# 35 vs 72 piece Collet set?



## LVLAaron (Mar 2, 2022)

Need a complete collet set and looking at these:



			https://www.precisionmatthews.com/shop/72-pc-precision-inch-5-c-collet-set-164-to-1-18/
		



I know twice as many is twice as good - it's also twice the cost and twice the space in my shop. There's not much info on the site - does anyone know the size tolerance these collets have? Should I get the full set? I'd be really cranky if my first project that needed a collet was an inbetween size and I had to go find one online


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## benmychree (Mar 2, 2022)

They would go by 1/64" steps in the 72 piece set and by 1/32" in the 35 pc. set.


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## davidpbest (Mar 2, 2022)

Even 1/64th steps in 5C doesn't cover the entire range.  Have look at the attached (especially pages 7-9).  If you want to be able to workhold any random diameter up to 26mm, you might be better off with ER40 instead of 5C (or in addition to).


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## 682bear (Mar 2, 2022)

I would definately get the bigger set... I bought the 35 piece set and regret it...

Unfortunately, as far as I can tell, I can't buy just the 64ths collets as a set... to get them, I would have to buy a full 72 piece set (and have duplicates of the 35 that I already have), or buy them individually, which is significantly more expensive.

I'll eventually buy a 72 piece set and try to sell the 35 piece set...

-Bear


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## LVLAaron (Mar 2, 2022)

davidpbest said:


> Even 1/64th steps in 5C doesn't cover the entire range.  Have look at the attached (especially pages 7-9).  If you want to be able to workhold any random diameter up to 26mm, you might be better off with ER40 instead of 5C (or in addition to).



Thanks that was helpful. looks like ER40 is a little less expensive as well.


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## davidpbest (Mar 2, 2022)

LVLAaron said:


> Thanks that was helpful. looks like ER40 is a little less expensive as well.


Quality ER40 products are linked to in the attached.


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## benmychree (Mar 2, 2022)

I'd stick with the 5 C set, as there are likely more fixtures that use them.


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## wachuko (Mar 2, 2022)

benmychree said:


> I'd stick with the 5 C set, as there are likely more fixtures that use them.



Huh???

I ended up ordering both... 5C and ER40 chucks... 

Have not ordered the ER40 collects because I can't remember if it was better to order the metric ones or the SAE...  I remember reading a thread on this that suggested one over the other as it would work fine without having to buy both sets...


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## LVLAaron (Mar 2, 2022)

ER40 set in the mail. Thanks @davidpbest


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## davidpbest (Mar 2, 2022)

You're very welcome.


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## Aaron_W (Mar 2, 2022)

wachuko said:


> Huh???
> 
> I ended up ordering both... 5C and ER40 chucks...
> 
> Have not ordered the ER40 collects because I can't remember if it was better to order the metric ones or the SAE...  I remember reading a thread on this that suggested one over the other as it would work fine without having to buy both sets...



I don't see why it matters, ER has a fairly large range for work holding compared to 5C so 15/16" or 1" vs 25mm or 26mm moves the break points slightly but won't make much difference. I go with inches on my ER collets because I'm more likely to work in inches. 

A metric set by mm will fall in between a set of 16ths or 32nds (being roughly 25ths).


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## wachuko (Mar 2, 2022)

Aaron_W said:


> I don't see why it matters, ER has a fairly large range for work holding compared to 5C so 15/16" or 1" vs 25mm or 26mm moves the break points slightly but won't make much difference. I go with inches on my ER collets because I'm more likely to work in inches.
> 
> A metric set by mm will fall in between a set of 16ths or 32nds (being roughly 25ths).


