Paul Krush

I milled a wax blank that is 38mm dia x 3mm thick with a 1/2mm deep area in the center. I’m am designing a few test pieces that can give people an idea of what a finished coin looks like, and what design elements are possible. This project is going too slow!

I’m pretty darn excited about taking a pass with a 1/32” tool bit on brass key yesterday. I cut .5mm deep and cut a few lines. The tool bit I used is not made to cut metal. It’s got like a nine to one reach. This means the tool is nine times longer then the diameter. It did break after an inch of cutting. It’s rather dumb that I tried a long reach tool, but it did not chatter. I did not doubt the mill could cut metal, I just never tried it. Bits & Bits has like 3 to 1 reach cutters (like .5mm diameter and 1.5mm cutting length) that would work fine.

Even though my Revo mill can cut metal, I am not sure I want to mill metal, as it would be too slow for this project. I would have to go to a smaller coin size. Mills this size I guess could cut four to six 38mm coins VS about 24 waxes a day. I would rather use a Minitech for metal then a Revo.

I can get the coins cast for far cheaper then milling. At some point I think I could custom build multi spindle wax mills at a price of less then $1000 per spindle that could run months 24 hours a day without breaking down. I only need to cut 1mm of wax! It would be nice to get the price of a whole coin (38mm x 3mm) under a dollar.

I posted this in the Challenge Coin Association on eBay:

I plan on making around 400 unique custom coins a month using a lost wax casting process. I plan on having only one standard size of coin to make things as easy as possible. I’m doing orders of one. Yes, the quality of cast coins is not as good as die struck coins, but I’m using the equipment I have. Also I am getting into to this more for the designs and not the final product. Coins are just an easy start. It could be anything smaller and flat.

What size should I choose? Challenge Coins are new to me, but seem to be the largest type of custom coins. I am thinking of the 1 1/2″, 38.1mm size, as this seems to be a standard challenge coin. This is a silver dollar size.

What about Thickness? I would like to go with 3mm, because I am going to let people design ½mm into the coin each side leaving me with a 2mm thick center at times.

2mm think seems to be something of a standard, but I think a 1mm center is too thin as I am not stamping, but casting.

I don’t know why I am beating myself up on this. I just need to start making coins and see what people tell me.

A 1 ½ inch by 3mm coin seems a little big to carry in a pocket or to be on a key chain. A pendant would be way too big. What do you think? You guys carry these coins. If you look at history silver dollars were never really used. I tried carrying around a silver dollar and I thought it was too big. I thought a half dollar was perfect. Before I really started looking at challenge coins I thought the half dollar size was the best.

With a lower price for a single custom coin I see coins based on personal goals, affirmations, and constitutions a bigger market then challenge coins. I see these coins being carried not just displayed. The coin designers will determine the market, but am I am just trying to come up with a great size.

Thanks much for your input,

Paul Krush

I am trying to define where PaulKrush.com designers/users are going to come from. I have to give it a shot even though I might be better just waiting to find out. I’m sure users from the professional CAD/CAM for jewelry group will be dipping into our world to pull designs and have a bit of fun. But I really don’t think they are going to be the main users. I think the average user will use the site for more than the just himself, but not on a professional level. I really see the users as pro-hobbyists.

Per Wiki, Pro-Am is short for professional amateur. I define Pro-Am’s CAD CAM jewelers as people loosely in the jewelry world, but have expertise and tools that run at the same level or higher then professional jewelers. The amateur can do some things much better then the professional. It turns the profession a little upside down in certain areas.

Traditionally this group could be the Tucson going, Ganoksin.com writing, bead stringing, weekend warrior, craft show presenting group that hangs at the edge of jewelry profession. There are 50,000 serious jewelry related businesses in the US and another million that are loosely involved. There are no hard boundaries in what a jeweler is. I have seen customers know far more about certain aspects of diamonds then most jewelers.

I think the users will be far more then this traditional group. Really you can start with the group of people that understand or can learn 3D, and willing to share files online.

I view using this site as an introductory CAD/CAM for jewelry Internship. I am very limited in what I will let people do, but this focus enables people to learn. This public service bureau concept is a sandbox for people that want to get into CAD/CAM.

