Jet 1024P - Construction and Build

You might remember from my last post that I’ve acquired an old Jet 1024P metal lathe. The machine is solid but appears to be poorly [if at all] maintained and extremely dirty. In process of removing what looks like three decades worth of chips and grease, I was finally able to closely inspect the lathe, and even run the spindle for a few minutes. I will reserve the final judgement on the condition and quality until the overhaul is done. On the other hand, I have a good idea of the features and the construction. Since I’m upgrading from a 920 lathe, this will be somewhat of a side-by-side comparison of features that I’ve found to be important for my particular needs.

My New 30-year Old Jet 1024 Lathe

Late '70s Jet 1024P Lathe

This weekend I picked up an old (presumably late '70s) Jet 1024P lathe. Surprisingly, there is little or no info on the internet about this machine. I suspect I'm not the only one having trouble finding the information, therefore, as I'm working through the lathe, I will be posting detailed write-ups and pictures.

Gumdrop Case to Make Galaxy Tab Garage-Worthy

7" Galaxy Tab 2 in Gumdrop Protective Case

Swarf-covered mill or lathe is hardly the an ideal environment for a brand-new Android tablet. I have a bit of OCD when it comes to keeping my toys in mint condition, therefore the first order of business for me was getting a protective case for my brand-spanking-new Samsung Galaxy Tab 2. None of the local stores carried any cases that looked remotely rugged. Online, though, there are several cases that looked promising, ranging from $10 for a generic silicone case to $70 for a top-of-the line Otterbox. At the end I took a bit of a shot in the dark and ordered one of the Gumdrop Drop Tech cases four around $60.

Choosing an Android Tablet for the DRO Application

When I started the Android Digital Readout project my only tablet was a rooted B&N Nook Color. At that time it was one of the few tablets that could be had for under $300, but it came with a few limitations. First of all, it required rooting to be usable, which voided the warranty etc. Second, the Bluetooth was included “by accident”. While Bluetooth was a part of the wireless chip, the feature was not fully implemented on the hardware level, and was lacking an antenna. This reduced the range to a few feet at most. Finally, even the custom ROMs only went up to Android v2.3 [Gingerbread]. There is nothing inherently wrong with this particular version, but Honeycomb (3.0) and Ice Cream Sandwich (4.0) have much better tablet support.

Android Digital Readout Micro FAQ

Since I first posted the screenshot of my Android DRO app I've received a lot of questions and feedback. Additionally, there have been discussions about the project on several forums and groups I read. In this post I will try to provide some answers and explanations as a mini-FAQ.

Android Digital Readout Source Code

Main screen of the Touch DRO Androd app

Since posting the screenshots of my Android DRO application I've received a lot of feedback and a number of requests for the source code. As I said before, I intend to post the source code for the whole project, but the last few months have been insanely busy, and I didn't want to post broken code. Over the last few weekends I was able to clean the project up and get rid of the "failed experiments" code.

Arduino DRO Serial Protocol Considerations

Last time I posted the schematic and firmware code for the Arduino DRO, for reading the iGaging scales. The plan is that the Arduino will read the positions and send it over UART to the app running on Android tablet via an inexpensive Bluetooth module. The nice part of using a serial-to-bluetooth adapter is that it's completely Plug-and-Play, so the hardware layer isn't too complicated. On the Arduino side we simply connected the Rx and Tx to the Tx and Rx on the Bluetooth board respectively, and provided power via Vdd and Ground. On the Android side all you need to do is to pair with the device. These Bluetooth modules use the so-called SPP (Serial Port Profile), also known as RFCOMM. When the controller is paired with the tablet it will behave like a regular serial port.

Arduino Wireless Digital Readout (DRO)

Application screenshot taken from Nexus 7

Recently I started working on a new version of my DIY digital readout project to that uses an Arduino DRO controller and an Android tablet. The DRO I'm building for my milling machine uses three inexpensive iGaging scales. (The whole set for my Hardbor Freight Mini Mill set me back less than $100 on amazon, in fact.) Since the bulk of the functionality is handled in the digital readout application, the controller design becomes much simpler, requiring only a few extra components. The parts list

In reality I've been toying with the software-based design for some time, and even wrote a basic desktop application on my computer. I scraped the idea of Windows application because without a touch screen the unit would be too cumbersome. When my Nexus 7 arrived in late July, it only made sense to use it for the DRO display unit. I've done some Android programming before, so it didn't take too long to get a basic app up and running. The app in the screenshot is a crude proof of concept, but I should be able to post a working version in a week or two.
As I mentioned before, my unit uses three iGaging scales and a controller based on Arduino UNO board to read them, as shown in the schematic below.

DIY DRO with Arduino and Android

Google Nexus 7 Running an Early Version of DRO Application

UPDATE October 2022: Since the time of the original posting, I've developed a few new designs that perform much better, work with more scale types and read the scales more reliably. The latest version uses an ESP32 wireless module. You can find the circuit diagram and instructions on the ESP32-Based DIY Digital Readout. Other designs that use MSP430 LaunchPad development board can be found in the Do-it-Yourself DRO Build Instructions

Having a full-featured DRO on a milling machine or a lathe would, no doubt, be very convenient. Unfortunately the cost of commercial units is very high, so the only way I could afford one would be to go the do-it-yourself route. My initial plan was to build a tradition digital readout unit using six 7-segment LED displays per axis and an ARM microcontroller (STM32VL Discovery Board). To build the first prototype I used the free version of Atollic Studio. Even though it was "crippled", compared to the full version, at least there was no code size limits. Well, as of the last version, Atollic added a code size limit so I decided to scrap the idea of an ARM-based DRO. Instead the DRO would consist of an Arduino-based scale driver and an inexpensive Android tabled as a readout display.