Milling Machines

Hi Steve,

I don't know if this has been pointed out by others but RE taper is not a collet system it is an alternative taper system to Morse tapers. The 'E' system of collets are used in holders or chucks which can have Morse or R8 tapers (there are other systems but these two are the most common).

The ER collet systems are useful because they can hold a range of size in each collet, unlike other less versatile systems. Hence a 6mm collet can hold work or cutters between 5 and 6mm because of the 'compressibility' of the collet. The system can be used to hold work or tools so is very versatile. So if you have an E collet chuck with a few collets for the milling machine that is really all the toolholding you need. There is no need for a different 'milling' chuck. My MT3, E32 chuck is hardly ever removed from the milling machine and it can hold all but my largest drills and milling cutters. I have a seperate lathe collet holder which I can use for much of my turning when I need accurate concentricity and repeatability

As another 'old schooler' I can honestly say that I never have to do more than nip up the drawbar in my milling machine with an MT3 taper housing and my MT2 drilling machine has never dropped it's chuck or the large MT drills I sometimes use and the MT taper in my lathe headstock and tailstock have never let me down.

The problems with morse tapers combined with drawbars is that folk tend to tighten them with too much force and consequently need to hammer the drawbar to free the taper. Worst problem is that they then use a steel hammer instead of a copper one (or similar) to bash the poor thing when struggling to remove the chuck. In all my years of machining I have usually just had to give the drawbar a light rap to release it, only rarely had to use a lot of force but have used a copper hammer and caused no damage to the machine. Then again I was taught in the toolroom but did witness a few gorillas in the production machine shop who thought that they had to use a lump hammer on every spanner and locking lever in sight.

The advantage in the home workshop of MTs is that tooling is common to lathe, drilling and milling machines, I can transfer my E32 collets and other tooling from lathe to milling machine or drilling machine with ease. No need for duplicate collet chucks.

My advice as to actual machine is to get the most solid you can, I have the equivalent of the Warco WM18 with a similar pressed steel stand and find it perfectly adequate and solid when bolted down. It's not a patch on my mate's Bridgeport but it does what I need without complaint.

Regards

T

Edited By Terryd on 16/01/2013 08:44:41

I have a WM-16, and find that the stand is ok. I couldn't bolt it to the floor, so I bolted it to the wall instead, and it's fine. One of the reasons I chose this mill was because it had MT2 taper, and so all the lathe stuff is interchangeable with the mill. The drawbar on these mills unscrews against a collar screwed onto the end of the spindle, pushing the taper out, so you never have to bash the end of the drawbar with a hammer.

Phil

There are R8 to MT2 adaptors available for a few quid.

I dont quite understand what you mean. Depending on what machine you want, there are many makers of mini-mill and mini-lathe. Motor sizes, wattage, length and type of bed for lathe, and different lengths of table etc. for mills, depends on what the importer wants out of each manufacturers range. Some parts will be different on 'twin' machines. eg. lathe mini-lathe from SIEG has a different bed from the one manufactured by some other factory. Saddles may be different.

Ketan at ARC.

Who fed you this rubbish ?

Ketan at ARC

Correction: I misread the meaning here. Yes they can be variable

Edited By Ketan Swali on 16/01/2013 13:22:38

Edited By Ketan Swali on 16/01/2013 13:26:21

Edited By Ketan Swali on 16/01/2013 13:27:02

The original Realbull went bankrupt a few years ago. Various people left it and started their own small units, including Realbull Mark II. So, there are now at least three makers of mini-mill and mini-lathe in that area alone.

Some of what is said above is marketing 'stuff' fed in the American market. Big Dog does not buy from SIEG. Most of the others including Micro-Mark do. Each have their own specification for what they want. Now and then, some of them digress from SIEG to experiment with other factories.

Ketan at ARC.

