Mill DRO - How many axis?

Decided to fit a DRO to my Mill but would like advice on Z axis please.

I have got a Sieg SX2.7L Mill. Same mill as Jason has used for the Milling for beginners series but with a slightly larger table (hence L). I was all set to buy a 3 Axis kit from ems-i with magnetic scales when I realised my Z axis moves in 2 ways. Course adjustment by hand wheel moving head up and down the column and also a fine feed on the quill. The fine feed has a small electronic vernier type scale and readout already as standard. This is battery powered which I have to remember to switch off and is not easy to read without getting head inline with small screen.

I’m assuming the most used axis on DRO will be the X and Y hence are definates. So I think I have the following options.

1. DRO only X & Y axis.

2. DRO X, Y and replace current fine feed readout on Quill with new scale and use this as Z axis.

3. X, Y and fit Z to vertical column and keep using fine feed scale already fitted.

4. X, Y and fit new scale to both Z column and fine feed and use readout that allows addition of both Z scales into one Z readout.

The price increases with my option numbers. So I think option 2 is favourite but I’d appreciate opinions if I’d be making a mistake not putting scale on the Z column.

Thanks, Dave

I would stick with the two axis dro; I have a WM16 which has a very similar 'Z' readout to your mill & I have found that this is accurate enough for my needs. I have fitted a 2 axis readout system with remote read outs for 'X' & 'Y' axes, to date this set up has not disappointed in any way.

George.

I would go for option 3 other wise how do you set a depth of cut that is greater than the quill to table travel without going back to your pre DRO system?

I did Option 1 and fitted DRO XY only to the table. I was too mean to update the existing quill LCD, but you're right, it's not easy to read, making Option 2 a sensible runner.

Based on my experience putting a DRO on the vertical column would be waste of money. I've never used the existing graduated scale, not once. It's because I always reference the quill from the work. Procedure is to lower the head within spitting distance however close that is, don't care, and then zero the tool and readout relative to a known surface on the job. This works whether the job is bolted direct to the table, or in a vice, or in a rotary table.

I expect there is a reason why the vertical column scale is handy, it's just I don't know what it is! #

Dave

# Posted just after Dave Halford who mentions very deep cuts.  Never done that, not even drilling.  As always it depends what you do with your machines!

Edited By SillyOldDuffer on 23/06/2019 17:55:11

Option 5. Fix X, Y and Z to head then just use the head to put on a cut. This is how I use my X3 but it is a bit easier to raise & lower the head with the handle at the front.

Your Option 4 would be ideal, maybe get the readout that allows summing and only buy 2 scales for now to fit X & Y, add X1 and X2 as and when you find the need or not

Wow, thank you all for suggestions and quick responses. Consensus would seem X & Y are definite need to have and Z is the 'luxury' item.

Jason, are you saying you don't use the fine feed on X3, just put cut depth on by moving head up and down the column? Interesting.

I'll do a little more price comparison and then decide. Thanks again.

Yes, the X3 does not have a fine feed for the quill. Mostly leave it fully retracted and locked which is the most rigid but for light work sometimes do like Dave and bring the quill down until tool touches work, lock and zero the DRO

Thanks for clarification Jason

In general as I am not familiar with the Sieg mills, but I'd go with your Option 3.

X and Y travels first, as they are the primary dimensions, but you may as well fit the 3-axis version all at the same time..

The ems-I kit may be like the Machine-DRO one I'm fitting to my VMC mill, and it works independently of the feed method by measuring the table and knee travels. To think the Sieg way I had to read your post carefully a few times and see how it compares to my machine!

Put the Z reader on the head, not quill. Leave the quill read-out in place though: it's there and you may as well keep the option.

Then in use, lock the quill at the top surface, null the Z reading, then use the head travel for depth.

It does depend on the sort of things you are making, but very often the X and Y co-ordinates are the critical ones, the depth or height being less so, within reason.

