@WillAdams thanks, the ER20 model is still 66$, much better but still above my arbitrary psychological price threshold.
@Winters636 and @luc.onthego this makes sense, I don’t own one but I looked and I could buy one in the low 30$ range, and then “just” change the head indeed.
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If you do use a crows foot or anything that extends the arm of a torque wrench, you will need to do a mathematical formula to ensure you are getting the correct torque. I used to know them, but Im sure if you search google for torque wrench offset it will pull some examples up
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Is 59 ft-lbs appropriate for Carbide 3d’s HDM Spindle (ER20) collets?
IMO, monkey tight is more than fine for the machine and spindle capabilities you have. You are running much less radial and axial depths of cuts than industrial machines that require a bit more detail to the tool assembly. An ER collet is a compression collet and holds the tool shank with much less torque than your standard router collet.
Add: Two wrench system is more than adequate.
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We used a tool very similar to this when working with fuel and refrigeration connections. Maybe a local tool vendor could offer some suggestions.
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I’m actually more concerned about over tightening (with those huge wrenches) than under tightening. But not if 59 ft-lbs is acceptable.
Nice kit - perfect if the wrenches are the right size for Carbide 3d’s ER11 and ER20 spindle collets! 
Usual preface, I’m with PreciseBits so while I try to only post general information take everything I say with the understanding that I have a bias.
Short answer is it depends on the collet bore size you’re using.
Most times you will just see the max torque that the standard (ER20, ER16, etc) is rated for. Personally I go back to REGO-FIX for this as they are the inventors of ER collets. Their spec for all the collets is based on the nut type and the diameter of the bore of the collet (you can find it listed in their catalog (Link), currently on page 298).
For a standard ER20 collet with a standard nut it breaks down to:
- 12 ft-lbs for up to 1mm (0.0394")
- 25 ft-lbs for 1.5-6.5mm (0.0591"-0.256")
- 60 ft-lbs for 7-13mm (0.276"-0.512")
That being said I have a lot of experience with mounting and testing collets in our measuring systems. For a good collet these are way past the point you need to reduce TIR but you may need more torque to reduce vibration in cutting. It does wear the collets and especially the nuts faster the higher the torque you use. When testing we could get around 400 cycles out of an ER20M nut at 20 ft-lbs before it started showing increases in runout (testing with ER20 1/4" collets). Reducing it to 12.7 ft-lbs would over double this with collet TIR within margin of error of the 20 ft-lbs measurements.
All of the above will depend on the fit, finish, materials, hardness, coatings, etc of the collets and nuts. The point I’m making is that like for like there’s more wear for the higher torque used in a meaningful way. Haven’t got any good data on cutting with it, and if the lower torque isn’t reducing vibration enough that’s going to wear the collet more in cutting.
Hope that’s helpful. Let me know if there’s something I can help with or expand on.
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Thanks! Are speeds and feeds recommendations available for PreciseBits products?
I won’t get into too much brand specifics here for fear of crossing the marking line.
It’s something that we always fight with. In the real world, especially when you are talking about application specific cutters, there’s no useful easy answer to give. Your best cut is going to be limited by either the bit, the system, or the material.
To give an example let’s make up some numbers and materials. Let’s say that I have a 2 flute cutter that’s been designed to cut well at a 0.004" chipload in X wood/plastic/metal. It’s been tested, it gives a beautiful cut, has long tool life, etc. So now I put that up as the recommend chipload.
Now we sell that cutter to a customer with a system with 0.001" TIR and now my “recommend” number is giving poor results. Instead lets say that have good runout but their system can’t take the deflection, or a more brittle but just as hard similar material that then fails running that chipload, a wood that’s close to what we tested but has silica in it, or the same wood with twice the moisture etc, etc.
One solution to this is to add a margin to the chipload numbers. That typically results in giving someone with no issues worse finish, cycle time, and tool life. Another is to add a caveat that no one reads etc. What we decided on was to instead give guidance to test and a process to find the right feeds and speeds for YOUR material on YOUR machine (which is what I recommend you do with ANY tool no matter the brand). We obviously have internal data and numbers and we will give more specific numbers when we know the system, material, and setup used. We’ve also been working on some new ideas for the existing method especially as we started making bigger tools. But that’s why you won’t really find “recommended” chiploads or feeds and speeds on our site (some exceptions).
