The HuntingPA.com Outdoor Community banner

1 - 11 of 11 Posts

·
Registered
Joined
·
695 Posts
Discussion Starter · #1 ·
Mechanical Engineering Project Design/Machine Bow

I am a senior at Penn State for Mechanical engineering technology. As part of our graduation requirement, we had to design/engineer something and build it. The parameters of the project were wide, leaving it up to our own interests and abilities. Back in September of 2009, we had to submit a proposal to for our projects, outlining what the scope of the project was and how we planned to accomplish the project. I had no trouble coming up with ideas, in fact, I had so many Ideas, I didn’t know which one to pursue. I had ideas ranging from a log spiltter, to a tree stand, to a tow behind mower for an atv. I also happen to work in a machine shop part time so this opened the door for even more projects. One of my friends who knows that I am an avid archer suggested that I try to design my own bow. I thought about it, and really liked the sounds of it.

I figured that I would put in a proposal for it, and see if the professor would allow something that could be considered a weapon. Turns out, he thought it was a great unique idea. This started out as the idea to make a compound bow. After a few weeks of sketching, researching, and talking to various people on various internet forums, I began to lean more in the direction of making a ‘modern’ ILF style recurve riser. (mainly because it would eliminate the complex design of cam system. I believe I could design it, but the time constraints had me worried…) ILF stands for International Limb Fit. The concept of the ILF system is that any ILF riser can accept any ILF limb regardless of the manufacturer. Obviously, I wanted to be able to get limbs and eventually use this bow, so I revised my proposal to: “Designing and Machining a Riser for a Recurve Bow”.

So my first step was to try to obtain the geometry of the limb pockets for the ILF system. Sounded easy enough…Needless to say, this took longer than I expected. I posted in all the archery forums I could find, asking for measurements, drawings, loaner risers to measure myself, everything. Got a few drawings, a parasolid file, and some contacts, but it still wasn’t quite what I was looking for. Then…Some major help came along. A businessman, and store owner who has designed some bows of his own contacted me and invited me down. He showed me several bows and risers, told me the pros and cons to various design aspects on the market. He also lent me two risers so that I could measure the geometry off the pockets. I used calipers and a CMM at the shop for this.

Now that I had the needed geometry, it was off to the drawing board again, or in 21st century the computer software

I created a base model in solidworks ( a solid modeling software) which had the grip location, and the limb pockets. From there, I just started making prototypes. Some I completed, some I didn’t. It got to the point (mid march) when I decided, I had to take one and run with it, or I wouldn’t have time to program and machine it. (Due date April 30, 2010). I didn’t quite achieve all the innovative things that I had in mind, but…I can work on that later. For now, I had to focus on making a presentable riser.

Took the computer model to work, talked it over with some of the very experienced machinists. We made a plan on how to machine it, and started making chips! After a couple late nights, and some professional help, I completed the riser.

As part of the class requirements, we had to present our projects to the Engineering faculty, students, and anyone else who wanted to watch.

For now, Its not quite finished, but its close. I am planning to anodize it or camo dip it.

Special thanks to Lancaster Archery Supply for their contributions and help! As Im sure many of you know, they are great people down there, and know their ins and outs of archery.


Working on programing the model.


First two opperations complete, limb pockets and back side.


Front side


Just need to clean up the edges and profile it.


Yeah I was nervous taking all that to the bandsaw!


There it is...well under my goal of <3 lb.


Fully assembled! Just needs a finish!
 

·
Registered
Joined
·
615 Posts
Re: Mechanical Engineering Project Design/Machine Bow

Thats cool!!!!! stick and string!!!!and your own design!!!!!!!
 

·
Registered
Joined
·
24,796 Posts
Re: Mechanical Engineering Project Design/Machine Bow

Now that is a post!

Very well done. Very nice of your employer and staff to help out. Also nice to see our HuntingPA Sponsor, Lancaster Archery, step up to the plate and help you out.

Very cool. How's it shoot?
 

·
Registered
Joined
·
3 Posts
Re: Mechanical Engineering Project Design/Machine Bow

Hi Steve;
Awesome Job!! Bring it down for us to shoot it!.. I can send it away to have it camo-dipped or made BAD, in Black for you!
It was a lot of fun working with you on your bow; Congratulations! Rob
 

·
Registered
Joined
·
5,576 Posts
Re: Mechanical Engineering Project Design/Machine Bow

I'm always afraid with the advanced design/computer aided production, that the modern engineer could make the bow so efficient, that the harvest would be so high, archery season would be reduced to one week in Pennsylvania.

PA went to the inefficient flintlock muzzleloader because it would make harvesting of deer difficult and enable some days of hunting possible.
 

·
Registered
Joined
·
695 Posts
Discussion Starter · #10 ·
Re: Mechanical Engineering Project Design/Machine Bow

Thanks for the the comments guys..

Rob, thanks again for your help, will stop by ASAP.

SBT, yea I stil have the liberty. I love that bow...I dont see myself gettin rid of it anytime soon. IDK, I might even take my own bow out this fall if it shoots okay.
Saw you harvested a dandy and called one in for a youth.
I havent pulled the trigger yet. I called one in for my uncle the first day, and called some jakies up this week, but still workin on it.

Mus42tang: You make a good point. The technology and manufacturing processes exist to make some rediculous wheapontry, however cost to design/manufacture is still holding back some of the technology making it into your local bow shop. (IMHO) I was limited on time for my project, it had to be done to turn in. Maybe this is obvious, but there really is no cap to where the industry is heading. Its just who can think the ideas up, and find a way to implement them!
 

·
Banned
Joined
·
2,524 Posts
Re: Mechanical Engineering Project Design/Machine Bow

Let me know if you want to get out after em. Ill do the calling and run video if you want. Lets get it done with a bow man. PM me and let me know. Im free pretty much every day of the week unless I decide to sleep in.
 
1 - 11 of 11 Posts
Top