NuTools Md350m head rotation help

[trevor gettyParticipant @trevor-getty]

Hi everyone.

I require some help with my new/old NuTools md350m mill/drill combi.

I understand this mill is similar to the sealey/naerok mill.

My issue is that I loose the tramming on the mill every time I move the column head.

There is a rack on the side of the column but it isn’t attached it is effectively just snug between the cap and the recess at the bottom.  So when you loosen the head you can spin the entire head around on the column.

Not something I ever want to happen.

I seen an picture of a person with a spare column to keep his head aligned.

Is there anyway to actually just attach the rack so it stays in place.  I could deal with a small offset due to the rack and use a lazer pointer or similar there.  But currently it’s just wildly different every time I move the head.

Would I sound crazy to tram the head alignment and then glue or bolt the rack to the column at a few spots along it to prevent the majority of the move?

If anyone has any help or links to any of the articles covering this kind of modification please let me know.

I will never be using the rotation of the head, and would just prefer ability to move up and down reliably lol.

Also I see no locking lever on either side only 2 bolts at the back right hand side just behind the lock lever for the motor tensioner.

Are the 2 bolts to lock it at height when your ready, should there be any quick lock mechanism on it like the spindle quill has. ?

 

 

[Howard LewisParticipant @howardlewis46836]

Your machine looks rather like the ones that used to be sold by Warco as the Minor or Major. (Probably listed as a RF30 or RF35)

I don’t think that moving the head up or down the column loses the tramming.

What it does do is to lose the alignment, which can be a nuisance if the head is moved part way through operations.

The quick and nasty way to realign is to enter a drill into the hole that is has just been drilled, and move the head, extending, or retracting, the quill to keep the drill engaged, before relocking the head.

Then recheck that the drill enters the hole easily, and without any binding.

My method was to buy a cheap laser from a DIY shop, and fix a bracket (With a slot, milled on the machine) to a bracket fixed to the head.

Having aligned the head, as accrately as possible, by eye, with everything locked up, the laser was switched on

DON’T look directly at the laser!

I then drew a pencil line on a wall, about ten feet away. The late Stan Bray said that that resetting to that line should align things within a thou.  Certainly, in my experience, it will allow a drill, reamer, or any other alignment device, to re enter the hole.

HTH

Howard

[Howard LewisParticipant @howardlewis46836]

The head is locked to the column by the two nuts at the rear of the head, as you say.

Always recheck alignment after locking, as tightening can move the head very slighly.

There is no facilty to lock the spindle. When using an ER collet chuck, I made up a spanner (Using the mill) to hold the chuck body while the clamp nut for the collet is tightened or slackened.

You don’t have to use the ability to rotate the head about the column, it is feature of a machine designed to be built at minimal cost.  You get what you pay for!

In fact it might be possible to use this feature, to extend the Y range, slightly, although in over 20 years of ownership, I have never yet found the need for it.

It might be worth checking the alignment of the Motor pulley with the intermediate one. My machine shredded the primary belt within 6 months because the motor was misaligned. Not difficult to cure, just slacken the four setscrews and nuts, and use a straight edge across the pulleys. The Motor is heavy (I used a scissor jack, with a piece of wood on the jack head, to lift it back into alignment) The replacement belt is still satisfactory, all these years later.

Don’t over tighten the clamp screws for the internediate pulley carrier.  The cast flanges are thin and easily cracked.

Howard

[BazyleParticipant @bazyle]

There are several styles of round column mill that have been made for at least 40 years so probably a million of them worldwide plus every Chinese factory will have a dozen for making the small bits of whatever cheap household item you bought yesterday.
There have been many threads on here discussing it – search “round column mill”. All with the same problem. In reality the most sensible solution is to choose your tooling so that you do not move the head by making some short drills that fit your milling collet for initial drilling, then open up if needed on a proper drill. If you are milling profiles with more than 3 inches of Z range regularly then you need a different machine.

There is also a recent thread on the HSM forum. https://bbs.homeshopmachinist.net/forum/general/2095422-round-column-mill-solution if you have time to read 17 pages.

[john halfpennyParticipant @johnhalfpenny52803]

The Naerok RDM350 is different. The rack is effectively a fixed key between the column and the base, so rise and fall of the column maintains the head on a fixed vertical axis as the key slides in its slot; the rack pinion is on the base. The Naerok head could be loosened on the column and rotated, but I have found no need to do so because, as you say, it would be difficult to get the vertical axis in the same place (this is not a tramming problem, as I understand it).

[john halfpennyParticipant @johnhalfpenny52803]

A picture of the Naerok arrangement.