One last thing to take away from this in general. EVERYONE has this issue. Some manufactures will just go and put what the tool can take without a horrible cut on a perfect industrial machine. Some will give a very conservative number that will leave a lot on the table for cycle, finish, and tool life. Some will give a range, use a formula, etc. There’s problems with all of those, and frankly also with our “solution”. I personally don’t know what the right answer is, I just know that I hate all my available options. (Gets even worse after you throw marketing into it).
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For their standard ER11 Collets/Clamping Nuts, Rego-Fix also recommends a maximum torque of
- 6 ft-lbs for 1.0-2.9mm (0.039"-0.098")
- 24 ft-lbs for 3.0-7.0mm (0.118"-0.256)
Maybe half those values would be appropriate for Carbide3d HF Spindle collets/nuts?
I wouldn’t say it’s that simple. The problem is that it really depends on the finish and how well your collet and spindle match. If you have a good finish and well matched and conforming tapers then you can get away with a lot less torque.
For all of the below, don’t hold me to this, this isn’t an official recommendation, etc. Basically this is all at your own risk and your evaluation.
If I was going to try and find a method that didn’t require new equipment or tools it would be this. With everything freshly cleaned, take ideally a blank (or a tool but don’t hurt yourself doing this) and insert it into the collet without the nut. Make sure that the blank is far enough in that it’s making contact with the entire length of the collet. Then put that in the spindle (again, without the nut) and put a decent amount of hand pressure pushing the collet into the spindle. While doing this grab the end of the blank and try to move it in multiple directions (at least one per leaf). You want to do this with a decent amount of force.
What you will find when you have a good match is that their no spots where you can feel movement. In cases where there’s not a good match there will be “soft” areas where it can move. It’s not really going to be enough to see but you’ll be able to feel it. You should also be able to do this by a bit more than finger tightening the nut but it’s going to be a lot harder to tell as the taper in the nut also starts to come into play.
Just to cover it now, if you do have some wiggle in the collet it doesn’t mean that the collet is bad. It also doesn’t mean that it’s a good collet if you don’t. e.g. you could have a massively off center bored collet that would feel good because the taper matches and there’s a good bore size for the blank. Also to cover it now, a worn nut is going to throw any of this right out the window. Make sure you don’t have any grooves or smeared metal in the nut taper.
If you have any of those “soft” areas I’d say just go to the torque limit. Either the tapers or the bore don’t well match and your going to need the extra torque to compress the collet. If you don’t then you can probably scale back the torque. On my one set of data I wouldn’t say you can scale by half though. For that ER20m test I referenced above, we saw changes in the TIR going from 20 ft-lbs to 10 ft-lbs, hence the 12.7 ft-lbs I referenced. It didn’t change on all of them so it might have just been on the ones that weren’t a perfect match. Regardless, for some margin I’d say go 65-75% of max. Again this is not an official recommendation just my best stab at it with what I know of collets and the loads those here are usually hitting.
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Shouldn’t axial loads be considered?
Not sure what you mean? In general yes, to the test above it isn’t a test for load, it’s a test to see how much the collet matches the spindle. If there’s not slop in the match between the collet, spindle, and blank then you will get good clamping barring either a bad nut (wear or incorrectly made) or a spindle that has been reground one too many times or incorrectly machined. I guess you could also have a matching taper collet with too short a length before the groove for the extractor ring. No way you’re getting load or really any empirical numbers without test equipment though (might be able to use a phone with a vibration app but I don’t really trust those that much).
Only other thing I can think of here would be to see if you could pull the blank out of the collet (don’t try that with a cutting tool).
Again though, it’s not my official recommendation. I’m just proposing something that at least has a check before wholesale lowering the torque. To really test this you would need to run at both torque numbers under your maximum cutting load and measure the vibration. That would be on top of checking the TIR at both the torque numbers.
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My (albeit quite limited) experience suggests that axial endmill forces are usually the dominant factor in endmill clamping, Z-axis rigidity, and workpiece mounting requirements.
Unlike Rego-Fix’s, Techniks’ ER collet nut torques aren’t dependent on collet shank size.
