Magnetic or optical scales for DRO

Does anyone have an opinion (I'm sure they do!) about which is best for price and reliability?

Brian

Brian

I can only offer comments on magnetic scales. I fitted these to my Dore Westbury mill a year or two back. I chose them because I had very little space available, and they were much more compact than optical scales. They have proved to be 100% reliable, and I am very happy with them. My set up came from MachiineDRO. From memory the magnetic scales increased the overall cost by about 15% compared to the version with optical scales.

Brian, I too chose m-dro magnetic scales. Very compact and easily cut to length.

Brian, I have had M-DRO scales (both glass and magnetic) on my lathe for about 4 years now with no issues whatsoever. I've just fitted a magnetic scale to the quill of my turret mill, purchased from EMS-I at the Ally Pally show and am very pleased with that also. Be aware that scales from different manufacturers will have different pin layouts in the connectors. I had to re-wire the EMS-I unit to match my existing DRO head, simple enough if you are handy with a small soldering iron. The read head on the EMS-I unit is significantly smaller than the ones I purchased from M-DRO not sure what their current units are like.

Are you saying that the same display unit can be used to do both mill & lathe?

I bought the EMS unit at Ally pally for my mill but no one suggested that I might only need a set of scales to add to the lathe.

I am not worried about all the fine tune stuff such as indexing etc

Is that possible? just a straight readout on X & Y

 can one just pull the plugs & swop them over?

Edited By Sam Longley 1 on 15/02/2018 21:32:09

Brian I to fitted magnetic from M-DRO on myford ml7 very pleased going toget some for my chester champion 16v mill anyone done the same how did you find it?

Edited By A G BRENNAN on 15/02/2018 22:52:37

+1 for EMSI

Can someone point me to where these magnetic scales are on the MachineDRO website please, so that I can avoid another troll through one of the more annoying websites that I've experienced lately?

The only scales I found didn't seem to actually specify the technology and looked more like capacitive scales to me.

I tried a search on ' magnetic scales' but the dumb search engine would only take a single term (duh!).

Bandersnatch

Look under the category “digital readout systems”. You will then find magnetic encoders in both the hobby and industrial sections.

We have an in-depth review of the Machine DRO magnetic scale kit for the S7 coming up in a few issues time for MEW. Without pre-empting it too much I have seen a rough draft and it is positive about the quality of the units.

Neil

HI CHAPS

I have 2 sets of DRO with magnetic pickup from EMS which I fitted 5 years ago. One is 3 axis fitted to a mill and the other to a lathe. the magnetic strips are VERY easy to cut to length. I even fitted a bit of magnetic tape onto the down spindle sleeve on the mill. They are very resistant swarf and coolant . They have worked faultlessly on every occasion. I have just ordered a third unit for another lathe. Good product, good service, very helpful and extremely knowledgable. EMS Without doubt.

Thanks Mike - found em. (You forced me to go through the site again )

Many thanks all for the comments; I've just had a look at the EMS-I site and there is an informative piece describing the different systems with fors and agains.

Brian

Hi Sam, it very much depends on the display head, the original one I purchased from M-DRO (their own branded unit) is specifically programmed for a lathe. I have since bought the EM750 unit from EMS-I which can be configured for lathe, mill or grinder. As my lathes and mill are not near each other I have separate units on each machine.

I have also had both optical and magnetic scales fitted to my machines and both types have worked perfectly. The magnetic scales take up much less room and are ideal where space is tight, but they are more vulnerable to swarf getting between the bar that holds the magnetic strip and the read head, so care has to be taken to prevent this.

​ I did have a problem with one of the LED 7 segment displays on the display module, where one digit had a segment that stopped working. Machine DRO helped me sort that out so the after sales support is good from them.

Doug

Unless you can closely match a glass scale length with your machine travels, and manufacture the bespoke bracketry and mounts then you can easily end up with what to my eyes looks like scaffolding all over your machine with massively oversized universal brackets. They might possibly fit in with a machine weighing a few tonnes on the shop floor in a factory but on a hobby machine in a shed they often look simply ridiculous.

The cut to length magnetic scales certainly enable quite tight integration without losing y-axis travel on a more compact machine and while the magnetic tape and rails are quite cheap the read heads for the magnetic scales are a very significant part of the overall cost (more than 3 x the cost of a glass scale read head) . The bundled packages tend to hide this in the price so sharing a display head between machines is less of an advantage than it might appear to be.

With almost one thread pitch or nearly 2mm of backlash on a new chinese built UK supplied milling machine they are IMHO essential.