Sieg SX2P – DRO, power feeds, CNC? What first?

[nevilletParticipant @nevillet]

Hi all,

I’m looking at getting a 3-axis DRO for my very compact SX2PG mill.

I also want to get a power feed for the X travel – and possibly the Y and Z.

…and possibly in the future I could add PC controlled CNC functionality…

I have several questions:

What are the general considerations?

What are the order of works for something like this?

Are the relatively cheap DRO’s on sale on Ebay appropriate and any good for a mill like this?

Being such a small mill, is adding all the hardware required for CNC just too cumbersome and OTT?

Any thoughts or pointers would be great.

Many thanks.

[Clive Brown 1Participant @clivebrown1]

I have a Warco 16b mill, slightly larger than the SX2. A 3 axis DRO is an excellent upgrade. I purchased from Ebay and am satisfied with price and quality. Bear in mind that the supplied bracketry will almost certainly be of litte use for your particular installation and some self-manufacture will be needed which will take time and some ingenuity.

Also bear in mind that the usual glass scales take up proportionately more space on a small mill. Perhaps not an issue with X and Z travel, but more so with the Y travel where you will lose some movement.

Can’t really comment on power feeds but I don’t really feel the need for them, particularly Y and Z.

 

[John HaineParticipant @johnhaine32865]

A DRO for me is a must, I have a Machine DRO mag scale type fitted to my VMB and wouldn’t be without it now.

Autofeed on the X axis is very useful, reduces handle turning tedium and gives a better finish.  One approach to that is to fit a stepper and control it using GRBL which is an open-source CNC program that can run on an Arduino.  Once you do that if you want to go the whole CNC hog you have a starting point.  The next axis (if you don’t go full CNC) would be Z for boring.

No reason that the size of the mill precludes adding CNC, I also have a small Denford Novaturn which is smaller than the SX2 (but much more rigid) and it’s very useful.  Looking at the specs for the SX2PG though it seems that the vertical feed is via rack and pinion?  Unless you have ball screws on each axis CNC would be pretty difficult  so adding a Z axis leadscrew would probably be needed.  Fitting ballscrews to the SX2 could be tricky and would probably need another mill to do the mods!

[ZanParticipant @zan]

Do one or the other, Power feeds and DRO  all come with the cnc conversion. So adding motors for power feeds is wasting money if you ever go for the cnc conversion

See  ME from march 2019 for details of how I converted mine. It’s a long interesting process, but it makes a great little cnc machine, with a highly satisfying work envelope

however it’s only cnc now, difficult to get manual/cnc usage on this machine

[ZanParticipant @zan]

Ah John is correct another mill is needed esp for the mods needed to the saddle  there’s not much room in there for mounting the ball screw nuts

I used a fixed ball screw to the head for the z axis

if you just go for the dro, what about the self adhesive magnetic type, mentioned by John are so much smaller than other types , esp glass scales

[JasonBModerator @jasonb]

DRO would be the first one using magnetic tape, if like the SX2.7 then the read head fixings are already there. But you won’t need that with CNC as you will get a readout as part of the CNC controller.

Similar with Power feed, you could fit a similar unit to this or make your own. If you are going CNC then use the stepper for that to give you the power feed and then you only have two other axis to think about when you go full CNC.

The XZY envelope is large enough for CNC just set your cutting parameters to suit the abilities of the mill.

[SillyOldDufferModerator @sillyoldduffer]

DRO is a no brainer.   Before understanding that, several years ago I fitted my mill with Arc Euros cheapest offering, a pair of these:

Didn’t expect them to last, just fitted as a proof of concept, to be upgraded later if valuable.  They work very well, and have continued to do so.   They don’t have any clever functions, and having two displays isn’t ergonomic, but they still transform the mill!  When one breaks, I’ll be into glass scales etc, but so far the pesky things refuse to die.

I’m on the edge with power feed too.   Mainly take short cuts rather than long sweeps, so bearable.  Nonetheless I’d probably have upgraded had not illness and other distractions kept me out of the workshop.  Or gone CNC.

