# ER40 collet retaining nut is bad!  Check your items as soon as you get them!



## Firstgear (Apr 9, 2019)

I got a couple of ER40 collets chucks to use with my set up.  Two different orders came via Amazon, but were shipped from China.  A third order was via eBay.  The problem in all cases is the retaining ring on the inside of the nut that the ER collet snaps into is offset relative to the rest of the nut and will not allow the collet to be inserted.  Beware and check your pieces when you receive them!

Right side in the photo below has clearance but when you look at the left you can see that the entire snap in part is offset to the nut and won’t work!  Grrrrrrr!


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## pontiac428 (Apr 9, 2019)

That's how ER collet nuts work.  The retaining ring is eccentric.  Pop the collet into the nut, put the nut on the holder, put the part into the collet, and tighten.


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## T Bredehoft (Apr 9, 2019)

Insert the  empty collet into the  nut on a slight diagonal and push until it clicks in. This allows you to unscrew the  nut/part, turn it another half turn and the collet will release the clamped work.


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## macardoso (Apr 9, 2019)

That's a feature, not a bug


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## Firstgear (Apr 9, 2019)

Okie. Dokie......chalk it up to Mr. Newbie!


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## wlburton (Apr 9, 2019)

Did you ever notice most of the tools and accessories we buy don't come with instructions?  I guess we're just supposed to know how they're supposed to work, even though we've likely never seen one--let alone seen one being used.  I would have had the same question.  That's the great thing about this site: people ready to explain stuff to us novices without displaying a bunch of attitude!


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## markba633csi (Apr 9, 2019)

I actually made the same assumption, the vendor sent me a replacement and didn't even point this out either, then I finally read about how they work-
DOH!


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## T Bredehoft (Apr 9, 2019)

No attitude here, I started out as a know nothing apprentice, hope to help as much as I can....

I suspect that most of the things we buy  were made to  sell to professionals (or their employers) who are replacing worn out tooling. They don't need instructions. 

That's why we are here. So (newbies) can ask their questions without being slandered.


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## Tozguy (Apr 9, 2019)

I had the same frustration when it came to inserting ER collets in the nut for the first time. Trick is to rock the collet into place.


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## Firstgear (Apr 9, 2019)

Oh I am not even an apprentice!  I need an apprentice teaching me!


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## Norseman C.B. (Apr 9, 2019)

I bought a set of ER-32 to R8 collets a while back and had the luck of the nut not retracting the collet.
After going through the hoops with them through Ebay I got a full refund, perhaps when I can look at them without getting angry
I will buy a nut from a reputable vendor and put them to use......................They popped in the groove fine but would not pull the collet out


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## Firstgear (Apr 9, 2019)

I bought some ER nuts with integral bearing in them from Mari Tool.  Getting them with bearing doesn’t cause an uneven loading on the collet from the nut.  Nice quality.  Http.maritool.com


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## Norseman C.B. (Apr 9, 2019)

Firstgear said:


> I bought some ER nuts with integral bearing in them from Mari Tool.  Getting them with bearing doesn’t cause an uneven loading on the collet from the nut.  Nice quality.  Http.maritool.com


Thanks I will give them a look........................


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## mikey (Apr 9, 2019)

Norseman C.B. said:


> Thanks I will give them a look........................



Also look on ebay for Rego-Fix HiQ solid nuts. Rego-Fix were the innovators of the ER system and know how to make a good hardened nut that is very accurate. In my opinion, good collets and a good coated nut are the keys to accuracy for an ER system and Rego-Fix is probably the world standard for that. ETM and Techniks also make good coated solid nuts.


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## Cooter Brown (Apr 9, 2019)

Be careful buying ER nuts from Mari Tool they have their own proprietary thread size....

They talk about it at about 5:00 minutes in...


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## Norseman C.B. (Apr 9, 2019)

Thanks for the suggestion and the heads up Mikey and Cooter.................


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## Aaron_W (Apr 9, 2019)

wlburton said:


> Did you ever notice most of the tools and accessories we buy don't come with instructions?  I guess we're just supposed to know how they're supposed to work, even though we've likely never seen one--let alone seen one being used.  I would have had the same question.  That's the great thing about this site: people ready to explain stuff to us novices without displaying a bunch of attitude!