Edited By Ketan Swali on 16/01/2013 13:28:55

Good example of why we dont do shows, as covered elsewhere on another topic on this forum. There are a lot of people out there who are not compitent with a set of spanners, including me!. Everyone chooses to believe what they want to. This is also one of the reasons why we removed the preparation service too.

At present, simply put, price dictates your decision, and I wish you the best of luck with it.

Ketan at ARC.

Hi Alan,

So far we have been selling the brushless motor version machines for between two to three years, depending on which machine it is. Most of the boards on the brushless machines have been found to be more up to the job of dealing with overload than the brushed versions. This doesn't mean that one should overload!. But as you say, they can be expensive to replace, and we do not have a long enough life history on them to make a judgement for how long the board will last.

These boards have now been around for about five years, even though we have adopted them for between two to three years, after programing modifications were made on the board to deal with torque. The brushed motor version models have been around for more than 20 years, with the boards which are marked FC...or XMT..... and they are still available. Keeping this history in mind, I would think that the boards for the brushless motor versions should be around in five or ten years time.

But, I cannot say with certainty who or what or which company will or will not be around in five to ten years time. I cannot say what progress in technology will have been made by then.

If we were to say that we are faced with the situation today with a very old machine, and if there was no replacement board available, then today I would direct potential buyers to consider installing a three phase motor and inverter to their machine. This is often done with Myfords. With advancement in technology, this solution is probably cheaper and better solution than trying to replace the original old motor, and bring the machine up to date?

Ketan at ARC.

By the way Alan,

I am aware by your various posts on the forum that that you work to a certain high level of precision.

As you are aware, we no longer offer a preparation service. Whilst ours and rest of the Chinese mills available on the market do meet a certain level of precision - assembled machines based on price, these are still very much hobby, budget machines, fit for the purpose of general use - not high precision. They drill and mill as they come. We do not provide any accuracy certificates, nor do we commit to any. Our competitors may or may not provide such certificates for such cheap machines, and it is everyones choice if they wish to believe what they read.

We would not consider these machines as high precision, and as they come, I do not think that any of the Chinese machines be they ours or anyone elses will meet your expectation, even though we believe that they are fit for purpose.

Ketan at ARC.

I would like to add my two pen'orth.

I bought Warco's mini mill - no longer sold by them - because a) it had a MT3 taper thus matching my lathe; and b) it was as heavy as I could handle.

The MT3 taper decision has been proved correct as I can use the MT3 direct or finger collets along with plain shank endmills & slotdrills in both machines. The writer who commented on the height saving is quite correct - something like 2"/50mm out of 8"/220mm is saved by using these collets. I rather suspect that buying the collets as necessary would also be better, as it is I have bought all the metric versions available yet only appear to use two or three of them, but also, having a quantity of ¼" diameter steel available, I could use the ¼" collet which, of course, I haven't got.

The point about the weight was, in retrospect, a huge mistake as I had forgotten that the machine could be partially dismantled before installation. I now believe that the X3 or equivalent would have been better.

My machine, and that of a friend, suffered almost immediately from broken plastic gears. My friend replaced his with metal gears from Arc Euro Trade, I replaced mine with plastic gears but have bought a metal set against the day that I break them again.

Regards,

Peter G. Shaw

Hi Peter,

What type of collet chuck did you buy, ER collets are very versatile and a 7mm collet would be able to hold 1/4" as well. It is that versatility as well as the concentricity which has made the type so successful.

Best regards

Terry

Hi Peter,

Luckily, the Brushless SX2P has a belt drive and a fixed column, so not plastic gear breakage. However, I do believe that the original plastic gears in the original X2s are a failsafe to deal with certain overload scenarios. I am aware that not everyone shares my view on this, and I for one would keep the plastic gears rather than change them to metal gears, if I owned the original X2, even though ARC does sell the metal gears .

At the same time, I can also see why changing them to metal gears may appeal to people, especially as the changing process can be time consuming.

Ketan at ARC.

