How useful is high 5000rpm spindle speed in a mill

[jaCK HobsonParticipant @jackhobson50760]

Posted by jaCK Hobson on 07/02/2022 13:08:45:

Does the SG vice come with bolts or do I need the smaller of these:

https://www.arceurotrade.co.uk/Catalogue/Workholding/Clamping-Sets/Hold-down-Clamps

No, and No.

[jaCK HobsonParticipant @jackhobson50760]

[jaCK HobsonParticipant @jackhobson50760]

Some minor glitches with the mill, but I'm over that now. The box it comes in is huge and an almighty bother to move but now the mill is in place it is 'just the right size'. I have already moved its location in the workshop several times as I work out where it fits best. The Mill comes with 4 Tnuts to help fit the vice.

 

I took a punt on the cheapest 2 axis DRO that still had the sexy features I'll never use like radial coordinates. Just over £100 delivered due to special offer on the day from Vevor. I only gave it 50/50 that I'd receive what I expected, and that it might take months…

The DRO did come in two separate deliveries… but it all arrived in not much more than a week, and it works! Already I'm happy!.

The X axis is 1m so a bit long… I'll just take an angle grinder to it and see what happens. Not sure if I put this on the mill or the Myford… Do I need 3 axis on a mill that already has dro on spindle?

Edited By jaCK Hobson on 22/02/2022 17:12:23

[Pete RimmerParticipant @peterimmer30576]

You can't cut the scales down with an angle grinder they ar made of glass inside.

[SillyOldDufferModerator @sillyoldduffer]

Posted by jaCK Hobson on 22/02/2022 17:10:44:

… Do I need 3 axis on a mill that already has dro on spindle?

I manage without!

My mill came with a electronic scale on Z, and dials on table X and Y. As dials are error prone I added two of ArcEuro's basic scales, which have served me well:

Despite not being well protected against swarf and cutting fluid, they've survived! They make the mill much easier and faster to use.

The main disadvantage of the basic system is the X, Y and Z displays aren't grouped together or particularly readable. Big clear numbers and controls on the same visually convenient panel are an obvious improvement, but in practice I manage without.

Most of my milling is done by moving the table (X,Y) after the tool-height is set (Z). I only watch Z when drilling and plunging. Z is handy, but I could manage without a digital scale. DRO on X and Y provide most of the value in my workshop.

As always the value of an accessory depends on how the machine is used. Fitting a DRO of the simplest type to a mill is almost a no-brainer – it transforms the machine. After that, reasons I might upgrade to a 3-axis display include:

• Getting fed up with reading displays scattered around the machine. Not having a central display doesn't slow me down badly enough to fix it. But sometimes it gets close!
• Repetition work
• Frequent switching between metric and imperial. (I'm 95% metric, so not worth it for me.)
• Drilling lots of PCDs and lines of holes.
• Milling lots of curves or inclines.
• Need to recall absolute zero (I work from a succession of relative zeros)
• Convenience of a built in calculator for tool offsets, cutting speeds etc.
• Wanting to measure feed rate

Dave

[jaCK HobsonParticipant @jackhobson50760]

Posted by Pete Rimmer on 23/02/2022 18:50:24:

You can't cut the scales down with an angle grinder they ar made of glass inside.

There are people on the internet who claim to have cut glass scales with methods including slitting disc in an angle grinder, metal cutting bandsaw, diamond wheels, dremmel, handsaw…

I didn't actually come across any reports of anything going badly wrong but I guess people are less motivated to publish their fails.

[jaCK HobsonParticipant @jackhobson50760]

I went ahead and cut the glass scale with a slitting disc in the angle grinder. I got lucky and it cut perfectly. I had a lot of extra scale so had the opportunity to try multiple times. Worst case was 2cm of scale chipped out at the end.

I reckon there isn't anything special about the angle grinder – I would guess that glass just shatters under stress but tends to go across scale rather than along… which makes sense from a 'science' point of view. Band saw, hack saw, just snapping without even scoring… I bet they all work within 2 cm. I was 'careful' but that is only within the limits of how careful you can be with an angle grinder.

Edited By jaCK Hobson on 27/02/2022 13:53:28

[Pete RimmerParticipant @peterimmer30576]

Well done is all I can say. Fair play to you for just going ahead with it Jack.

[jaCK HobsonParticipant @jackhobson50760]

The DRO works. Bargain.

X is neat:

I'm a bit worried about Y – I should really turn the scale up the other way to minimise dirt getting in (for now I leave a bit of extrusion resting on top).

