How to use a round column mill

[Howard LewisParticipant @howardlewis46836]

I have been using a Warco Economy Mill/Drill for about 20 years. Yes, it is not ABSLUTELY rigid, and the head needs to be clamped to the column quite hard. If it is not, a cutter will dig in and shift everything.

It sounds as if your machine has play in it, possibly in more than one place. (I am assuming that your cutters are sharp; and that you are not climb milling )

My advice is to go through the machine check for clearances and eliminate them. The alignment strip is only an approximation, from what you say.

Is the column firmly fixed to the base?

Are the X and Y gibs correctly adjusted?

Is there a lot of play between the quill and the head?

Are the quill bearings, in the head in good condition, and correctly adjusted. They may be taper roller bearings. The manual should show you, and possibly advise on how tom preload them.

In any case, the head needs to be clamped firmly to the column

As you eliminate unnecessary clearances, things should improve.

HTH

Howard

Edited By Howard Lewis on 02/07/2019 20:23:28

[iNfParticipant @inf]

It looks like a game of 'snap' with regards to your milling machine. Your mill is the 1st one I've seen identical to mine, see this previous thread Link

The symptoms you describe are exactly the same as my machine and I get around it by drilling a hole 1st as described by others. Also in another of your threads you made a new oil lift screw and mine also broke! My solution wasn't as elegant as yours, I just drilled and tapped the end for a cap screw and cross drilled the end and attached to the motor with a split pin.

Dave

[Sam StonesParticipant @samstones42903]

Machine issues aside, it's great to see such clear photographs chaps.

OH for a workshop Gray!

Sam

[iNfParticipant @inf]

Gray

Regarding your modifications to the Emco, is the 3rd picture down an extended slitting saw arbor? What do you use it for? Also in the 4th picture is the slot for the stops on the Y axis something you have fitted or is it standard on the Emco as it's not present on my copy.

Dave

iNf

[not done it yetParticipant @notdoneityet]

Posted by iNf on 03/07/2019 07:54:10:

Gray

Regarding your modifications to the Emco, is the 3rd picture down an extended slitting saw arbor? What do you use it for? Also in the 4th picture is the slot for the stops on the Y axis something you have fitted or is it standard on the Emco as it's not present on my copy.

Dave

iNf

I’m guessing that as horizontal mills have an arbor support, he has done much the same for the vertical arbor. Smallish slitting saw, gear cutters or anything else that might be used on an arbor and benefit from a little (or more) support. Rigidity is the ideal characteristic for most metal cutting machines and every little extra helps towards that goal.

[Graham MeekParticipant @grahammeek88282]

Posted by iNf on 02/07/2019 21:58:31:

It looks like a game of 'snap' with regards to your milling machine. Your mill is the 1st one I've seen identical to mine, see this previous thread Link

The symptoms you describe are exactly the same as my machine and I get around it by drilling a hole 1st as described by others. Also in another of your threads you made a new oil lift screw and mine also broke! My solution wasn't as elegant as yours, I just drilled and tapped the end for a cap screw and cross drilled the end and attached to the motor with a split pin.

Dave

Hi Dave,

The Over arm support is used mainly for gear cutting, the additional support improves the finish.

I have also added an bracing system when using very large DP or Module cutters.

Lastly the Y-Axis stops are another of my designs,and are not fitted to the machine as standard.

Regards

Gray,

[AdrianRParticipant @adrianr18614]

Gray,

In your first picture, is that a quill lock?

Trying to get to the bottom of why the ZX-16 is more flexible and looking at your pictures, I am getting the feeling the column may be a larger diameter than the ZX-16, I have measured mine at 3". What is it on the FB2

Thanks

Adrian

[Graham MeekParticipant @grahammeek88282]

Hi Adrian,

Yes the first picture is a quill lock. What a lot of Emco owners do not realise is that there is a Tufnol gear in the input train from the motor to the gearbox. These have been broken in the past where owners use bottom gear to lock the quill.

This little unit ensures there is no strain through the gearbox.

My column is 78 mm diameter. One of the posts above mentioned checking the condition of the slides on the table. I once had a problem with the finish on the end of any bar when cleaning up the face with the side of an end mill or slot drill. Of course initial thoughts turn to play in the spindle, but as this was ruled out I looked at the slides. Sure enough both were a little on the loose side.