Edited By Ketan Swali on 16/01/2013 15:36:03

Terryd,

I don't have a collet chuck - just the finger/direct collets that plug straight into the mandrel. What I have done in the past is mount a length of this ¼" stuff in the three-jaw and turn it down to a suitable metric value then transfer over to the appropriate direct/finger collet. The thing is that this ¼" steel, although scrap, is actually very free cutting hence I am thinking about obtaining the correct direct collet.

Ketan,

I appreciate and understand your comment. Thanks.

What really annoyed me was that these things broke within three weeks of receiving the machine and I was most definitely not overloading - if anything I was probably too light in terms of tooth load etc. Another reason why I bought this particular machine was because of the uprated motor, hence I expected that the control electronics would have been uprated as well to cope with the additional probable loading, as should have been the plastic gears - but obviously not.

Changing the gears was a right pain and involved at one point some brute force involving a club hammer, lumps of wood and a pair of bricks. Hardly good engineering practice. Which is why when they fail again, they will be replaced by metal gears along with new mandrel bearings.

Regards,

Peter G. Shaw

Hi Ketan,

Hope Christmas was ok and that you're keeping well. I agree with you on the plastic gears, putting a weak link into a drivetrain is considered good engineering practice, better to have a cheap plastic gear or shear pin fail than an expensive motor or worse.  I recently had a shear pin fail on my lathe, if it had been replaced with a stronger one as some have advised elsewhere it would probably have sheared a couple of gears in the gearbox.

We always designed our drive units (overhead conveyor systems and other materials handling equipment) with shear pins or similar as a fail safe to prevent damage to expensive equipment or operators. I too would be very wary of replacing such a device with an alternative which doesn't break but causes much worse damage.

Looking forward to visiting ARC again soon,

Best regards

Terry

Edited By Terryd on 16/01/2013 16:33:34

Thanks, now I don't know what to do, the E system sounds good, one collet being able to clamp a couple of different sized bits would be a bonus in my eyes. Is it like the system on a Dremel machine then where the 'cap' screws down tightly squeezing the collet around the tool's shaft?

Does the 'cap' part eat into/take away some of the available work height though? Would the R8 be better in this aspect?

In the past I've been told that it doesn't really matter which one you buy, they all come from one or two factories period.

This guy were saying that's bull because there are so many different wattage motors alone fitted to these machines, why would say two factories make/fit several different motors in the first place?

Ah, I see. I am aware that for around the past four years, Warcos mini-mill came from the Yangzhou area - possibly Real Bull and derivatives. I know that they put in a higher wattage motor. Cannot comment on the results, as not from the SIEG stable.

SIEG have not uprated their brushed motor on the X2. They simply moved to the 500w Brushless motor belt drive in the SX2 series. In turn, some competitors entered into a 'my one is bigger' contest offering 600w brushed motor offerings with geared head or belt drive. Cannot say if it has improved things for them. However, I can definitely say that the 500w brushless on the SX2P has more torque than the 600w brushed on the original X3!.

Ketan at ARC.

Thanks Terry, hope to see you soon too.

Hi Steve,

The collet holder and cap of the 'E' system does take up a little 'headroom' but much less than a drill chuck or say a Clarkson style holder. You have to have some method of hiolding milling cutters and this is probably the best

As for R8, it is simply a taper locating system as an alternative to Morse Taper. The 'E' collet holders are available for both systems, You will probably have a Morse taper on your lathe hence personally I keep to those on both my lathe and milling machine but others prefer the R8 taper for their milling machines. As for an R8 to Morse adaptor, I personally prefer not to add yet another link in the chain which may lead to inaccuracy - I'm just a simple bod at heart (and in mind perhaps )

Best regards

Terry

Edited By Terryd on 16/01/2013 17:06:55

I bought an SX2P last year to convert to cnc(see here). I chose the MT3 version for compatability with the lathe. As Ketan has said it is not a precision machine however it can be improved with very little effort. If it's to be your first mill I would recommend using it a received. You can always improve it later if you need to.

Russell.