Tony Bird
Senior Member
Hi,
For some years I have been considering fitting a DRO to my 40 year old Myford Super 7B. As well as the cost of buying a DRO the prospect of having to move the lathe to fit the saddles linear scale and encoder was a little daunting (001).
At the Bristol Exhibition held in August this year a more reasonably priced DRO was on offer a EMSI system that was suitable to fit to a Myford. Its price reduced one of the problems so it was decided to buy the DRO kit and try to fit it without having to move the lathe (002).
I had previously fitted an inexpensive DRO to a much modified equal inexpensive Chinese Seig C-O mini lathe where it has been very useful (003).
The EMSI DRO units came very well packed and contained a digital display with a mount, 2 magnetic encoders, a 300 mm and 900 mm long linear scale and a fitting kit (004).
The first and easy job was to fit the digital display to the workshop wall above the lathe (005).
Before starting on the assembly some research was done; a friend who had fitted a DRO to his Myford sent me some photographs of his installation (006 & 007).
At a engineering show I took a photograph of a DRO system that didn’t require holes to be drilled in the lathe to fit it (008).
Neither of these products are the same as the DRO purchased
Not having to drill holes sounded attractive! It was obvious how the linear scale was fitted to the cross slide using modified T bolts. Looking at the back of the bed the linear scale used the screw holes that were intended for a taper turning attachment. The mount for the encoders was held by using the bolts that secured the rear saddle strip to the saddle (009).
This system looked like the way to go, so two modified T bolts were made (010).
Clearance slots were made for the cross slide adjustment screws in the 300 mm linear scale (011).
A test assembly of the linear scale to the cross slide was tried (012).
The disadvantage with fitting the linear scale this way was that cross slide T slots were shortened and could only be accessed from one side. So it was decided to lower the linear scale on the side of the cross slide to the bottom of the T slots. This required sawing off a 6mm length from the securing side of the aluminium angle for the linear scale (013).
The angle was then filled to size (014).
The Cross slide was removed from the saddle (015).
The aluminium angle had holes drilled in it to give access the adjusting screws on the side of the cross slide. The angle was clamped to the side of the cross slide using some HSS tool bits in the bottom of the T slots to position it (016 & 017).
The cross slide was drilled for tapping (018).
The aluminium angle screwed to the cross slide (019).
Checking the level of the angle with a DTI (020).
Checking the clearance for a spanner on the locking bolt of the saddle (021).
Happy with progress so far the next job tackled was fitting the 900 mm long linear scale the back of the lathe bed. As the Super 7B is a long bed all of the 900 would be needed. First because it was thought it might cause a problem the protruding lip of the saddle rear strip was filled away, in the event it wasnt found necessary to do this (022).
To secure the linear scale to the lathe bed some hexagonal spacers were made which were threaded ¼ BSF to screw into the lathe bed and threaded M3 for screws to hold the linear scale to them (023 & 24).
One end of the linear scale was drilled and screwed to one of the spacers fitted to the lathe bed. The other spacer fitted in the lathe bed had a threaded scriber fitted in it and was used to mark the position of the other hole in the linear scale (025 & 26).
Photograph (027) shows the linear scale fitted to the back of the lathe bed.
The parallelism of the scale was check with a DTI and adjusted by reducing the height of a spacer for one plane and elongating one of the linear scales screw holes for the other. It was found smoother to use the power feed of the lathe to move the DTI along the bed rather than by hand (028).
I had looked at the method of holding the encoder bracket to the lathe by using the bolts that held the rear saddle strip to the saddle. The system looked a little messy regarding access to the bolts when the bracket was fitted and I think it might also have been difficult to adjust the saddle encoder. So it was decided to attach the encoder bracket directly to the end of the saddle. So a drilling jig was made from aluminium angle and was held to the saddle by the saddle locking bolt and a blacked off screw hole which I believe was something to do with fitting a coolant system (029).
After fitting the jig holes were drilled and tapped in the end of the saddle (030).
The jig was then used to drill the fabricated encoder bracket (031).
Photograph (032) the encoder bracket fitted to the end of the saddle, the bracket was made too long so that the saddle encoder could be offered to it to gauge its position, this done the bracket would be suitably shortened.
First the cross slide encoder was attached to the bracket using some aluminium angle (033 & 034).
The saddle encoder was then fitted to the bracket (035).
Which was then fitted to the lathe (036).
Clips for the encoder cables were fitted into existing holes in the back of the lathe (037).
Now it was time to fit the magnetic strip and its protective cover to the groove in the aluminium angle. It is very important that the orientation of the magnetic strip and its encode is correct there are marks on both components that allow this (038).
When fitted the magnetic strip and its cover are about level with edges of the groove in the aluminium angle (039 & 40)
That finished the installation on the lathe (041 & 042) so the encoders could now be connect to the DRO and you can start to play.
There are light indicators on the encoders that are green if they are correctly positioned red if they are not (043 & 044).
Photographs of the DRO in use (045 & 046).
Notes.
The kit comes with instructions with the tolerances allowed when fitting and positioning the encoders. Given that the kit is intended for different lathes there is not much in the way of instructions regards fitting of the components. Except for the aluminium angle that the encoders are fitted to I didnt use any of the fitting kit as it was supplied. It was cut up to supply some parts and I added some aluminium angle of my own. The linear scales can be cut to any length but on my lathe they were used at their full length.
I cannot comment on this brand or type of DRO kit compared with other manufactures as I dont have the electronic knowledge or enough practice in using DROs. Once I had got my head around it, it was fairly straight forward to fit even without moving the lathe. Though I have to say it was a bit of an effort having to lean over the lathe bed and set up some of the parts using a Mirror!
