certainly an error. It should point downward at a slight angle, otherwise the quarrel will not fly true.
Thank you for this detail, I would have made similar error if not knowing.
110 cm, and 7 leaf? It must be rather powerful.
Do you know the material of the stock?
It is a hard or soft wood?
@TheAzn
Im sorry to use your thread, hope some of this information helpful to you also.
Stephen Selby
It's not specified: but surely not a soft wood... Cherry is quite plentiful, so maybe they used that. There's a longish Chinese text accompanying the image. The meaning is not entirely clear to me. Along the stock are three 'bamboo trigger pegs'; but I can't really understand the instructions that go with them. Maybe if I upload it, someone would translate it.
