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R8 or morse taper 3?

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Jeremy Smith 211/06/2020 19:29:15
81 forum posts
13 photos

I have an rf-30 milling machine, which accepts morse taper 3 tooling. Will it also accept r8 tooling?if so, what is needed to make it work? Which is better to invest in - r8 or m3 tooling?

I came across these in the classifieds - will these work in my **LINK**

what do you suggest i invest in to get started?

John Haine11/06/2020 19:43:35
4186 forum posts
242 photos

No it won't. No point in buying R8 for an mt3 mill.

Emgee11/06/2020 20:12:40
2158 forum posts
265 photos

Hi Jeremy

Best buy a collet holding chuck, MT3-ER25 or ER32, not sure of the size of your mill or the work you will be doing, ER25 takes collets capable of holding to 16mm (5/8" ) the collets will hold tools securely for milling and they can be used to cover a range of 1mm diameter, but always best to keep with closest size.
The ER32 is quite a bit larger and may not always allow you to work on small chuck held parts, the body is likely to clash with fixtures.

You can also get single size MT3 collets that do not take up as much space below the spindle.


Edited By Emgee on 11/06/2020 20:14:45
closing bracket after the " sign produced a frowning face, didn't get it off 1st time.

Edited By Emgee on 11/06/2020 20:16:45

Jeremy Smith 211/06/2020 22:18:26
81 forum posts
13 photos

Do the er25 collet tools also use a drawbar?

obviously, the er20 collets would most likely to be too small,?

Edited By Jeremy Smith 2 on 11/06/2020 22:21:39

Emgee11/06/2020 22:51:46
2158 forum posts
265 photos

ER20 collets take up to 13mm (1/2" ) , not too small if you don't intend to use larger diameter tooling, the chuck body will be a good bit less diameter and less weight.

You always need to use a draw bar when milling, the side loads will loosen the taper if not, so best to order a chuck with the existing size drawbar used.


Martin Connelly11/06/2020 23:10:44
1899 forum posts
205 photos

This is the sort of item Emgee is talking about. If you don't have a taper ejecting system on the mill then removing morse tapers that have been pulled up too hard can be troublesome. Putting one of these in the spindle and leaving it there for a long time could cause it to be hard to remove.

MT3 to ER32 chuck

They are available with different drawbar threads and also from other suppliers, this is just an example. The advantage of MT3 collets over one of these is that they do not stick out below the spindle as much. The disadvantage of MT3 collet chucks is that they are really only good for their specified size, ER collets cover a range of 1mm (for ER32 collets). This means that a set of ER collets requires less collets to cover a full range from 20mm down to 4mm. This is important if you are going to be holding lots of different sizes of tool. The reality is a few collets will cover all likely milling cutters and you may be better off using a MT3 arbor plus drill chuck for drills. The choice is for you to make based on your preferences and how much you want to spend. There is no definitely right answer.

Beware of used items, you can't tell what sort of abuse they have had if you can't inspect them properly.

Martin C

oldvelo11/06/2020 23:42:10
276 forum posts
54 photos

Hi Jeremy

Morse Taper Tooling is what you have. The drawbar on morse tapers needs to hold the tool from falling out. Tighten with the correct size spanner. In the distant past my old mentors advice was put your thumb on the jaw of the spanner and tighten with your pinky and a little light assistance with the ring finger.

One trap with morse tapers is to insert the Cold tool into a spindle that is running Hot then winching it up tight with the drawbar. Very difficult to remove this shrink fitted tool holder.


Paul Lousick11/06/2020 23:57:07
1861 forum posts
661 photos

I have an RF-45 (clone) milling machine which has a MT3 taper and use an ER32 collet holder for most of the milling operations. I do not have any problem ejecting the collet holder.

The drawbar only needs a moderate tightening to secure tools in the spindle and releases with a slight tap. If a cutter does not release easily, there is a slot in the side of the spindle for using a wedge. (The same as used on a bench drill). Just extend the spindle and insert a wedge to remove the tool. (photo shown with drawbar still attached)


taper removal.jpg

Jeremy Smith 212/06/2020 00:38:30
81 forum posts
13 photos

In regards to the most vommonly sized tool, is there one? I mean i know its a generic question. Most of my applications will be for modifying pulleys, building spacers, hinges... all car related.