Regards Tony.
For some years I have been considering fitting a DRO to my 40 year old Myford Super 7B. As well as the cost of buying a DRO the prospect of having to move the lathe to fit the saddles linear scale and encoder was a little daunting (001).
At the Bristol Exhibition held in August this year a more reasonably priced DRO was on offer a EMSI system that was suitable to fit to a Myford. Its price reduced one of the problems so it was decided to buy the DRO kit and try to fit it without having to move the lathe (002).
I had previously fitted an inexpensive DRO to a much modified equal inexpensive Chinese Seig C-O mini lathe where it has been very useful (003).
The EMSI DRO units came very well packed and contained a digital display with a mount, 2 magnetic encoders, a 300 mm and 900 mm long linear scale and a fitting kit (004).
The first and easy job was to fit the digital display to the workshop wall above the lathe (005).
Before starting on the assembly some research was done; a friend who had fitted a DRO to his Myford sent me some photographs of his installation (006 & 007).
At a engineering show I took a photograph of a DRO system that didn’t require holes to be drilled in the lathe to fit it (008).
Neither of these products are the same as the DRO purchased
Not having to drill holes sounded attractive! It was obvious how the linear scale was fitted to the cross slide using modified T bolts. Looking at the back of the bed the linear scale used the screw holes that were intended for a taper turning attachment. The mount for the encoders was held by using the bolts that secured the rear saddle strip to the saddle (009).
This system looked like the way to go, so two modified T bolts were made (010).
Clearance slots were made for the cross slide adjustment screws in the 300 mm linear scale (011).
A test assembly of the linear scale to the cross slide was tried (012).
The disadvantage with fitting the linear scale this way was that cross slide T slots were shortened and could only be accessed from one side. So it was decided to lower the linear scale on the side of the cross slide to the bottom of the T slots. This required sawing off a 6mm length from the securing side of the aluminium angle for the linear scale (013).
The angle was then filled to size (014).
The Cross slide was removed from the saddle (015).
The aluminium angle had holes drilled in it to give access the adjusting screws on the side of the cross slide. The angle was clamped to the side of the cross slide using some HSS tool bits in the bottom of the T slots to position it (016 & 017).
The cross slide was drilled for tapping (018).
The aluminium angle screwed to the cross slide (019).
Checking the level of the angle with a DTI (020).
Checking the clearance for a spanner on the locking bolt of the saddle (021).
Happy with progress so far the next job tackled was fitting the 900 mm long linear scale the back of the lathe bed. As the Super 7B is a long bed all of the 900 would be needed. First because it was thought it might cause a problem the protruding lip of the saddle rear strip was filled away, in the event it wasnt found necessary to do this (022).
To secure the linear scale to the lathe bed some hexagonal spacers were made which were threaded ¼ BSF to screw into the lathe bed and threaded M3 for screws to hold the linear scale to them (023 & 24).
One end of the linear scale was drilled and screwed to one of the spacers fitted to the lathe bed. The other spacer fitted in the lathe bed had a threaded scriber fitted in it and was used to mark the position of the other hole in the linear scale (025 & 26).
Photograph (027) shows the linear scale fitted to the back of the lathe bed.
The parallelism of the scale was check with a DTI and adjusted by reducing the height of a spacer for one plane and elongating one of the linear scales screw holes for the other. It was found smoother to use the power feed of the lathe to move the DTI along the bed rather than by hand (028).
I had looked at the method of holding the encoder bracket to the lathe by using the bolts that held the rear saddle strip to the saddle. The system looked a little messy regarding access to the bolts when the bracket was fitted and I think it might also have been difficult to adjust the saddle encoder. So it was decided to attach the encoder bracket directly to the end of the saddle. So a drilling jig was made from aluminium angle and was held to the saddle by the saddle locking bolt and a blacked off screw hole which I believe was something to do with fitting a coolant system (029).
After fitting the jig holes were drilled and tapped in the end of the saddle (030).
The jig was then used to drill the fabricated encoder bracket (031).
Photograph (032) the encoder bracket fitted to the end of the saddle, the bracket was made too long so that the saddle encoder could be offered to it to gauge its position, this done the bracket would be suitably shortened.
First the cross slide encoder was attached to the bracket using some aluminium angle (033 & 034).
The saddle encoder was then fitted to the bracket (035).
Which was then fitted to the lathe (036).
Clips for the encoder cables were fitted into existing holes in the back of the lathe (037).
Now it was time to fit the magnetic strip and its protective cover to the groove in the aluminium angle. It is very important that the orientation of the magnetic strip and its encode is correct there are marks on both components that allow this (038).
When fitted the magnetic strip and its cover are about level with edges of the groove in the aluminium angle (039 & 40)
That finished the installation on the lathe (041 & 042) so the encoders could now be connect to the DRO and you can start to play.
There are light indicators on the encoders that are green if they are correctly positioned red if they are not (043 & 044).
Photographs of the DRO in use (045 & 046).
Notes.
The kit comes with instructions with the tolerances allowed when fitting and positioning the encoders. Given that the kit is intended for different lathes there is not much in the way of instructions regards fitting of the components. Except for the aluminium angle that the encoders are fitted to I didnt use any of the fitting kit as it was supplied. It was cut up to supply some parts and I added some aluminium angle of my own. The linear scales can be cut to any length but on my lathe they were used at their full length.
I cannot comment on this brand or type of DRO kit compared with other manufactures as I dont have the electronic knowledge or enough practice in using DROs. Once I had got my head around it, it was fairly straight forward to fit even without moving the lathe. Though I have to say it was a bit of an effort having to lean over the lathe bed and set up some of the parts using a Mirror!
Regards Tony.