Tightening the slides made a world of difference, but, and it is a big BUT do not over do the tightening. To adjust any slide way you need to take off the feedscrew and push the slide by hand. If it is that tight, that you cannot then this will cause premature wear. The only correct way to adjust the head to column slide is with the head off and feedscrew removed. The Gib strip on the guide key wants to be loose so that you can set the adjustable clamping bolts to get the slideway sorted, once these are set then adjust the Gib.

Get this wrong and you can get to a stage where the slide will stick, then suddenly drop to take up the play in the feedscrew.

Regards

Gray,

[Howard LewisParticipant @howardlewis46836]

Not being a precision engineer, after moving the head up or down the column,to align the head, a cheap laser is temporarily placed on a custom made bracket, on the head, and used to shine a line of red light onto a pencil mark on the most distant part of the shop. At a range of ten feet, (3 metres ) or so, an error of the width of the pencil line only approximates to a good old English thou (25 microns for those who are metricated )

HTH

Howard

[AdrianRParticipant @adrianr18614]

Hi Gray,

Yes I have tightened it to the point where you get the sudden drop, decided it was not good and loosened it off.

Well 78mm = 3" so it must be either the tube wall is thinner or the steel is not such good quality. I am now 99% sure the vibration is coming from the spring in the tube and castings. I have tightened every thing up to almost jamming solid point and it still does it. Plus Inf also says he has the same issue.

Just some thing I have to live with or buy another mill.

If i really must cut blind slots I just need to by 4 flute center cut end mills as they work perfectly. Or maybe i should just invest in a good quality 2 flute to see if that works. I am tempted to try making a D bit to see if that works.

Adrian

[AdrianRParticipant @adrianr18614]

Howard,

Yes the laser is a good idea, your article in MEW inspired me to look further. Did you know that on ebay you can get just the laser diode line module and a psu plug. It is a lot smaller than the laser line unit you used in your article.

Adrian

[iNfParticipant @inf]

Adrian

You have a PM

Dave

iNf

[AdrianRParticipant @adrianr18614]

Latest news about slot cutting on the ZX-16

I have found that of the 5 new milling cutters I inherited, I have a Maydown Triplicut 3/8" long series cutter. It is centre cutting and will do a perfect plunge cut. I also tried a rather large and blunt 2 flute Osborn cutter, same head wobbling problem.

I am also learning how diffrent cutters can be. I have Maydown, Franken and Osborn that cut perfectly and the £85 set of 20 are terrible. They seem to be sharp and do cut but the finish is all torn and very rough.

Any sugestions for reputable supliers of HSS cutters that dont cost an arm and a leg?

[iNfParticipant @inf]

I am unable to use my mill at the moment As I had to take it apart to move it. The reason for moving it is that the builders are coming this weekend to start on the garage extension (Yay!) Maybe then I won't have to dance around my bike to use it or the ml7!

When I eventually get it in it's preferred position I will take on board Joe and Gray's advice regarding adjustments

Has anyone ever filled the column on a round column mill with concrete or similar to improve the stiffness or is it not a good idea?

Dave

iNf

[Anonymous]

Posted by AdrianR on 04/07/2019 12:06:01:

I am also learning how diffrent cutters can be.

That's an important lesson to learn, and one that is not always understood.

I don't buy many new small HSS cutters (I use carbide as standard), but when I do I use Drill Service in Horley.

Andrew

Edited By Andrew Johnston on 04/07/2019 15:15:37

[Thor 🇳🇴Participant @thor]

Posted by AdrianR on 04/07/2019 12:06:01:

I am also learning how diffrent cutters can be. I have Maydown, Franken and Osborn that cut perfectly and the £85 set of 20 are terrible. They seem to be sharp and do cut but the finish is all torn and very rough.

Any sugestions for reputable supliers of HSS cutters that dont cost an arm and a leg?

Some of the HSS cutters I have are Dormer, they work very well but are expensive. I have also bought HSS cutters from Tracy Tools and ArcEurotrade and they have worked OK for me. I also have cheap cutters that I regrind and use for roughing.

Thor

[Graham MeekParticipant @grahammeek88282]

Posted by iNf on 04/07/2019 14:21:08:

Has anyone ever filled the column on a round column mill with concrete or similar to improve the stiffness or is it not a good idea?

Dave

iNf

Hi Dave,

The theory is good but unfortunately I think you will find the concrete shrinks on setting. You then end up with a concrete block floating around in the column.

