# ER40 vs. 5C collets accuracy in a lathe?



## Alan H.

I am trying to sort out my direction in terms of buying a collet chuck for my PM1340Gt lathe.  I am trying to decide between a ER40 or 5C collet system. 

I have read and studied here and found a lot of information.  I have evaluated the numbers of collets required, cost, etc.  In addition, I have reached out to a few of my friends via pm and as usual, gotten good insights as to what one can buy and where as well as some of their experience.

So meanwhile, one direct question here -
*Which will achieve the most accuracy in a 1340 D1-4 mount lathe with readily available hardware,  ER40 or 5C?*


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## Bob Korves

That is a loaded question with too many variables.  Both are capable of excellent accuracy when well made and accurately fitted to the lathe.  They can be more accurate than the lathe spindle.  Assuming a lathe spindle with great accuracy, including the internal spindle taper, all of the accuracy of the finished work will be determined by the runout in the tooling.  With a hand wheel 5C (or other size) collet closer, the only additional sources of inaccuracy are the collet adapter and the collet.  With a 5C or ER collet chuck then the mount to the spindle and the collet holding stuff determines any loss of accuracy.  Any of the systems, finely built and properly used and maintained, can provide accuracy better than you can cut on the work.  What matters beyond that?


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## T Bredehoft

Well said, Bob. 
My input would be: given equal accuracy, ER40 is more usable with far fewer collets. The collets were designed in the metric system, supposed to accept one mm variation in size with no loss of concentricity. that's .040 in Imperial measure. That works out to be about 1/4 of the needed collets relative to 5C series.


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## Bob Korves

T Bredehoft said:


> Well said, Bob.
> My input would be: given equal accuracy, ER40 is more usable with far fewer collets. The collets were designed in the metric system, supposed to accept one mm variation in size with no loss of concentricity. that's .040 in Imperial measure. That works out to be about 1/4 of the needed collets relative to C5 series.


Adding to Tom's post, the 5C collets are perhaps more suited to production type work.  They will only really hold work properly within .005" of the nominal size.  They are however, faster to put work in and out of, or advance material from longer bar stock through the spindle for repetitive work.


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## Alan H.

Did not intend to be funny or put forward a "loaded question".  I am putting forward a serious inquiry.  So Bob, what is it that you use?


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## Bob Korves

I use 5C collets on the lathe, R8 collets in the mill.  Old school.  I was not aware of ER collets when I bought them.  If I had known about them I might have changed my mind, or maybe not.  It really depends on what you are trying to do, and that changes often in many of our shops.  The safe answer is that you need to have both!


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## Chipper5783

What do you mean by "accuracy"?

I use 5C collets on the lathe.  I have a set of ER32 and half a set of Er40 (for use with a T&C grinder).  I also have a set of OZ25 (perhaps a precursor to ER40?).  I certainly have not experienced any issues with the 5C that make me wish I had an ER chuck.  The biggest issue with the 5C seems to be the narrow clamping range - I have never run into a problem with this.  Most tooling and material stock comes in standard sizes - so the collets work fine.  For the occasional issue I suppose one could skim what need be to fit the next size collet (I have reduced drill shanks for various reasons, though not to make them fit a collet).  Also, for an occasional odd ball issue you can usually use a 3 or 4 jaw chuck (for small stuff, I'll use a drill chuck in the head stock).

My vote would be for 5C because the drawbacks are so easy to work around.  What I like about the 5C is there is a large selection available (sizes, and shapes), you can also get soft collets and cut them to fit the job (i.e. to hold washers), you can also get oversize collets for quite large short items, you can get/make ID gripping collets (with an expander plug) and can easily set up an internal depth stop on 5C collets.  I have never seen them, but you can probably get square holding ER32 collets or soft collets for cutting in unusual shapes - and all the above advantages I described above, but they certainly are not common.

If you get 5C you will not be disappointed.  Like Bob says, you will end up with multiple collet systems anyway.

Pretty well any collet system will be pretty accurate.  With the typical machines and tools folks hear are working with, any short coming in accuracy (to +/- 0.0005") is because of the operator.  If you want better than 0.0000x" then you need to rethink your entire game plan.

What sort of accuracy are you after?


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## Bob Korves

Another advantage of 5C collet system is that small chucks are made to fit into the 5C collet holders.  If you are in the middle of doing work with the collets, you can switch to a small chuck just as easily as changing a collet to get a task done, then back to collets again, easily and quickly -- without breaking down the collet setup.  That is a definite advantage, and I plan to purchase a collet chuck so I can do that.  I am not aware of any ER equivalent to that.