Still fitting my milling-machine's DRO, once I had the long and cross travels sorted, I am not finding it a disadvantage still using the manual scale for depths, ironically for making the Z-axis bracketry, because there are only a few to measure.

Whichever way you go on the scales, buy a 3 axis console as the incremental cost isn't that high over two. Then you have the future option of an upgrade. I did that on my VMC when the original console died and have just added a Z axis scale.

I've effectively done both Jasons Option 5 and your Option 3 albeit on Chester Lux / Rong Fu style bench mill and Bridgeport respectively rather than a Sieg but principles still hold.

Having the DRO Z scale on the quill feed of the bench mill worked fine in practice then but I'd not want to go back to that system. Or to a bench mill for that matter.

I have a BW electronics pull wire sensor on the Bridgeport quill which goes on neatly witout obscuring things. Fitting a conventional glass scale beign a royal pain. Especially fi you want to keep easy access to the depth stop. I tend to use the quill scale is mostly for setting the depth stop whilst the knee does the accurate base settings. Which seems to suit the work I do pretty well.

I'm not totally convinced by axis combining on the Z. Would love it for some jobs and hate it for others. Not sure that I'd be convinced even after trying the system out.

Bottom line is either way will work fine and you will quickly settle on a way of working that makes best use of the advantages and minimises the disadvantages. As is so often the case the best way for you will turn out to be the way you have gotten used to.

Clive

Edited By Clive Foster on 23/06/2019 19:34:22

Not in the same ballpark as a benchtop mill like the SX2.7L but on my Ajax AJT4 turret mill, I originally had a 3 axis X, Y, Z DRO, which subsequently developed the 'jitters'. At Ally Pally this year I bought one of their 4 axis 750 series LCD head units (already have the 3 axis unit on my large lathe). This head allows combining of the Z and U axis or having them display separately. For the most part I use them separately but it is a simple matter of changing one setting to combine them when the need arises. Having DRO on the knee (or in your case the moving head) and also on the quill is a luxury I would now not be without.

Gray

If you go 2 axis leave room to upgrade, you'll probably want to as it's common sense to have three and straightforward penny pinching not to.

Mine is the same as JasonB's, lock up the fine drive and use the handwheel vertical to apply a cut. the three axis readout is all you need.

My Centec has a 3 axis DRO on the long travel, cross travel and knee. It also has a separate read out for the quill. I don't use the quill for milling unless for an awkward access job - it usually only gets extended for drilling jobs.

The Raglan (no quill) is slowly getting separate readers on the three axes - but the full DRO system has so many extras that make the extra initial cost worthwhile.

I use all three axes equally.

If you can afford, go for 3 rather than 2. If not, get X and Y but fit a 3-axis readout as you will want Z when you discover how useful the others are.

Neil

Dunno how well that comes out, but the Z axis isn't that hard to do on the 2.7,
Minor bodge to get the mag reader in place where the stock battery operated DI was mounted then it reads on the main DRO display.
only fine quill feed. (It won't register moving the head up or down)
If you want more photo's just PM me and I'll send any you want.

Thank you everyone, some great advice and also a few ideas on new ways of working which I will definitely try.

To conclude, I've ordered a 3 scale DRO kit planning to put the Z on the pillar of the mill but I've upgraded the readout to have 4 ports so if I later decide to put a read head on the Quill as Roy has shown in the photo I've got the option to do so. Taking the advise of many of you to future proof.

Thanks again everyone.

Dave

Following on from my question back in June, thought I'd update the post with what I ended up doing in case it helps anyone else.

The mill is a Sieg SX2.7L and I fitted a 4 axis DRO from EMS with scales on X,Y,Z and the Quill (U) to replace the Sieg digital scale which I found a little difficult to read. The Z axis can be displayed as 2 separate values or set to add them together as a single value. Not the cheapest solution but very happy with the result.

There are more photos in my DRO album.

Thanks for letting us know what you actually did as many times you wonder what happened. Any thing you would have done different with hindsight.

David