[Dave HalfordParticipant @davehalford22513]

This machine was never intended to use the rack for taking a cut, just the fine feed.

Warco use to list 3 versions Economy (1/2hp) Minor (1hp) and Major (2hp) They usually came with just a drill chuck which are hopeless for holding milling cutters as the first owners had to find out the hard way.

Howard warning seems to also explain why so many of these machines have drive belt parts missing.

[john fletcher 1Participant @johnfletcher1]

I have Naerok RDM350 and if trevor getty sends me a PM with his email address, might be able to help him out. John

[ChrisLHParticipant @chrislh]

I had the same problem with my Dore-Westbury milling machine. Because I had a contact who had the facility, I asked him to cut a keyway along the axis of the collumn. This was engaged by a thick washer suitably shaped to form a key which normally prevented the collumn from rotating. It is possible to disengage the washer however for those rare jobs which need the collumn to rotate. I’m not familiar with your machine so this may not appeal but if it does I’m happy to provide more detail.

[trevor gettyParticipant @trevor-getty]

There is 2 washers at the top that are already slightly rubbing on the column that holds the central spindle tension on the belts.   They could be changed in shape to act on a keyway as you suggest.  I could setup a scribe center the column and move it down to mark the keywau location and if slightly off I could always make a bronze locater slightly offset of required.  Good idea and simple.

This means I don’t need to drill into the rack teeth to add locating screws and give an easy way to revert back if I ever needed to move it.

If you could add pictures of your setup would be great.

 

Many thanks. Or other ideas please fire away.

Trevor.

[trevor gettyParticipant @trevor-getty]

Great link thanks.

The main points are great and the fact of using a keyway or anything right at the column will likely never give the precision required.

How about this, now take a deep breath.

If I make an alignment pin drill rod or something for the spindle and drill and small alignment hole at one far end of the table.  Then move the table over and align into this hole every time I move the head.  That way I don’t upset the vice or part setup and I just require different lengths of alignment pin.  I would try and use thicker pins where possible to prevent deviation.  Maybe something 1 inch thick with a small taper for alignment so it doesn’t bend but aligns very precisely.

I don’t mind a small alignment hole on the side I don’t use.

Would that work?

[DiogenesParticipant @diogenes]

..but then you’ll have to always have the head low enough to stick a pin in the table..

I’ve honestly never really found it much of an issue (Warco Major), tho’ I do have an ER collet chuck and a full set of collets which makes life a bit easier..

– if you are swapping between say finger collets, a drill chuck, and trying to use taps with a follower stuck in the chuck then you are going to be moving the head a bit, I guess.

A lot of it has to do with being a bit canny about toolholding, and also planning the work – it sometimes pays to lay out the tooling you’ll need for a particular set-up, and see if you can even up the lengths..

These days there are plenty of reasonably-priced options for toolholding.

Are there particular operations/sequences which seem to cause particular grief?

 

[Howard LewisParticipant @howardlewis46836]

Ir might work, the accuracy being determined by the clearance between alignment pin and hole, and the flexibility of the pin. Although if fixed in position it could impede table movement, unless very carefully located, and the hole is unlikely to be at one end.

But an alignment pon long enough to align the head, high up on the column, would limit how far the head could be lowered.  By the same token, a short (and stiff ) pin would be incapable of aligning the head when high on the column.

The more that I thinnk about it, the less I like the idea.

The advantage of using a laser or light beam, is that will not cause obstruction or sag under its weoght.

It does call for drilling and tapping holes for the bracket to carry the laser, instead of drill and tapping the column to lock the rack in position. (The weight of the head will still be carried by the rack bearing against the top of the column foot.)

And, if you are  1.5mm (1/16″) out of position over ten feet, the angular error will be small.

Tan 0.0625″ /120″ = 5.166:x10^-4, equating to 0.0296 degrees.

Howard

[trevor gettyParticipant @trevor-getty]

I like the laser pointer idea but simply don’t have room to use it accurately enough. I only have a about 4 feet to the wall behind me and it has shelves on it

For some context.

The purpose of me buying the mill was to allow the extra height required when sometimes facing off an exhaust gasket face on a old a series engine block or head and then the next day I might be making a small gear for a watch or clock.

I don’t have the budget to allow for a £2-3k plus mill to suit so I got what is otherwise a great strong mill for a good price but it definitely needs some mods to help it for my use case.

It’s not really about tool holding issues and more to do with the varying work heights that I have to deal with.