CNC is very tempting.  I originally saw CNC as only valuable for repetition work which I rarely do.   But CNC also pairs well with CAD, allowing the designer to specify cuts moving simultaneously in 2 or 3 dimensions.  These are all but impossible to do manually.  Starting again today I would immediately go CNC because I’ve realised not having CAD & CNC is holding me back.   (Learning to drive 3D-CAD is a major investment too.  Already have it for other reasons, so not an obstacle for me.)

Dave

 

 

[duncan webster 1Participant @duncanwebster1]

It’s always tempting to feed too slowly by hand, resulting in blunt cutters. I’d fit a stepper motor driven X feed which can be used later in CNC if you go that way. If you’re not going CNC straight away, as others have said DRO is a no trainer.

[nevilletParticipant @nevillet]

Thanks for all your advise.

So plan of action:

1.  DRO
2.  Stepper motor based power feed on Y-axis
3.  Stepper motor based power feed on X-axis
4.  Stepper motor based power feed on Z-axis
5.  Possible CNC ???

Looking at the various DRO’s on Ebay it appears there are two styles of interface.

One type is what i’d decribe as traditional with the 3-axis read outs on LED’s and a multitude of buttons.

The other version looks smaller in scale and has a full digital display with F keys for selecting functions.

Apart from space saving of the second type are there any pros/cons to consider?

 

[Peter Cook 6Participant @petercook6]

Neville, I fitted a 3 axis DRO to my SX1LP, which I think has the same XY table as your SX2. There are some pictures here of my installation. The rest of the thread is the one I found when looking for inspiration. I bought glass DRO scales and the bigger display you mention direct from Ali Express for just over £200 delivered, and they were all great. The only error I made was getting 1micron scales instead of 5 micron, but they work extremely well and make the little SX1LP a pleasure to use.

I was able to engineer the Z axis scale so that it reads the actual head position, that gives me Z axis plus the quill movement which is handy, but I don’t think your SX2 has a separate quill so that will be less of an issue.

[HuubParticipant @huub]

I have had the cheap igaging DRO’s (same as @sillyoldduffer) on my mini mill for more than 6 years and they work flawlessly. I will convert my new mill to CNC but even then, want to use the mill manually so I did mount the same type of DRO.

I use a vice for most of my parts I make. The back left corner of the vice is my zero point.
If I move the battery powered igaging dro, even when switched off, the DRO will record the move. All 2/3 axis DRO’s that I have found, needs to be switched on (display can be dimmed) all the time or such movements will not be recorded. I can’t use these mains powered DRO’s because I switch off the power when I leave the shop.

I have read that there are absolute DRO scales that can be safely moved when switched off but I couldn’t find these. They are probably not for a hobby budget.

 

[SillyOldDuffer]

On SillyOldDuffer Said:

DRO is a no brainer.   Before understanding that, several years ago I fitted my mill with Arc Euros cheapest offering, a pair of these:

Didn’t expect them to last, just fitted as a proof of concept, to be upgraded later if valuable.  They work very well, and have continued to do so.   They don’t have any clever functions, and having two displays isn’t ergonomic, but they still transform the mill!  When one breaks, I’ll be into glass scales etc, but so far the pesky things refuse to die.

I’m on the edge with power feed too.   Mainly take short cuts rather than long sweeps, so bearable.  Nonetheless I’d probably have upgraded had not illness and other distractions kept me out of the workshop.  Or gone CNC.

CNC is very tempting.  I originally saw CNC as only valuable for repetition work which I rarely do.   But CNC also pairs well with CAD, allowing the designer to specify cuts moving simultaneously in 2 or 3 dimensions.  These are all but impossible to do manually.  Starting again today I would immediately go CNC because I’ve realised not having CAD & CNC is holding me back.   (Learning to drive 3D-CAD is a major investment too.  Already have it for other reasons, so not an obstacle for me.)

Dave

 

 

I have the same ArcEuro basic DRO on the Myford S7B on the Z axis – saddle/carriage travel and it’s very good.

The motivation for this was previously machining a replacement poly-V pulley for a planer/thicknesser with a pitch between the grooves of 3/32 – 0.09375″ using the leadscrew handwheel@ 0.125″ per rev, backing off using the topslide @ 0.03125″ to get to the required 3/32 tool travel while retaining the zero point.

What with interruptions and phone calls you can see why I went for a DRO.