Remember... newbie here... easily influenced


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## xr650rRider (Mar 2, 2022)

I've got the full 72 piece set of 5C and you'll never use all of them but it's hard to say which ones you might need so I like having them all.  I've also got full set of ER-40 imperial and metric.  I find I use the ER-40 more in the lathe but only parts that are fully supported.  5C can hold shorter work.  I've got the Bison set tru 5C chuck and use a speed wrench but I can still swap parts quicker in the ER-40.  I finally caved in and bought the Rego-fix ball bearing nut for the ER-40 and evidently I don't know the magic handshake as honestly I prefer the nut that came with the chuck.  Hell of a lot harder to snap a collet into the Rego-fix.  Can't say one has less runout than the other, that seems to be more collet/chuck dependent.  I've also got an ER-16 with R8 for the mill and doing gunstock work it's much better.  You can reach down into stock with up to 3/8" end mills


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## LVLAaron (Mar 2, 2022)

I got:

* A set of blocks from Little Machine Shop
* Metric set of collets (https://allindustrial.com/techniks-...18IfcaUpmnvVxLUU9zR_qr3HTMs9xCFBoC6GkQAvD_BwE)
* ER40 chuck D1-5 (and 2 gallons of gearbox oil, unrelated!) from PM.


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## benmychree (Mar 2, 2022)

wachuko said:


> Huh???
> 
> I ended up ordering both... 5C and ER40 chucks...
> 
> Have not ordered the ER40 collects because I can't remember if it was better to order the metric ones or the SAE...  I remember reading a thread on this that suggested one over the other as it would work fine without having to buy both sets...


I am referring to various devices such as collet blocks and indexers.


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## davidpbest (Mar 2, 2022)

benmychree said:


> I am referring to various devices such as collet blocks and indexers.


All of which are available with ER40 or 5C.


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## Beckerkumm (Mar 2, 2022)

If you go 5C you really do need 64ths and some metric.  I found a NOS set of Lyndex 32 set reasonable and have spent a fair amount of time watching for additional collets.  I only consider Hardinge, Royal from England, or Lyndex and the process is slow but the quality of those brands is or was very good.  My goal is < 25 per new collet but I might give up for the last few and cough up.  Dave


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## Janderso (Mar 3, 2022)

davidpbest said:


> All of which are available with ER40 or 5C.


What about all the 5 C emergency collets, square, hex, etc.
Are these products available with the ER platform?


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## wachuko (Mar 3, 2022)

Janderso said:


> What about all the 5 C emergency collets, square, hex, etc.
> Are these products available with the ER platform?


I know the question was for David...

But, Hex and Square, yes... I have a set of those.

Another thing I need to google... 5C emergency collects... what the heck is that used for... searching...

EDIT: 5C Emergency Collects

_"They are used when you have an odd size, shape or configuration in your work piece and you machine them to suit the work."_


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## davidpbest (Mar 3, 2022)

ER collets are available to hold nominally sized hex stock from _*Maritool*_.  I have seen ER collets for holding square stock, but can not suggest a source of supply. If square stock feeding is a common need, then 5C might be a better choice - or use a 4J (scroll) chuck. Emergency 5C collets are mostly employed to hold oddball (non-nominally) sized materials since there are lots of diameters that 5C sets can't hold because of their narrow clamping range.  A full set of ER collets will handle any diameter from 1 to 26mm obviating most needs for an emergency ER collet.  This is all discussed in *the paper* I posted earlier.


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## wachuko (Mar 3, 2022)

ohh... for square stock...


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## T Bredehoft (Mar 3, 2022)

Since the Original Inquirer (OI) has completed his accumulation of over 100 collets, I'll chip in with my experience. Fourteen years after retirement,  I  bought a PM 25 mill and went back to playing with metal. Currently have a 10-30 PM Lathe, and bought an ER40 Zero Set collet chuck from one of the vendors and went on about my playing, ordering a collet as the need occurred. I've got about 20 now, fractional, and haven't needed a new one for several years. McMaster Carr delivers next day, and i have no need for any faster shipment, I did retire to relax, not work to a schedule. 

[Asside] Typing on a Computer in Holland, the normally spelled English words get red underlined if they differ from the spelling of Dutch words.  Makes for intersting proofreading.


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## mmcmdl (Mar 3, 2022)

davidpbest said:


> If square stock feeding is a common need, then 5C might be a better choice - or use a 4J (scroll) chuck.


