I just added 50 mm of daylight...

Thanks to a helpful hint - maybe on here? - I found a Chinese supplier of finger collets that directly fit into a BT30 / Int30 taper as used on my Novamill:

Quite reasonable price and as you can see compared with a typical BT30 / ER16 collet chuck it saves about 50 mm of tool projection, so gives me that much extra workpiece height to play with - well worthwhile. Not only that but I can now hold a 12mm cutter which would otherwise have needed a larger ER chuck with even more projection. I have 4, 6, 8, 10, 12 mm sizes.

With only 190mm(?) available, saving about 50mm is like an increase of useable headspace of something like 30-40% in practice?

Spindle to table is quoted as 180 mm in the machine spec so the usual holders eat up about 30%. Over on the Denford forum someone described making a 70mm raising block for their Novamill, this is much easier though you get rather less increase.

How firmly does an Int30 collet grip? Is it better than making a plain shank holder with a (recessed) set screw?

I'll let you know!

The taper is the same as for R8, so that should be a guideline.

PS:- have you got a link for the supplier? (Get thee behind me Satan).

Mark, I can't remember! Wasn't on ebay or aliexpress. I'm sure someone mentioned them on a forum and gave a link but can't remember where.

Glad you like them John.

As the collet face sits flush with the spindle nose, you've probably gained more than 50mm, but watch out for the drive dogs!

As my machine does not have a spindle brake, I use an adjustable spanner on one dog when tightening the drawbar and then remove them before actually cutting metal.

Mark, they are off Aliexpress:- NT/ISO30 Collets

Bazyle, they appear to have the same grip as an R8. I've had no problem with cutters pulling out, in the 3+ years that I've been using my set and that includes a 20mm cutter.

Edited By Nick Hughes on 25/10/2019 10:11:32

That's it! Thanks Nick. $54 I think for 5, had to pay £18 customs but still a good price.

Hi John,

I have the same milling machine, and on mine the BT30 holder was an adaptor, into an R8 spindle taper.

So on my mill the actual spindle is R8, removing the adaptor gave a lot more headroom.

HTH

Christmas is coming. Unless over-weight for normal postal delivery, they are more likely to clear customs, without charge, in the rush just before Christmas. Also more likely to get lost in the post as well, I suppose!

Every time I have been charged, the items have come via Parcelforce. Guessing that any parcel attracting duties gets directed to the ‘parcelforce’ conveyor.

Do you have a manual drawbar? I looked for the split collets on ebay UK and there were none, but I noticed some er32 ones like this which were shorter than your er16, there may have been other er sizes available.

**LINK**

Deleted

Edited By Mark Rand on 25/10/2019 21:03:04

Chris, that's odd, AFAIK there was never an R8 option on the Novamill. Anyway mine is definitely NOT an R8, I wish it was as I use those on my manual mill.

OM, yes, manual drawbar, but some versions had an ATC for which I think you attached pull studs to the collet thread. As Nick pointed out, they're on AliExpress not eBay. I have looked and looked by found no short ER16 chucks, but anyway now I don't need one.

John, thank you for drawing these to my attention and , Nick for identifying the supplier.

I, too, have a Novamill, converted to Mach3, with which I'm very happy apart from the lack of daylight. Mine came with a Coventry quick-change tool holder and just one fitting: an er16 chuck. This really eats into the available headroom, so I feel an order coming on.

I presume there is somewhere in the order process where you can say which sizes you need - I haven't gone far enough to find it yet.

Incidentally, as far as I know, the Novamill never came with the usual 30 International drive dogs, relying on the taper for a drive.It worried me at first but has never given any trouble with slippage.

Mike

Hi John, after you said the Novamill was never available with an R8 Spindle, I had to go and check to make sure I was not having a senior moment, the mill is not being used at the moment, but yes it is an R8 spindle.

Photo included of the Coventry Easy Change/ R8 adaptor.

Chris, interesting! I did say "as far as I know" but what do I know?! I also got an Easychange with two ER16 chucks when I bought mine, but got a couple of Int30 to ER16 chucks which I mainly use as they do give a bit of extra height.

We have a full set of metric, and several imperial R8 collets and I have had an unforeseen problem with one of the first ones I tried using on the Tom Senior. The TS is converted to R8 and I elected to leave out the pin in the spindle which is there only to stop the tooling from turning when the drawbar is being tightened. The drawbar is newly made and can be slightly tight in some of the tooling. This happened with the 5mm collet which I wanted to use, and persisted even when I ran a 7/16 UNF tap down the threads. The downside of the collets is that there is nothing to get a grip on if they turn with the drawbar. I may have to drill three axial holes in the collet nose to use a pin spanner. The spanner would have to work with the 20mm collet downwards, so I will have to be careful with the positioning and size of the holes. A job for the rotary table with a chuck on it, and maybe a small carbide drill. I will do them all to prevent an occurrence of the problem.

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... or released

MichaelG.

Dead right Michael, the problem is that the threads in the tooling are not always exactly in line with the axis of the spindle. The drawbar of the drill mill is more forgiving due to slight wear. There are a lot of tools to test out on the TS, just running the tap down has cured most that I have tried. Having a self extracting drawbar will make the tight ones more difficult as they cannot be slammed home in the taper before engaging the drawbar. However niggling these problems are, I will not put pins in the spindle, or change to a loose drawbar. now I have experienced the advantages of the present setup.

 I wonder if the ISO30 spindle could have similar problems with the drawbar thread being tight?

Edited By old mart on 27/10/2019 19:15:43

Edited By old mart on 27/10/2019 19:16:28