As long as you take care to shield the scale from swarf/coolant/cutting oil and arrange a saddle travel end stop to avoid wrecking it,  they are as good as any DRO.

 

[nevilletParticipant @nevillet]

So I’m now looking at DRO’s on Ebay & AliExpress.

More questions…

1.  The encoders seem to be optical devices – does that not present potential probles with detritus getting in the sensors?

2.  All of the head units apear to use 9-pin D connectors for the encoders. Does that mean there is a common standard between head units and sensors?

[Peter Cook 6Participant @petercook6]

Q1 Good practice is to fit the scales so that the opening along which the sensor head slides is facing downwards, and then fit chip guards over the scale. Most scales will come with an aluminium chip guard, although they are quite bulky and eat space on a very small mill. I intended to fit some plastic angle over my scales as being neater – however I still haven’t got round to it and things are working OK after a year, although I do hoover the mess up after each job and don’t use flood coolant – just a paint brush!

Q2 The consensus seems to be that there is no standard convention for the pin-out on the D-sub connectors. Kits bought from one of the big boys should be fine – or you send them back. Buying on a mix and match basis from china is probably a bigger gamble unless the vendor can provide the pin-outs. There are posts on the internet describing how to diagnose them, and then resolder the plugs to match your head unit. That said the scales and head unit I bought (from the same China vendor) worked out of the box.

[nevilletParticipant @nevillet]

Hi Peter,

What are the dimensions on your DRO head unit?  (every mm counts around here…)

[Peter Cook 6Participant @petercook6]

This is the install drawing.

It corresponds to mine except that the arm length on mine is 373 rather than 417.

The depth of the head unit is right at 78, but you need to allow another 70-80 behind that to allow for the D-Sub plugs and armoured cables. I have mine mounted to the wall at the back of the mill. The pivot on the wall is 220mm from the centreline of the mill, and the arm is usually at 45degrees

If you are passing anywhere near Hungerford I would be happy for you to drop in and have a look.

 

[nevilletParticipant @nevillet]

The orders in for the DRO.

I’ve gone for a UK based Ebay supplier and ordered the TFT version DRO along with the axis scales.
Order value was £285.

https://www.ebay.co.uk/itm/124772884635

I went with Ebay because:
Local support and returns will be easier & delivery will be about 3 days.

I’ve purchased from AliExpress in the past but it’s been for small hand tools and never anything as complex as this.

Many thanks for your kind offer Peter – similarly, if your ever in Southampton…

[Clive Brown 1Participant @clivebrown1]

I purchased from that same supplier about 3 years ago. Smooth transaction and, so far, no problems. Nice to see that they’re not “fly-by-night” operation. Also prices seem to have changed very little. The LCD display is, IMO, the better type due to its greater versatility in displaying graphics and suchlike, esp when using the different programmed features.

[Martin ConnellyParticipant @martinconnelly55370]

I would just like to add that if you set up a machine for CNC and have a controller that allows manual data input (MDI) and use of a pendant with a manual pulse generator (MPG) you only need to know a few G codes to use it like a manual machine. This would, as stated above, render the external DROs redundant, along with the handwheels.

By a few G codes I think G0, G1 and F cover almost all manual movements.

Martin C

[nevilletParticipant @nevillet]

Thanks all.

I struck me that coming from a experience level of zero with mills, DRO’s and machining in general, the GUI of the DRO I purchased would help.

[Julie AnnParticipant @julieann]

It would be a good idea to learn the basics of how to use the mill before rushing out and buying bells and whistles. All the items mentioned help one make more efficient use of a mill but they don’t teach the basics. They’ll just allow you to mess it up more quickly.

Having said the above my take on the suggested additions would be as follows:

DRO – I bought a professional (Newall) DRO for my Bridgeport many years ago and it is the single most useful accessory I have ever bought. My DRO is 2-axis and that is fine. Most work, such as hole locations, is inherently 2-axis and I’ve never felt the need for a third axis. For thickness and accurate depths when needed a micrometer and the knee dials are good to a thou or so.

Powerfeed – I have power feed on the X-axis of both my manual mills and it is a time saver, and generally results in a more uniform finish. Plus, on my manual mills, I couldn’t wind the handle fast enough to reach the higher feedrates I often use. Powerfeed also saves a lot of physical effort.

