Providing draft and pattern plate

[Photon713]

Good Evening, all...

I have a pattern for casting. The companies are asking for a 2-3% draft. A couple requested a pattern plate. My pattern has straight sides all around...1/2 to 1 inch thick. It would be difficult to add draft top and bottom. So, thinking of solving both problems by slicing the pattern into two pieces, providing the necessary draft and providing a pattern plate. I've no experience with pattern plates. My first inclination is to mount both halves on 1/4 inch Lexan so I can see what I'm doing. Perhaps I can drill small holes through the piece before I slice it to allow alignment through the plate. So, the questions are -- is there a standard size for a pattern plate? Is there a recommended way to mount both halves so they are properly aligned? What material is normally used for the plate? My pattern is wood. Thanks for any suggestions.

[rapidtraverse]

Regarding your draft. Have you considered a draft End mill? They come in a variety of sizes with 3% draft designed for this very purpose.

[Photon713]

Thanks rapidtraverse...I've been searching the web since your reply. Do you know who carries them? I had no luck in my search...Thanks

[beone]

I often use 1/4 plexi for pattern plates, in my own 8x12 flasks. Most foundries will use 18x18 flasks and the plexi will be too flexible. Check with thhe foundry for what flask they use. What are you casting? size? material? quantity?
Dave

[Photon713]

Thanks, beone...

I am having a prototype professional horseshoe cast in ZA12. My pattern is currently made from Oak without draft. I only need one to test the weight and strength. A gentleman indicating he will cast the shoe is requesting a 2-3% draft. I am considering slicing the pattern in half, adding the necessary draft and mounting the slices on a 1/4" Lexan pattern plate. However, I'm not comfortable with changing the angles in certain areas of the shoe. So, I've begun to research making another pattern out of foam to see if this is a better option. The horseshoe is 7-1/4" wide, 7-5/8" long and majority 1/2" thick. The toe caulks are 1" thick tapering down to 1/4". The thumb caulk adds 1/4". The volume of this shoe is slightly heavier than the legal limit of 2 lbs 10 ozs when cast in ductile iron. Thus, I am considering ZA12. I'm really trying to find a casting firm who will turn each prototype around fairly quickly. I am hoping to have something ready for production for the coming pitching season. The shoe must first be approved by the National Horseshoe Pitchers Association. I am expecting the return of my first prototype in a week or two cast from ductile iron. I'm hoping to keep the cost to about $50 per prototype. So, whatever I can do on my end to reduce the cost for the caster I will do. So there you have it...