I use a Bison 4 jaw scroll chuck with a set-true plate quite often . That and a Bison 3 jaw ST pretty much covers the gamet of stock sold .


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## xr650rRider (Mar 3, 2022)

First time you knock a digit off on a 4-jaw or 3-jaw, you'll understand the attractiveness of a smooth chuck if you need to work close.


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## RJSakowski (Mar 3, 2022)

There seems to be some misconception as to how a 5C collet functions. Firstly, the grip range of all my collets are about 1.2" long. Secondly, to function properly, a 5C collet grips the work along its entire length of the cylindrical bore.

The drawing below shows a 5C collet in a collet chuck. The collet' features include a cylindrical work holding region, A, formed by three split fingers and a flexure region, B. When a work piece that is smaller than the nominal diameter is inserted and the collet tightened, the collet fingers will bend in region A to grip the work. The collet first bends in a simple arc at point F, shown exaggerated for purposes of illustration, causing the collet fingers to grip the work at C, and pulling the fingers away from contact with the chuck at E with point D providing the contact with the chuck.






At this point, the clamping of the work is unstable as it is only a ring of contact and the work can pivot around that point. This can easily be demonstrated by mounting an undersized bar in a collet, using only enough clamping force to grip the work. If you apply force to the far end of the bar, the bar will deflect and will take a new position, as can be verified with a dial indicator.

Further tightening draws the collet deeper into the chuck, forcing the collet flexure region to take a "S" shaped curve with bends at F and G until the collet makes contact with the work along the entire surface A and point B is again in contact with the chuck.

It is often recommended that undersized work should be limited to .003" less than the nominal diameter. This is because forming the "S" curve introduces considerable stress to the collet fingers which increases dramatically as the work diameter departs further from the nominal diameter. There is another reason as well and that is when the work diameter is less than the nominal diameter of the collet, the collet fingers only make contact with the work along three lines, shown as points F in the end view. This is why "emergency" collets are used when the number of pieces justifies the additional machining. The collet is bored to exactly match the work, insuring contact around with the full work surface.

A 5C collets ability to grip undersized work is limited by the width of the slits between the fingers and by the ability to tighten the collet in the chuck. The smallest diameter that can be gripped by a 5C collet is slightly less than the nominal diameter less the slit width, in theory. In practice, the force required to properly close the collet on the diameter may be more than can be applied by the collet closure mechanism. The slits on my collets are between 019" for the 1/16" collet and .055" for the larger collets. A collet set by 1/16th's would not be able to cover all possible diameters. A set by 32nd's would be able to close on any diameter within its range. A set by 64th's would create less stress on the collets in the case where the work diameter was slightly oversize for a nominal collet, requiring to go to the next larger size but may not be warranted for the occasional user.

For the user not wanting to purchase a set by 32nd's, there is a suitable workaround. A shim made from a beverage can will increase the diameter of a piece of stock by about .008" and some roofing flashing by .020". Cut a length slightly less than the circumference of the work and roll around the work. Insert the work and position the end of the shim next to one of the collet slits. Tighten and you're good to go.

Edit: deleted redundant drawing.


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## mmcmdl (Mar 3, 2022)

/\/\/\ . And this is why I prefer the Jacobs flex collet system over the 5C on a lathe . The flex collets are also a heck of alot better for thin wall tubing etc .


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## davidpbest (Mar 3, 2022)

/\/\/\ . Exactly as I understand the functioning and use of 5C collets as well, and why I prefer ER40.


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## mmcmdl (Mar 3, 2022)

Not that I never use the 5Cs in the lathe or any other fixtures , but you will spring them and ruin the collet if you go way undersize on your part . That's what E collets are for .


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## Janderso (Mar 3, 2022)

davidpbest said:


> ER collets are available to hold nominally sized hex stock from _*Maritool*_.  I have seen ER collets for holding square stock, but can not suggest a source of supply. If square stock feeding is a common need, then 5C might be a better choice - or use a 4J (scroll) chuck. Emergency 5C collets are mostly employed to hold oddball (non-nominally) sized materials since there are lots of diameters that 5C sets can't hold because of their narrow clamping range.  A full set of ER collets will handle any diameter from 1 to 26mm obviating most needs for an emergency ER collet.  This is all discussed in *the paper* I posted earlier.


