This entire DRO series has been invaluable for a novice like me. I was able to install all three of the DROs on my PM-949TS and feel confident in their accuracy! I've been going through your other videos as well! Keep up the great content!!
Top tip when adjusting the height, measure it with a depth mike from the top of the table , subtract the required movement lock up then put into position again. Put back into position rais the scale to touch it. Repeat again until in position.
Thanks for your videos - they helped me a LOT. One thing though: I also got SINO scales like yours, and at least on one of the scales the position of the reader head was terrible with the transport fittings mounted - and that was in both directions (distance from head to scale and off-center on the scale). In fact I feel that the mounting of the reader heads are by far the worst part.
For whatever reason, all mfr's and suppliers of these seemingly keep it a secret how to choose and install them. There is another secret that I never seen addressed, and that being, what if the scale choices available are either too long, longer than the table, or too short, less than travel? I encounter this issue, and so, chose a completely different system, less accurate, but it works. I found those scales that are caliper scales. I reckoned I could just cut them, and yes, that works. I have some machines that I would love to have more accurate dro's on, but, unless there is a known way to install the type in this video, I will install the other type. I know another person who has the same issue too. Likely there are a real lot of people with this issue. Your video is right on when installing the more accurate kind on a mill when the proper length is available. I have done this too.
You can do it with a scale longer than the table. You just need a bracket that is the length of the scale and mount that bracket to the table. Obviously, this opens up the possibility of running into the scale with other equipment, so you have to move with caution around them.
Hi folks. Getting the scale level seems to be rather tricky. I've not installed one - yet - but one idea I have, if there is the space - is to have a sub frame that is vertically adjustable, at least on one end, by using a fine threaded machine screw. Possibly more trouble than it is worth! BobUK.
Hello Stuart! I just installed 3-axis and one person commented on setting them parallel. It's always good to eliminate possible error. I set mine very close as I was working off machined surfaces on my mill but I never checked them with an indicator. I'm certain I'm parallel well within .030". If you do the math for a 10" long scale an alignment error of .100" would result in a .0005" error over 10" of travel. I'd say my scales are much closer to being within .030" which would result in an error of .0002" over 10" or .0004" over 20". Striving for perfection is always good but I'm totally okay with less than a half! I'm not so good at math so feel free to correct me if I'm wrong. Is there something in the scale reader head that freaks out with minor side to side movements? My first install was a magnetic $35 DRO (per axis). Compared to the table dials it was off .015" over 20-inches but I borrowed a 20" caliper from work and both axis were dead on. The dial discrepancy was likely due to it being a Chinese mill and lead screw wear. Was I just lucky or are glass scales more particular???
Having the scale mounted at an angle can result in an error in your reading because you will be measuring along the hypotenuse of a triangle instead of the flat bottom. The readout will say you have traveled X amount, but in reality you have gone less than that.
I just can't see losing an inch of y travel to mount the DRO. Is there really no way you could have mounted this on the front side? Ugly, and you've got stops to work around, but there must be a way.
There are plenty of people who have done that. The big challenge is making the adapter to hold the reader head since the front of the saddle is angled compared to the table. You also lose the ability to use hard stops on the table. To me, the main issue is that the scale will be more exposed on the front of the table. This makes it more likely to get some damage when moving the vise or heavy parts on or off the table, or when handling longer pieces of material around the machine.