I expected things to be very slow to start. All I am offering is waxes. I am starting a new eBay wax auction for a half-dollar size coin wax once a day. There are 5 out there all starting at a penny. I have no pictures of waxes or finished coins in the auction text. It’s dull, but you have to start somewhere. Heck, I haven’t cut any waxes myself. Once I make some prototypes of finished silver coins I will start offering custom silver coins for a penny. This will force people to look and bid because it will be a more valuable service. At some point I want to have a contest and give one silver coin away each day to the best design.

When I use this term service bureau for jewelry I mean a company that makes clients wax models from the 3D file they provide. The idea that a service bureau would share these files online does not exist in the jewelry industry currently. All service bureaus are private as they can command much higher rates for keeping their client’s work private.

When I say a public service bureau I mean a company that shares clients designs on the Internet for all to see and download.

Public service bureau (PSB) possibilities:

• Over time a PSB would create a database of designs for other people to use.
• It would create a community of users using and improving other people’s designs.
• Such a service could create a competition among users further motivating people to use the service.
• Some people are will be motivated to send in files just to create an online portfolio.
• Some designers will just want their models used by others.
• If the public service bureau was efficient and could profit from the content of the users the price per model could be reduced or even free.
• Advertising and promotion expenses could be very low due to word of mouth.

The motivation for clients to send in files would need to be huge. Some people would see this as giving away their work, and never use a PSB. Others would see the service as a fun experience, and just plain valuable. The service will grow if the model price is low enough and there is a critical mass of users. It’s all theory now, but I am going to invest some serious time and money into testing these ideas.

This is not the same as a discount service bureau. Creating the models would be an experience for the users. People will upload design because it’s a fun experience. This is the same as tom sawyer convincing everyone painting the fence was fun. It’s win-win for everyone.

Similar working concepts:

• A lot of websites have users successfully uploading content (YouTube, Blogs, MP3 sharing sites, etc).
• It’s a little like watching the paper photos come out at the developer. (I’m dating myself)
• Some jewelry sites post pictures of past work.
• It’s like a watering hole. Free water for all, and it makes a good place for conversation.
• A PSB is like an Internet forum that content (writing, pictures, files, etc) is uploaded for the moment, but retains value over the years.
• I want to say it’s like a 3D model sharing service but I don’t see any great examples of this yet with models for manufacturing.
• This is like shoppers willing to have their buying habits recorded in exchange for discounts on products, AKA grocery store discount cards.

What would a public service bureau need to survive?

• An easy to use system of uploading and sharing files.
• A way to fight the tragedy of the commons problem.
• A way to keep out spammers.
• A well maintained forum for users.
• The service has to be fun to use.

I think a public service bureau set up right would really grow as it’s database and user base grows. Change a low enough price and users have no other option but to use the service. I see such a service being used by the Pro-Am jewelry making community.

Theory is great, but some people experienced in the trade have to be shaking their heads at me. Yes there are a lot of issues with this. This is why I am starting tests with the simplest part I can, a half-dollar size coin. Changes will be made on the fly. It’s going to be fun to get this concept off the ground so others can copy us. I just want to see this happen, and I am compelled to do it.

Day one.

I’m sure this is going to be a slow and disappointing start. It could be a month or more before I really have people bidding on my auctions. It’s going to take time to get the PaulKrush.com site up and running and to get the right people to notice these auctions. For now I am going to start with one wax auction a day. Starting at a penny, I might have some that end under a dollar. I know the going rate is $50 for a wax like this, but I don’t care, it’s going to be that way for months. I bet one person wins over half of them because he is the only person that understands what I am doing. I’m sure most of the auctions will be won, but the winning bidder will not submit a file to be cut for whatever reason. After a while the right hobbyists will find my offering and take me up.

This is not a halfhearted attempt; I’m in this for the long run. I am planning on the site to handle thousands of models a month, most of which I will not handle physically. I see arrays of double spindle CNC mills pumping out buckets of waxes or even finished metal parts an hour. I can’t think small. In fact I am thinking about a goal of one million parts made from our systems in 2009.

So Michael Gibson one of the guys who help start writing Rhino is working on some CAD software that is like Rhino.It’s really Rhino like, limited, but easier. The snaps are very intuitive. It reads 3DM and IGES and outputs 3DM, IGES, STL, 3DS and OBJ.

