Post by springcrocus on Apr 3, 2016 18:46:42 GMT
There are plenty of references across the various forums concerning fitting DROs to lathes and milling machines but the information tends to be a bit scattered and piecemeal so I have jotted these notes down covering the start-to-finish process of puchasing and fitting a 2-axis DRO with glass scales to a small milling machine.
My own milling machine is an SP2217-III from SPG Tools but it is physically identical to the Warco WM-16, the Amadeal AMA25LV and the Chester 20V and all these machines have a 700mm x 180mm table.
The first thing one needs to do is decide whether one wants a 2-axis or 3-axis measuring system and source the product accordingly. I only want 2-axis because my machine already has a small DRO on the quill, and this will suffice, so it is left to the reader to devise how they may fit the third axis if required.
The next important thing to know is the size of the scale to use on each axis and a scale slightly longer than the overall travel of the table needs to be chosen. However, there is no point in choosing a scale that is much larger than the table travel because such a scale will probably overlap the ends of the table and be prone to accidental damage. Another thing that needs to be taken into account is that the scales come in various sizes in 50mm increments and the overall length of the glass scales is 140mm longer than the travel length. In my case, the longitudinal travel (X-axis) of the table is 485mm and, therefore, a scale length of 500mm was chosen while the cross traverse (Y-axis) is 175mm and a 200mm scale was chosen. Remember, however, that the physical length of the scales are 640mm and 340mm respectively but it is 500mm and 200mm scales that one is ordering.
There are many suppliers listed on a certain auction site and the price for a full kit of parts is about £ 180 delivered to the UK and one has to let the seller know what size scales one requires. I have issues with this auction site (my own personal hang-up) so I bought the self-same thing from one of these companies through Amazon and paid £ 192 for mine. As soon as I placed the order, I used the Amazon email service to contact the seller and advised them that I required scales of 500mm and 200mm and a reply was received next day confirming that these sizes would be dispatched. Just prior to delivery, I was contacted by the carrier with a request for a payment of £ 19.00 for the VAT that was due. All the sellers on both Amazon and the auction site state that VAT or duty may be payable on the goods as they originate outside the EU so was not unexpected. The order was received seven days after being placed and was immediately unpacked and checked for completeness, arriving as two separate packages.
The first package contained the display unit and this is what was in the box.
The second package contained the scales with their read-heads. Be aware that they come with a small transit locking screw holding the read-head firm on the scale and which needs to be removed before attempting to move the read-head.
Everything appeared to be in order although the instruction manual appears to be one of the worst translated documents I have ever seen and will probably be discarded. Common sense and an internet search will sort out most things rather that trying to decipher this gibberish.Containing my impatience to hook it all up and conduct a test, I sorted out the brackets and mounted the display unit in position to the right of the machine and then went off to find a spare computer lead to apply power because the one supplied was the European format. It all assembled easily although I have placed a couple of fibre washers between the wall bracket and the arm to fill the space and allow for easier adjustment of the display unit.
After this, I removed the transit screws from the scales and plugged them in to their respective ports on the rear of the display unit which was then turned on. The unit automatically set both scales to zero and I slid the read-heads along both scales to check that they were working properly, also changing from metric to imperial units to check this function and all was fine. A word of caution. Don't be tempted to slide the read-heads up and down at high speed whilst connected and turned on. I don't know the reason why but have been advised that it is easy to damage the electronics if overspeeding occurs. These things are too expensive to find out if that is just a myth or not so I treated them with respect.
After offering up the scales to see how best to fit them, I then marked up their respective limits and centres of travel because the scales are not symetrical. I also centered the table and saddle, making loads of marks with a felt-tipped pen, and then removed the table and saddle as a single unit from the machine. I had decided that it would be too much hassle trying to drill and tap all the fixing holes with everything in situ. This involved removing all the paraphernalia from the front of the table, the jib strip with its front adjusting screw, the rubber bedway cover at the back and the Y-axis leadscrew and handle. Once these were removed, the saddle was slid as far forward as possible and the two screws that hold the leadscrew nut were loosened and the nut allowed to fall down so that the saddle would come off the knee completely.
