ER Collet Sets

[Shaun ChurchillParticipant @shaunchurchill54517]

I havent posted in a while as been busy trying to master Fusion 360 and also get to grips with my Tormach CNC mill and recently acquired Bambu Lab 3D printer. I have been looking on the net at ER collet sets and totally lost in terms of what is a reasonable make / quality versus cost compromise. Just hoped that someone could point me in the right general direction. I am looking at a metric set of ER20 and ER32 collets. I currently have a Vertex ER25 set which I purchased from Rotagrip some years ago, but alas this brand seems to have gone up in price considerably in the intervening years. Many thanks in anticipation. 

[JasonBModerator @jasonb]

If it is for the CNC you may be better off with a few common cutter shank sizes in a higher spec and then make do with the odd ones in something more reasonably priced. 4, 6 and 10mm should cover most metric shanked carbide tooling to suit the Tormach.

I would also suggest that you go ER16 as it allows better access for air/mist systems that may hit a larger collet before they hit the work/tool where you need it.

I run a mix of ARC in most sizes – 32, 25 & 16 and a few Cutwel in 16

[Shaun ChurchillParticipant @shaunchurchill54517]

Thanks Jason for the advice. I do use both Cutwel and Arc for stuff. I acquired the Tormach with a TTS tooling pack which contains several ER20 and ER32 holders and zero collets😂. I did manage to import an ER25 TTS collet chuck so currently limited to the Vertex collets I already had for use on my Tom Senior manual mill. I also found that the Shear Hog single point cutter that Tormach push has incredibly expensive and hard to come by inserts so hence why I am trying to expand my tooling library with the help of ER collets.

[JasonBModerator @jasonb]

Oh they are a bit spendy. For larger similar surfacing jobs a 25, 40 or 50mm facemill and aluminium specific inserts would do a good job. The larger number of inserts on the 40 and 50 will also mean you can feed faster for the same chip load. You can get parallel 3/4″ arbors for them which will go in the TTS or probably a TTS x 22 or 28mm arbor which would be even better.

Cutwel have the fully ground face inserts a bit like the Tormach which cut very well in the ARC heads or the ground and moulded APKT ones like ARC do cut almost as good.

If it is to set up a range of TTS holders then I ould say you will mstly be using 4,6 and 10mm shank in those and your existing set will cover and odd drill size etc.

[Anonymous]

On my Tormach I use TTS 6 and 10mm sidelock holders for my two standard size shank cutters that do the majority of my basic machining. I also bought 3 TTS ER20 collet holders. I bought my ER20 collets from a commercial supplier, Carillion Industrial Services, that at the time were fairly local. I doubled up on 3 and 4mm collets. If I needed more ER collets I’d buy from Cutwel; ARC don’t seem to give a runout figure.

I learnt early on that on the Tormach it is better to use a small(ish) cutter at high speed and feedrates than a larger cutter. I’ve never felt the need to use facemills on the Tormach, only used them on the Bridgeport and horizontal mill. I use the Tormach TTS system on the Bridgeport, only changing for special tooling such as large endmills (>16mm), face mills, a Clarkson style threaded endmill chuck, slitting saw arbors and boring heads.

When I first bought the Tormach I also bought some imperial sidelock holders, but have never used them. All my CAM programming is done in metric, with metric cutters, irrespective of whether the part is designed in imperial or metric.

Andrew

[Ketan SwaliParticipant @ketanswali79440]

Hi Andrew,

ARC does give runout figures for ER collets, and has been doing so for a while now. Earlier ARC didn’t. For ER11, a range has been specified 0.008 ~ 0.015mm, and for the rest 0.008mm has been specified.

Ketan at ARC

[Ketan Swali]

On Ketan Swali Said:

ARC does give runout figures for ER collets

For the sake of discussion, education and insight into the world of collets, how is the given figure determined by any collet supplier? Would the supplier simply report or pass on a number provided to it by the collet manufacturer?

Do suppliers have a quality regime where they pick samples from the collets supplied to them by a manufacturer and send the samples for independent verification of runout (like a UKAS lab. for more mundane items such as soil and concrete)?

