ER40 collets

[vtsteam]

I've been wanting collets on the lathe for quite some time, and since I have a full set of R8s for the mill, my first thought was making a chuck to fit those. But Then I got to thinking about the ability to pass longer stock through the spindle -- both R8 and MT3 taper (which the spindle has already) won't allow that. I also have some 5C collets, and those would do, but after looking at the prices for a 5C chuck ($250 without backplate), and the complexity of making one, I didn't see much hope.

ER seemed the best bet, and would be the easiest to make a chuck for, but I don't have a set of those. ER-32 seemed a little small in holding capacity, ER-40 seemed about right, but they are fairly expensive, and usually shipping was steep from most suppliers. Also  the inexpensive sets I could afford seemed to have a fairly crude TIR spec, as far as I could see.

Then I hit on an ad in Ebay from Shars for these:

http://www.ebay.com/itm/SHARS-Ultra-Precision-7Pc-ER40-5-16-3-8-1-2-9-16-5-8-3-4-1-ER-40-Collet-Set-NEW-/331117420838

Free shipping, .0003" runout and $57.65! Not a full set, but will fit most of the sizes of stock I use and up to and beyond the full capacity of the spindle.

I also bought an ER 40 collet nut from them (free shipping again) $14.95:

http://www.ebay.com/itm/ER40-ER-40-COLLET-NUT-FOR-COLLETS-CHUCK-CNC-MILLING-NEW-/300892303557

So I guess I'll be watching John's collet chuck making videos again!   

[awemawson]

. . . .and we'll be watching your build with interest 

I seem to have a plethora of different collet sizes and styles  Like most things it's a situation that 'developed'. My lathe has Burnerd EC11 multi-size collets, and I have a key operated and lever operated chuck:

http://rotagriponline.com/index.php?page=shop.product_details&product_id=37&flypage=shop.flypage&pop=0&keyword=4+jaw+chuck&option=com_virtuemart&Itemid=29

I also have a nose piece for the lathe for 5C collets, and a reasonable selection of those

The the Bridgeport uses R8's of course - so I have an Imperial and Metric set of those.

Then the Die Sinker EDM has TG75 as it's native spindle nose - I have a few collets, but usually it holds a parallel shank  ER25 collet chuck in one and I use ER25's of which I have a full set.

Then on the CNC milling machine I have a CAT40 spindle, and chucks that take TG100, TG75, ER32, ER25, ER16, ER11, BE180

Then the CNC lathe has VERY odd ball collets on it's main and opposing spindles, but most of the circular tool holders are either ER11 or ER25


So all in all it's a standardisation nightmare, and there is no rationality in any of it 

[vtsteam]

Andrew, what, no ER-40? 

[awemawson]

There probably are some somewhere - that was a list from memory, and it's not what it was 

[ieezitin]

Hello

That is not a bad price for the selection and quantity your getting, but still you have to make a chuck. I like you have the same dilemma with my collet inventory ( 5C and R8) and I too have to make a chuck but I figured I would plow the extra monies on split size collets that I already have ie 1/64 divisions, its been a dream of mine for years to have a full set.

I too look forward to your build, as I am in the middle of my design its very challenging to make a chuck for collets.

Keep us posted..


Anthony.

[vtsteam]

Anthony, I think the ER series makes it a lot easier to make a chuck because the nut on the front does the tightening, rather than an external thread on the back OD (5C) or the back bore (MT and R8).

 For those types you either need a drawbar (MT R8) or a draw tube or internal nut (5C).

For the 5C the problem then becomes how to rotate that internal nut or tube. The tube is a problem on a lathe because it reduces the spindle bore -- a draw tube is used on 5C collet spinners because they use a very large bore. So you're left with an internal nut as the only solution for a smaller lathe, if you want to pass stock through the spindle. How do you rotate that nut? Well in commercial chucks the nut is a gear and this meshes with a pinion driven by a chuck key.

The ER's external nut is easily turned with a wrench, greatly simplifying the whole problem of a chuck. Basically the only part that needs to be made (the body) has a straightforward internal taper and an external thread to fit the nut. The nut itself can be purchased for $13 (Shars) so half the work (and parts) making up the chuck is already done.

