Spindle taper...

The big moment has arrived to place my order for my new mill....and I am still undecided as to whether to go for a MT3 or R8 taper in the quill?

My lathe has an MT3 taper in the spindle so it seems logical to go for this as I could use any appropriate tooling on both, but I have read a lot of comments about R8 being easier to release, more tooling available and so on

The mill will be metric and the R8 fittings all seem to use a 7/16 UNF drawbar but I don't suppose this will be a big deal (MT3 seem to be available with 7/16 UNF and 12mm drawbars)

What is the general consensus?

Chris

Well all my macines are MT3 and being a very old miserly Scot. I have kept everything the same,saves purchasing at a lot of dosh more tools.I have never had any problems give a light tap and out. Think these people who have problems think they are tightening up bolts for a large bridge then find the poor item is well stuck in.
Enjoy your new machine
Bob

It's more a legacy thing.

How much MT3 tooling do you have that can fit the mill and be useable ?

Main thing is to ask yourself is tool holding, how are you going to hold cutters ? MT3 collets or move up to a collet chuck and do you have one ?

If the answer to these questions is lots and well equipped then go MT3.

If you are lacking and need to buy they I would go the R8 route. End of the day the decision is yours.

If your tools are more MT3 orientated then get MT3... silly to spend sorely needed cash when you can mix & match between machines. I use MT2 between lathe & mill tailstock / spindle with only the headstock having a MT4, for which I have a MT4 collet holder.

George

Personally I'd go with R8. I never use milling cutters in the lathe spindle (which is MT5 anyway) so the issue of interchangability doesn't arise. The R8 taper is more widely available from both ME and industrial suppliers, so there is a wide price/quality range available. Come what may you're going to need a drawbar, so what thread it has on it isn't really germane.

Regards,

Andrew

I use the MT3 tooling from my mill in the lathe with a MT4-3 short sleeve, large flycutter and boring bar are the most used and if I do need to hold a milling cutter then the ER holder does that.

Maybe it depends on th size of mill you are getting, JS and AJ both have large mills that will cope with ME size jobs but I have an X3 and sometimes things are better off bolted to the lathe cross slide due to size.

Should have said the only MT3 tooling I have currently is the centre that came with the lathe (that I haven't found a need to use yet)

Think I am leaning towards getting an ER32 collet chuck to hold the cutters - and an R8 spindle but it looks like Arc are out of stock of the mill with an R8 spindle (SX3) at the moment, nuts

Gives me more time to do some research I guess

JasonB, why bolt things to the lathe cross slide 'due to size'? Is the SX3 not good for smaller work pieces? Or have I misunderstood you? I have previously looked at milling on the lathe (getting a vertical table, chucking, making a drawbar etc) but came to the conclusion that if I wanted to do some milling it's better to buy a mill - and a big (ish) mill will do small (ish) jobs but not vice versa?

Chris

I think what JasonB was saying is that a part that is too big to fit on a SX3 may well fit on the cross slide of the typical ME lathe for milling instead.

In my case if the work doesn't fit on the mill it definitely will not fit on the lathe cross slide; like this, at a bit over 6 feet long:

Regards,

Andrew

Ahhh...although the cross slide on my lathe is a lot smaller than the mill I am looking at...

That is one impressive machine, I would not contemplate ever milling work of this size, but in the years to come I may well eat my words

I am fretting over the weight of an SX3 - I cannot imagine having to move a Bridgeport around <g>

There is an option to buy a larger table (700mm) but it is still pretty small compared to your mill

Might consider this at some point if the need arises but you can't have it all at once!

Chris

Yes as Andrew says its more a case of things that are two big for the mill can be done on the lathe

This casting is 10" long or 10" tall on the X3 as it would have needed to be mounted vertically, add in the boring head and tool and the area being cut is a long way from teh table so not that rigid, plus the lathe gives power feed.

And flycut at the same setting

Or when I made this table the waterjet legs were about 600x720 and could not be milled for nylon protector blocks a sthe X3 head does not tilt so they were done with the lathe.

Even drilling the top ring was a bit tight in my shed

And before you all slap my wrist I only needed a rough slot so thats why teh cutter is in the 3 Jaw, I was not worried if it moved

Edited By JasonB on 27/08/2013 14:16:19

The posts on here are always so interesting!

It amazes me to see the extent to which someone's ingenuity will extend - my 'batcave' is so small I am fairly sure if I can get the work in it, I will be able to machine it <g>

I am getting an SX3 which does tilt but still think I would be struggling to fit your table leg in...and the advice seems to be tilt the work, not the mill head to avoid having to keep retramming it?

Did debate getting a trolley for the stand so I could perhaps move the mill a bit (at an angle?) to help fit things on the table somtimes, but this wouldn't help with your casting. I have never tried to machine a casting (another thing to learn in the future)

My lathe has a 16 inch bed/8.5 inch swing - yours looks to be a lot bigger!

Chris

Yes its generally easier to tilt the work if you can though does depend on the job in hand. Not mine but this one needed the head setting horizontal and lathe topslide mounted on teh table

There are a few more interesting setup on that engine of mine and a write up on dealing with the castings on MEM if you have a spare few minutes.

Lathe is a Warco 280VF so 11"x28" not that much more swing.

Chris, you will need a crane to lift the X3 up onto a bench. It is very heavy. I did mine by building a pillar of 2 x 4 lengths of wood all screwed together and tilted the machine each time I raised one side.

I then slid it over to the bench on 2, 2 x 4. to get it into position. Took me half a day to unscrew all the wood. I could not get a crane into the postion to lift it where I wanted it.

Mine is MT3 and works fine for me. There is a great variation in the quality of MT3 collets so pay for good ones.

Clive

Way to go Clive. Where would we be if the Stonehenge builders had said - "mmmm yes we're just waiting for someone to invent a crane...."

Stepladders make good supports for loads equivalent to 1 body weight though you are a bit over.

If you have not used an engine crane before bear in mind the legs are always in the way , will need to get under or around your bench with 8inch clearance, and the advertised loading is only with the beam retracted. It is about 1/4 rated at the length you want to use.

Jason's engine boring does show the advantage of interchangeable boring head though you can get ones with swapable arbors but if you are going ER collets you will want a through hole adapter for the lathe and blind one for the mill so less significant.

R8 tooling seems to be much less common on ebay, but maybe I'm just overlooking it as I don't have a need.

In my case, the Mill/Drill came with MT3 after I was horrified by what the way that the Rodney milling attachment did to my Myford 7. Shook it like a terrier with a rat. maybe I was a bit heavy handed, but 0.020" cuts don't seem heavy to me!

The replacement lathe has a MT5 mandrel and came with MT5/MT3 sleeve, so I use MT3 for virtually everything, (even ex Myford days MT2 with a MT2/MT3 sleeve.

So standardisation/rationalisation was almost a no brainer.

Occasionally, I need to separate the ER25 chuck for use on the HV6 Rotary Table, so I made up a simple extractor.

If anything sticks in the Mill Drill, I also modded the top nut on the quill to allow me to use a screw extractor, rather than beating the bearings to death with a mallet. But if takes anything more than a light tap to release, you've overtightened things!

Ultimately, "you makes your choice and pays your money!" for what you believe will suit, and work best for, you.

I don't like 'metric' but how about going R8 and get an R8 to MT3 adapter?

I would agree that being able to use boring head in mill and lathe is useful. Also being able to put an ER collet chuck in the lathe for small, round things is potentially rather useful, if you turn lots of accurate small round things.

Neil