Someone else would have to answer for sure but I know at least some of the cast arnt aluminum.

 

Here is a fairly good article on the differences between Cast, Forged, and the use of CNC machines. It is not particular to archery - but does discuss the different applications of each.

http://www.sheldonbrown.com/dp-forging.html

 

well i have a 98 magnatech cast riser and a o4 protech forged

magtech;
riser is thicker,bulky looking
seems to be more hand shock
and when i shoot it it sounds allmost hollow kind of,it does seem louder

this is my back up bow and i have switched back to 2216s and man this bow still stacks the arrows and the heavy aluminums soak up alot of the vibration

protech;

riser is thiner and cleaner looking
shoots very well and no hand shock
not shure if its just newer technology command cams vrs cam1/2, solid limb vrs split limb or if it is the cast vrs forged riser but i will tell you they will both stack arrows any day....

not shure if the newer hoyts casting process is differant than 10 yrs agoe but i have never had a problem with my older cast riser..

 

A bow with a cast riser can still be accurate and well-made, but forging and maching an aluminum billet into a riser normally produces a riser that is stronger, less prone to bending and will not have the potential of having spots inside the riser like a cast bow may have.

 

A bow with a cast riser can still be accurate and well-made, but forging and maching an aluminum billet into a riser normally produces a riser that is stronger, less prone to bending and will not have the potential of having spots inside the riser like a cast bow may have.

Exactly! I saw two bows break the same day for a guy at a shoot once. They both broke through the handle and you could see voids where bubbles had been during casting.

 

The process of forging a piece of metal will "align" the grain structure of the metal to produce a stronger piece. If one was to take a billet block of aluminum and machine it out to a riser shape, it would be lighter but less strong/stiff then a forged one. The drawback of forging is that complex shapes are hard to do, thats why they then machine off excess material after the intial shape of the item (riser/engine block, etc) is done. Then you have the best of both worlds. A strong, stiff (in this case a riser) and optimum weight.

Anyone can build a light or a strong component, it requires careful engineering to achieve both.

 

The process of forging a piece of metal will "align" the grain structure of the metal to produce a stronger piece. If one was to take a billet block of aluminum and machine it out to a riser shape, it would be lighter but less strong/stiff then a forged one. The drawback of forging is that complex shapes are hard to do, thats why they then machine off excess material after the intial shape of the item (riser/engine block, etc) is done. Then you have the best of both worlds. A strong, stiff (in this case a riser) and optimum weight.

Anyone can build a light or a strong component, it requires careful engineering to achieve both.

Not if the billet is anaerobically cast and THEN forged.

This is just not a subject that can be discussed on a forum in its full
scope to understand mettalurgical proprties and how they change
during different processes and amalgams.

 

You're paying mostly for the labor cost to do the machining. Vibration and handshock are more associated with limb angle. I personally like the look and feel of the narrower machined riser.

 

machined is stronger than cast, not even close.

cast risers were AM60 and AZ91
extruded and "billet" are essentially the same as "billet" is actually extruded. Grain is different though between the two.

 

It is my understanding that most riser come from an extrusion which is then machined. This increase strength, and limits waste while reducing machine time. The only draw back is that the extrusion could warp. But if a company has good quality control, should not be a problem.

Please feel free to correct me if I am wrong.

 

they start out with a giant block of alluminum and using a high speed water jet, cut little slices of of it... then it goes to the mill to get its machining.

 

I watch the tv show about how they make pse xforces. And they start with a block that is big enough in every demention of the risor then they machine awy probably 90% of the aluminum. They should do it like Ruger and cast the aluminum to a rough easy mold shape and then do the details with the CNC. I bet it would save time and materials. But that's TV.

 

Most of you people will never understand,

The complexities of this subject. Neither will I.

However, I don't think and engine block can be compared to a bow riser. Try a lawnmower blade, a leaf spring, a coil spring, maybe a bridge truss.

Different processes for different applications. Aluminum castings tend to be brittle, though inexpensive. I'm betting, pound for pound, forgings and extrusions are better at standing the stresses found in risers than castings, albeit more expensive.

Where are the matellurgist when you need them?

 

One other point: most if not all of the cast risers you see are magnesium, not aluminum.

 

i do believe cast metal with break as forged or machined will bend.

 

What happens if you take the high pressure casting straight out of the die and forge it??? I think I remember crankshafts blanks being made this way.

 

Nobody is casting Magnesium.

Hoyts "Mag" casting is an Aluminum/Mag alloy.

 

If you want to get picky, most "die cast magnesium" is AM60A, which is a blend of 94% magnesium, 5% aluminum and few other trace elements. There are other similar formulations that I'm sure have been used. We use a lot of this in the instruments we design at my day job.

 

All good thoughts gentlemen - If bow risers were made of steel, I would be able to tell you the differences better myself, as I am a blacksmith and knifemaker, but I do not know all the properties of aluminum and how it reacts to pressures. I have done some light forging/modifications on aluminum horseshoes and know that it doesn't take much heat before you have a crumbly mess. I would think, as it was said, that the casting process has everything to do with the integrity of the product. However, I do know that cast aluminum is overall a better product than cast iron given each it's own uses.

The long story short, I was considering the new Hoyt Turbohawk bow, and it's having a cast riser. Given Hoyt's reputation of "no questions asked" warrenty, it all may be a moot point.