Following a successful Part 1, we will show you more measuring tools, followed by some milling and lathe operations.
Note that our post is written as a general intro for our hobby community, we are using our own tools from Binary Taskforce R&D lab for simplicity reason. Hope our write up can provide assistance to you in the future for your RC modeling and hobby needs. Please visit our Flickr page for larger photos.
More Measuring Tools
Clockwise from top left: Metric Screw pitch gauge, Metric Radius gauge, Center gauge, Tool for drilling a center hole, Edge finder and Feeler gauge set.
Metric Screw pitch gauge and Metric Radius gauge
Metric fasteners (i.e. screws, nuts, bolts) are popular amongst RC hobby kits from Asia, where most parts are designed and measured in millimeters (i.e. M5 x 20 socket head). If you need to find out the thread pitch of any metric screw, simply match each blade against the thread, if you find a complete match from start to bottom, read the pitch shown on the blade. Radius gauge works pretty much in a similiar fashion, just match blades against an unknown arc.
More info. on metric ISO thread standard.
Two center gauges are shown next, one (looks like an arrow) is used for lining up cutting tool on a lathe. The next one (looks like an inverted “Y”) is to be mounted on drill press (not milling machine, its no where close to precise), see bottom picture. It allows you to quickly drill a centered hole on a round.
The small round cylinder is an Edge finder, this tool lets you precisely determines the edge of workpiece in relationship to the spindle of the machine. Here is video on edge finder how to.
Last tool is the feeler or thickness gauge, a tool with many metal pieces of various thickness. You can take them apart and use individual piece for parts alignment and measuring purposes. Here is a how to on feeler guage.
Desktop Milling and Lathe Operations
Most Aluminum alloys we use in our lab are in 2000, 6000 and 7000 series. Nope, you won’t find them from Home Depot, you buy metal stock from Metal supply store (i.e. Online Metal Store or Metal Supermarkets), they carry metal stock for various purposes. Beside Aluminum, we also use Brass, Nylon and plastic.
Featured in our previous blog, our desktop milling machine is a Harbor Freight Two-Speed Variable Bench Mill/Drill Machine equipped with DRO, we often use it to scratch build prototype parts. However, the new emerging 3D additive printing technology may soon take over. We have no CNC, everything is basic, manual cranking, turn-by-turn milling.
The machine uses collet with R8 taper. Below left photo shows drill bits and end mills on the left and four collets on the right. To install an end mill, end mill is first placed in the collet, then the collet is placed into the milling machine’s taper. Using drawbar, the collet is tightened from above the spindle.
Photo (Right) shows more Drill bits and End mills
Holding your work!
The workpiece must be stationary and holding securely before start of any milling work. Yes, we can use a milling vise (Above left) to clamp it down. Sometimes you need parallels (Above right, there are four parallel sets and they do come in pairs) to elevate the workpiece on milling vise so that it can be machined.
You use a fly cutter (Above right picture, top right) to prep your workpiece, fast! Fly cutter takes shallow face cut that covers a large area with good finish.
Milling and Making holes
To make accurate sized hole with tight tolerance, you need a boring tool (Below left photo) or a straight Reamer (Below right photo, in the middle)
(Above right photo, from left to right)
- Center drill – Use this to start a hole for larger drill bit. Remember always drill past the taper to create a funnel to guide the bit in!
- A 2 flute end mill – Regular end mill for milling operations
- Metric 8mm straight reamer – For making accurate holes
- Metric 4mm counter sink cutter – For making counter sink M4 socket head
- Boring bar for boring tool or a lathe – For large accurate holes beyond drilling
Desktop Lathe operations
Our lathe is a Craftex 7″ x 8″ model B1979C lathe, we have it since 2004. Web site mini-lathe.com writes exclusively on these mini machinery with full introduction, how tos, tips and other valuable information. The picture (Above left) is our lathe with standard 3″ three jaws chuck and (Above right) is a bigger 4″ four jaws chuck.
Work holding on a lathe:
Inside and Outside jaws: The above picture (Top left) shows a 4″ four jaws chuck with “inside” individual adjustable jaws. The bottom check is a 3″ three jaws chuck with “outside” jaws. Note that the outside jaws have concave gripping surfaces and can hold much larger workpiece. The next photo (Top right) shows individual key behind each jaw for separate adjustment.
Facing, Turning and Parting
Facing is a workpiece cutting process where cutting tool is right angled to the workpiece rotating axis. Similar to facing, Turning is a process which cutting tool is moving along, parallel to the axis of workpiece rotation. Parting is a facing process using a special parting tool, the finished workpiece is completely cut off from stock.
Boring holes and drilling
Of course, you can bore or drill holes on workpiece on a lathe. First, boring is a process to enlarge a hole using a single point cutting tool, it started with an existing hole and we keep enlarging it using the boring tool.
For regular hole drilling, you will need to have a drill chuck mounted at the tail stock. Here is a how to.
Wow, this is a long post. Part 3 is next.
All the best.
- Part 1 – Previous article on Height gauge, Calipers and Dial Indicators
- Part 2 – This article you are reading now