This is something I really appreciated and I rarely see commented on with the Sherline machines and tooling. They include good instructions for set up and use with almost everything they sell. A huge plus for somebody new coming into this hobby without a clue.


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## Firstgear (Apr 9, 2019)

Cooter Brown said:


> Be careful buying ER nuts from Mari Tool they have their own proprietary thread size....
> 
> They talk about it at about 5:00 minutes. in...


Not sure what you heard, but I can screw my Mari Bearing Nut on any of my ER tooling pieces.  They do have a “special wrench” for tightening that fits much better than any of the wrenches I had with other kits.


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## Cooter Brown (Apr 9, 2019)

Firstgear said:


> Not sure what you heard, but I can screw my Mari Bearing Nut on any of my ER tooling pieces.  They do have a “special wrench” for tightening that fits much better than any of the wrenches I had with other kits.



I heard the Owner of Mari Tool tell me that its a much finer thread in that video and that it wont work properly... However they do make they regular style as well they also say that in the video.... guess you didn't watch it....    I'm just letting him know they make a product that looks exactly the same but won't work....


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## PT Doc (Apr 9, 2019)

I just bought a bunch of Techniks Stuff. ER collet chucks, drill chuck, milling chuck, ER collets and milling chuck collets and extra collet nuts. Their quality is VERY nice. Their ER collet nut has some serious claims behind them. Looks like more holding power than bearing nuts.


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## Firstgear (Apr 9, 2019)

Sigh.....this is the ER40 collet bearing nut from Mari Tool.  I didn’t ask for anything but this on their web site. 

Here is the detail from their sheet...notice it says that it fits most tool holders regardless of brand!

Product Info
View complete catalog page »


Bearing Collet Nut holds all ER40 collets
Fits most tool holders, regardless of brand
Made from alloy steel hardened to 54 - 56rc
Precision ground ID thread and taper
Has an internal thread of M50 X 1.5 pitch
Outside diameter is 2.470 inches (62.7mm)
This nut is a bearing nut and has internal ball bearings
Our TG100-WRENCH works on this collet nut
Internal cam removes collet when unscrewed
Black oxide finish
MariTool Part# ER40-BNUT






						ER40 BEARING COLLET NUT MariTool
					






					www.maritool.com
				




Here is the photo of the Mari Tool collet bearing nut from above on my R8 ER40 tooling.  I am not sure how to show you anything more than this that it fits and isn’t a special thread or anything else.....perhaps you should call Mari Tool, ask for Frank Mari.  He will get you sorted out.


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## Firstgear (Apr 9, 2019)

PT Doc said:


> I just bought a bunch of Techniks Stuff. ER collet chucks, drill chuck, milling chuck, ER collets and milling chuck collets and extra collet nuts. Their quality is VERY nice. Their ER collet nut has some serious claims behind them. Looks like more holding power than bearing nuts.


Yes the torque value for the standard style nut is higher than the bearing nut.  Mari says the bearing nut is 20% lower.  One other forum member had terrible results in terms of runout when measured with the stock nut and cut the results about in 1/2 to an acceptable performance level with the bearing nut.  You just have to watch the bearing nut tighten up a collet and you can understand how thestock nut might not uniformly load the collet given that the clamping mechanism also puts a torque component to the collet.


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## mikey (Apr 10, 2019)

Firstgear said:


> You just have to watch the bearing nut tighten up a collet and you can understand how thestock nut might not uniformly load the collet given that *the clamping mechanism also puts a torque component to the collet*.



Have a care with this one, Firstgear. A bearing collet nut uses 20% less torque because the balls cannot handle excessive amounts of torque, not because they are so superior in clamping that they require less torque. I have not heard that a solid nut puts torque on a collet that would affect the accuracy of the assembly before. Can you tell me where you got this information from? I'm not hassling you. I really want to know the source.

Most of the top tier ER collet makers recommend a hardened coated nut for maximum tool holding power and accuracy. Given that these same makers also produce bearing nuts, it infers that there may be something to this solid nut business, or at least it seems that way to me. In my own tests between ETM and Rego-Fix solid coated nuts VS two Asian bearing nuts from two separate sources, I found the solid nuts to be at least twice as accurate as those cheap bearing nuts. This means absolutely nothing except to me. I have no clue how a Maritool bearing nut would compare but if someone wants to buy me one, I'll test it and offer a report. 

