Riser design

ADE

New member
Hi all, I?m looking for a bit of help. My son, as part of his design and technology project for college, has decided to build a recurve archery riser. It will be a CNC machined riser, hopefully with IL fittings, but what he needs is a basic idea on what goes on behind the design of a riser, what criteria it needs to match, any FITA regs on riser design etc, so if anybody out there has a link/document on any useful information he and I would be very grateful. Thanks.


ps he is not planning on going into business, just wants to get a good mark :)
 

geoffretired

Supporter
Supporter
ADE, it sounds like a great project.
Perhaps I can help a little with some of the simpler stuff.Perhaps you know this already, but just in case.
Length= the standard sizes will, with different length limbs, produce bows of the usual range in total length. I would guess that a non standard riser might be difficult to sell.
Exit angle= the angle that the limbs lean back( away from straight up/down)
If unusual angles are used, the bow may be too lightly/heavily stressed when strung.
Overall shape, side view.= the shapes are straight, reflex, deflex.
straight speaks for itself.
Reflex has the limb pockets further from the string line than the grip.
Deflex has the pockets closer to the string line than the grip.
( there are more precise descriptions than that, but I think you can see the idea)
Overall shape ,front view= the sight window is the cut away that allows the arrow to be fitted to the rest so it could point straight ahead and still have clearance for fletchings.Window length needs to take into account the sight movements up/down when used with a range of limb stiffnesses. If the windown is too short, some higher powered bows will shoot arrows too high at shorter distances.( sight window is on the other side for left handed use.)
Grip position= some makers put the throat at the centre so the hand is half way along the length of the bow. Some put the arrow rest/button hole at the centre.I don't think anyone makes risers outside those two limits, but I'm not sure.
Grip= some are part of the metal of the riser; some have machining that allows different grips to be fitted easily, chance here for the archer to select their preference.
Threaded holes for attachments= nearly always one below the grip to fit a long rod.Some have hols facing the archer for back weights. Usually 5/16" unf. Similar for button and sight, threads vary for sights.
 

greysides

New member
Balance needs consideration. Target archery risers will be balanced with the limbs and all the toys on. Risers with a good barebow lean will be better balanced without the toys, and probably have an option for putting in proprietory weights.

e.g. Hoyt v. Spigarelli

Overall appearance, being pleasing on the eye, may well affect sales.
 

Mufti

Member
I have found a good stress package (software) is a must at the initial design stage - assuming a 3D application is being used, otherwise many trials (and errors) will be the result.

What might look like a workable design will fail at the first hurdle when put under load (unbalanced, uneven, twisting, warping etc).

My thoughts after many design trials are available in this forum if you wish, but I am sure your son will have his own ideas.
 

rohenwto

Member
Hi all, I?m looking for a bit of help. My son, as part of his design and technology project for college, has decided to build a recurve archery riser. It will be a CNC machined riser, hopefully with IL fittings, but what he needs is a basic idea on what goes on behind the design of a riser, what criteria it needs to match, any FITA regs on riser design etc, so if anybody out there has a link/document on any useful information he and I would be very grateful. Thanks.


ps he is not planning on going into business, just wants to get a good mark :)
This may or may not help
AMO standard can be dowloaded from here.
http://www.archery-interchange.net/...ery-manufacturers-merchants-organization-399/
 

not dead yet

New member
Ironman
Hi all, I?m looking for a bit of help. My son, as part of his design and technology project for college, has decided to build a recurve archery riser. It will be a CNC machined riser, hopefully with IL fittings, but what he needs is a basic idea on what goes on behind the design of a riser, what criteria it needs to match, any FITA regs on riser design etc, so if anybody out there has a link/document on any useful information he and I would be very grateful. Thanks.


ps he is not planning on going into business, just wants to get a good mark :)

i'm sure for a small fee merlin may sell you a billet of ally.....
and maybe give you some info...
although you must remember it is their buisiness....
so don't be offended if they don't
 

darthTer

Active member
Supporter
Ironman
American Shoot
i'm sure for a small fee merlin may sell you a billet of ally.....
and maybe give you some info...
although you must remember it is their buisiness....
so don't be offended if they don't
Even just speaking to them would be of assistance.....
 

SimonW

Member
Wow - I think this might be a little ambitious.

Don't take this wrong, I think this is a great idea but I think the resources required (mostly time and materials) may be prohibitive.

I guess you could just copy an existing riser. Probably the easiest would be the Stylist range which were/are very simple (but very effective) - not ILF though. It depends I guess whether you want to end up with a bow that can be shot.

(I suspect the college marking system will not require this)

If it were me, I would go for a sight - though they look very complicated they are in fact much simpler to design and most importantly to engineer.

(I made a couple at uni, not CNC, just lathe, milling machine, hand and eye)

Good luck!!

Simon
 

ADE

New member
thanks for everyones imput and to those who have offered help, i'm sure my son Dan will be in touch.
 

Nick Forster

Member
Ironman
Help

With todays technology and a decent machinine centre (peferably a 5 axis machine) this task is not to difficult, as one person has previously stated a good cad programme is a must.
A font of all knowledge is also required, try Keith Gasgonge at KG Archery. Keith has been a bowyer for nearly 50 years and I have always found him very helpful and informative when it comes to the dark art of riser design.
Best of luck with the design
Nick
 

not dead yet

New member
Ironman
Wow - I think this might be a little ambitious.

Don't take this wrong, I think this is a great idea but I think the resources required (mostly time and materials) may be prohibitive.

I guess you could just copy an existing riser. Probably the easiest would be the Stylist range which were/are very simple (but very effective) - not ILF though. It depends I guess whether you want to end up with a bow that can be shot.

(I suspect the college marking system will not require this)

If it were me, I would go for a sight - though they look very complicated they are in fact much simpler to design and most importantly to engineer.

(I made a couple at uni, not CNC, just lathe, milling machine, hand and eye)

Good luck!!

Simon

BAE systems have a cnc m/c that will scan and produce anything....inc a riser....i asked a cnc m/c rep 5 yrs ago.
 

Harrison Ooi

New member
Make sure not to design the riser so it is "over stressed" as this could lead to cracks and potential injury, making sure that the geometry is good is also important, as even 1mm or less of difference between the two limb pockets could be disastrous.This is pretty much common sense, but I'm just trying to help.
 
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