What *should* a Warco Super Major Milling Machine be able to accomplish?

[SillyOldDufferModerator @sillyoldduffer]

Posted by Lee Jones 6 on 22/05/2020 10:39:22:

Just to clarify, my original question was:

What *should* a Warco Super Major Milling Machine be able to accomplish?

… because that's the machine I have. I just want to know what it can reasonably do.

I'm not in the market for a newer, larger machine.

Sorry Lee, I was trying to rank the Super Major relative to other machines.

The point is all milling machines cut metal, but that powerful rigid machines get results faster and generally make life easier for the operator. In particular it's more difficult to do accurate work with the lighter machines because they flex.

It's not as simple as saying a WM14 can only take light cuts in cheddar while a Super Major will plough through 12" armour plate. Rule of thumb for all machines is 1HP will remove about ¾ of a cubic inch of mild-steel per minute. So in theory an Super Major and a Bridgeport should do about the same amount of work in the same time. BUT a Super Major is lighter and less rigid than a Bridgeport, so in practice the operator has to adjust to maintain the same level of accuracy, because Super Majors bend more than Bridgeports. It doesn't mean a Super Major is a waste of space.

My initial contact with machine tools was discouraging. A combination of carp metal in my junk box and me not understanding tool options, depth of cut, rpm, feed-rate and the need to snug everything up caused the impression the machine was faulty. Not so. Once I got the hang of it, chatter stopped, tools stayed sharp longer, finish improved, and jobs got done faster. Bit like learner drivers mastering a clutch; who didn't start by kangarooing and smoking the clutch on hill-starts. There is nothing wrong with the car, you have to learn to drive it!

You have to get a feel for what a particular machine can do by using it. As a Super Major is a fairly big hobby beast, it's less restrictive than smaller machines like my WM18. But my WM18 does everything I need of it, and a Super Major is 'better' because it's bigger. The main limitation is the size of the table.

A Super Major would come unstuck if used for continuous production. It's sized for intermittent work allowing the motor to cool down, and it's lack of rigidity would cost too much in operator time and skill. But it should do a good job in a home workshop, better than my milling machine and streets ahead of a milling slide on a lathe.

Two common beginner mistakes are pussy-footing and Gorilla expectations. Nervous light cuts blunt tools very quickly. Tools must cut rather than scrape and rub. And beginners persist with blunt tools long after an experienced machinist would have changed them. Mr Gorilla is even worse; he may be brutal enough to damage the machine by overheating the motor and electronics, stripping gears, bending tools and causing excessive wear and tear. And disappointed because finish and accuracy are poor. The ideal is somewhere in the middle; moderately deep fast cuts within the capability of the machine. Let the machine do the work, and have it working hard rather than soft. I do it by ear: having selected a suitable tool and rpm, I adjust depth of cut and or feed rate until the motor is heard to be working without labouring.

Jason Bellamy's recent MEW series on Milling is an excellent introduction. Jason doesn't do anything in his write-up that isn't well within the capabilities of a well adjusted Super Major.

Dave

[JasonBModerator @jasonb]

Not far off the 0.01mm (4/10ths) I just got on the SX2.7 using my thumb and with the tool 6" up from the table as having the head down low would have no doubt reduced the reading as the column waved about wildly.

[Anonymous]

Lee, I've sent you a private message. Look for the flashing envelope top left when you're logged in.

Andrew

[Lee Jones 6Participant @leejones6]

Hola. Back again.

Sorry about the delay. Machining was deprioritised for a few months.

So had a big play today and guess what?

Well, a picture paints a thousand words:

TL;DR; Bolted machine down (didn't change much), faster speeds (1000RPM), faster feeds (250mm/m).