Anyway, on to my point. I suggest you test that Maritool nut. Measure the static spindle run out and the run out at the chuck taper. Then chuck up a precision gauge pin in the best collet you have and check the static run out of the assembly. Then you will know what the nut can do. If it is within 0.0001" - 0.0002" TIR then you have a good collet and nut.


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## Firstgear (Apr 10, 2019)

ER 32 Collets
					

I wanted a cheap back up set of ER 32 collets, for my Rockwell vertical milling machine (#21-100). On the 2 larger mills, a Jet JVM-836 and a 1940s era Bridgeport, for the last 10 years or so, I used a SYOZ 25 (EOC 25) series collet chucks and collets, for the Rockwell, I was given a LMS R8 x ER...




					www.hobby-machinist.com


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## mikey (Apr 10, 2019)

Yeah, I got the same results - 0.0007" TIR with the Asian bearing nuts tested on my ETM chuck, which is unacceptable to me. In contrast, an ETM solid nut will run out in the neighborhood of 0.0001 - 0.0002" TIR using a ETM collet in an ETM ER-40 chuck that has 0.0001" TIR at the chuck taper. That is a BIG difference in run out and that translates into a difference in tool life, finishes and accuracy.

Run your own tests so you know what your system can do. Don't believe what other guys say; believe what you say.


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## darkzero (Apr 10, 2019)

Bearing nuts are all hype, all us hobbyists have been tricked into spending money on them!  

All these inexpensive bearing nuts weren't really around when I bought bearing nuts. I have Lyndex bearing nuts & they weren't easy to get. I do have China bearing nuts on my ER-40 collet blocks but only cause they were dirt cheap when I bought the collet blocks, $8.50 ea. Maybe they're too cheap. Lol. I never tested them, I probably should. They should be fine for my collet blocks but if they're junk I'll just put my standard Rego-Fix nuts or Bison nuts on them.

If I could do it all over I would have got ER-32 with standard nuts rather than ER-40. Wish I could but too late to turn back now. I'm happy with my ER-16 chuck & slim nut though.


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## mikey (Apr 10, 2019)

I have to stand corrected on the bearing nut thing. When I looked into this over 5 years ago there wasn't much info available. However, Rego-Fix did a video that I just found and it appears that they fixed the ball bearing nut issue they had and the performance of their nuts is surprisingly good. Have to re-evaluate my thinking now.


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## darkzero (Apr 10, 2019)

Yeah back when I bought my bearing nuts I couldn't find much info either. Again, there weren't all the China bearing nuts readily available like there are now. I bought the Lyndex bearing nuts based on a recommendation from a machinist on another forum I used to frequent (not a machining forum) long before I found/joined this site.

IIRC Rego-Fix didn't even make ball bearing type nuts back then. Which reminds me, I remember buying a Rego-Fix nut on ebay that was a friction bearing nut. I forget if I sold it or have it stashed somewhere. I'll check tomorrow.


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## macardoso (Apr 10, 2019)

There is a Haas tip of the day that discusses the different kinds of nuts and the benefits of each. Collet twist is a real thing that adds error into your assembly. Basically, friction between the nut and the collet causes the top of the collet to twist relative to the bottom (which is fixed in the much steeper lower taper). This can cause uneven spacing of the slits in the collet which pushes the tool off center.


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## markba633csi (Apr 10, 2019)

Interesting Macardoso- I wonder if the problem is worse with larger tool shank diameters?
mark


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## macardoso (Apr 10, 2019)

Not sure? I've definitely seen it happen with a 1/4" endmill on an ER20 holder. I use a solid nut, a clean dry collet, a clean dry chuck, and a lightly oiled nut when assembling. I hope that the oil on the nut taper reduces this twisting effect.

John Saunders at NYCCNC also has a video where he explains that you can torque a chuck halfway and then indicate the endmill true by tapping it with a soft metal bar (copper). After it is true you can torque it all the way down. This is important for small tools where 5 tenths of runout might be equal to the desired chipload where 1 tooth would end up not cutting and the other cuts double.