I did this ring from checking out the site to install to saving in about hour. You just use it. I did steal the gem from Matrix. But diamond models are out there for free.

Sure it’s very limited, but did I say it’s free? This is first software I have seen that is free and really can be used by people to make jewelry with no investment at all.

It’s very exciting to me because see a lot of growth in CAD-CAM for jewelry coming from people who first play around with 3D as a hobby. I could say so much about this, but I am not sure this forum is the place.

It’s called MoI (Moment of Inspiration): http://moi3d.com/index.htm

Here is the 3DM file: moi_ring_test.zip

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I cheated and rendered this in matrix:

This is my first eBay auction for waxes. It’s crude and with no pictures. I think it would be cool to start with the 3D content from the users. I did a few examples models, but I want to see what this generates. For now I am going to post one of these auctions a day. With my Revo CNC mill I can do around 500 of these half dollar coin size waxes a month, but I don’t think I can handle the admin work to do this without software.

It’s going to be fun watching this evolve.
This auction is for a wax model of a custom US half dollar size coin that you design and we mill for you. Please email me at paul@paulkrush.com if you have any questions.

This wax can be cast using a lost wax casting process, but this auction is for the green wax model only. You have to summit the 3D file(s) to have the wax created.

This is NOT private. By submitting the 3D files you are granting us unrestricted use of them. We are going to post them on the Internet for anybody to download.

These terms of this auction are very restrictive, yet liberating once you understand why they are restrictive. We are opening up the world of CAD/CAM for jewelry to a far greater audience. Normally to mill a wax this size would run about $100!

As per the US Mint:

A half dollar is 30.61mm diameter by 2.15mm thick. The only thing you control is the front and back surface 29mm is diameter and 0.5mm thick. You can’t change the rim, outline, thickness, or put holes in the wax. Take .5mm off each side and the center will be at least 1.15mm thick.

Think of us as a printer that the world can see printing. Or think of us as a jewelry store in which the customers fill the cases. We can’t do anything unless you supply us with a 3D file.

The design submit must be copyright free, PG13, and not contain private information. We reserve the right to refuse any design.

The wax will have a tolerance of +- .2mm. It will be better that this most of the time.

The wax will still have tiny tabs from milling so will need to be cleaned up for casting. It’s just a little filling.

Depending on your design the model also may have packed wax from the milling process that we can’t clean automatically. Wax dust might get packed in a tiny hole say .5mm in diameter and .5mm deep. Avoiding this comes with experience.

Casting a coin is not the same as stamping one like most coins are made. Detail gets lost in the casting and polishing process. Details smaller then .3mm might get lost. You might have trouble with text under 2mm and 1mm high text is difficult to make. 1mm high text on a stamped coin will be crisp. The advantage to casting is you can do one coin at a time for much less money.

For now you are going to have to email us the 3D. We will accept STL, OBJ, 3DS, 3DM, and many more 3D formats. You have to be able to import the 3D into Rhino 3D CAD software. We will also take a 2D file grayscale image file with the image color representing height. We might also take vector formats Adobe illustrator or Corel Draw.

We will be using green wax for the coin.

Shipping – US mail only, $2 for the first and $1 for each additional wax. You can combine auctions.

Payment is by Paypal only.

This auction is our first offering in this process. We will be writing better auction description, FAQ’s and pictures soon. For now please ask questions.

Please email me at paul@paulkrush.com if you have any questions.

In the field of rapid manufacturing and mass customization of small simple items:

• To provide an entertaining and challenging experience for site and local Pro-Am users.
• To connect small businesses and individuals around the world.
• To provide a very large open database of simple manufacturing models always free of charge and unrestricted.
• To be an in depth source of information and training both on and offline.

This mission statement has deep meaning to me and took weeks to write. I love this mission, and have been working on piece and parts for over ten years. You would not think 69 words could mean so much. At the core this is a business of providing experiences. I am creating a new type of hobby. One that can pay for itself, or even is profitable depending on how people pursue it. I see the PaulKrush.com website being a super-connector for people and information in this subject. We will become the franchise holding company for this hobby/business. PaulKrush.com is going to help create jewelry stores in which the customers fill the cases. It’s ground breaking in one sense that it is going to happen, but simple in the fact that people have talking about this stuff for years.