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## darkzero

Neither are more accurate over the other, as mentioned, too many variables but it comes down to the quality of the collect chuck, closure, etc as well as the quality of the collets, thay are not all equal. Each has their advantages & disadvantages which you have to decide what suits you better.

I have ER40 for use in the lathe but only cause I use ER40 in the mill & don't have a set of 5C collets. If I didn't use ER40 in the mill, I might have ended up using 5C for the lathe or if I had to do it over I would use TG150 collets for the lathe.

ER collets were not designed for workholding, they were designed for toolholding, the same for TG collets. But of course that doesn't matter or stop anyone. The use of ER for workholding seems to be popularized by hobbyist. You don't often see ER collets being used for workholding in machine shops if at all.


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## ronboult

Alan
With limited experience I offer the following observations.
My recommendations would be a ER 40 or ER50 Collet chuck for your lathe. Why?
1 ER collets have a much greater ability to hold a range of diameters in the same collet( >1mm) Need less collets.
2 The size of bar that can be held in a ER40 or ER50 is greater than 5C
3 ER collets are split back and front and grip the workpiece along the full length of the collet. I believe ER collets were developed for holding cutters etc in Mills which requires a very strong grip.
5  While 5C can be held in the spindle taper, to use either collets with through bar, you need some sort of collet chuck. A 5C collet closer is quick for production work but of limited relevance in a hobby shop.
6 A ER50 collect chuck can be made into a set true using a D1-4  backplate so it is easy to remove replace and can be adjusted to negligible runout depending on the skill of the operator.

At present I use an ER32 collet set in a MT5 collet chuck in my lathe. I have the ER32 collets from my mill. The chuck uses a draw bar and I cannot use through bar which is a pain. Changing up to an ER50 gives a much larger range of diameters that can be held 1-32mm or up to 1 1/4 " I think you can obtain special oversizeER collets that are even larger.
I intend to purchase a cheap ER50 Chuck and machine the D1-4 backplate  with the locating spigot turned slightly undersized so I can use it as a Set Tru quick adjust. Hopefully being a collet chuck, once set it will rarely need further adjustment but for critical work the option is there.
Ron


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## Bob Korves

ronboult said:


> (SNIP)5 While 5C can be held in the spindle taper, to use either collets with through bar, you need some sort of collet chuck.(SNIP)


Not true, Ron.  A 5C to Morse taper adapter (to match spindle internal taper) and a hand wheel or lever type collet closer will take work up to 1" through the collet and through the spindle, if the spindle has a big enough bore (1-3/8" or more typically.)


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## ronboult

Thanks for the correction Bob
My limited observations(I have never used a 5C collet) was that a 5C collet changer mounted on the outside of the spindle and used a rotary motion using the collet external thread to close the collet. I wasnt aware of the tubular draw bar option.
I still think that for hobby use the ER system is more versatile and cheaper. Given the price and number of 5C collets it could become very expensive. We wouldnt want to buy anything less than Hardinge
Cheers
Ron


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## darkzero

I loved getting to use a lever type collet closer. I don't think there's anything quicker that will release & reengage a piece of stock, well that I'm aware of anyway (CNC machining centers don't count). It's great for production/repeatative work. What's also cool is if you're careful & know what your doing, you can even swap a piece out without even having to turn the spindle off.


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## ronboult

Cool definately ! Usefull in home shop Maybe.
My current project involves making 1/2 doz identical short pieces made from 30mm bar. A lever action collet closer would save time but in the overall scheme maybe less that 1-2%  of the actual time spent machining all the seperate operations.
Normally my jobs are one off and I am more than likely to change the stock and the holding method between jobs. A collet closer would add virtually nothing to my workshop.
On the other hand good manual collets are great because of the ability to quickly remount without significant runout. I dont yet have a set true 6 jaw A external mount ER50 collet chuck that allows through stock is the most economical solution.
Ron


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## mikey

ronboult said:


> A external mount ER50 collet chuck that allows through stock is the most economical solution.
> Ron



Hey Ron, do you have an ER-50 system? If not, have you looked at the prices for the collets? I have an ER-40 chuck and would own an ER-50 if they made a direct mount (I don't want it badly enough to cobble one up) and just buy the ER-50 collets over 1", but they don't. Actually, the most economical solution is a 3 or 4 jaw chuck because truth be told, a hobby guy really doesn't NEED a collet system. My 3 jaw chuck isn't as fast as a 5c collet lever closer but its close enough.