I chose to fit the Y-axis first as I thought that would be the most awkward and the first job was to mark out, drill and tap two M5 holes in the knee to allow the scale to be affixed. These were done freehand using a 3.0mm bit in a pistol drill to act as pilot followed by a 4.2 drill, taking care to keep things as square as possible and not too much force. Then I tapped them M5 freehand with a spiral-pointed tap because they are less likely to break than any other type and because they self-align as well.
I also made a couple of spacer bushes from some 1/2" brass but they needed dressing by hand at one end because of the shape of the casting. I suppose I could have spot-faced the M5 holes but I couldn't be bothered to grind a drill up for it.
Next I had to make a bracket to couple the read-head to the saddle and a hunt through the scrap box produced a door-mounting coat hanger and this was promptly modified to suit. The table and saddle were then upended on a workbench and the saddle marked out from the bracket and then drilled and tapped M5.
Tapping was proving to be a bit problematic because of access but eventually I managed it by using a small drill chuck. I didn't want to separate the table and saddle, too much work.
After offering everything up to check that it would all work, it was time to fit the X-axis and I have fitted it to the rear of the table even though I have lost about 25mm of travel. I feel this is less important than losing the dead-stop adjusters and the slideway locks. Even the embedded rule on the front will be useful and mounting the glass scale on the front would have meant that all these facilities would be made redundant. This time the scale and read-head were mounted with M4 screws and I was able to use the mill to drill the holes.
Unfortunately, I got a bit carried away and forgot to take pictures of the next couple of stages but basically everything was centered and holes were spotted through, drilled with the mill and tapped by hand.Finally, the mill saddle and knee were thoroughly cleaned and given a film of hydraulic oil prior to reassembly. The
only awkward part is getting the leadscrew nut aligned before locking into place but even this was not too much effort. Then the scales and read-heads were fixed to the machine and carefully aligned, and the leads taken to the DRO. The pictures should be self-explanatory.
And here is the final arrangement with everything checked and working perfectly. Now to get some work done....
I hope that someone may find this useful, especially if they were contemplating getting some kit but were reluctant to take the plunge. It's a relatively painless process if you can afford it.
Steve
My own milling machine is an SP2217-III from SPG Tools but it is physically identical to the Warco WM-16, the Amadeal AMA25LV and the Chester 20V and all these machines have a 700mm x 180mm table.
The first thing one needs to do is decide whether one wants a 2-axis or 3-axis measuring system and source the product accordingly. I only want 2-axis because my machine already has a small DRO on the quill, and this will suffice, so it is left to the reader to devise how they may fit the third axis if required.
The next important thing to know is the size of the scale to use on each axis and a scale slightly longer than the overall travel of the table needs to be chosen. However, there is no point in choosing a scale that is much larger than the table travel because such a scale will probably overlap the ends of the table and be prone to accidental damage. Another thing that needs to be taken into account is that the scales come in various sizes in 50mm increments and the overall length of the glass scales is 140mm longer than the travel length. In my case, the longitudinal travel (X-axis) of the table is 485mm and, therefore, a scale length of 500mm was chosen while the cross traverse (Y-axis) is 175mm and a 200mm scale was chosen. Remember, however, that the physical length of the scales are 640mm and 340mm respectively but it is 500mm and 200mm scales that one is ordering.
There are many suppliers listed on a certain auction site and the price for a full kit of parts is about £ 180 delivered to the UK and one has to let the seller know what size scales one requires. I have issues with this auction site (my own personal hang-up) so I bought the self-same thing from one of these companies through Amazon and paid £ 192 for mine. As soon as I placed the order, I used the Amazon email service to contact the seller and advised them that I required scales of 500mm and 200mm and a reply was received next day confirming that these sizes would be dispatched. Just prior to delivery, I was contacted by the carrier with a request for a payment of £ 19.00 for the VAT that was due. All the sellers on both Amazon and the auction site state that VAT or duty may be payable on the goods as they originate outside the EU so was not unexpected. The order was received seven days after being placed and was immediately unpacked and checked for completeness, arriving as two separate packages.
