Hi I'm Bob Badger. I wanted to be an engineer 50 years ago but was talked out of it. Since I'm about to retire this is my chance. I've bought a Harrison M250 Lathe and a milling machine. So far producing some small precision components for optical equipment (and some less precise parts for a 100 year old machine) under instruction from a qualified engineer. I now need to install digital readout on my lathe and would appreciate some advice from anyone who has installed DRO on a Harrison M250 lathe. On retirement I plan to make model engines to my own design.
Wecome Bob,
I can't help directly with a Harrison M250 but I have fitted a DRO to a Boxford 1130 which is a similar sized machine.
I don't know if you intend to fit a glass scale type DRO or one of the much cheaper digital caliper type. The glass scale ones usually have a better accuracy and resolution. The resolution is usually 0.005mm which means that one increment is equal to 0.01mm on diameter. The SINO display has many features which I've yet to explore including storing the offset settings for several tools. The functions on the caliper type displays tend to be very limited.
[Edit: I now notice that they are offering 1 micron resolution scales now!]
Mine is a SINO and I got it from
http://www.digital-caliper.co.uk (usual disclaimer) at a good price. (They were open to a little bit of haggling over price - they weren't quite the cheapest but they do offer a 3 year warranty.)
The Display is a universal 2-axis one (SDS6-2V) which can be configured for a lathe or milling machine.
I used a standard sized scale for the y-axis (length of lathe) which is mounted on the machined surface at the back of the lathe. For the x-axis (cross slide) I used a smaller section scale (KA500) which is mounted to the right hand side of the cross slide. It's protected with a substantial cover (made from 3mm thick aluminium angle) which protects the scale from swarf and from impact when sliding the tailstock up to the cross slide.
Various mounting accessories were supplied but I only used the cover for the y-axis and the swivelling mount for the display - I found it easier to make new mounts for the scales rather than codge together the universal bits they supplied.
I spent a long time thinking about how and where to fit the scales so that they didn't get in the way of any adjusting screws or lubrication points.
I can't get access to take any decent photos of the y scale without removing the splashback on the lathe and I can't do that without moving my CNC miller and......... This is the best I could do and just shows the bottom of the bracket which holds the scale reading head to the saddle.
If you need any more info/help just ask.
Cheers.
Phil.