The rod idea to hold alignment seems ok and I have found a site with accurate linear rods with flanged bearings especially the accurate long flanged or mounted bearings which could allow the head to be fixed tighter for axial movement while allowing linear movement

Does anyone have a feeling at how thick a drill rod would be needed to be reliable at the distance required here of about 50cm.  Making a housing which could move on dove tails for accurate alignment top and bottom is easy but if I was to do this I would prefer it didn’t bend easily lol.

 

 

[trevor gettyParticipant @trevor-getty]

Sorry the bearings and rods example was here.

No affiliation just for example.

LMEK-L Series

 

[Howard LewisParticipant @howardlewis46836]

Could you aim the laser beam onto a mirror, set at an angle, to incresase the length from laser to target?

Although you seem reluctant to modify the machine, fixing the radial position of the hed would be an improvement to a machine which is a Mill / Drill (ie a beefed up pillar drill)

If a bracket is fixed to the head, so that a reamed hole in it runs on a vertical rod, fixed at top and bottom of the column,, this should satisfy your need.

Cromwell Tools will sell you a 1 metre length of silver steel, for the guide rod At least 1/2″ diamedter would be ny choice)

Drill and tap the rod, once cut to length, to secure to the upper and lower brackets. The hole in the bracket foxed to the head should be resaonably long, and a really snug sliding fit on the silver steel rod.

My method would be to fix one bracket to the column, fix the bracket to the head, and then to feed tghe alignment bar thraough it and secure to the bracket. The head should then be adjusted to the other end of the travel, a so that the alignment bar is vertical, before drfilling and tapping for the fixed bracket.

In this way, the head shouild be kept in alignment as it is moved up and down the column.

Obviously, the brackets should be as short and sturdy as possible, to maximise rigidity.

The problem might be finding the locations for the brackets!

Howard

[trevor gettyParticipant @trevor-getty]

I am in no way reluctant to modify the mill.  In fact any good cheap modification is fine.

The bar option seems not only cheap but also very easy to add and remove as needed.

The Lazer option needs a very fine Lazer and can cope with fuzzy images, and errors especially on a mirror that is not exactly flat and long enough to cater for the height adjustments required.  So the Lazer wasn’t really a good fit for me at least.

So any adjustment seems fine.  I was going to go with alignment pin but even that requires me to dial in after movement.  So any brackets as detailed above seems great to keep movement to a minimum and if using the long flange bearing hopefully it won’t be too far out especially the further I make this from the head.

The other linked article from person above shows a nice setup although it does alter the crank handle I might try to avoid this but otherwise seems fine, I would adjust it’s position and use liner mounted bearings otherwise seems fine for my purposes.

Any other pictures of people who have tried and either failed or succeeded appreciated as a picture paints a 1000 words like this one.

[BazyleParticipant @bazyle]

If you really insist on moving the head you don’t have to go to all that trouble. The only thing that is going to change is the relationship to the X axis. You would have to be miles out to affect the Y axis.  Just mount a DTI firmly to the quill or hold it in the drill chuck with the measuring finger aligned with the X-axis.
Touch off and zero against the last bit of face you machined to give a YZ plane and zero or note X handle index. You might be able to use the side of the vice jaw as the reference point or you could clamp a 123 block to the table as a semi-permanent location.
Raise head to new position, lower quill and touch off again at your reference point. Note the deviation on the X handle index and compensate.
Before anyone says the movement of the quill is not true to the Z axis then you have a problem to fix before you do any more machining anyway.

[trevor gettyParticipant @trevor-getty]

This method you say is perfect if my range of height adjustments is within the quill range.

So when moving from say a small great setup on my rotary table 2 or 3 inches off the table top.  To milling the top and side of a block. I need a large range of checking.

I like the dti for small quick movements within say 3 inches more height for larger tools in the same setup this is perfect

But for large changes the quill cant be used so I could add a long drill rod also but them im back to differing pin lengths and using a dti instead of a locating hole which is fine and avoids deviation.

 

The dti approach means you need to check after each move but it’s not permanent on your machine. But takes some time.

Or the alternative is to setup something permanent which means you don’t really need to check as it’s been prevented moving.

I think it then depends on how often you need to move the table height.  Definitely for now I’ve got straight half inch drill rod held in a collet in the spindle and then a dti at vice or table height to check quickly for now.

Then think of a permanent solution that means I can just move and forget longer term.

The half inch rod is fine for dti gauge approach I will use for now.

It seems a bit thin for longer term linear bearing to run on. Maybe 3/4-1 inch.

There is a nice space at back right just behind locking nuts where I could locate it to the head, base and column and not impact the quill handles or any motor movements etc.

Thanks everyone.

No ideas are bad ideas just different ones more suitable to people’s budgets and use cases.