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## darkzero

ronboult said:


> I dont yet have a set true 6 jaw A external mount ER50 collet chuck that allows through stock is the most economical solution.



If you get a 6-jaw Set-Tru, the only reason to get a collet setup is if you don't want to bust your knuckles doing hand work close to the chuck. My Bison 6-jaw"s accuracy is more than I can ask for. I rarely even use my ER4o chuck. I use the 6-jaw most of the time.

I see a lot of people mentioning ER50 lately & personally I don't see why. ER50 are very uncommon. Sure they'll give you 1/4" more capacity over ER40 at 1.25" but keep in mind they only go down to 1/2" & most places only only carry them in the "common" sizes. TG150 is so much more common. Just search on ebay, barely anything found for ER50 used but you'll see a good selection of TG150 collets. Not important I guess if you're buying new but ER50 ain't cheap!

TG150 goes up to 1.5" and the way the collets close are similar to ER. But they too will  only go down to 1/2" but they are available in a all sizes in between "common". TG150 are also designed for workholding, you won't see any TG150 collet chucks in R8 or Morse Taper so you'll have to make your own chuck for the lathe.

Before & I'm sure I've said somewhere else that if I could start over & if I wasn't using ER40 for my mill that I would go TG150. Well I take that back now, I'll stick with ER40. I did not realize TG150 also did not go smaller than 1/2".  That would be a deal breaker for me not being able to go smaller than 1/2". But then again I could always just stick my ER16 straight collet chuck in a 1" TG150 collet, like this:


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## ronboult

Mike 
No I dont have an ER50 external mount chuck. It was next on my list. Just ordered a ES 12B readout to upgrade my lathe DRO?
I just searched for an ER 50 chuck without success. Didnt realise they were hard to get. Might have to settle for a ER40.

Will
Thanks for the heads up on the TG150 collets. Will have to do some research. I was not aware they existed -learn something new everyday.
PS   ER50 collets are available down to at least 6mm and I am sure I have seen down to 1mm advertised somewhere.

The OP might like to check out the TG 150's also.

Will I assume that the ER40'chuck you show above has an D1-4 backplate. Since you have TWO lovely Bison 6 jaws the ER is clearly no use to you. Just post it over to me - I would be glad to pay the shipping
Ron


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## darkzero

ronboult said:


> Will
> Thanks for the heads up on the TG150 collets. Will have to do some research. I was not aware they existed -learn something new everyday.
> PS ER50 collets are available down to at least 6mm and I am sure I have seen down to 1mm advertised somewhere.
> 
> Will I assume that the ER40'chuck you show above has an D1-4 backplate. Since you have TWO lovely Bison 6 jaws the ER is clearly no use to you. Just post it over to me - I would be glad to pay the shipping



Ah I see, don't know that. I only just checked Techniks website & didn't bother to look at Maritool & the other affordable quality brands. Thanks for clarifying. 

I think I mentioned earlier in this thread though, with the large size collets, holding on the smaller diameters can give you problems with slippage. Although you probably won't be taking heavy cuts with a small end mill you really have to crank down on the nut to get them secure. So with ER50 it may be even worse. 3/8" dia is my prefered cutoff for the ER40, then I go down to ER16. And for clearance, ER40 holding a small litte endmill is awkward. But that's for tool holding.

Yes my ER40 is D1-4, it's not the integrated plate, I machined a backplate to fit & made it a "tap-tru" so I can adjust runout if/when needed. But sorry, not letting it go.  That's one of 2 ER40 plates that I got from Jeff at tools4cheap which is no longer around.

Oh and my old avatar that showed the 2 Bison 6-jaws. One is a 6.3" that I have now, the other was a 5" that I had on my mini lathe. The 5" chuck is gone, I sold it when I gave the minilathe to my brother. I just had to a get a group pic of it. Well now that I'm back spending too much time again here, maybe I should throw my avatar back up.


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## bss1

Regardless of what collet system you choose, make sure you get a set of collet blocks to use in your mill vise. MKSJ recommended that to me when I got my 5 C set and it opened up an entire secondary use for the collets that I didn't have before.


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## Alan H.

Thanks for all the feedback.  

