Milling for beginners

[JasonBModerator @jasonb]

This is a thread to complement the one relating to "Lathework for Beginners" by our Editor Neil Wyatt and will relate to my alternating series "Milling for beginners" that will start in MEW 261 and run in alternate issues. Thanks to a sponsorship deal with Arc Euro Trade Ltd I will be introducing the mill, tooling to suit and how to use it aimed at the beginner who has little or no knowledge on the subject.

There are now two dedicated threads for the two series on the forum at http://www.model-engineer.co.uk where you will be welcome to ask further questions or even suggest topics or techniques you would like us to explore as the two series develop.

This thread is for questions about the Milling for Beginners series. Please keep it on topic, this thread is for general discussion of Milling techniques and using different accessories not issues like merits of one machine versus another. Off topic comments will be moved or deleted!

Neil and I both plan to include ‘tips and wrinkles’ that will be of interest to more experienced hobbyists as well, so we hope that this new initiative is something that all readers will enjoy.

Thanks,

Jason

[JasonBModerator @jasonb]

Please use this thread to ask questions of make suggestions about the series in MEW

[Neil WyattModerator @neilwyatt]

Sneak preview here.

[JasonBModerator @jasonb]

As mentioned in Part 2 of my Milling for Beginners Series here are some links to the products featured in the article that are available from the series sponsor ARC Euro Trade Ltd.

 

R8 Collets and Morse Taper Collets

R8 End Mill Holders and End Mill Holders for MT2 & MT3 spindles

ER Collet Chucks and sets for R8, Morse Taper and with straight shanks

Individual ER Collets and Low Friction bearing nuts

Drill Chucks and Arbors including the Mini Drill Adaptor

Boring Heads and Boring & Facing Heads

Fly Cutters

Milling and Saw Arbors

Shell Mill Arbors

The introduction should have read "This new series will build into a complete guide to using a milling machine. This month Jason Ballamy looks at the Mill’s spindle taper and the range of tools available to use in it" but it looks like someone forgot to change it from last months.

Edited By JasonB on 22/12/2017 17:35:33

[JasonBModerator @jasonb]

Any owners of X2.7, X2.7L, SX2.7 and SX2.7L mills please read this thread about correct operation of these mills

[NigeParticipant @nige81730]

I have been looking at the SX2.7 mill tonight with the thought "where would the bits for a 3 axis DRO fit". Has anybody done this yet?

There appears to be plenty of space to fit scales and sensors the only scary position being the back of the table where you might want to fit the X axis sensor which would probably entail removing the table hence being scary !

Y axis looks like scale and sensor would fit nicely on the right hand side with scale fixed to base of machine and Z axis on left or right. This is all dependant on scale and sensor sizes of course.

Another question is do we use magnetic or optical scales/sensors ? Got some more investigation to do

[JasonBModerator @jasonb]

Cordless drill and a decent bit will son have some fixing holes in the back with no need to take the table off.

When I did my X3 the magnetics were not about but worth thinking about now as they can be smaller and with the right covers a bit less prone to swarf/coolant not that I have had any issues with my glass ones.

[NigeParticipant @nige81730]

Part way through 4 part DRO PRO videos fitting scales to a mill on YouTube and magnetic certainly seems the way to go as you can cut the scales to size quite easily

[Gas_mantle.Participant @gas_mantle]

Hi Jason,

How do I view the 2 dedicated threads ? I may have a few questions but the link you gave seems to just take me back to the homepage.

[Paul LousickParticipant @paullousick59116]

Nige,

I used to have an SX3 and removing the table is easy. (assume similar for SX2.7). Remove screws securing the thrust bearings at end of table and unscrew the leadscrew, loosen gibs and slide out the table. Table is heavy but can be lifted by hand. My SX3 already had a Z-axis DRO fitted and I added scales for X & Y. Note: These cheap DRO's started to give problems and I replaced them with Easson glass scales and readout.

[David George 1Participant @davidgeorge1]

I fitted the X axis scale to the front of the table as if it had been fitted to the back it would have restricted the movement and possibly traped swarf. I had to remove the stops and pointer on tape scale riveted to the table, but when you have a DRO you don't use it.

David

[Paul LousickParticipant @paullousick59116]

The X axis scale on my old SX3 and new RF-45 have the scale at the rear and can still achieve full travel. The SX3 was fitted with a splash guard at the rear to keep swarf and coolant from flying everywhere. The Easson glass scale which I now have come with a cover to protect them from swarf. Even though I have the DRO, I still use the travel stops at the front when doing multiple passes to a set position.

Paul.

[JasonBModerator @jasonb]

Peter, the two thread one of which is this one can be found as stickies at the top of this section of the forum

The SX2.7 table goes back a long way beyond the spindle so room enough to fit the scale as you won't often be machining work hanging that far off the front of the table.

Also there are two M4 tapped holes already provided that can be used to take the read head bracket for the X-axis scale, these are what Sieg use on their own brand scales. So just two holes in the back edge of the table to drill and tap which are easily accessed with a cordless.

Edited By JasonB on 21/06/2018 09:10:21

[NigeParticipant @nige81730]

Jason: Thanks, I had spotted 2 holes behind the table but hadn't investigated any further.

