One of the important things about using the lathe is keeping track of how much material you're taking off, once removed it's very difficult to put it back on..
Don't forget to divide the amount you want to remove from the diameter by 2 as you are removing material from both sides .. sort of.
Using the dial on the slide is OK but I've seen lathes with digital readouts, how much are those I wonder?
- On a milling machine a 3-axis DRO shows the X- and Y- positions of the mill table plus the Z-axis position of the cutting tool. On a lathe, a typical 2-axis DRO shows the positions of the carriage and the cross slide.
- Here are some details on the installation of linear scales on my 9x20 lathe, and the DIY DRO and speed controller I built for it. Linear Encoder Scales. I originally purchased a pair of Chinese style scales to use on my lathe.
After some research I found a really good alternative to the standard slides and readouts available from the usual suppliers, I found a DIY version for around a fiver (£5) plus a bit of DIY.
Dec 29, 2009 A Homemade DRO for the 7x Mini-Lathe By Rob on December 29, 2009 The DRO uses an inexpensive digital dial indicator that's held in place on the apron with powerful rare-earth magents. The stop clamps to the top of the cross-slide and presses against the indicator's plunger, which measures the movement of the cutting bit. Mk 11 characters dlc. The DRO-350 is a three-axis digital read-out (DRO) for import Chinese scales and most quadrature encoders that is designed to be as capable as commercial DROs but be a low cost alternative for the metal-working hobbyist. The DRO-350 is a do-it-yourself (DIY.
It's based on this digital LCD tyre depth gauge off ebay. It's basically a variant of the digital vernier but without the sharp pointy bits.
I attached mine on the cross slide by mounting a piece of steel plate using the travelling steady mounting holes (at least I think they are for the travelling steady) this then allowed me to use a magnet to stick the body of the gauge to, the end of the plunger has a magnet glues to it so that it will stick to the cross slide. It could also be stuck on the lathe bed and measure the saddle travel.
| My DIY DRO attached to the lathe |
One of the problems with the mini lathe is actually finding space to mount the gauge as there's not a lot of room.
What I like to do is touch the tool to the material to be cut and set the DRO to '000' then move to tool to the right and move in the tool until I've reached half the amount I need to remove then reset the DRO to '0.00' and then turn down the material until I reach the '0.00' point and that's that.
So far I've found it quite accurate but noticed that it gets covered in swarf when in use, I thought about forming a piece of thin perspex to curve round the gauge and protect it from chips but then found an empty rectangular packet in the recycling bin that was about the size of the gauge but made of clear plastic, thin but strong enough to keep it's shape, this slid over the gauge and protected it completely and was flexible enough to still be able to press the buttons.
| DIY DRO with plastic cover |
Comments/ideas/feedback welcomed.
The remaining gauges have been attached to the DRO. There's now 3 gauges on the lathe and three on the mill. All of the gauge channels are now populated and attached:
Each card has a PIC on it that converts from the gauge serial protocol to I2C. The main ARM processor then interrogates each of the relevant gauge channels over I2C and displays the values.
Each of the gauge channel PCBs is identical, the firmware is almost identical, the only difference is the I2C slave address, which is 0x30 and 0x40 for each pair of PCBs on the same I2C bus. There's three I2C busses.
The main DRO PCB has an ARM processor on a commercial LPExpresso card:
The TFT screen is a touch screen and there's a menu system running on it. The DRO can be set to display the lathe channels or the mill channels. The smaller OLED displays then show the appropriate axis tags. When running in lathe mode the two X axis values can be added together.
The gauges have been attached with 3D printed plastic mounts. I may re-make them in metal if they aren't rigid enough.
The gauges are held in clips that can have screws clamping them from the sides:
I've removed the buttons from the gauges if they were pressed by the clips. The buttons aren't needed and you also don't need to read the displays as the DRO does that.
The batteries aren't needed either as the DRO channels all have a 1V5 power supply. The gauges run from that and are powered all the time the DRO is powered. The power down of the gauge display doesn't stop the serial data stream, either, which is nice.
The mill X gauge is mounted in a similar way:
The Y as well:
The Y as well:
Diy Lathe Machine
And the Z gauge:Diy Metal Lathe
The lathe bed gauge was one of the more complicated mounting arrangements.Diy Lathe Dro For Sale
I've started to use the DRO and it certainly makes measuring things much easier. I need to check that the gauges are working correctly by comparing with a dial indicator.Diy Lathe Machine