Here's some of what I have learned with your help:

1.      5C is for work holding

2.    ER's are for tool holding 

3.    Many have applied ER’s in work holding as well

4.    Get a good chuck for 5C

5.    Lathe chucks for ER are hard to come by 

6.    Get decent holders for ERs – mill and lathe application

7.      Nice to have ER holding capability for the tailstock of the lathe for tools

8.    5C is narrow in clamping range for an individual collet

9.    Buy a complete set of 5C collets up front and get it over with

10.  ER's come in multiple ranges

11.  May need fewer ER collets due to their flexibility in clamping range

12.  Buy decent quality collets

13.  Get collet blocks for use in the mill 

14.  Both 5C and ER are accurate - depending if you apply them as intended and you buy good quality hardware

15.  Figure out how to store all these freaking collets

I have once again confirmed what I knew already – “A little here and a little there and soon you have spent some real money.”  One of my buddies here called it right via a pm, buy it all! 

Thanks for all the help, this forum is a great community.


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## Bob Korves

Alan H said:


> (snip)I have once again confirmed what I knew already – “A little here and a little there and soon you have spent some real money.”(snip)


I have a set of Interstate 5C collets (Chinese) by sixteenths, a 5MT to 5C adapter to fit the lathe spindle, an in progress shop made hand wheel collet closer for my lathe, a set of 5C collet blocks, and a spindex.  Oh, and a 5C end mill grinding fixture for the surface grinder.  I have about $250 into all that and it gives me quite a bit of capability.


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## mksj

I have seen some individuals make slide out collet trays out of steel or wood, very nice. Since I have no more draw space and I wanted the 5C collets readily available, I mounted three 5C racks on the end of my cabinet. I like being able to quickly stick stock in a collet to see if it fits for those odd size items. On the ER-32 collets and r-8 that I frequently use in my mill, they are in wood blocks in my machine tool cabinet draws next to the mill. My ER-40 collets which I use less frequently, I rebuilt the case that they came in to accommodate more collets and also so it wouldn't fall apart. Most of the cases the ER collets sets are pretty worthless. I went with a 1/32" increment ER-40 set along with a few high precision metric for my indicators. Note that many 1/32" ER sets are missing certain less frequently used sizes and I had to back fill the missing sizes, go figure.


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## woodchucker

darkzero said:


> Neither are more accurate over the other, as mentioned, too many variables but it comes down to the quality of the collect chuck, closure, etc as well as the quality of the collets, thay are not all equal. Each has their advantages & disadvantages which you have to decide what suits you better.
> 
> I have ER40 for use in the lathe but only cause I use ER40 in the mill & don't have a set of 5C collets. If I didn't use ER40 in the mill, I might have ended up using 5C for the lathe or if I had to do it over I would use TG150 collets for the lathe.
> 
> ER collets were not designed for workholding, they were designed for toolholding, the same for TG collets. But of course that doesn't matter or stop anyone. The use of ER for workholding seems to be popularized by hobbyist. You don't often see ER collets being used for workholding in machine shops if at all.


Possibly because a shop is already loaded to the gills with 5C's. So no need to invest in new.  Just sayin


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## Alan H.

Mark, Where did you acquire the 5C racks?


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## Tozguy

Alan, unfortunately I have nothing to say about the original question on which is more accurate. However permit me to disagree with some of your conclusions in the above post. My choice was an ER32 set for work holding. The reason being that my larger chucks do not hold work smaller than 1/2'' very well. Anything larger I can handle accurately with a 4 jaw independent chuck. ER chucks with through holding possibilities are available (ex. Beall). Many of us have made our own. So there is no problem using ER collets for work holding.

My initiation to collets was the purchase of an R8 ER32 set. Then I made up a D1-4 ER chuck and borrow the nut, collets and wrench from the R8 kit to use it. I also have made up an MT5 to R8 sleeve to be able to use the R8 chuck in the lathe spindle. This is gives me a fair amount of versatility with respect to undefined future needs. Buying tools before they are needed seems to me like a good way to end up with tools I don't need so I was conservative (I think).

I prefer to use an MT3 Weldon style holder with a drawbar for holding tools because it is easier to use than an ER chuck and more accurate in my opinion.

Hopefully your requirements are clearer than mine and your choice of 5C versus ER can be based on more specific needs.