Edited By Jeremy Smith 2 on 12/06/2020 00:40:21

Paul Lousick12/06/2020 02:45:18
1861 forum posts
661 photos

I would say that there is not a commonly sized tooling. It depends on the type of projects which you work on. Everyone is different.

For me the most used cutter is a 16mm and 25mm end mill with replacable inserts. Then a 4, 6 10mm carbide end mill. I also use other sizes, down to 2mm but I buy them and the matching collet as I need them.


not done it yet12/06/2020 08:04:58
6343 forum posts
20 photos

Shank sizes of cutters do not exactly reflect the cutter diameter. Standard shank sizes are used for cutters. Drill bits are a different matter, as are work-pieces when held in collets.

Oldiron12/06/2020 09:35:31
850 forum posts
23 photos

I use a 3MT to ER32 collet chuck on my AJAX MD20 which is a similar size to your RF30. There is 16.25" clearance from the quill to the table although the book states 15". My vice is 4.5" high so there is reasonable clearance to work with even long end mills or a fly cutter.

You can get collets up to 25mm for the ER32 chuck although the set from 21-25 cost me £75 a couple of years ago.

Never cinch up the drawbar like a gorilla a firm pull is that is needed and a little more for an interrupted cut.

I have never felt that I needed an R8 type mill as the 3MT holds very well if kept clean and treated properly.

Hope this helps. regards

John Hinkley12/06/2020 09:54:51
1187 forum posts
391 photos

To digress slightly and pick up on the point made by Emgee, above, my mill has an R8 spindle and I normally use an ER25 chuck to hold cutters and drills. I also have an ER32 chuck for the occasional use of larger cutters up to 20mmØ. On the very rare occasions when I've needed extra clearance that the ER25 chuck precludes, I've used an ER11 parallel shank chuck in a10mm R8 collet, held directly in the spindle. Obviously you'd have to use an MT3 collet, but the principle is the same. If you need greater capacity than the ER11 gives, an ER20 will give a little more wriggle room, up to 13mmØ as stated elsewhere. There is the additional minor benefit of an increase in throat height available with this set-up.


SillyOldDuffer12/06/2020 10:28:46
7562 forum posts
1680 photos

You might well ask what's going on with all these different tapers and tool holders! It's a mix of history and change.

When milling machines first appeared cutters were fitted directly into the spindle by whatever method the machine maker thought best. Not only were cutters incompatible with other machines, but all the holding systems slow and clunky - it took a long time to change cutters.

Around 1860, Stephen Morse invented the Morse Taper system in the USA, whereby the cutter is wedged into a tapered socket for grip, and - if necessary - secured with a drawbar. Taper tools can be changed quickly. The idea caught on and for good and bad reasons many alternatives appeared. Good reasons include better grip and/or faster tool-changing, bad reasons include proprietary lock-in, jumping on the bandwagon, and patent dodging. There are dozens of systems, many obsolete, niche or industrial. MT remains popular.

In a home workshop it's relatively unusual to plug tools directly into the spindle. Some form of chuck is more convenient and general-purpose. Most of my milling is done with an MT-to-ER32 collet chuck. ER32 collets cover a wide range of tool-diameters, and it will hold milling cutters, drills, a micro-drill chuck, fly-cutter and slitting saws etc. I also have a Jacobs drill chuck because tool changing is faster than ER32 when a lot of drilling of different sized holes is on the agenda.

Most tool-holding systems differ only in how fast tools can be changed and maybe how many horsepower they take before slipping. Both important factors when a machine is worked against the clock to feed the operator's starving children! Neither matters in my workshop; my 1.1 and 1.5kW machines aren't powerful enough to worry MT and taking a few minutes to change tools is irrelevant. MT is fine.

I'm not sure why R8 is rated in Europe. R8 was designed by Bridgeport for their eponymous and very popular mill. R8 tooling was far more common in the USA than anywhere else, which was a good reason for using it in the US. R8 has become available in Europe since the Chinese started making it, but I'm not sure exactly why R8 appeals here. I don't see much engineering logic - possibly chaps think R8 must be wonderful because Bridgeport Mills use it.

