Milling on the mini-lathe

Hi Gary,

I would consider a collet system to hold your cutters. They are consistently concentric, they are also useful for holding small diameter work concentrically in the lathe instead of a chuck.. If you decide on collets I would suggest perhaps the ER25 range. You can get MT3 holders but you can also get collet chucks which bolt onto your lathe in place of the standard chuck. The holder and collets can also be used on the milling machine when you get one.

\the beauty of the ER collets is that they can each hold a range of sizes, so a 5-6mm will hold that range, and if you have sequential collets they are capable of handling any size from the smallest to the largest collet size. Another advantage is that because of this range ability you can hold imperial as well as metric in the same collet.

As for cutter size, don't go too small or too large for a starter. Say 10mm. You can always use a flycutter for large areas.

What do others think ( ask 10 model engineers and you'll get 20 answers - it's the nature of the beast.)

Regards

Terry

Hi Gary,

To get finer control of the depth of cut, a handwheel on the end of the leadscrew is a great help. But if you haven't added one, fit a gear on the LH end of the leadscrew and rig up some sort of pointer. If you use an 80T gear, advancing it one tooth will give 0.0185mm carriage movement on a 1.5mm pitch leadscrew, or 0.00078" if your leadscrew is 12 TPI.

It helps to have a lock on the saddle, but a G cramp to hold the saddle to the bed would suffice.

Andy

Gary,

I would second Terry's advice, and add that the utility of the ER system is even greater than just holding milling cutters. You can hold material in a collet for turning; the advantages being that (a) it should give better concentricity than holding in a 3-jaw s/c chuck, and (b) as they grip the part all round, they are far less likely to cause damage as would the teeth of a chuck. For small-scale modelling work I use them almost exclusively.

David

Thanks for the suggestions Terry and Andy.

Terry, would the chuck that attaches to the backplate be the better choice or does it make no difference? Prices seem similar.

Andy, I've read that suggestion about the gear somewhere else in the last few days. A handwheel on the leadscrew is looking useful and I'd read about the modification on other sites but it was a bit too much work at the time. I might try the gear idea.

Gary

David, thanks for the advice. An ER system is looking favourite then. As you can see I was composing my previous reply for about 30 mins

Gary

As others have said, getting a set of collets that will suit both your lathe and mill is the best long term solution. However, if money's tight at the moment an MT3 endmill holder of this sort will do fine:

**LINK**

At £12 odd a throw they're not especially cheap so you can save a few more £s by buying an MT3 Blank End Arbor, boring it to match the endmill and fitting a grubscrew (assuming you have suitable screw tackle). See here:

**LINK**

Joe

Edited By joegib on 15/10/2012 14:53:45

Edited By joegib on 15/10/2012 14:55:44

Gary,

On the choice of collet chuck, be aware of this. A chuck on a morse taper shank will need to be held in with a drawbar (miling cutters do have a tendency to make cutters or chucks walk out of their locations*). The result of this is that there is no through bore, so you can only hold short lengths of material. The best ultimate position to work towards is this: a backplate fitting chuck for use on the lathe (such as **LINK**), and a morse taper (or R8, if that's what you end up with) chuck for the milling machine when you get one. Since the collets themselves are the expensive bit, this will give you the optimum utility for a moderate final outlay.

*This is why you should never use a drill chuck for milling. ER collets hold the cutters firmly enough to avoid this - but you must ensure you tighten them up properly.

David

Thanks Joe, the end mill holder you linked to was the one I had in mind but I'll probably go with the ER25 collet chuck that Terry and David suggested as it seems much more versatile.

David, I realised it would need a drawbar for the morse taper collet but hadn't thought through the fact that the bore would be blocked therefore the backplate fitting one you linked to is a more sensible choice when holding stock.

Thanks

Gary

Hi Gary,

I would personally go with the backplate for the lathe as David and I suggested earlier, and then later buy a taper collet chuck when you get the milling machine (I never call it a 'mill', although that is acceptable nowadays, but I think of a mill as a place where flour is made, or where steel is rolled ).

The versatility of these systems is the reason they are so popular. And you can buy as many or as few collets as you need, when you need. I had a basic set bought as a present some time ago and am perfectly happy with them.

Arc Eurotrade is a good place to get them (hear that Ketan, when do I get my commission? ). Seriously, as a satisfied customer I have always been happy with their quality and service.

Best regards and let us know how you get on,

Terry

I'll second everyone else's advice: ER collets, each of which will compress down by 1mm (0.5mm for the smaller ones) combined with a bolt-on collet chuck, would serve you well. Very good for holding stock on the lathe, in addition to gripping milling tools.

I have a set of ER25s (the 25 refers to the o/d of the collet at its widest point; the capacity of the biggest ER25 collet is 16mm), with a bolt-on collet chuck for the lathe. My old miller has a Myford nose thread, so I bought a screw-on ER25 chuck which screws on, thereby avoiding the heavy whacks sometimes needed to free tooling from its internal MT2 taper. If you do buy a miller, R8 tapers are much easier to free off.

But as Joe says, expense can be considerably reduced by making up your own holder holder. Here, the milling cutter is only retained by a grubscrew so it would be as well to go for one with a flat on its shank, and to pull the tool forward as far as the grubscrew and flat will allow before finally tightening up. Otherwise, the tool might try to screw itself into the work and drag itself forward in the holder.

Andy

Hi Andy,

I have never had to resort to 'heavy whacks' to remove my MT3 from my milling Machine.

T

Hi Michael

I also second or third or whatever everyone else says upto now BUT I`d go for the ER32 size for your Myford. I have and certainly don`t regret it. Main reason I chose this size was so I could make square collets as described by H.H. (& others) in various sizes. ER25 would have been to small for my requirement. I`ve currently made 4 sets & they work a treat. Dont know if this size would fit your "waco" mill though!

Regards Alan

Edited By Flying Fifer on 15/10/2012 23:01:40

A correction to my post of 15 October (third in the thread). Should read:

"... or 0.00078" if your leadscrew is 12 TPI."

Andy

Pleased to learn Alan that you are finding my square collet jaws useful. I first came up with the idea when I had to make about 100 2mm square nuts for a monmouth cart I was making. The thought of having to make these using a 150mm four chuck soon forced me into coming up with a better method. Incidentally, they are not tapped, just held on with a minute dab of adhesive.

If anyone is interested in the jaws for square material, see here

As you are presently working without a milling machine Garry, you may find the projects on my website for the lathe only workshop of interest. See this page for a list of them.

Whilst many of them will not be of interest to you, you will no doubt find some of the setups within them helpful, giving you an idea of just how much can be achieved without a milling machine.

Harold

So thats two cups of tea then

Andy,

I, for one, am confused by your "correction"

MichaelG.

So am I, Michael, now you mention it.

Should be 16tpi, for an imperial leadscrew on a mini-lathe. The 0.00078" advance is right, though.

Memo to self: turn the computer off well before 00.40am, and go to bed.

Andy

Thanks Harold

I've looked at your site before for the info on tapping drill sizes but I'll have another look at the suggested pages.

Gary

Thanks Andy,

That explains it.

MichaelG.