CNC – My personal view is that if you want to go the CNC route then it is better to buy/make a proper CNC mill rather than trying to convert a manual mill.

Julie

[nevillet]

On nevillet Said:

Thanks all.

I struck me that coming from a experience level of zero with mills, DRO’s and machining in general, the GUI of the DRO I purchased would help.

It does, enormously, but a DRO isn’t a panacea.     They fix two major problems with driving the mill on the dials, errors due to:

• Losing count when turning the handle manually.
• Forgetting to compensate for backlash

All other DRO goodies are secondary, mainly saving time and mental arithmetic.  Well worth having, but you can manage without.   (For example, defining where to drill a ring of holes on a PCD (Pitch Circle Diameter) is a common DRO function.  The same answer can be got using trigonometry, or an online calculator, or …)

Whilst a DRO GUI presents information clearly compared with a basic digital display, it doesn’t help with cutting and setup basics.   There’s much to learn about work-holding, planning cut sequences, materials, cutter types, feed-rate, RPM and depth of cut before a DRO becomes valuable.  A newcomer could spend a month or two developing basic machining skills before turning the DRO on.   No harm in using one from day one, but a DRO is no substitute for learning the ropes!

Dave

[nevilletParticipant @nevillet]

Hi all and thanks for all your advise.

Prior to getting the getting the mill i’ve been watching numerous YT milling videos on the Blondihacks and other channels. https://www.youtube.com/@Blondihacks

I’ve also ordered my first milling book – which is taking ages to arrive… for Amazon anyway.

I’ve been messing about on the mill starting off aligning the table and the vice using a dial indicator.
Then getting proficient at swapping the collet for the drill chuck.

I guess my biggest task is learning milling speeds, feed rates and depths of cuts which I guess will take some years.

Straight out of the box, I started milling some oak, progressing to brass and then mild steel.

On the steel I think I was using a too low milling speed (not wishing to Muller the cutter) but having a juddering initial cut. As my confidence grew so did the speed.

The mill does not display speed (0-2500) so I’ve ordered a Hall sensor tachometer which will sort that out.

Many years ago I injured myself in a car crash and as a result have limited movement in my right arm and hopefully the powered X feed will help.

[Julie AnnParticipant @julieann]

I am still learning about selection of feeds, speeds and depth, and width, of cut.

Within reason cutter speed is not that important. Too slow and the cut will takes ages but not affect the cutter. Too fast will heat up the cutter so some caution needed. Are you running HSS or carbide mills? A carbide cutter will run dull red although that is pushing it a little.

The most important parameter as far as the cutter is concerned is feedrate. Although it is better to think of it in terms of chip load, ie, feed per tooth. A milling cutter needs to cut, not rub. The quickest way to blunt a cutter is to run at too low a chip load. I am not familiar with small mills so others are probably better placed to suggest numbers.

It helps to think about the process of conventional milling. As a tooth comes round towards the work the initial cut is zero. As the cutter moves forward the tooth will start to encounter material left by the previous tooth. The problem arises because the cutter is flexible and the edge is not sharp but is rounded. It will initially tend to ride over the work and bend away from the cut before eventually overcoming the tendency to bend and finally cutting into the metal. It is that bending and rubbing of the tooth that causes rapid wear. It is why climb milling is better, in the sense that as the tooth contacts the work it is immediately cutting, no rubbing. I am not suggesting you climb mill on a small mill though.

The cutter edge may be sharp but on a small scale it will have a radius. The radius might be small, microns, but is there and affects the cutting process.

Good advice is don’t pussyfoot around with feedrates; feed slowly to “save” the cutter and the opposite will result. You need to produce swarf not fine dust.

Julie

[nevillet]

On nevillet Said:

Then getting proficient at swapping the collet for the drill chuck.

Don’t know what collet type you are referring to, but I would suggest getting an ER collet holder and set of collets. I have both ER25 and ER16 sets for my mill, but almost exclusively use the ER16 ones. I also use them most of the time for drilling. A set of ER16 collets will hold any drill from 1mm to 10mm, and unless I am doing a job with lots of different drill changes, its far quicker to simply hold the drill in a suitably sized collet than going through the faff of swapping out the collet holder for a drill chuck and then going back.

[Author]

Posts