 

 

[BazyleParticipant @bazyle]

You can reverse the position of the reference and DTI. Use a 3MT test bar (more reliable than a bit of random steel) in the spindle etc. Would give you about 8in of movement but as I said earlier you probably need a different machine. Bit like trying to run a one inch drill with a Dremel.

[trevor getty]

On trevor getty Said:

… ..buying the mill was to allow the extra height required when sometimes facing off an exhaust gasket face on a old a series engine block or head and then the next day I might be making a small gear for a watch or clock.. ..

 

.. ..It’s not really about tool holding issues and more to do with the varying work heights that I have to deal with.. ..

I’m still not sure I understand why you need to retain the same XY-axis reference between separate set-ups (especially as) in the examples you suggest – surely each job only requires the position of the spindle axis to be known in relation to some chosen reference relating to the part being worked on at that particular time?

[Howard LewisParticipant @howardlewis46836]

The problem of alignment arises if the head has to be moved part way through a job, because of tooling (drills for instance) being of different lengths.

Which is why I adoipted Stan Bray’s idea of the laser alignment. I use a cheap laser device, (£7.99 from B & Q if memory is correcty, after all these years)

If you can find a location for the alignment bar with flanges, you only have to make and fix the upper and lower brackets.  Having swung the head until it is at maximum distance from the column, the alignment bar can be fixed, and your problems should then be over, whether the head is high or low on the column.

Howard

[Diogenes]

On Diogenes Said:

On trevor getty Said:

… ..buying the mill was to allow the extra height required when sometimes facing off an exhaust gasket face on a old a series engine block or head and then the next day I might be making a small gear for a watch or clock.. ..

 

.. ..It’s not really about tool holding issues and more to do with the varying work heights that I have to deal with.. ..

I’m still not sure I understand why you need to retain the same XY-axis reference between separate set-ups (especially as) in the examples you suggest – surely each job only requires the position of the spindle axis to be known in relation to some chosen reference relating to the part being worked on at that particular time?

Great point and I didn’t think of that.  Moving radially doesn’t actually impact the tramming or nod of the head so it would still create square cuts exactly the same for each height.  It would only be fixtures that would be lost as it moves in the arc. If the height was changed within a setup.

I am so used to moving the head for every operation as my previous amolco mill for the myford had no quill so very z movement was a head move.  Tedious indeed.

So I can use any of the above ideas but it’s only to get alignment back if moving within a given setup and if so then accuracy is definitely only important based on the job.

Thanks for clearing that up for me, it’s such a pity as round column mills can be accurate.  My last one was round but it has a keyway and z axis lead screw both keeping it straight from factory.

As such I’ll just attach the rack on the flat at the bottom and top for now to keep movement from total rotation to a small deviation. Then I can use any approach from a Lazer, dti, dro or drill rod if I need to pick up a feature again to dial it in.

Thanks for that point as I really did miss that in my planning.

[DiogenesParticipant @diogenes]

Yes, I think they are a good machine – when I bought mine there seemed to be endless articles and videos dedicated to highlighting their deficiencies and providing increasingly complex ‘solutions’ to this perceived problem; some years later, I still haven’t found myself troubled enough by it to bother implementing any of them..

I did quickly discover that a decent edge-finder was a great benefit for relatively little outlay.

Nice Amolco!

 

 

[southernchapParticipant @southernchap]

I think the mill you have is a clone of the Rong Fu RF 15.  The vast majority of these mill/drill type machines are clones of the Taiwanese Rong Fu machines. Its possible that using the NuTools model in your searches may have led to you not finding as good information as you might.

If you google “Rong Fu”, or “RF 25”, or “RF 30” (the RF 25 and the RF 30 seem to be the most popular models but they all are similar enough in the way they work that the knowledge is transferable), you’ll find plenty of information about the various quirks of these machines.

 

There’s a YouTuber called “That Lazy Machinist” who has a fair few videos on his channel about his Rong Fu.  His videos are really good (he’s been a professional machinist and also taught machining) any they’re all worth watching.  Oh, and he’s Canadian, and quite amusing in a weird dry Canadian way.

 

Here are his two about this topic (there are loads of videos by lots of different people on this topic on YouTube, but these two videos are probably the best, as they don’t just give solutions but provide a really good explanation of the up and downsides of the solutions he suggests): https://youtu.be/wy9N-jg1AE0?si=c0BxB1C86jFWlsnK

 

There’s also a chap called Cuppa Joe who has videos on what he calls his “Wrong Fu”! His videos are worth checking out too.

 

I recently got my hands on quite a tidy Warco Minor (a slightly modified version of the RF 25) from the mid 90s and so will soon be going through the same learning journey myself.

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