While it's true that it's nice to have R8 or 5C collets down to a 64th to suit every possible size in the range, the ER-40's have twice the grip range of those other collets -- .032" is quoted for the set I'm getting. So it takes only half the number of collet sizes to complete a full set.

A set of 7 ER-40's, while roughly a half set, covers the same sizes as 14 R-8s or 5Cs.

These are the things that swayed me yesterday when the price looked finally affordable, so I took the plunge with yet another collet type.

[tom osselton]

I have to agree with vtsteam "grip is everything "  last night using a 1/2 " shank 3/4" cutter  with a r8 collet I thought was good and tight proceeded to screw itself downward into the part!  some filler and paint and it will be fine but it still shows"  grip is everything ".

[PekkaNF]

I will build (eventtually) ER40 collet chuck for lathe. I have not yet experience on this one, but I have used plenty ER11, E25, ER32 and probably going to buy a drill unit that uses ER20 collet. Never had milling tool slip on collet.

I tend to use collet that is that close to high end of the collet size for the shank size. Lower end of the shank size needs a lot of torque. Good idea too to remove all the storage grease from the collet. I have many nuts for ER25 and two for ER32, because I like to keep most used sizes as an assembly. Marginally faster to change tools of different shanks.

Now one thing I have learned that larger collet size needs a whole lot more torque you might think. ER11 you need to baby, ER25 feels about right for it's collet tool size, but ER32 tool fees small and what do you think about 130ft/lbs? which is often the maximum for ER40?

http://www.techniksusa.com/metal/torque_chart.htm


One day I came across of one post where someone has made 5C collet chuck using automotive differential gears as sun gear assembly. Scroll down a little.
http://www.cnccookbook.com/CCWishListBiggerProjects.html

Pekka

[chipenter]

I made a collet chuck for my lathe,when you test the fit of the collet , you must have something a dead fit in the collet outher wise it springs , and willnot grip properly or rattle .

[vtsteam]

Tom, ouch!

Pekka, thanks for the link. I was going to make my own wrench -- I didn't like the looks of the ones usually advertised, so ddn't buy one. Handle length will be gauged to requirements. I'll also have a wrench to counter so the tightening torque won't be on the back gear.

Chipenter, the fit will be good. I built my own lathe, milling attachment and turbine engine w/compressor scroll from scratch and am on all too familiar terms with Prussian blue for the job.

As well as hands, clothing, towels and bathroom rugs. 

[vtsteam]

Speaking of messes what do any of you who use them use for rubber gloves when doing hand work (not machine) -- I find that the box of throw-away latex gloves I bought are pretty useless, generally tearing with about 5 minutes use. The were pointless changing hydraulic hoses on the tractor. Any suggestions?

[Bigbadbugga]

Speaking of messes what do any of you who use them use for rubber gloves when doing hand work (not machine) -- I find that the box of throw-away latex gloves I bought are pretty useless, generally tearing with about 5 minutes use. The were pointless changing hydraulic hoses on the tractor. Any suggestions?

I use these nitrile ones from KBS....

http://www.kbs-coatings.com/Black-Lightning-Gloves.html

Bought them at a VW show last year, they are virtually indestructible. There is a uk supplier for them but the name of the company escapes me. Google might be your friend.

I think the nitrile gloves are the strongest though, so other brands may be just as good.

[tom osselton]

I've never used gloves I always thought it would be awkward unless it is doing something with grease or something messy.

[Bigbadbugga]

I've never used gloves I always thought it would be awkward unless it is doing something with grease or something messy.

I really only use them for car work, brakes, oil change and anything where horrible greasy gunk is involved.

[Ugluk]

A few months ago I made an ER40 collet attachment for my ancient lathe based on John Mills excellent design and videos.
I already had a set of collets for my #40 taper universal mill so it seemed a good idea, and it turned out to be excellent.

I use it for pretty much everything that fits and is fairly round. Repeatability and runout is below 1/100 of a mm.
When I need to clamp a small piece in the nose of the collet I put  a small piece of the same diameter in the very rear of the collet, and that makes it grip very securely and evenly.

[garym]

Hi VT,

I've just bought one of these ER32 nuts which incorporates a ball-bearing, type B on web page.

http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collet-Nuts-Wrenches-and-Spanners

Not had chance to try it yet, but I've read positive comments. Not sure if they are available on your side of the pond though.

Gary