Several people have asked me about my milling setup, and so I decided to write a bit about my setup, and getting started with your own setup. This will serve as a very basic guide to setting up your own mill. Milling allows for a very large degree in freedom not just in modifying locks but you will most likely find many other uses for it too. You may be surprised how useful you find it to have a mill, once you have one around:)
Sorry for the delay in getting the milling article published. There were a few lock events/conferences that I was hoping to have it done before but unfortunately it did not work out that way. It is important to keep in mind that I had no previous metalworking experience. I do have a few friends who are professional metalworkers but I have had no formal training. Most of what I say here is from my personal experiences and please make sure you understand what you are doing, I cannot be held responsible for anything resulting from this article. You should also try to keep in mind that the money it takes to get started will most likely be far more than you are first expecting.
The first item you need is a mill. There are many different mills out there from micro mills that are the size of a printer to 1000-2000 pound floor standing mills. When looking at a mill you want to look at how big of an item can it handle, how precise is the mill, and how fast can it go. Contrary to what you may expect you can sometimes pickup a second hand floor standing mill for not much more than a table top mill (provided you have the room and the space). The smaller the mill the smaller the bits and the slower you will be able to remove material from your work piece. I wanted to go with a new table top mill due to space limitations and my unfamiliarity with milling in general (so not wanting to worry about possible problems of a used mill). I do sometimes run into its size limitations (specifically on the Z axis), but for most items it is not an issue. Using a smaller mill does require many more passes over the same piece due to the fact it cannot remove as much material on each pass. If you decide on a tabletop mill there are many variants of the Sieg mills that are sold by companies like Grizzley or Harbor Freight, but they all have the same base model.
Once you decide on a mill the first item I would highly recommend is a good digital read out (DRO) kit. These will run at least around $400-700 or so dollars but are a must. The DRO controls give a digital readout of the position of your three axis so you always know where the piece is relative to a specific point. While all mills will come with some sort of gauge for each axis they can be hard to keep track of, and you must take into account the backlash when you change directions. I tried using my mill for a few months without DRO controls and it resulted in damage to a few locks to say the least. They are especially needed for table top mills when you need to make many passes to cut to the desired depth, and if you are off by a bit it will not look good at best.
Another item you most likely may be interested in are CNC controls or simple automatic feeders. An automatic feed will just replace the need for you manually to feed the piece and will do so at a very smooth rate. Automatic feeds are far cheaper than CNC controls, however they also have no real programmability meaning they run until you turn them off or they reach a manual stop. CNC controls are where you have a computer able to control the machine without you doing it manually. CNC controls are not always beneficial as when you are not sure how you want to cut a piece being able to manually eyeball it can be very advantageous. CNC Controls are also generally very pricy to add to a machine. At a minimum I would hold off until you become proficient at milling before looking at advanced controls.
Once you have your mill setup you will need some other items, one of the most important being a milling vise. This is a precision vise that will apply pressure very evenly, and is guaranteed to be parallel to your base. You do not want to buy a cheap vice, if you can’t count on your vice being accurate it will be far harder to get good, accurate, results. Next you will want some parallels, these are pairs of precision machined rectangular metal pieces that are also guaranteed to be parallel from top to bottom. They allow you to raise your work up off the base of your vice as needed. Frequently you may need to mount a piece that has a part you want to mill below the jaws, using parallels you can raise it to the proper height. On most of the locks I work on I am raising it above the bottom of the jaws, so don’t skip on getting some parallels. Next you will need a dial indicator, the dial indicator is a very precise measuring tool that you use to do things like align your mill, or install the DRO controls. Finally you will need some actual end mill bits, and some coolant. These are the very basic items I would highly recommend for anyone getting into milling. Some additional items you may find useful are digital calipers (for measuring items), angle blocks (used for mounting pieces at an angle on your workbench), and a tap and die kit (used for creating threads and threaded holes).
Now one item I glossed over were the end mill bits themselves. These are a very important part of milling, and come in a variety of options. The four primary factors are the width of the bit, how many flutes (cutting edges) it has, the coating/material on the bit, and finally if it is center cutting. If possible when you are making passes on a piece it is far more useful if the width of the bit can match the width of whatever hole you are cutting. Aside from not having to widen any cuts, or keep exact track of how much you adjust, the finish itself will be better and you will save a lot of time. It is useful to have bits of varying widths available. The number of flutes a bit has will affect the finish and amount of material you can remove at once with the most common (and frequently cheapest) flutes being two flutes. The coating/material the bit is made from will affect how frequently you will need to replace your bits, and how hard of a material you can cut. Unfortunately if you are getting into milling to cut locks you may end up cutting some very hard materials. Finally by definition an end mill bit is one in which you cut at the work from the side, rather than top down like a normal drill. Some end mill bits however have flutes that extend to the center of the bit allowing one to ‘plunge’ into the work like a traditional drill bit in addition to attacking it from the side.
Once you have all the tools you need you can start to prepare for using your mill. The first thing you need to do on any mill (new or used) is to ‘tram’ it or calibrate the head of the mill this ensures the mill is truly parallel to your work bed which is important to get smooth, clean, accurate cuts. Your mill will most likely include instructions for using a dial indicator to tram the mill (or you can find many guides online). After you have trammed your mill you will want to bolt your milling vise down to the table, and then use your dial indicator to make sure it is also mounted properly on your mill. Next I would recommend installing the DRO controls using the instructions they came with. It may seem like a bit of a large task to do if you have not done much machining work (as it may involve some milling of the parts) but it is well worth doing upfront. If you can find a friend who is more familiar to help with this as you want to make sure they are installed well.
If you are looking for a place to buy many of the tools/accessories listed here (and many others) the site: http://littlemachineshop.com is very useful.
Now you should be ready to start milling, good luck!1 comment
1 Comment so far
Leave a comment