Compound slide DRO thoughts?

I am shopping for a DRO for my schaublin 135 but this question is more general.

Is it worth the trouble to mount a third scale for the compound slide on a moderate size lathe? The cost difference isn't massive, but the install isn't super straightforward. I haven't used a lathe with such a set up but I know it is done. Seems like it might be nice given how coarse the main z axis is but I am not sure about that.

Thanks
Luke

Good Morning. I may just be having a "stupid" day but I don't quite understand your question about a third axis. On my lathe I just have X and Y scales unlike my mill that has X. Y and Z scales. What would the third axis be for on a lathe?

crossthread said:

Good Morning. I may just be having a "stupid" day but I don't quite understand your question about a third axis. On my lathe I just have X and Y scales unlike my mill that has X. Y and Z scales. What would the third axis be for on a lathe?

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Hello Crossthread


Doesn't your lathe have 1 of those thingies on that other thing??? You know, the 1 next to the whatchamacallit.

Meh... I wouldn't bother.

Get a CNC.

crossthread said:

Good Morning. I may just be having a "stupid" day but I don't quite understand your question about a third axis. On my lathe I just have X and Y scales unlike my mill that has X. Y and Z scales. What would the third axis be for on a lathe?

Click to expand...

To be really picky - on a lathe it's x & z axis, (x is the cross slide) so the OP is in effect talking about having 2 Z axis.

Getting back to the OP, a compound DRO is a sensible adddition provided the bulk of the scale doesn't interfere with machine operation - and on smaller lathe this is very likely.

Ideally, the stripped down elements of the DRO could be entirely enclosed in the clearance space between the slide's inner surfaces allowing passage for the nut. If you \can strip off the damn bulky external extrusion to the scale element itself and the encoder you can mount it internally leading the wire by some clever route where it wont be subject to chips and snags.

I managed this on the cross-slide of my lathe and I fervently hope nothing goes wrong.like I need a new encoder. Sony doesn't support this DRO scale anymore. If it breaks I have to start all over again.

Good luck. Remember you're a machinist. You can make or modify anything. You don;t have to mount cumbersome, clumsy-ass, lowest common denominator junk so the essential 10% of it can do its job.

The difficulty I see with adding the third scale on the compound is that the compound angle is a variable that gets change from occasionally to frequently depending on job mix.

The problem is that since the compound as et at some arbitrary angle depending on the task, operating the compound in and out effects the X and Z without changing the display.

I don't see what you would gain unless you add an angle encoder to the compound and then feed all three axis into a computer to calculate the actual tip of tool dimension and then this would be effected by the type of tool and the angle again.

. The end result is that you will have no idea what the actual reading is versus the displayed readings.

Hello Ziggy2
I only have a Newall 2 axis on my lathe, but the 3 axis has a vectoring feature where you enter in the angle of your compound & then the X displays the combined X axis movement, the Z displays the combined Z axis movement, & the Z(1) shows the Z axis movement as normal.
Or at least that's how I think that it's suppose to work.

Ciszewski said:

Hello Ziggy2
I only have a Newall 2 axis on my lathe, but the 3 axis has a vectoring feature where you enter in the angle of your compound & then the X displays the combined X axis movement, the Z displays the combined Z axis movement, & the Z(1) shows the Z axis movement as normal.
Or at least that's how I think that it's suppose to work.

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Now that would work. I didn't realize that Newall offered that. Makes a lot of sense.

DRO Pros offer an EL703 that does the same thing. Nice, but pricey.

If you do decide to proceed, Newall microsyn heads and rods are compact in size, and the shorter rods do not need to be supported on both ends. Below is a write up of my mounting one to a Hardinge UM/TM mill, with some pictures. The most relevant information is in post #15 as the length of scale you need is less than you would think.

http://www.practicalmachinist.com/v...e-mills-and-lathes/dro-hardinge-tm-um-238857/

I've seen it done on bigger lathes quite often. Most of them allow you to use the readouts independently or with the reading of the long travel combined with the compound reading. That's pretty useful.

Regards Tyrone.

I just cut the jaws off a 6" digital caliper and made brackets. It works great.

Thanks for the input folks.

I understand the issues with the compound angle changing but given that if it is generally used at a known angle that doesn't seem like a big deal. I would love an angle encoder on the compound (and the vertical head on my 13 mill) but haven't found a reasonable way to do that yet.

Forest, I like the idea of internal mounting but I don't think there is room to do it in the compound with any encoder I have seen. The cross-slide could be a better candidate.

Ruemema in Germany has a tidy way of mounting a slide on the compound although it requires milling a pocket which is probably fine if slightly unnerving. One of the local Schaublin folks has done it to his 135 and it looks well thought out so if I do decide to go this route I have an example to start with.

When I think about how I use the machine right now without a DRO it seems like not having the compound included in the DRO would be annoying. I think perhaps Schaublin lathes are a bit more "compoundcentric" if that makes sense. The instrument lathes like the 102 which I also have do all Z cuts with the compound. so I am used to both carefully setting the compound and doing a good bit of work with it.

I am still trying to pick a DRO as well, I have Newall on my mill and like it well enough but I haven't managed to find a local distributor yet and it seems like the resolution is a bit coarse for the cross slide. I know many people, particularly on the hobby side love DROpros I won't be buying from them for a few different reasons. Out of curiosity I do have a RFQ in with the company in India that makes the dro's they sell but will probably end up going European or Japanese which still leaves too many options

Luke

did you check out pewetools? seems to be out of stock for the moment.

NEUE Digitalanzeige / Positionsanzeige 4 Achsen | eBay

Forrest Addy said:

Ideally, the stripped down elements of the DRO could be entirely enclosed in the clearance space between the slide's inner surfaces allowing passage for the nut. If you \can strip off the damn bulky external extrusion to the scale element itself and the encoder you can mount it internally leading the wire by some clever route where it wont be subject to chips and snags.

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Most likely to be possible if you use the magnetic scales which are much more compact. Read head is still quite large tho'. Considering similar internal mount for my Smart & Brown 1024 cross-slide. External mag scale on the compound looks doable for me with the reader head alongside the dial assembly. As ever the major issue with external scales on cross and compound slides is keeping the scales from interfering with tailstock. Especially when working up close and personal. Its would be unfortunate if you forgot about the odd inch or so less space with a conventional scale and when doing what you always do and crunched things. I shall add a stout travel stop block to the cross slide to protect that one.

Clive

My vote is for 3x - 100%

Although mine is only summary z I still value it highly, If I were to get a new read out I´d want them separable and/or combinable for different angles of the compound as mentioned can be done on some.
Now you have a very nice lathe so maybe you won´t make mush use of it but I like that it keeps refenrece of where the toolpost actually is as I do have some backlash and no locking of it. Sure I pull same directions when changing tools and so but sometimes... maybe I bump into it or something.
I think now also there are many nice small scales that should fit reasonably well.

Hi Luke.

I'd like to suggest that you consider the Renishaw daughter firm RLS's new line of magnetic linear (and also rotary) encoders.

They are pretty amazingly small, and RS-422 compliant, so that you can use it with most any DRO system.

Their RLC2IC in particular is so small that it could be directly integrated inside the compound, and leaves nothing but the wiring to crash.

They have other solutions that could be built into the cross-slide to pick up the compound angle.

thanks Jcandlish, those look super cool and not all that expensive either. I will certainly be getting in touch with them.

Thanks Jcandlish,

I happen to be looking for rotary encoders and RLS's site looks promising.