I have considered putting a long stud up the centre and applying a pre-tension to the column, this should alter the natural vibration point of the column. However if it was over done it might distort the column.

Regards

Gray

[iNfParticipant @inf]

Posted by Graham Meek on 04/07/2019 17:00:55:

Posted by iNf on 04/07/2019 14:21:08:

Has anyone ever filled the column on a round column mill with concrete or similar to improve the stiffness or is it not a good idea?

Dave

iNf

Hi Dave,

The theory is good but unfortunately I think you will find the concrete shrinks on setting. You then end up with a concrete block floating around in the column.

I have considered putting a long stud up the centre and applying a pre-tension to the column, this should alter the natural vibration point of the column. However if it was over done it might distort the column.

Regards

Gray

Hi Gray

I had thought about the concrete shrinking. I was thinking along the lines of rigging up something with bungee straps applying constant pressure to the top of the concrete to try and make it stay in contact with the inside of the tube as it sets. I'm not sure how effective it would be, I may have to experiment with an odd piece of tube.

Dave

iNf

[not done it yetParticipant @notdoneityet]

If you want a no-shrink concrete, it needs to be a ‘dry mix’ barely sufficient moisture to set the cement off – usually applied around fencing posts where the final cement hydration takes place as moisture creeps in from the surrounding soil. There are some gap-filling products/grouts that do not shrink, but keying to smooth steel surfaces is always difficult.

[Frances IoMParticipant @francesiom58905]

there are several examples from the early days of cnc’ing a Sieg SX1 of filling the column with resin bonded granite chips – claimed to dampen vibrations

[Mike PooleParticipant @mikepoole82104]

It’s a bit more of a specialist material but doesn’t polymer concrete shrink very little? Had a quick google but can’t find anything to back me up or shoot me down.

Mike

[old martParticipant @oldmart]

As lasers have been mentioned, I will describe how the laser on the museums round column is set up.

The laser is one of the cheap gunsight types which has the flexible remote squeeze switch in place of the push button type. It is mounted parallel to the centres of the spindle and column. The beam reflects off a window 10 to 12 feet from the mill and back to a white mark painted on the end of the laser body. This should give an increased accuracy. The beam is about 8mm diameter in this distance. I don't know whether a higher quality laser would have a lower beam dispersal. I must try putting a mirror on the window to see if things improve. It is easy to find out the best way of tightening the head clamping bolts to give the minimum and consistent deflection of the beam. With care, accuracy of +- 0.001" is easy.

I tried mounting the laser tangentially to the head as there was a 60 feet sight line to a wall, thinking that it would be better, and it was useless. With hindsight, the shortcomings are obvious.

 Here is the ebay number for the type I bought. The remote squeeze switch and the mountings included made it easier to fit and use. Only the red was available when I bought it. 283044776422

 Filling up the bores of round column drill mills has been tried many times with generally disappointing results. In theory, filling up the bore with scrap metal and pouring in a liquid epoxy should improve the resonant frequency just by adding mass, the stiffness would not improve much.

 

Edited By old mart on 04/07/2019 21:44:47

Edited By old mart on 04/07/2019 21:54:24

[Graham MeekParticipant @grahammeek88282]

I think the devil is in the detail. I know the Emco FB 2 uses a high specification material for the column. If the "clones" have not followed with this material then there is going to be differences.

Some of the round column belt driven mills I know have cast iron, or cast steel columns. This would be considerably cheaper to produce than something like the Emco column.

Round columns for machine tools have been used for some time, I remember working on Jig Borer, an Oerlikon KC4, which had two round columns.

As regards the filling of the column with any medium I am not convinced. The column is experiencing more twist when milling, with some bending, but when drilling it would be just pure bending. Twist and bending are not good for concrete, plus a lot of concrete columns are seldom solid, they too are reinforced hollow tubes.

Regards

Gray,

[JasonBModerator @jasonb]

Chuck a bit of aluminium powder into the mix, that will make it expand. The reaction with the cement is what gives the bubbles in airated blocks. There are several admixtures that do the same thing with those ingredients such as Conbex/cebex 100

 

Edited By JasonB on 05/07/2019 12:33:39

[AdrianRParticipant @adrianr18614]

I would be worried where the water would go, it would take an age to dry out just through the ends. During which you could not use the mill.

A thought could be to use a dry mix and then ram it. That would put the tube under tension, but I could see that would easily deform it.

[Author]

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