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## mksj

The 5C racks are pretty standard, mine where from Enco, but most tooling companies and eBay list the same or similar collet racks.
https://www.amazon.com/30-PIECE-5C-COLLET-RACK/dp/B00DVTSAHM

On ER collets they are designed to hold material along the full length of the collet and the collet collapses/tightens from both ends. Short stock held in an ER collet will asymmetrically tighten the collet if the piece is not held by the full collet. The shorter the piece, the more this becomes a problem. I am often gripping very short pieces (0.1-0.25") in 5C collets, I do not think this would be possible using an ER collet. That being said, when threading I have had stock turn in 5C collets, and ER collet with longer stock would most likely hold it more secure when using it as a lathe chuck.


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## Bob Korves

mksj said:


> The 5C racks are pretty standard, mine where from Enco, but most tooling companies and eBay list the same or similar collet racks.
> https://www.amazon.com/30-PIECE-5C-COLLET-RACK/dp/B00DVTSAHM
> 
> On ER collets they are designed to hold material along the full length of the collet and the collet collapses/tightens from both ends. Short stock held in an ER collet will asymmetrically tighten the collet if the piece is not held by the full collet. The shorter the piece, the more this becomes a problem. I am often gripping very short pieces (0.1-0.25") in 5C collets, I do not think this would be possible using an ER collet. That being said, when threading I have had stock turn in 5C collets, and ER collet with longer stock would most likely hold it more secure when using it as a lathe chuck.


Mark, I have that same Enco rack and am using it horizontally.  It appeared to me when I first started using it that it would not work well vertically because the drawbar ends of the collets would drop onto the rows below due to gravity, causing problems with putting them back into the rack.  Yet you seem to have done it.  I can see that your empty bottom rack has no spacers between the rows.  Have your racks been modified, and how do they work in the vertical orientation?


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## Silverbullet

You can find good and bad in everything. I'm old school , graduated in 1974 from vocational . I've used many different collets and brands over the years . I have ran lathes with all styles of collets even three piece in turret lathes. Most if not all will do excellent work. That said I have 5 c on my logan lathe , but I will be having er32  collet set up on my mill. My reason is I'm in a wheelchair and the changing of tooling won't be a hardship for me to reach up to change r8 collets in it. Other wise I'd stick with the r8 s. I see nothing wrong with any of the collet choices other then size limits. Now with acquiring an atlas mill ill be using 2 morse collets to a er32 change over . Only to get the size change for tooling. I do remember one kind we had trouble with it was the rubber mounted Jacob's collet chuck system , we had them let material twist and even push sideways. I never had it but I've seen when it happened.  But if I owned one I'd use it.


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## Alan H.

Tozguy said:


> Alan, unfortunately I have nothing to say about the original question on which is more accurate. However permit me to disagree with some of your conclusions in the above post. My choice was an ER32 set for work holding. The reason being that my larger chucks do not hold work smaller than 1/2'' very well. Anything larger I can handle accurately with a 4 jaw independent chuck. ER chucks with through holding possibilities are available (ex. Beall). Many of us have made our own. So there is no problem using ER collets for work holding.
> 
> My initiation to collets was the purchase of an R8 ER32 set. Then I made up a D1-4 ER chuck and borrow the nut, collets and wrench from the R8 kit to use it. I also have made up an MT5 to R8 sleeve to be able to use the R8 chuck in the lathe spindle. This is gives me a fair amount of versatility with respect to undefined future needs. Buying tools before they are needed seems to me like a good way to end up with tools I don't need so I was conservative (I think).
> 
> I prefer to use an MT3 Weldon style holder with a drawbar for holding tools because it is easier to use than an ER chuck and more accurate in my opinion.
> 
> Hopefully your requirements are clearer than mine and your choice of 5C versus ER can be based on more specific needs.



Toz, no problem - I pointed out that folks use the ERs for workholding in my #3.    Didn't mean to say you couldn't and I am glad you find it good for you. 

Ref. my learning #5 on chucks (context of this thread was for a D1-4 camlock mount) - my research here and elsewhere showed few off the shelf D1-4 options for an ER chuck.  The one that is readily available has given folks some runout problems.  Btw, you mentioned Beall and I do have a Beall ER 32 collet chuck and collets for my Powermatic wood lathe but it is a screw mount and was intended for woodworking.  

Meanwhile, I will likely buy some of both types and use them as indicated.    I have a mill that I am also outfitting as needed.


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## Bob Korves

Alan H said:


> Toz, no problem - I pointed out that folks use the ERs for workholding in my #3.    Didn't mean to say you couldn't and I am glad you find it good for you.
> 
> Ref. my learning #5 on chucks (context of this thread was for a D1-4 camlock mount) - my research here and elsewhere showed few off the shelf D1-4 options for an ER chuck.  The one that is readily available has given folks some runout problems.  Btw, you mentioned Beall and I do have a Beall ER 32 collet chuck and collets for my Powermatic wood lathe but it is a screw mount and was intended for woodworking.
> 
> Meanwhile, I will likely buy some of both types and use them as indicated.    I have a mill that I am also outfitting as needed.