Techniks ER Collet Nut Torques.pdf (965.4 KB)] from. That makes life easier and seems sensible. What doesn’t make sense is how anyone is expected to get 59 ft-lbs torque from a ~1/2 ft long wrench! That would be hard to do even with the huge wrenches that came with our HDM. But I still wonder if that’s safe for the HDM collet nuts.
I recently destroyed the threads on one of my er20 spindles, most likely either due to too many tightenings or probably just cranking it down too tight. Would like to stop doing it wrong lol.
Found this torque wrench, iswiss tools collet torque wrenches.
Anyone use one before? They have one for the er20 with options for two collet nut styles, and lists 40/70 for torque. I don’t see a dial on it, is it one side torques 40 the other side 70? Why would they use these settings, I read that the er20 collet should be at 58 lbs?
Is 40 lbs good enough for aluminum work etc?
Which style collet nut is better, does anyone have a preference for any specific reason?
The Techniks wrench Gerald linked to is like 315 dollars and 16.5 inches long not including the tool end so it would probably be 20+ inches total, kind of big and might be hard to use while holding another wrench at the same time with your other hand.
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I’m still confused here I thought the whole point of this was asking if it was necessary to hit those numbers? Officially yeah that’s what they say to keep the system in spec for vibration and clamping. Unofficially, I think it’s too much and can lead to increased wear. I can’t tell you that you will get the same clamping force without testing. There’s margin built into all of these for manufacturing tolerances though. So if you have a good fit you are likely to not need the full number.
Like I said most just list the max on the whole spec and Techniks’ pretty much follows that.
Standard ER11 nut:
- REGO-Fix - 17.7 ft-lbs
- Techniks - 17 ft-lbs
Standard ER16
- REGO-FIX - 41.3 ft-lbs
- Techniks - 42 ft-lbs
Standard ER20
- REGO-FIX - 59 ft-lbs
- Techniks - 59 ft-lbs
One last note on torque numbers. gmack helpfully pointed out (not sarcasm) that on our site we had some incorrect torque numbers listed on a page for ER nuts. When I went and corrected them I found there’s some errors in the sheet from REGO-FIX. e.g. ft-lbs and Nm being the same for ER11. The Nm table makes sense in context of the group and to the next size, the ft-lbs does not. Go with the Nm and convert if needed.
One thing that has not been discussed regarding this is if all spindle threads can even handle these loads. I know from working with customers that there’s not been an issue with the spindle using these max torque numbers on Columbo, and HSD. However, those are pricey industrial spindles.
Can’t say anything about the iSwiss as I have no experience with the company. If I had to guess I’d say that it’s probably just a standard wrench remarketed to this application and they considered those numbers close enough.
Techniks uses Norbar (if you don’t believe me zoom in on the handle picture from the amazon link you used). If you really want that wrench (Link) it’s $173. However, that’s the 40-200Nm one so it might not fit your application. The Pro 100 is 20-100Nm and $163. Any of their 16mm spigot end ones should work with the heads from Techniks.
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[quote=“CNCInspiration, post:22, topic:15797, full:true”]
I recently destroyed the threads on one of my er20 spindles, most likely either due to too many tightenings or probably just cranking it down too tight. Would like to stop doing it wrong lol.[/quote]
Don’t you mean collet nuts, like shown here?
This kit includes a 22mm wrench (which should fit the motor shaft). But who knows what’s safe and appropriate - maybe @Vince.Fab?
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Mine locked up so bad I was not able to remove the nut. Got it loose about 2 turns, enough to get the tool out and it must have welded itself. I think it would take a vice and breaker bars to remove the nut if at all possible.
Realized I missed this in the previous message.
Be careful with different versions of nuts. There are 2 standard threads for most ER spindles. One is a “standard” also called A/UM/slotted. The other is a “Mini” also called M/castle/slotted (yes they both are sometimes called slotted). There’s also a style that uses the same thread as the standard nut that is larger that can be called an “E” style. As far as I’ve been able to see none of these go back to any standard. So watch the thread of the nuts you are buying.
Personal preference, I prefer the castle style with the castle spanners. To me they are the best combination of ease of use, and consistent force. Some don’t like them though as you can’t easily load a tool with a larger cutting diameter than nut diameter. I’m also probably bias as it’s one of the first styles I used and I’ve used them a lot. They are also pretty uncommon with a standard thread.
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