It would be interesting to find out what standard tests are used to arrive at this number (is there an ISO collet runout Standard?) and who (if anyone) in the UK has facilities to carry out these tests.

I guess you need some fairly specialised kit to carry out this test. I wonder what extra or different manufacturing steps the ‘better’ collets go through to attain the lower runout.

[JasonBModerator @jasonb]

I’ve seen the pics of the ARC ones being tested so don’t think they just put a random number on them. I hope that educates you to what goes on with collets from reputable suppliers.

I doubt many here want to pay the price for third party testing etc hence the whole reason for this post wanting less expensive sets

Also remember these figures are Maximum Acceptable. I have mostly the older ARC collets which were rated at more than the current 0.008mm (different maker) yet the ones I clocked were all within their max runout.

[Shaun ChurchillParticipant @shaunchurchill54517]

I have to say that I have always been totally impressed with the quality of everything I have purchased from Arc and service offered has also been second to none. I also like the simplicity of their website, although I guess one could argue its a tad light on product information. However, I would rather deal with a company that has a less flash website but is 100% reliable than some corporate that has a all the bells and whistles website but then you find out they dont carry any stock.

Thanks again to everyone who contributed to my initial question about ER collet suppliers. I see the point about purchasing a few good quality size collets over a whole metric set.

Cheers👍🇬🇧

[JasonBModerator @jasonb]

It is really a case of what you expect to be doing and at what sort of size.

As I have said I mostly use ER16 on the CNC. 4mm and 6mm will take care of 99% of my milling cutters. I have 1-5mm in 0.5mm increments so that will take care of things like tapping drills and pre reaming drills upto 6mm which is more than enough for the sort of size models I make.

Above that I could close down a collet or use a drill chuck if needed but for holes unless they are deep forming them with a milling cutter is another option having it spiral down and then enlarge the hole to the required size.

Also think about what you will hold work with. If I’m say milling out the dog bone shaped cutout inside an IC piston I may well hold it in a collet but as I will clock its position I don’t need the accuracy that the cutter wants holding with.

So a reasonably priced full set and then maybe just the cutter holding sizes in a higher spec. If you have several holders of the same ER size then you will likely want separates for them anyway as you would keep the commonly used cutters setup. My most used are 3-flute coated and 3-flute uncoated non ferrous, both 6mm so if I had a quick change would keep those two permanently in holders.

[DC31k]

On DC31k Said:

On Ketan Swali Said:

ARC does give runout figures for ER collets

For the sake of discussion, education and insight into the world of collets, how is the given figure determined by any collet supplier?

We don’t know!

Would the supplier simply report or pass on a number provided to it by the collet manufacturer?

Always exceptions,  but it’s unusual for wholesalers or retailers to retest manufactured products. They pass the spec on.

Do suppliers have a quality regime where they pick samples from the collets supplied to them by a manufacturer and send the samples for independent verification of runout (like a UKAS lab. for more mundane items such as soil and concrete)?

Maybe.  Quality processes are a major subject in their own right, and there have been massive improvements since the 19th century.   In the early years of WW1, there was a major problem with British shells.   Production was low, costs high, and quality poor.   This was partly due to a quality system in which an inspector would sample one of a batch, and reject the whole batch if it were out of spec.   As applied to shells in 1914-1915, a bad system, very wasteful, and it allowed lots of duds to reach the front-line.   Today, the best manufacturers apply a quality system called ‘First Time Right’.  FTR rejects the idea of inspectors and statistical sampling in favour of building quality into all stages of the production process.   If, later on, a part is found to be out-of-spec, a team of engineers descend and fix whatever was causing the quality problem.   Could be due to a gap in a machine’s maintenance routine, different machine needed suboptimal cutter or material, operator deficiency etc.   FTR works by tackling root causes, not individual malfunctions, and it is the deadly enemy of bodgers!    Whether or not a collet maker applies FTR or not is down to them.   It’s expensive to set up, so a smaller firm might compromise, in the worst case making collets with a clapped out machine driven by a child, who just adds a sticky QA label before packing them.    