Does anyone want to encourage me to turn it upside down, or do some people live with a scale this way up?

Tips for installation:

I started trying to complete the install without any dismantling of the mill but it is so much easier once you do! And tapered gib strips make is simples.

Again I am glad I got this size of machine and not any bigger – the cross slide is about as heavy as I would like to handle on my own without any assistance.

Thoughts on the SX3.5

The flaking paint issue is extensive on my mill. I was forewarned so I'm managing not to let it bother me. Be careful to check if paint is going to bother you!

The X power feed installation feels like it lets the side down. The electronics and motor are fine, but the hosing is thin plastic and will not last much longer. I have had to take the cover off a few times and if you put the wrong screw in, or over tighten, then the plastic cracks and that screw hole is then no good. I got 2 screws left holding the panel on… and they come undone because I don't want to over tighten like I did the others. I thin I will be 3Dprinting a new box within 12 months. The wire to the limit switch dangles around … not sure what the soln would be though. The power is via a separate brick about the size of an old laptop power supply, and the power input socket has its threads stripped so dangles out the box. Note that there are extensive power supply options hidden in an enclosure behind to column so a nice soltion would to have been to provide the power from there.

The column is no where near as massive as it seems in the sales pictures – most of that is a steel sheet covering to enclose the power and electronics.

The Z power lift however is a nice install. Enclosed power supply, hidden wiring etc.

The quality of finish, including surface finish, tends to be good enough and no more. An example is the gib strip. Where you might expect a scraped surface, you have the same effect but achieved with a hand held grinder. The actual points of contact are probably less than 10 across the whole gib – but these are at the extremes so it does its job. I don't know what impact this might have on wear.

The rest of the wiring and circuit boards are all neat.

As far as being a good or bad mill… I have no idea as I have nothing to compare to. But if you are buying, then be prepared for the above and you will be much more likely to avoid dissapointment.

[JasonBModerator @jasonb]

My scale is the other way up.

I was sent one of the same power feeds by Ketan 4-5years ago to trial before he made a decision to stock them and it's still working fine with no signs of cracking or breaking and I have had it apart a few times as part of the evaluation process, all screws still present and correct..

Edited By JasonB on 07/03/2022 14:40:17

[Mike PooleParticipant @mikepoole82104]

I would remount the scale so that gravity is on my side rather than working against me, a stray chip could destroy the scale as they are usually glass and once broken or even damaged it will be game over. When I was a sparky in a tool room you had to wonder how swarf got to the places it finds, but almost nowhere was safe.

Mike

Edited By Mike Poole on 07/03/2022 15:04:19

[jaCK HobsonParticipant @jackhobson50760]

I made something, mostly on the mill, using lots of different cutters, saw, power tapping, workholding, positioning etc!

I just made it up as I went along, so design flaws, but lots of fun! I haven't quite worked out how to use the thing best in all situations but I can at least use it. Not got to 5000 rpm yet.

I failed to make a brass thread to fit despite using matched M6 tap/die! Std m6 bolt goes in brass hole, std m6 nut goes on thread, but brass thread don't go in brass hole

[Mark RandParticipant @markrand96270]

Posted by jaCK Hobson on 26/07/2022 16:10:39:.

I failed to make a brass thread to fit despite using matched M6 tap/die! Std m6 bolt goes in brass hole, std m6 nut goes on thread, but brass thread don't go in brass hole

 

Either it's a little bit tighter than the commercial nuts and bolts (which tend to be a rather sloppy fit). If so tighten the die up ever so slightly and take another pass.

Or there's a bit of a burr on the start of one of the threads that the chamfer on the commersical nuts and bolts are navigating ok. If so, a bit of work with a file or deburring tool might help.

 

Meanwhile:- Nice work.

Edited By Mark Rand on 26/07/2022 17:47:08

[Robert Atkinson 2Participant @robertatkinson2]

Interesting thread. I've been thinking about buying a small mill and was looking at the Sieg SX2P package from ARC. Most of my work will be on non-ferrous material for electronics projects. Quite a lot of drilling small holes too (will be adding a DRO). I was concerned about the 2000 RPM top speedof the SX2LP. This thread has helped me decide that the SX1LP would be better suited to my needs. The slightly larger Y travel may be an advantage when doing panel cut-outs too. The MT2 collet is not Ideal but I will probably get a ER collet which sorts that issue.
Now I just need to decide if I have room….

Robert G8RPI.