This is how I left it *after* changing to Arc's "known good" inserts – so much for high hopes:

Thoughts: maybe the setup is janky – too much flex:

Yuck. Change back to the vise, pronto:

Ooooo, faster (and don't let the trailing edge catch it):

Missing test, back edge was trashing the finish, so mill the other way:

The money shot:

Pretty:

[Mike PooleParticipant @mikepoole82104]

Would the improvement gained by changing direction seem to indicate a problem with the tram of your mill? Assuming that the tram is adjustable.

Mike

[not done it yetParticipant @notdoneityet]

As per Mike. You would likely find the surface is dished (concave). Perhaps not a lot but imagine a wide piece and cutting with a fly-cutter – it would be noticeable then likely preventing you squaring up th part, if that was what younwere wanting.🙂

[SteviegtrParticipant @steviegtr]

I did see one article by Hass who said if the cutter is wide enough, do not run it central down the work. Slight offset gives a better cut. I do this now if the piece to be cut is narrower than the cutter, to allow such a cut.

Also when the trailing edge of the cutter comes along, does it show a arc on the work the opposite way. Meaning the cutter is touching at both ends.

Only from a amateur prospective of course.

Steve.

[Lee Jones 6Participant @leejones6]

Yes, the trailing edge makes reversed arcs on the way through.

And yes, it must mean the head is out of tram.

Although when I checked it, it was about 0.02mm over 400mm, which I thought was reasonable.

I've since ordered a new DTI holder to re-check it.

[JasonBModerator @jasonb]

Spot on tram will cut on the trailing pass giving an almost holographic look, best way to check if tram is out is to take a cut from both directions, if the trailing edge only cuts in one direction then you are leaning towards the leading edge.

As Stevie says you can get a smoother cut by offsetting the cutter as it will keep at least one tip engaged all the time this makes for smoother running particularly if you have any gears in the mill's head.

[Lee Jones 6Participant @leejones6]

Annoyingly I like the current surface finish, so I'm at pains to tram to 100%.

The main issue for me is that it's trammed the wrong way.

I'd like the best finish to be a result from pushing the cut into the fixed jaw really.

[not done it yetParticipant @notdoneityet]

I'd like the best finish to be a result from pushing the cut into the fixed jaw really.

Do you want a pretty-looking finish or a flat surface? JB’s pic is of a flat surface.

[Lee Jones 6Participant @leejones6]

I would like all the things please.

[SteviegtrParticipant @steviegtr]

From your comment do i assume you are milling with the Y axis,

Steve.

[Lee Jones 6Participant @leejones6]

That is a fair assumption. Using the power feed.

[SteviegtrParticipant @steviegtr]

Posted by Lee Jones 6 on 26/09/2020 20:55:37:

That is a fair assumption. Using the power feed.

Sorry but my power feed is on the X axis. It was just you saying you push the work against the fixed jaw.

Steve.

[Lee Jones 6Participant @leejones6]

Sorry, Daddy brain.

Think about the cut pushing material outwards towards the fixed jaw.

[SteviegtrParticipant @steviegtr]

Posted by Lee Jones 6 on 26/09/2020 21:32:10:

Sorry, Daddy brain.

Think about the cut pushing material outwards towards the fixed jaw.

Ah yes now i see what you meant. Oops.

Steve.

[not done it yetParticipant @notdoneityet]

Posted by Steviegtr on 26/09/2020 16:48:02:

I did see one article by Hass who said if the cutter is wide enough, do not run it central down the work. Slight offset gives a better cut. I do this now if the piece to be cut is narrower than the cutter, to allow such a cut.

Also when the trailing edge of the cutter comes along, does it show a arc on the work the opposite way. Meaning the cutter is touching at both ends.

Only from a amateur prospective of course.

Steve.

If the cutter is wider than the workpiece, cutting to one side should emulate conventional milling (avoiding climb milling on smaller machines), while cutting with It offset . As always, I suppose there are limits to how far the cutter should be offset, to avoid other issues…

[SteviegtrParticipant @steviegtr]

When using the 63mm widax cutter i offset it strangely by the amount that it sounded right. + the cut was the cleanest. This was when the left side of a clockwise cut was about 10mm beyond the left side of the piece. & the right side had around 30mm overhang. It cut beautifully. As others have remarked on this forum that trial & error is the best way to achieve.