An MT to R8 adaptor is a bad idea. Adaptors are a handy way to allow occasional use of other tools on a machine but they take up head space and reduce all-important rigidity. Avoid.

I think 90%+ of small workshop needs would be met by an ER32 collet set and MT chuck. ER32 covers 2 to 20mm which is a good compromise. The other ER ranges are more specialised: ER11 is 1-7mm in 0.5mm steps, so good for small work. ER40 is 5 to 26mm, its suits bigger work, but fluffs below 5mm. (Imperial sizes also available.)

As always people have their favourites. ER is relatively new, but it's become massively popular. The reason seems to be convenience and general utility. Other collet systems have slightly better grip at the cost of much reduced range, or take longer to swap, or are more expensive for little in return. Unless there's a specific reason for choosing an alternative, ER is generally effective.



Edited By SillyOldDuffer on 12/06/2020 10:30:37

Douglas Johnston12/06/2020 11:01:58
760 forum posts
34 photos

I would bet that most people who have changed from Morse taper machines to R8 would not want to go back. I used a Morse taper machine for many years before getting an R8 one and there is just something about the R8 spindle that makes it much nicer to use.


Andrew Johnston12/06/2020 11:06:08
6278 forum posts
677 photos

Posted by SillyOldDuffer on 12/06/2020 10:28:46

I'm not sure why R8 is rated in Europe.

Because there are a lot of Bridgeport mills, and clones, in Europe. Some real Bridgeports, including mine, were built in the UK. Tooling with R8 tapers has been available in the UK from commercial suppliers from long before the hobbyists started using it. Popularity is dictated by the commercial market not the home one.

Of course R8 is power limited, I think around 2hp is regarded as the maximum it can cope with. Another plus compared to Morse tapers is that it is, in theory, self-releasing, so no stuck tooling. It's a bit dinky, but it suffices on two of my mills. The third mill uses INT40 which is in a different league.


JasonB12/06/2020 12:19:34
21449 forum posts
2453 photos
1 articles

As far as R8 on hobby machines go then the market is dominated by the high numbers that the Americans buy so understandable that the far eastern makers will build machines for that market where R8 dominates and would rather not make MT for UK and Europe.

The small bench top mills are likely to have MT2 due to price as it means the rest of the machine can be made small, saves having to fit a larger dia spindle, bearings, etc into a small head so keeping the price down.

Like Douglas I prefer the R8 on the two mills I have over the MT3 one, the only real thing MT has going for it is that you can use some tooling in the lathe as well but I would not let that be a major factor when deciding what mill to buy.

old mart12/06/2020 13:18:03
3347 forum posts
208 photos

I would only recommend R8 over MT3 if the machine had not been purchased at that stage. The recommendations for er32 are sound, just make sure that there is provision for both spanners on the tool. I have found that the standard length spanners are not long enough, so I found some tube to extend both to at least 300mm, 1 foot long. Then you can tighten and slacken off without disturbing the tool in the spindle. After the initial slackening, the nut goes tight as the collet is broken free from its taper. You must have something soft like a wad of rags to catch the cutter as it falls. I have found that buying a full set of collets ends up with some never being used. I think it is best to buy collets to match the sizes of the cutters you have, 6, 8, 10, 12 and 16mm are common shank sizes for milling cutters.

Michael Gilligan12/06/2020 13:34:28
18970 forum posts
944 photos

Posted by SillyOldDuffer on 12/06/2020 10:28:46:


[…] I'm not sure exactly why R8 appeals here. I don't see much engineering logic - possibly chaps think R8 must be wonderful because Bridgeport Mills use it. […]


I think you answered your own question, Dave

R8 was designed for a milling machine : Morse Taper wasn’t

and the Bridgeport mills are small enough that hobbyists can ‘relate’ to their design.


David Davies 812/06/2020 13:47:38
147 forum posts
9 photos

Hi All

As a user of a small mill with an MT2 spindle I can't comment on R8 versus MT3 debate but I am curious that no-one has mentioned Int. 30 taper. Are any machines available with this type of Spindle? Int 40 is common enough but is in a different league, as Andrew has said above.


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