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## Robo_Pi (Apr 10, 2019)

Don't feel bad.  I've been working with machines for years.  Never used an ER collet system.  I recently decided to buy a set of ER 20 collets.   When I saw the offset inside the collet nut I thought precisely the same thing.  "_How could anyone have made such a horrible machining mistake and not catch it!_".

Then like you, I quickly discovered that I'm the one who is totally ignorant of how an ER collet nut works!

Pretty clever design actually.   But yeah, nothing in any instructions said anything about this.  Apparently we're supposed to be born knowing how ER collet nuts were designed.


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## pontiac428 (Apr 10, 2019)

I seem to recall a thread on this forum where the recipient of a new collet holder chucked his collet nut into his lathe and "fixed" the eccentric ring.

I much prefer lessons learned on someone else's dime.  I mean that without offense.  The unplanned down time kills me!


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## mikey (Apr 11, 2019)

macardoso said:


> There is a Haas tip of the day that discusses the different kinds of nuts and the benefits of each.* Collet twist is a real thing that adds error into your assembly. Basically, friction between the nut and the collet causes the top of the collet to twist relative to the bottom (which is fixed in the much steeper lower taper). This can cause uneven spacing of the slits in the collet which pushes the tool off center.*



I finally had a chance to look at this video. Two things I noted. Bearing nuts have evolved and are now in favor. The second thing is that nowhere in the video did I hear him discuss this collet twist thing. He referred to a collet stop in one of their holders but nothing to even suggest that the collet can twist. There was one instance where the slots of the collet were not even but this was due to an improperly installed/torqued nut. My takeaway is that not much has changed and proper care and use of your collets matters. The nuts, specifically bearing nuts, have gotten better and I'll have to consider buying a good one to test for myself.

One other point he made, and many others have also raised this, is that proper torque is important for both accuracy as well as tool holding power, regardless of the nut in use. My big problem is that I don't want to spring for a spigot nosed torque wrench from a European maker like Norbar but almost all the torque adapters for ER nuts use this type of wrench. You would think that some enterprising hobby machinist would buy a big arbor press and some broaches and make "crow's foot" wrenches out of them and sell them to us. You can buy these types of adapters but they are not common and are expensive beyond what they're really worth. I plan to buy the wrenches that fit my nuts, cut the long handles off and drill and file a square hole to fit my torque wrenches. I'll also break down and make fixtures for all of my ER chucks. And yes, I know most of us don't bother torquing these things but I'm going to give it a go and see if it makes a difference in tool performance, just because I'm curious.


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## macardoso (Apr 11, 2019)

mikey said:


> The second thing is that nowhere in the video did I hear him discuss this collet twist thing.



Whoops! Must've been a different video then. Been doing a lot of research on ER collets since I just bought a ton of chucks.


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## macardoso (Apr 11, 2019)

Not what I originally found, but same idea:

https://www.mmsonline.com/articles/be-kind-to-to-your-collets

"6. When tightening the nut, torque down on it only to the value specified for this nut. Use a quality torque wrench to observe this limit. Exceeding the torque does not provide more clamping force; it just leads to runout. In fact, the more force is applied, the more the top of the collet wants to twist with the nut. Too much force can actually twist the collet’s top, deforming the collet, which will increase runout and reduce clamping force.
7. Avoid this collet-twisting phenomenon by using a nut that reduces the friction between the nut and collet. Different varieties of nuts achieve this low friction using an impregnated coating, a ball bearing or a friction bearing."


About the author: David W. McHenry is a product engineer for toolholder and collet supplier Rego-Fix Tool Corporation (Indianapolis, Indiana). 

They designed the ER collet


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## mikey (Apr 11, 2019)

Yeah, I know Rego-Fix developed the ER collet. I just wanted to make sure we all understood that a good coated nut, used properly and using proper torque, will not deform the collet.

The friction effects and slot deformation thing has been known for quite some time. This is what led to the development of coated nuts and, subsequently, ball bearing nuts. As far as I know, the cheap Chinese nuts that many hobby guys use are not coated. Most hobby guys also do not use fixtures or torque wrenches. That leads to undetected tool slippage, poor finishes, inaccuracy and excessive tool wear. When you point these things out, the commonest response I've seen is "Meh, this is just a hobby and it's good enough for me. I'm not making parts for NASA." Okaay ...


