Hello welcome to Enots engineering. I'm Alan
This week we're looking at DRO scales and the readouts for the lathe
This is a two axis scale from Banggood
we'll be looking at what you get in the kit with this
and also be looking at how to fit scales to the lathe
This is one of the scales will be fitting one to the bed of the lathe
and then one to the cross slide
So let's go to the workshop and see how we do it
Well today I've had some parcels arrived from Banggood
I will show you what they are
First of all we've have the instructions in English for the digital readouts
A power lead now this power lead is not a UK type power lead
That sockets okay but this socket is a none UK
So I found a lead I can use instead of this
this is a standard UK lead three-pin plug on the one end
and the same socket on the other end. You can get these for monitors or for kettles
or you could chop the plug off the end of the one supplied and fit a standard three-pin UK plug
The display this comes with this plastic cover which you can take off
it stops the dirt and oil on your hands getting on the keyboard
and on the back it has some cutouts for the cables to go through,
I'll take that off now so that the light doesn't reflect off the plastic.
This one's a two axis X and Y you can get them with the third axis which is there knowing what I know now
I would buy the readout with the three axis because it's only a few pounds more
and you could use it on your milling machine or the lathe
the internal programming is the same
well turn it round on the back you have your on/off switch the plug for your power supply
and the two sockets for the x and y-axes
If you're thinking of buying one I'd go for the 3 axis they're in identical cases
and you can change the program to say whether it's fitting a lathe or a milling machine
you can swap the negative and positive so if you're traveling towards your chuck and it's going negative
you can change that in the program
If I just run through what we have
we have X&Y readouts we have a screen for information
it could also display what sub datum you're on or the answer to any calculations
You have a calculator which is a standard calculator
it has sine cosine tangent square root you can convert from metric to imperial
just by touching this button at any time without losing the position of the x and y axes
you'll just swap over instantly from metric to imperial
You have an Enter key cancel key and down the bottom here
you have programs for drilling holes on pitch circles and the key to change from
absolute to relative position on the readouts
and SDM is for sub datum
you can store up to 200 sub datums and when the power switched off it will
remember those positions
these are the zero buttons for the scales and if you
press the Y or the X enter button you can put the size in
So if you're at the end of a bar and you're lathe you can touch the tool on that
and then if you want to go in 10mm you just press the X or Y and enter the distance on the keyboard
and then that will put the 10 mill position in the readout
and with the readout you also get a mounting bracket
I'll just get the parts out
The scales are glass scales and I was surprised that there were no instructions or documents at all with the scales
I would expect some guidance on to how to set the scale and what distance sthe sensor needs to be from the scale
but there was nothing at all
you also get in the kit a bag of screws nuts and some cable ties
for fitting the scale
you get the bracket for fitting the reader too it's the same bracket whatever scale you buy
The scale comes with the cable already fitted let's move the display out of the way
we can look at the scale you can get other scales so this is a glass scale
buy that what we mean with a glass scale inside here is a piece of glass
and on the glass is marked or etched divisions so as this reader travels along it reads the divisions
you can get magnetic scales which are very similar to the scale on a digital caliper
they are a lot smaller and probably be more suitable.
this is a section of the material used to hold a magnetic scale
all it is, is an extrusion you can see it's smaller
nearly half the height it's a bit wider than 19 millimeters about 20 but this
you get in a length and you just cut little into whatever you need
the magnetic tape goes in this groove here and the magnetic tape is in in a length as well
it's sticky back so you just cut it to the length you need
and the head is smaller. Then you might think about why didn't I go for that
And the reason is the magnetic scales for some reason are four or five times the cost of a glass scale
so I thought well I can have two or three of these easy, for the price of one of these
The other thing you get with the scales are these aluminium covers
There just an extrusion -see that- and you just screw that over the top
On the end you have the plug which fits to the readout box that's held on with two screws
and scale itself. Now the scales are held onto the machine with two screws
one through the side or through the end on both ends so you need to drill and tap
Two holes into your bed or your cross slide to hold the scale
and the reading head here which is held on temporary with the cable ties.