I think some people machine their own setup with a separate back plate, and leave the register a bit sloppy on purpose so they can use it as a "bump true" adjustable chuck for initial setup and for dialing it in with fussy work.  That makes good sense to me...


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## frugalguido

I just received one of those D1-4 ER40 chuck and sent it back. The measured TIR on it was, the worst at .0013" and the best at  .0009" . The advertised TIR is .0008". I wish some one would produce a quality chuck that is a reasonable price, maybe someone like Bison.


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## darkzero

Bob Korves said:


> I think some people machine their own setup with a separate back plate, and leave the register a bit sloppy on purpose so they can use it as a "bump true" adjustable chuck for initial setup and for dialing it in with fussy work.  That makes good sense to me...



Yup, that's what I did with my ER40 chuck for the lathe & the cheap 3-jaw that came with my lathe. I call it "tap-tru".

I don't trust anything that is direct mount cam lock, I always prefer a seperate backplate. Well except for my 4-jaw. It doesn't really matter cause it's independent, direct mount in this case reduces weight & overhang.


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## mikey

frugalguido said:


> I just received one of those D1-4 ER40 chuck and sent it back. The measured TIR on it was, the worst at .0013" and the best at  .0009" . The advertised TIR is .0008". I wish some one would produce a quality chuck that is a reasonable price, maybe someone like Bison.



If you are referring to the D1-4 ER-40 chuck from HHIP, I have no clue why their concentricity is so out of whack. I do wonder how folks are measuring concentricity and whether or not they are using quality collets and an accurate pin to measure run out. The nut that comes with the HHIP chuck is typical Chinese quality and the nut, all by itself, will introduce some run out. Chinese collets may run out with double or triple the run out of a quality collet. So, is it the user, the nut, the collet, the pin or is it actually the chuck?

My experience with the HHIP chuck was that it was an amazingly accurate chuck for about $70.00.


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## frugalguido

mikey said:


> If you are referring to the D1-4 ER-40 chuck from HHIP, I have no clue why their concentricity is so out of whack. I do wonder how folks are measuring concentricity and whether or not they are using quality collets and an accurate pin to measure run out. The nut that comes with the HHIP chuck is typical Chinese quality and the nut, all by itself, will introduce some run out. Chinese collets may run out with double or triple the run out of a quality collet. So, is it the user, the nut, the collet, the pin or is it actually the chuck?
> 
> My experience with the HHIP chuck was that it was an amazingly accurate chuck for about $70.00.



I purchased the chuck after reading your favorable review, since I also have a Super 11 that I purchased new. I did question HHIP about the listed concentricity of .0002" before ordering, they said it should be listed as .0008" and they changed the listing to reflect this.  I measured at the inside outer edge at ER register with  no collet with a tenth indicator, just wouldn't meet their spec, ( which seems to me to be a little fluid and changeable ). In fact I did find the chuck listed in other parts of the world with a TIR of .002" with the same part number. Maybe they changed their supplier from when you purchased yours or  your just one lucky guy. I also did try the measurment with a swiss manufactured collet, no change in the measurment as a test. It's to bad, cause I could really use a quality ER40 chuck for the Super 11. I did try to get them too send me a replacement,(maybe just got a bad one) but they said that their out of stock now, even though they show stock on the Ebay listing, so who knows.


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## mksj

I ordered the same ER-40 with a direct mount D1-4 from HHIP about a year ago, mentioned a TIR of 0.0002" at the time, but this seems to change all the time. Mounted it an did a slew of measurements including indicating the chuck collet seat. It was out over 0.002", so off by a factor of ten and had even more skew with a ground rod. I used a Maritool bearing nut and high quality collets, still out 0.002-0.003. I think it is hit or miss with these ER-40 chucks. I spoke to HHIP, they say they are just an importer, they have nothing to do with the inspection or quality of what comes in, not will they check anything. Other ER-40 direct D1-4 mount chucks all seem to be the same Chinese manufacturer. Tormach has one that mounts to a back plate and looks a bit different, but they have no information or specifications on there website. Pretty lousy pickens. I will probably go with a back plate version and mount it to a D1-4 back plate so I can tweak the TIR adjustment. Have looked at other ER-40 options for the lathe like mounting a collet block in my chuck, but not impressed with what is available. My 5C does the job 99% of the time, there are a few occasions where I would like more holding power from an ER collet. I mostly use the ER system for holding end mills either in the lathe tailstock or an R-8 holder on the mill. 