[Robert Atkinson 2Participant @robertatkinson2]

OK, this is weird.

I've been looking at mills for sale and I just took a telephone call from ARC Eurotrade asking for SWMBO by name. SWMBO would not know a mill from lathe if her life depended on it. We do have an anniversary coming up though.

Robert G8RPI.

[Mark RandParticipant @markrand96270]

Maybe she's decided to take the hobby on.

[Bob Unitt 1Participant @bobunitt1]

Posted by Robert Atkinson 2 on 27/07/2022 11:51:41:

OK, this is weird.

I've been looking at mills for sale and I just took a telephone call from ARC Eurotrade asking for SWMBO by name. SWMBO would not know a mill from lathe if her life depended on it. We do have an anniversary coming up though.

Robert G8RPI.

Have you got a birthday coming up ?

[jaCK HobsonParticipant @jackhobson50760]

Posted by Mark Rand on 26/07/2022 17:45:50:

Either it's a little bit tighter than the commercial nuts and bolts (which tend to be a rather sloppy fit). If so tighten the die up ever so slightly and take another pass.

Or there's a bit of a burr on the start of one of the threads that the chamfer on the commersical nuts and bolts are navigating ok. If so, a bit of work with a file or deburring tool might help.

Meanwhile:- Nice work.

The die is not split. Comes from the std machinemart metric tap/die set.

I can't work out what happened. Maybe the thread blank was oversize slightly when I cut it – I remember it being a little tricky to start. I filed off about .5 mill of the thread diameter and ran the die up and down with positive/negative pressure etc to try and get a bit more metal off… but the threaded hole just won't have it.

[Robert Atkinson 2Participant @robertatkinson2]

Posted by Bob Unitt 1 on 27/07/2022 14:43:33:

Posted by Robert Atkinson 2 on 27/07/2022 11:51:41:

OK, this is weird.

I've been looking at mills for sale and I just took a telephone call from ARC Eurotrade asking for SWMBO by name. SWMBO would not know a mill from lathe if her life depended on it. We do have an anniversary coming up though.

Robert G8RPI.

Have you got a birthday coming up ?

No , she got me a spectrum analyser for my birthday. This would be wedding anniversary

[Robert Atkinson 2Participant @robertatkinson2]

Another example of excellent customer service fro ARC Euro Trade today. They called my wife to ask what sort of work I was likely to be doing becuse the mill she ordered was designed more for "electronics" work than traditionsl model making.
She was able to assure them that I am "electronic" in my hobby (and work).

Great example of somone at ARC actually thinking about the order and not just ticking the box.

Robert G8RPI.

[jaCK HobsonParticipant @jackhobson50760]

A couple more useful basic milling projects.

[jaCK HobsonParticipant @jackhobson50760]

Glad I didn’t go for a smaller mill. And I finally used the extra travel length on the 3.5 over the 3. Hurrah

There is an argument I needed a bigger mill…

 

[Ady1Participant @ady1]

The big problem I found with high speeds and small carbide cutters on a proper machine tool was taking a small enough bite without damaging the cutter

I have a parkside dremel type thing and put a tiny carbide cutter into a collet at 10,000 rpm and applying it gently by hand removed a lot of material with no appreciable stress on the cutter at all (On steel)

So the work envelope parameters are small, but it can be done

[Neil LickfoldParticipant @neillickfold44316]

A great thread. I am looking at modifying my ZX45 mill, and using the 20k max spindle sold for wood routers, and belt drive it to the ZX spindle at 1 to 4 with a max speed of 5k for use with small cutters and a min speed of around 1200 or so. This will still give  the quill function , like when cutting ports on liners for example.

The other option is to remove the existing spindle and motor etc, and replace it with a 15k spindle , sold for metal cutting, so has stronger bearing arrangement, and more torque in the lower rpm range apparently. Then there will be no quill, but I could then make it into a cnc on the XYZ , and incline the work piece for cutting ports for example. The idea of using small cutters and cnc (Maybe) , is that there is significantly less cutting forces and deflections happening.

Has anyone tried the reduction to try and get 5k from a 20k motor ? Or is it being unrealistic?

 

[JasonBModerator @jasonb]

If I do go down the high speed option on the CNC I’ll likely mount a ER16 spindlemotor or small INT 20 one on the side of the head and have variable speed to the spindle. My CNC has no quill anyway and there is enough table either side to still allow me to use all the X travel.

I would have said take a look at Andrew johnston’s Albums as he has something similar on the side of his Tormech

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