I would appreciate thoughts about whether to fit a 2 or 3 axis kit to the mill. 2 axis is cheaper and I'm trying to think why or when the position in the Z axis is useful for anything other than drilling holes to a known depth which is already quite easy by hand with the digital vernier already fitted. Or am I missing something fundamental?

Edited By Nige on 21/06/2018 22:37:13

[Paul LousickParticipant @paullousick59116]

Nige, An option is to buy a 3-axis display and 2 scales. Then you will be able to add the extra if required later..

The better quality DRO readouts have extra functions. PCD positions for holes, inclined positioning, ability to machine a curved surface. + more. Some of these features can be used in the Z direction with a 3-axis readout. (Easson DRO's have a good explanation on the web) https://www.youtube.com/watch?v=jeCYSLuwktU

Paul.

 

Edited By Paul Lousick on 21/06/2018 23:30:47

[JasonBModerator @jasonb]

I did what paul says and originally bought a 3 axis display but just X&Y scales. Added the Z about a year later, I don't have the fine feed or digital Z on my X3 so more likely to need a 3 axis than you.

Times when it may be needed, when you are working on a large part with several different height machined surfaces and the quill scale won't cover that range, curved work using the functions of the DRO and easier to read, no battery issues and more reliable than what is essentially a cheapish calliper scale fitted to the machine already.

"Pimp your SX2.7 tip" Part 2.- Make sure that when the nuts that hold the end of the supplied scale to the forked quill bracket are tightened they don't pull the scale off line as this can make the quill action tight. Best to undo nuts and fit a small washer either side of the forked slot so nuts tighten onto that.

[NigeParticipant @nige81730]

Paul and Jason: Thank you guys

[Gas_mantle.Participant @gas_mantle]

On the subject of DRO's is it much of a job to fit them to a mill? I know the makers usually say its so easy a 5yo can do it but we've all heard that kinda thing before.

I have a Chinesium mill of a similar size and spec of the Sieg 2.7 and have considered a DRO, I don't mind a bit of cutting and drilling but I don't really want to start milling out large slots or dismantling a lot of the machine etc.

[NigeParticipant @nige81730]

Gas_mantle: I have been watching a series of four videos on YouTube from DRO PROS about fitting a DRO to a mill very similar to the Siege and it does in fact appear to be a reasonably easy process.

[NigeParticipant @nige81730]

A word of caution when using the saddle power feed. It is VERY EASY to go straight through the neutral position and straight into the cross slide power feed position when disengaging the saddle power feed as I found today. This happened today even though I had practised the gentle movement required and knew the possibilities !!! Fortunately it didn't cause too much damage to the work piece as the lathe stalled as the tool dug in and I was able to get the E. Stop hit.

[Ron LadenParticipant @ronladen17547]

I started a thread and asked peoples advice on using my bench drill for lightweight mill work, a lot of the guys came back and said DONT. General opinion was to get a mill slide for the minilathe or better still get a mill. I have decided to save until I can afford a small mill.

I have some basic understanding on operating the lathe but none when it comes to a mill. A few years back a friend gave me a small selection of cutting tools for a mill and I was looking at them yesterday evening and it sparked a question.

What is the difference between a slot drill and an end mill and which does what when milling. I,ve read a few bits and pieces but not much. Would I be correct in thinking that a slot drill will plunge cut as well as cutting on its sides, whilst an end mill will not plunge cut but its cutting edges are on the sides only. Sorry for the poor description but I dont know the correct technical terms yet.

Ron

[not done it yetParticipant @notdoneityet]

Both will do the same basic job apart from the end mill does not have cutting edges which cut to the centre on the end. That means that if you try to plunge cut there is a central area left uncut, preventing any plunge. Basically as simple as that.

[Ron LadenParticipant @ronladen17547]

Thanks, Now I,m probably being stupid here but what is the point of an end mill, why not use a slot drill for everything..?

 

Edited By Ron Laden on 01/07/2018 13:18:08

Edited By Ron Laden on 01/07/2018 13:18:35

[JasonBModerator @jasonb]

Sorry I can't agree with that old way of thinking, many "end mills" produced now have centre cutting edges and would now be better named "4-flute milling cutters" as they can plunge cut. Ok this is a rougher but same applies you can plunge, ramp and side cut with 4-flutes

2-flute cutter also tend to cut a lot closer to their nominal size where as a 4-flute can cut over width if it deflects in a heavy cut.

Have a read of part 4 of my series for a bit more info

Not the best photo but the 4-flute on the right will plunge cut

 

 

Edited By JasonB on 01/07/2018 13:46:21

[JasonBModerator @jasonb]

Posted by Ron Laden on 01/07/2018 13:17:13:

Thanks, Now I,m probably being stupid here but what is the point of an end mill, why not use a slot drill for everything..?

– If you were to slice a 4-flute cutter across the flutes the cross sectional area would be more than that of a similar diameter 2-flute one so they are more rigid handy for long deep cuts or when using a lot of the cutters side.

– for the same optimum speed and tooth loading you will be able to remove twice as much material with a 4-flute than a 2-flute so job takes half the time.

– For the same cut a 4-flute will remove twice the metal of a 2-flute before the cutting edges are worn to the same extent so cost and time savings

[Author]

Posts