It would be interesting to find out what standard tests are used to arrive at this number (is there an ISO collet runout Standard?) and who (if anyone) in the UK has facilities to carry out these tests.

I doubt there’s a run-out standard for collets.   The manufacturer says what it is, and the buyer selects accordingly.  I guess any calibration lab in the UK could measure run-out.  

I guess you need some fairly specialised kit to carry out this test. I wonder what extra or different manufacturing steps the ‘better’ collets go through to attain the lower runout.

Done by working to closer tolerances than doing anything extra.   Of course achieving higher tolerances may require  different production techniques.

The most expensive ER collets are rated to run at high speed, 30000rpm or more.   These have to be balanced as well as low-runout.  Don’t see much value in buying these for my 2800rpm max hobby mill!    And I’m very suspicious of the notion that buying better tools will improve a basic machine.   My WM18 is good for about a thou, and spending extra on posh collets won’t improve it much.   If I want it to work in the tenths range, I’d have to work through the entire machine, applying a long list of tweaks and upgrades.

Dave

[Shaun ChurchillParticipant @shaunchurchill54517]

I think what a lot of people perhaps dont understand about any type of collet used for tool holding is that if say you are running a small diameter cutter and its running out a thou or more this puts an incredible strain on the cutter. Of course this becomes less relevant on larger diameter cutters. Hence run-out is important unless you are happy to see a scrap box full of broken small diameter cutters.

[Ketan SwaliParticipant @ketanswali79440]

Hi DC31k,

I can only speak for the procurement process we follow for ER collets.

Around 18 years ago, the late JS encouraged me to look at ER collets as a standardisation for the hobby market, which before then was used to using a Chinese standard collet which is a longer collet which looks similar to ER.

A factory was found with whom I was happy. In addition to ER collets, we purchased other items and developed some items with them which JS created, with the help of a specific engineer in that factory. Over the years we worked closely with a set of people in the factory. They have a set of procedures in place to check each product on specific product related testing equipment.

About nine years ago, the specific engineer with whom we worked, left and started his own factory which specialises in ER collets. Two years after he started his factory, we moved our procurement of ER collets to him. We continue to buy a spread of items from the original factory, along with ER collets specifically manufactured by him. I have visited him on several occasions and seen the checking process.

Checking is done manually by an experienced checker who checks each collet for runout on a specific test rig. the collets are then separated into small bins by runout range. There is a market for every runout spec. Price we pay for 0.008mm is 10 ~ 15% higher than 0.015mm.

We are regularly offered prices cheaper than what we pay our manufacturer supplier, however I prefer to buy from people I am happy to work with, and I have been working with this team for around 18 years now.

So, above is the process ARC has for quality control. Any problems are usually flagged up after receiving three consecutive complaints with which we agree, for the price range at which a product is offered.

If certification is required, I would suggest Regofix.

Checking for accuracy outside a test rig, and on a milling machine can achieve mixed results as there are too many factors involved, including the accuracy of the spindle, milling head, arbor, nut, cutter, column alignment, how hard or not the collet system is tightened. For these reasons, in the early days, we were less confident of specifying ER collet runouts, even we were originally offering 0.015mm runout. An observation on one mill was found to be different from two to three others.

However, over time we saw others offering Chinese origin ER collets specifying runouts as a marketing tool, in the hobby environment, and we are confident that the prices suggested were difficult to achieve for the runout specified. So we decided to specify the runout as specified by our manufacturer, a few years ago.

Manual machines are less accurate than CNC. They work at lower speeds than CNC too. Although there are specific CNC machine specks ER collets, different from what we sell, there are CNC machining workshops in U.K. and Europe, to whom ARC supplies ER collets for use on their CNC machines. The ER collets we sell are fine for use on Tormach machines.

If one was to use seriously big/multi axis CNC machines for something like aerospace component making, then a different type of ER collets should be considered.

Ketan at ARC

 

 

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