that fits to a bracket which is supplied with the part here's the brackets and that bolts onto your machine as well
So the first thing you need to do is measure the length of travel of your machine before you order the scale
Because when you get the scale it'll be longer than the length of travel this one's a 200mm scale
and it's 340mm in length and that's because on the scale the readout
is in the middle where this little arrow is and when it moves to the end
it's a good inch and a half in each end to get the read out length that you need
the scale will therefore be longer
let's say you've measured your machine and you want a 175mm of travel
Looking at the scales they come in 50mm ranges so you could have a 150 mm which would be too small
or the next size is 200mm which you would fit so when you purchase your scale you'd ask for a 200mm
but it actually come out another 140mm longer due to the reader width and the end fittings
I'll plug the readout into the back of display
on the back of the display you have your two inputs
or three if you bought the three axis one so I'll plug the cable in there
and it has two screws to hold it in position the mains voltage is 80 to 265 volts
At 50 to 60 Hertz I plugged the mains power cable in at the bottom
and switch on the power
It does a check, Check through its system and displays the results
now I'm not going to go into detail at the moment on this because it gets a bit boring
all I will say you've got X Y and you might have Z if you buy the three axis one
this is an information box that's just telling me that sub datum number one is here
you can Zero X and Y any position. If I want to put 150mm in X press X and 150 enter
and it will start at 150mm
if you want to work in
Imperial you just press this button millimeter two inch and that changes it
instantly from millimeters to inch it remembers both so you can switch between
millimeters to inch as many times as you like it still remembers it if you switch
this off it will remember the position and the subtitles that you've saved with
the subtitles here you can feed in up to 200 different positions which could be
tool offsets as this scale moves you can see the digital reading moving
I think really there's too many decimal points there for inches
if you go on to metric you've got three decimal points
At the bottom here you've have some other features but for the Lathe these are not used.
There use for milling machines for hole positions and putting pitch circles in
We will now look at how I fit this to the lathe
This is the lathe at the moment what I've done to get better access
I've taken the carriage off the top the cross slide compound slide.
all I did to do that was undo two Alan screws that go in the front here
and two that go under the back to hold the saddle on
I can take the saddle off
and I've taken the tail stock off to give me access to the back easier
it was either that or remove the lathe from the cabinet and put it on the workbench
which I didn't really want to do is a lot of work to do that
Just get yourself a piece of steel and drill a hole in the steel which is the size the tapping size for the screw
This steel will be the guide to make sure that when I'm drilling the bed I'm square
The size of the screw is 5mm and this
is a 4mm drill so that's one thing you'll need and the other thing is
a clamp should be able to clamp under the bed to clamp the piece of metal in position
Now what I've done before that took the saddle off I move the saddle
fully down this end and I've marked here the farthest it moves down and then
I moved the saddle fully down this end and I've put another mark down
this end where the saddle moves down I know that my scale has to be within those two marks
In other words the reader on the scale has to travel at least between those two marks
that gives me an idea of the positioning also bear in mind
that when the saddles on there's a clamp that goes underneath this part
of the bed I can't come too high I need to leave a good half inch between
The radius here of the casting and the top of the scale. To still put the cover over once it's fitted
Now I've got the scale and on the scale I have marked
70mm in each end and I put a black mark and that is the length that the scale will move
That's the 500mm the other bit on each end is the extra to allow you to bolt it down
That's my 500 mil mark that mark needs to at least be where the red mark is so
at least at least I need to know that I can get there you can see down here I've
got a problem already I have to move it slightly off so I'm not in this hole in
the casting we can just get in on the end of that red mark if I put it there
so what I think I'll do first is drill the hole in this end
I've of clamp this block of Steel with the hole in for the drill in the position I want the hole to be
and that's just a matter of drilling the hole
about 10mm so that should be okay now I can take the clamp off and the steel
and now just tap the hole
Thats okay
Now using that as a location I will bolt the scale on and then mark the position of the second hole.
Well that's the scale fitted this reader will slide along the scale
and I hope the cover will fit it will go over there
Now I've fitted the bracket on to the sensor and I've used the four cap heads that come with the kit
and the four washers but I've added four spring washers just in case these come loose over time.
So now I'm ready to finally fit the scale on the back
I'm making sure I have this the way round I want with the cable coming towards the headstock
I've made some aluminium spacers that go on the back of the scale
just to bring it 3mm off the casting
because I noticed the scale was trying to bend which means that the casting
has either a lump in it or it's not perfectly flat
Thats going to be a problem here because underneath this I've have another piece of steel to go on
this end is -0.01mm
and the other end is -0.01mm
so I think that's the top of the scale level
Well that's it for this week we'll carry on next week
fitting the sensor and then start work on the cross slide
I hope that was useful hope you enjoyed it and we'll see you next time
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