Make A CNC Milling Machine

Make a CNC Milling Machine.

I recently decided that I wanted a CNC Milling Machine to add to my workshop. A CNC Milling machine will allow me to do my prototype work in my workshop instead of using a service.

Now CNC Milling Machines are not cheap. they can cost tens of thousands of dollars. I am not made of money so I guess a $50,000 CNC Milling Machine is out of the question. But what if I #Make a CNC Milling Machine instead? Could  I keep the cost down to a level that won’t break the bank? Can I get decent performance without having to take out a new mortgage on the house?

My original plan was to modify my Harbor Freight Minimill to use CNC. This would be a quick project because I already had a Minimill and it would greatly reduce the cost of making the machine. So I did some research and found a set of plans online from http://stirlingsteele.com. I ordered the plans and began to fabricate the parts  to make the conversion.  It was a good set of plans and the

work went fast. However  as I got further along into the project I began to realize that the Minimill was just too small for my needs. I was lucky because I hadn’t spent a lot of money on the upgrade so far since I had been using materials I had on hand to make most of the parts.

Grizzly G0704 Milling Machine CNC Conversion

I have been doing a lot of metal working lately at work. I am an instructor at a local college and I teach a Mechanical Engineering Technology program. One of my responsibilities is to teach the students how to use CNC milling machines to fabricate their projects. During the school year, we get to make all sorts of things on the CNC Mill. So by the time summer rolls around I am having withdrawal symptom for the CNC Mill.

Opening the box I felt like a kid in a candy store.

I began to think how nice it would be to have  a CNC mill of my own. Well buying a $60,000 Vertical Machining Center is out of the question until I hit the lottery. So if I wanted a CNC mill about the only way I would be able to afford it is if I made it myself. So I began looking for a small manual mill that I could convert to CNC.

Most people would be afraid to tackle a project as complex as a CNC Milling machine but not me. I have already built several other machines including a CNC router table so I feel confident I can tackle this project. Most projects can be tackled if you take it in small chunks and especially if you follow in the foot steps of someone who has done it already.

I looked around on the web and found a number of Youtube videos that showed completed machines that people had built. I began to notice that a lot of people were converting a milling machines made by Grizzly Tools., the G0704.

A bit more research found a DVD available from Hoss Machines which had plans to convert  the Grizzly G0704 to a CNC Milling machine. The DVD offered a bunch of additional projects and choices and was money well spent. After reviewing the DVD I decided to go in  a slightly different direction.

 Why do you need a CNC Milling Machine Anyway?

Before I get too far into the project you might be wondering Why do you need a CNC Milling Machine Anyway? Most people never have a need for computerized milling machines. But I do. For one thing  it is my hobby. Another reason I need a CNC milling machine is to make parts for my business. I currently have several parts machined from a 3rd party source and I would like to bring those parts in house so I have better control over the finished product.  Bringing these parts in house is also the only way I can compete with larger businesses.

I took the crate off but the mill is still attached to the pallet.

There is one other reason I need a CNC Milling machine and that is to do my part to bring manufacturing back to the U.S.  When I was a kid there were machine shops all over the place and now they are few and far between. More manufacturing here in the U.S. means more jobs here in the U.S. I would love to see the cottage industry movement revitalized. That is what making is all about.

Lastly, let us not forget the huge number of Geek point I will gain. Enough said.

I chose the G0704 milling machine because it had one of the largest cutting areas of the mills in it’s price range. It had a very long X axis  (left to right and a very high Z axis. With some modifications the Z axis travel could be vastly increased to nearly the same as a knee mill.

The only area where the mill fall short is in the Y axis travel. However I intend to open the Y axis up and add a few more inches of travel.

Another reason I chose the Grizzly G0704 is because it matched the tooling I already owned. I have a Harbor freight Mini-Mill that also uses the R8 tooling.

Another reason I chose the G0704 is because there is a large body of information available about it online. Obviously it is an advantage when you have others who have documented their changes before you begin. Knowing that any changes you make to the machine voids your warranty really forces you to focus.

 What I bought and why.

This is my third milling machine so I have a good idea of the accessories and minimum features I wanted.  One little know about owning any machine tool is that you sped as much on accessories for the machine as you do for the machine itself.  Because I knew this, I factored that into my budget before I ordered the machine.

I looked at the tooling I already had for my Mini-mill and decided what types of machining I was likely to do but didn’t have the tooling or fixture for.  Since both machines used R8 collets and I already owned a collet set, I decided not to buy a conventional collet set for this mill. I did however want to make tool changing easier and faster, so I looked at the TTS system from Tormach.

The TTS System consists of a specially shaped R8 collet and a series of specially designed tool holders that fit the collet. Because of the way the tool holder is machined, each one fit the spindle in a precise, repeatable  way. Many Makers are using the TTS system tool holders as a basis for an automatic tool changer. A starter set is available for around $190.

There are also several vendors who make compatible tool holders which fit the TTS collet. I talked with some machinist who had tried these off brand holders and got good reviews. There is also a video that teaches you how to make your own holders if you like. I ordered the TTS set from http://littlemacchineshop.com

One other thing I ordered was a mobile base for the machine. Most of the tools in my workshop are on wheels so that I can easily rearrange the tools when I need them or roll them out of the way when I don’t need them. The base I got was the Shop Fox Mobile Base G8683. It includes leveler  feet as well. I also ordered a set of step blocks from Enco tools http://use-enco.com.

I also ordered a Vice from Shars.com. The vise is a 4” CNC vise which is flat on all sides so that it can be mounted upright or on it’s side. The vise is a lock down vise. That means that as the vise is tightened  the workpiece is clamped with a downward pressure and locked in place flat with the vise face.

Moving Heavy Equipment

So here is a short list of things to consider before moving heavy equipment.

1. Have a professional do it if you can. The pros will have the proper equipment on hand to do the job.

2. Get help from several strong friends.

3. Have a game plan before you get started.

4. Lift with your legs not with your back

5. Rent a Material mover or an engine hoist.

6. Use a chain winch.