The first package contained the display unit and this is what was in the box.
The second package contained the scales with their read-heads. Be aware that they come with a small transit locking screw holding the read-head firm on the scale and which needs to be removed before attempting to move the read-head.
Everything appeared to be in order although the instruction manual appears to be one of the worst translated documents I have ever seen and will probably be discarded. Common sense and an internet search will sort out most things rather that trying to decipher this gibberish.Containing my impatience to hook it all up and conduct a test, I sorted out the brackets and mounted the display unit in position to the right of the machine and then went off to find a spare computer lead to apply power because the one supplied was the European format. It all assembled easily although I have placed a couple of fibre washers between the wall bracket and the arm to fill the space and allow for easier adjustment of the display unit.
After this, I removed the transit screws from the scales and plugged them in to their respective ports on the rear of the display unit which was then turned on. The unit automatically set both scales to zero and I slid the read-heads along both scales to check that they were working properly, also changing from metric to imperial units to check this function and all was fine. A word of caution. Don't be tempted to slide the read-heads up and down at high speed whilst connected and turned on. I don't know the reason why but have been advised that it is easy to damage the electronics if overspeeding occurs. These things are too expensive to find out if that is just a myth or not so I treated them with respect.
After offering up the scales to see how best to fit them, I then marked up their respective limits and centres of travel because the scales are not symetrical. I also centered the table and saddle, making loads of marks with a felt-tipped pen, and then removed the table and saddle as a single unit from the machine. I had decided that it would be too much hassle trying to drill and tap all the fixing holes with everything in situ. This involved removing all the paraphernalia from the front of the table, the jib strip with its front adjusting screw, the rubber bedway cover at the back and the Y-axis leadscrew and handle. Once these were removed, the saddle was slid as far forward as possible and the two screws that hold the leadscrew nut were loosened and the nut allowed to fall down so that the saddle would come off the knee completely.
I chose to fit the Y-axis first as I thought that would be the most awkward and the first job was to mark out, drill and tap two M5 holes in the knee to allow the scale to be affixed. These were done freehand using a 3.0mm bit in a pistol drill to act as pilot followed by a 4.2 drill, taking care to keep things as square as possible and not too much force. Then I tapped them M5 freehand with a spiral-pointed tap because they are less likely to break than any other type and because they self-align as well.
I also made a couple of spacer bushes from some 1/2" brass but they needed dressing by hand at one end because of the shape of the casting. I suppose I could have spot-faced the M5 holes but I couldn't be bothered to grind a drill up for it.
Next I had to make a bracket to couple the read-head to the saddle and a hunt through the scrap box produced a door-mounting coat hanger and this was promptly modified to suit. The table and saddle were then upended on a workbench and the saddle marked out from the bracket and then drilled and tapped M5.
Tapping was proving to be a bit problematic because of access but eventually I managed it by using a small drill chuck. I didn't want to separate the table and saddle, too much work.
After offering everything up to check that it would all work, it was time to fit the X-axis and I have fitted it to the rear of the table even though I have lost about 25mm of travel. I feel this is less important than losing the dead-stop adjusters and the slideway locks. Even the embedded rule on the front will be useful and mounting the glass scale on the front would have meant that all these facilities would be made redundant. This time the scale and read-head were mounted with M4 screws and I was able to use the mill to drill the holes.
Unfortunately, I got a bit carried away and forgot to take pictures of the next couple of stages but basically everything was centered and holes were spotted through, drilled with the mill and tapped by hand.Finally, the mill saddle and knee were thoroughly cleaned and given a film of hydraulic oil prior to reassembly. The
only awkward part is getting the leadscrew nut aligned before locking into place but even this was not too much effort. Then the scales and read-heads were fixed to the machine and carefully aligned, and the leads taken to the DRO. The pictures should be self-explanatory.
And here is the final arrangement with everything checked and working perfectly. Now to get some work done....
I hope that someone may find this useful, especially if they were contemplating getting some kit but were reluctant to take the plunge. It's a relatively painless process if you can afford it.
Steve
) advice.