Many individuals claim the advantage of the ER collets is greater range/compressibility, relative to 5C collets this is true, but I haven often had problems with ER collets collets not compressing down uniformly when at close to the edge of its specified range (+/- 0.5mm). So although it is claimed that a 1 mm increment set will work with both metric and English sizes, I opted for a 1/32nd increment ER-40 set along with a 10 and 12mm high precision collets for my edge finders.

The 5C racks are slanted and work fine in a horizontal or ventricle format. I have often have seen machine shops with wall racks for all the 5C collets, but also some nifty sliding draw racks.


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## mikey

Thanks, guys. It appears then that we are dealing with the typical Chinese variations in quality. I think I must have just lucked out and gotten a good one. My apologies if my review mislead anyone. I was being honest but it appears that things have changed.

I actually have one of the Tormach ER-40 chucks. Tormach told me it is hardened. It, too, is Chinese and meant to mount to a rotary table. It can be adapted to a back plate, the accuracy of which depends on the end user. I have the back plate for it but ran into the HHIP chuck and never mounted it.


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## whitmore

ronboult said:


> Cool definately ! Usefull in home shop Maybe.
> My current project involves making 1/2 doz identical short pieces made from 30mm bar. A lever action collet closer ...
> Ron



The clear bore of 5C collets is one inch (there are larger grips, to 1-1/8 inch, but those
are really step collets, the work bottoms in them).  So, 30mm won't fit through.   You can get
short grip on large items like that, with big-faced premade or blank collets, though.


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## ronboult

BSS1 raised an interesting idea in post #19 when he suggested getting collet blocks for use in the mill vice.
I suddenly remembered that I actually have square and hexagonal through ER32 collet blocks that I use on my mill.
Why not mount the square ER32 collet block in the 4 jaw, adjust for minimal runout and use to mount longer stock through the spindle on my lathe.
Anybody need a surplus MT3 ER32 collet chuck.
Ron


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## frugalguido

I just wish a quality manufacture would make one. There would seem there is a market, it's not a complicated item, not like a scroll chuck . I did take some basic measurements of the chuck before I sent it back, so I might make one and send it out for finish grinding. I don't think the HHIP one is even hardened, because there was some dings on it.


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## Bob Korves

A collet chuck is not inherently an accurate plug and play setup, because whatever accuracy it has can be compromised by multiple issues outside of the collet chuck itself.  The spindle, the headstock bearings, the spindle register, the alignment of the headstock, etc.  The good news is if you get the spindle turning without radial and thrust bearing looseness and in line with the lathe bed, regardless of spindle runout, a collet chuck can be accurate to however tight a tolerance you want to chase it, regardless of the accuracy of each component individually, IF it has a separate spindle mount.  If anyone thinks that a stack up of tooling, none of which has been carefully calibrated individually, should make the final tool in the stack accurate, they are kidding themselves or do not understand how tolerance stacking works.


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## Stanshire

A few additional points. 
My Bison SetTru 5C chuck is on the lathe 90% of the time. It takes just a few minutes to clock it in to darn near zero runout. In truth, even though I check it occasionally, it rarely goes out.
I don't believe that anyone has mentioned the 5C hex or square collets. Very useful.
My collet collection is a combination of used ebay Hardinge collets (I may be lucky, but the Hardinge collets have all been perfectly true), some new Interstates (I've gotten a few that were out and returned them) and some new Lyndex-Nikkens (dead on).
I believe that the larger sizes (above .75") have an internal shoulder that prevents work from going into the spindle bore.
In those cases, I will switch to the 3 or 4-jaw.
The 5C 3-jaw chucks are not particularly accurate in the runout department. 
Switching collets, with a chuck key, takes many, many turns. I use a screw gun with a shop-made adapter to fit the square holes in the chuck. With that, changing collets takes a few seconds.


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## Dataporter

I didn't see it mentioned above, but with 5C you can get collet stops. You need 5C collets with the internal threads in the back (although I think some stops don't need them).  The stops are real handy when making several parts the same exact length. I haven't seen stops for ER-40.   The stops are also very handy when you use the collet in a block on the mill for secondary operations like drilling holes in the side, milling flats, slotting, etc.