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## macardoso (Apr 11, 2019)

mikey said:


> When you point these things out, the commonest response I've seen is "Meh, this is just a hobby and it's good enough for me. I'm not making parts for NASA." Okaay ...



I don't subscribe to that philosophy. There is a lot of room between NASA and treating your tools like crap.


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## darkzero (Apr 11, 2019)

Well I make parts for NASA, but they always ignore me & never buy from me.  

Ok ok, of course not true but I do pretend to make parts for space shuttles. Maybe that's why it takes me so long to finish stuff. 

I knew Rego-Fix invented the ER system but after watching that HAAS video I had no idea that they invented them i  the 70s. Never thought ER collets were that old. Cool that HAAS mentioned Lyndex bearing nuts in that video, that's what I use on all my ER-40s. Oh, I couldn't find my Rego-Fix nuts, I must have sold them which is odd, I rarely sell any of my tools. I couldn't even find my standard Rego-Fix nuts, I know I had 2 of them & 1 friction bearing nut. But I did find 2 extra brand new Lyndex bearing nuts & a Lyndex ER-16 straight shank collet chuck with bearing nut that I forgot I had.

Speaking of HAAS. Saw this today. Someone in Argentina is getting 2 big new machines soon. HAAS is not that far away from me & I see HAAS shipments all the time on the fwy. But they're usually wrapped in plastic, first time I have seen them fully crated. Those are some big crates! I guess they only crate them for overseas shipments.


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## mikey (Apr 11, 2019)

I think you can't go wrong if you use nuts from an established maker of ER equipment - Lyndex, Rego-Fix, ETM, Techniks - they all make good nuts that most of us can afford. I only use coated nuts but after seeing the Haas video I think I will try a Rego-fix bearing nut to see what kind of accuracy I can get from it. 

I watched the Haas video on making one of their CNC machines. Impressive, and yes, those things are big!


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## darkzero (Apr 11, 2019)

Mike, I know you have ETM, nice! When I was in the market for ER collet chucks I wanted a ETM chuck so bad but they were so expensive. I wanted their collets too as they were said to by top notch like how Lyndex & Hardinge are for R8 & 5c collets. I couldn't afford them at the time. I ended up getting a Bison R8 ER-40 collet chuck & a Glacern R8 ER-16 collet chuck with slim nut. I went with Techniks collets. Later on I bought another Bison R8 ER-40 collet chuck from a member local to me I knew from a flashlight forum & here for a good price. Been happy with them.

Speaking of Techinks, I thought that was pretty cool to see them in the vending machine in the HAAS video. That vending machine is pretty cool, never knew stuff like that existed. Takes away the jobs from from tool room guys though.


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## mikey (Apr 11, 2019)

darkzero said:


> Mike, I know you have ETM, nice! When I was in the market for ER collet chucks I wanted a ETM chuck so bad but they were so expensive. I wanted their collets too as they were said to by top notch like how Lyndex & Hardinge are for R8 & 5c collets. I couldn't afford them at the time. I ended up getting a Bison R8 ER-40 collet chuck & a Glacern R8 ER-16 collet chuck with slim nut. I went with Techniks collets. Later on I bought another Bison R8 ER-40 collet chuck from a member local to me I knew from a flashlight forum & here for a good price. Been happy with them.
> 
> Speaking of Techinks, I though that was pretty cool to see them in the vending machine in the HAAS video. That vending machine is pretty cool, never knew stuff like that existed. Takes away the jobs from from tool room guys though.



Yeah, ETM makes some good stuff, very accurate but I've found that the nut and collet you use makes more of a difference than the chuck. Even my cheapy Tormach ER chucks run very accurately if I use Techniks collets.

I agree - I want a vending machine that spits out high precision collets, too!


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## Firstgear (Apr 12, 2019)

Home
					

GDP Tooling (formerly GUHDO) has been serving the US wood and composite industries since 1986 with highest quality tooling and accessories.



					www.guhdo.com


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