Thanks for taking this one.
I find sacrificial 5C collets to be a valuable tool. Holding a thin part in a 5 C emergency collet that has been cut to depth and diameter is a very handy tool to have in your arsenal. I’m not aware of an ER platform that has this option.
Are there emergency ER collets?


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## Janderso (Mar 3, 2022)

T Bredehoft said:


> Since the Original Inquirer (OI) has completed his accumulation of over 100 collets, I'll chip in with my experience. Fourteen years after retirement,  I  bought a PM 25 mill and went back to playing with metal. Currently have a 10-30 PM Lathe, and bought an ER40 Zero Set collet chuck from one of the vendors and went on about my playing, ordering a collet as the need occurred. I've got about 20 now, fractional, and haven't needed a new one for several years. McMaster Carr delivers next day, and i have no need for any faster shipment, I did retire to relax, not work to a schedule.
> 
> [Asside] Typing on a Computer in Holland, the normally spelled English words get red underlined if they differ from the spelling of Dutch words.  Makes for intersting proofreading.


Says here you in Ohio?
Just watched a Seinfeld episode where George and Jerry are sitting in a coffee shop with a globe and an Atlas. Holland is not on either.
Jerry said, maybe Holland sunk like Atlantis.
So, what’s the real story?


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## davidpbest (Mar 3, 2022)

Janderso said:


> Are there emergency ER collets?


I have not seen any, nor do any show up searching.  The ER40 collets are much shorter than the 5C, and since they are designed with staggered slots from both ends and have a 1mm clamping range, every ER collet I have seen is made from some kind of spring steel that's very tough material.  An emergency collet needs to be soft enough to machine to the desired bore or profile.  Intuitively it seems to me that the springiness of the steel required to function well with the ER taper angles would not be a suitable material for modification.  Of course, this is all just my speculation.  

That said, I do believe it would be possible to machine an inner insert that fits in a larger standard sized ER collet, has a more narrow clamping range, and made of a material that could be machined to fit production parts including a depth limit stop.  Kind of a collet within a collet.  Again, pure speculation.  

Each collet type has it's own set of advantages and disadvantages, and 5C with a quick-release chuck is probably better for production work.  But if your need is variety/randomness of clamping diameters with the least number of collets for prototyping and one-off work, ER40 is probably a better choice IMO.  And then there's the tradeoff of how much insertion is required to attain a specific TIR tolerance.


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## ahazi (Mar 3, 2022)

LVLAaron said:


> Need a complete collet set and looking at these:
> 
> 
> 
> ...


I have this 72 piece set set and it is very good so far.

Ariel


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## T Bredehoft (Mar 4, 2022)

Ohio, yes, that's home, visiting an old school friend. Weather here ( Holland, just south of Rotterdam) is better than Ohio at this time of year. We're working in the garden sporatically. Flowers blooming all over the place.


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## Larry$ (Mar 4, 2022)

My ER40 chuck, set of imperial collets and an ER to R8 adapter for the mill came yesterday. I put the studs in the chuck mounted it on the lathe and adjusted the 4 setscrews until I had barely any wiggle on the dial test indicator running in the chucks taper. Snapped a 1/2" collet in and put a 1/2" gage pin in. Using my Mitutoyo dial test indicator to check runout and was very disappointed. Too long to explain here. I'll start a new thread.


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## Ischgl99 (Mar 4, 2022)

davidpbest said:


> That said, I do believe it would be possible to machine an inner insert that fits in a larger standard sized ER collet, has a more narrow clamping range, and made of a material that could be machined to fit production parts including a depth limit stop. Kind of a collet within a collet. Again, pure speculation.


I did that before I got my 5c collet chuck.  It worked ok, but I made the clearance too loose, so it took some effort to clamp properly.  If it fit better, I think it would work as an emergency collet.


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