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## Stanshire

Correction and an addition.
All of my  5C collets except 1.0625 and 1.125, allow the part to pass through the spindle. Those two have a reduced area at the bottom of the gripping area to provide a sufficiently thick wall.
The reasonably priced Asian spindexers have 5C tapers. Just used it yesterday to make some 5/16" hex bar from roundstock.


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## David VanNorman

I use 5C collets as my Spacer used 5C so I made a chuck for my SB 9A. I would rather  Have an ER40 chuck, but the number of times I need a collet is not that often so I am happy with the 5C.

Dave


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## ranch23

Alan H said:


> Thanks for all the feedback.
> 
> Here's some of what I have learned with your help:
> 
> 1.      5C is for work holding
> 
> 2.    ER's are for tool holding
> 
> 3.    Many have applied ER’s in work holding as well
> 
> 4.    Get a good chuck for 5C
> 
> 5.    Lathe chucks for ER are hard to come by
> 
> 6.    Get decent holders for ERs – mill and lathe application
> 
> 7.      Nice to have ER holding capability for the tailstock of the lathe for tools
> 
> 8.    5C is narrow in clamping range for an individual collet
> 
> 9.    Buy a complete set of 5C collets up front and get it over with
> 
> 10.  ER's come in multiple ranges
> 
> 11.  May need fewer ER collets due to their flexibility in clamping range
> 
> 12.  Buy decent quality collets
> 
> 13.  Get collet blocks for use in the mill
> 
> 14.  Both 5C and ER are accurate - depending if you apply them as intended and you buy good quality hardware
> 
> 15.  Figure out how to store all these freaking collets
> 
> I have once again confirmed what I knew already – “A little here and a little there and soon you have spent some real money.”  One of my buddies here called it right via a pm, buy it all!
> 
> Thanks for all the help, this forum is a great community.



One more thing, turn a complete set of fractional drill bits to fit in collets, then you dont have to mess with a drill chuck in the mill.


Sent from my iPhone using Tapatalk


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## 65Cobra427SC

darkzero said:


> If you get a 6-jaw Set-Tru, the only reason to get a collet setup is if you don't want to bust your knuckles doing hand work close to the chuck. My Bison 6-jaw"s accuracy is more than I can ask for. I rarely even use my ER4o chuck. I use the 6-jaw most of the time.
> 
> Before & I'm sure I've said somewhere else that if I could start over & if I wasn't using ER40 for my mill that I would go TG150. Well I take that back now, I'll stick with ER40. I did not realize TG150 also did not go smaller than 1/2".  That would be a deal breaker for me not being able to go smaller than 1/2". But then again I could always just stick my ER16 straight collet chuck in a 1" TG150 collet, like this:



DarkZero, I was online and happen to notice MariTool has ER40 collet sets in sizes under 1/2" (9/32, 5/16, 11/32, 3/8, 13/32, 7/16, 15/32 ) although I don't know if they're sold separately. Just wanted to let you know.

Also, I want to purchase a set of collets for my PM1236 and wondered if you would still get the ER40 collets, or purchase another set instead.

Thanks


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## ddickey

I think you meant ER50. smallest I see is .1972" for $41.


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## P. Waller

Deleted member 43583 said:


> Thanks for all the feedback.
> 
> Here's some of what I have learned with your help:
> 
> 1.      5C is for work holding
> 
> 2.    ER's are for tool holding


You have it figured out.
5C may be closed from the back requiring no tools and are pass through. This is fast.
ER requires a tool to open and close. This is slow.

If your major concern is accuracy use an independent 4 Jaw chuck at all times. This is slowest.


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## Jimsehr

Nobody has said that with a 5c setup you can get square ,hex, emerancy collets and a collet to hold a washer shape part like 1/8 wide 3 inch dia part with ease. Or that you can hold a part on it’s bore with an Id collet. Also with most 5c setups you can move the 5c held parts to the mill or the drill press for the next operation. Also with a lever collet setup you can load parts in seconds while the spindle is running.


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## magicniner

I use ER40 for most lathe work because I regularly need 30mm through capacity and ER40 gives me 2mm to 32mm through capacity with excellent runout, when I chuck up a 1m length of 30mm bar with 30mm protrusion at the front there is negligible run-out on the end hanging out at the back. 
Despite much faux-information to the contrary I have found that I have no problems holding regular polygonal material with ER collets, I'm sure really heavy cuts could cause slipping but I've had no issues up to now.


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