I have taken this premis on board & always listen to a cut. It works well.

steve.

[Colin ThorburnParticipant @colinthorburn94238]

Lee, I've had my Warco Super Major about 3 months now and can confirm the same disturbing head noise demonstrated in your video so it looks like we're both on the same learning curve. "Surely it's not supposed to sound like that" is the question I've been asking myself almost every time I a take a cut. With everything nipped down, I took a 2×3 deep x100 mm conventional cut at 1600rpm in mild steel with a brand new Banggood 12mm carbide 4 flute choked down in an R8 collet at about 1 mm/sec feed and it sounded like the head was going to start stripping gears any second. That's not even 1cubic centimetre let alone 3/4 of a cubic inch and over nearly 2 mins! I persisted and got a nice cut but that's not how it sounds on you-tube was all I was left thinking. So I am very dubious about removing metal in any quantity or I need to change my expectations about what noise is 'right'. Warco (et al) could do worse than produce a reference musical – call it the Sound of Milling.

[Dave HalfordParticipant @davehalford22513]

Colin,

But then no one would buy them

[Anonymous]

Posted by Colin Thorburn on 12/12/2020 10:57:14:

With everything nipped down, I took a 2×3 deep x100 mm conventional cut at 1600rpm in mild steel with a brand new Banggood 12mm carbide 4 flute choked down in an R8 collet at about 1 mm/sec feed and it sounded like the head was going to start stripping gears any second.

I can't comment on the mill, as I've never seen one let alone used one. But one ought to at least give it a fair test. One, use a quality brand cutter. Two, get the feeds and speeds correct. Spindle speed is a little low, although I think it's the top speed of the mill. The big problem is that the feed is far too slow; 1mm/sec is 60mm/min giving a chip load of 0.0094mm per tooth. The cutter will be rubbing rather than cutting. The problem will be exacerbated by a low cost cutter which may be blunt from the off compared to better quality cutters. I'd be running at more like 250mm/min for a chip load of 0.04mm per tooth.

Before someone points out I'm using a Bridgeport I'd point out that at 1.5hp the Bridgeport is somewhat lower power than the mill in question, and it's old and worn out. Bit like the operator.

Andrew

[Martin ConnellyParticipant @martinconnelly55370]

Andrew, surely you are wearing out and not yet worn out, just like a lot of the forum members

Colin, conventional cutting ends the cut with a sudden release of torque at the end of the cut. Using a 12mm cutter, even with 4 flutes, to do a 2mm wide cut means that as one edge does the cut the next one is in free air. There will be a time between the cutting process finishing for one edge before the next edge engages. This releases the pressure on the drive between each cut taking place and you get a pulsing torque on the spindle that is transferred up into the gearbox and will cause a lot of noise. Sometimes a smaller cutter will be better for shallow cuts like this, you don't have the shock absorbing benefit of drive belts.

Recommended step over for finishing is 3-5% of diameter of the cutter. Recommended step over for roughing is 30-50%.

For Ø12mm this gives a finishing step over of 0.36mm to 0.6mm and a roughing step over of 2.6mm to 6mm. Your 2mm step over is falling between the two into the light roughing area and is probably the the noisiest option you could have.

Martin C

[Colin ThorburnParticipant @colinthorburn94238]

Martin, what you say makes perfect sense when you think about it – which of course never occurred to me. I was thinking 'big rigid cutter'. I'll be in the shed…

[Tony Pratt 1Participant @tonypratt1]

This type of mill is always going to sound unpleasantly loud due to the gearbox or you may have excessive play between the drive pulley & the spindle splines, if your machine is built up that way? Build quality will determine how loud your noise is. A 'work around' could be light cuts & high feed rate but that doesn't really solve the basic problem.

Tony

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