Saved my bacon. I've never used a collet set before and thought it was broken or a rubbish cheap rip off. But as you said, in the video, All I needed to do was clip the jaws into the nut first, but I didn't do that the first time around and got the jaws locked into the body. After a struggle, I got them out then followed your instructions, and now it works just fine. Thanks very much buddy.
Same here. This video saved me. I was on the edge of sending my new collet set back and leaving a withering comment. Said in another way - i was on the brink of making a complete moron out of myself. But then i found this video. All of my 19 collets are fine, the holder is fine and the wrench also. And all that for under 80,- €.
What a timely video!! I recently purchased an ER collet set and was dismayed they did not seem to fit. The horror! Now your video shows up explaining everything and the world is in a slightly better place. Thank you and a joyous Christmas.
I’m glad it was of assistance, we have all been there and it’s hard to believe they don’t provide instructions for these things but for some reason they never do. Enjoy your collets and Merry Christmas.
Nice info. I have an ER32 collet chuck for my wood lathe, my metal lathe, and my benchtop mill (when I get it), and I have a full set of SAE collets. These have been very handy when I have had to hold small diameter rod stock for either machining, or for holding a ring mandrel on my wood lathe.
Great video, I just recieved my ER32 collet, and block set, first time user. I want to be sure on how to use them properly, thanks to your video I can use them with confidence, THANKS
Great Video! There's one thing that I think belongs on that list though and that's that ER collets and clamping nuts wear out with use. This is less important with larger tooling but if you're using micro end mills (e.g. 1/32" and smaller) the nut and collet must be in good shape to have acceptable runout.
Everything wears out eventually. With high quality collets and chucks it’s only a problem for heavily used collets and chucks in high speed CNC machines, not for the home. Ok, some questionable info here. Look at the back of the collet to see how long the gripping length is. It’s not the full length on all sizes. The smaller sizes have shorter gripping lengths. Also, each collet has a gripping range. These aren’t R-8 or “C” style collets that can only grip the stated size. ER collets have the gripping range on the face of the collet, such as 5-6, 6-7, 7-8 in millimeters, or in 32” in inch. There are half millimeter sizing collets as well.
Fantastic video, came here with questions and left satisfied with the knowledge I have received. One more question though: How to chose between the different ER size offerings for a particular application?
Thanks, as far as I know it’s driven out of the size range you need as each ER size has a maximum and minimum size available in the collet range. This is limited by the shape of the actual collets. There is also increase strength in the bigger collets.
Another thing that took me a while to figure out is how to take a collet back out of the nut after you've clipped it in, since the tapered shape makes it hard to grip (especially with little ER11 collets). Instead of trying to pinch and pull it straight out, push from the side to tilt the collet in a circular motion and it will ride up the surfaces in the nut and come right out.
Agreed, even with the larger ones they are puzzling until you know the trick for removing them. I found they would come out sometimes and not others and you really have no idea why until you understand how they work.
great video, I especially appreciated #1 as today I stumbled on it the hard way, figured it out could have done it more efficiently and confidentially if I had watched this first. Thanks
They were developed from the E series collet by the Swiss tooling firm Rego-Fix and patented by them in 1973. The E series, which I believe are now obsolete, didn't have the circumferential groove in the collet nor the eccentric in the nut. So ER started as a marketing name and became a widely recognised reference term.
The drop in collet nut is made for a "sealed collet" for a machine with through spindle coolant. The sealed collets don't have much flex. The standard spring collets just snap in.
@@piter_sk Sometimes that's a blessing. I've used that trick several times to wash chips out of a milling cut when trying to mill a slot and not regrind chips.
@@Kaptn_Obvious actually with HSS drills, it´s the best way to get coolant to the cutting edge... it´s literally going down the flutes to the tip.... today, I was drilling 16.7mm hole like that, 0.12mm/rev feed and 550 RPM (which is between 20-30m/min recommended for HSS in mild steel).... the chips weren´t even slightly warm comming out of the hole...
so you need 12mm collet for 12mm endmill. can you help me.. Im looking to buy er11 for my spindle for pcb engraving. but all I could find are 0.5 to 3mm end mills all with 3.175mm shank. problem is all the er11a and er11 I could find only have 1, 2, 3, 4, 5, 6, 7 mm collets. so according to you none of them would fit a n end mill with a 3.175mm shank..
At the size you are looking at a 4mm will likely work without a problem, the issue usually comes when you use a 7mm collet with a 6mm endmill which is likely slightly under 6mm and outside the range of the collet. If you do have any trouble with them not gripping tightly or slipping the it looks like 3.175mm is the equivalent of an 1/8 inch so that would be the correct collet.
Late answer but ER collets also come in 0.5mm steps; 3.5mm ER11 collets are available from various manufacturers including Rego-Fix and Vertex; ER collets were originally developed by Rego-Fix.
Endmills only need a few sizes as the shanks are generally standard sizes, for metric 6,8,10,12... . The reason for having a bigger set is for work holding, such as in the lathe or with a collet block in a mill.
You may also come across 4mm shank endmills for anything smaller than 4mm depending on the work you are doing, but other than that yes 6,8,10mm for end mills usually. ER16 is pretty small so assume the machine is relatively small if this is the case 10mm may be on the big side of what it’s capable of. The collets I use with my machine are ER32 if your interested here’s a link to a tour of it czcams.com/video/IhoZlG0Rj64/video.html
Hello, I use ER20 for coiling proccess, so I have to insert both ends of the 2 metres SS wire/mandrel that is 27” OD into collets, tighten them with torque wrench and start coiling procces. The problem is that the mandrel is lined with a extremely thin wall liner that is very fragile and of course it gets damaged after being squished inside the collets, whats better to do? Will I try to apply some kind of protective sleeves on the ends of mandrel before inserting them into collets or maybe there is a rubber inlets or something to add into collets ID? Also my mandrel tends to slip off of the collet, so I have to play around and once it holds quicklu tighten with torque wrench. Thank you.
Hi Sandra, that’s an interesting setup, certainly beyond my experience but hope one of the viewers can assist you. One thought that comes to mind, is there a lot of tension in your coiling process or could you tighten the collets less to reduce damage to liner.
It certainly something we all want to know, not sure it helps when you know the answer. www.productionmachining.com/blog/post/whats-in-a-name-er-collet
Nope. They were invented by a company called Rego-fix, who made several changes and improvements to the already existing "E-collet". Originally they named their invention *E*-collet by *R* ego-fix, but that was too much of a mouthful for them, so they abbreviated it to *ER* collet.
Interesting question Alfonz, I can’t say I’ve tried it but the purpose of an ER collet is to run very true and give good side support. Adding a shim is counter productive to that. Another suggestion is to look at import collets which can be significantly cheaper than the brand name ones and true enough for the home workshop.
I guess I may be in 'toytown' here compared to your equipment! .............. I'm using ER16 collets. For use on a spindle motor on a CNC machine. I have a bizzar issue, and you may know ( or your viewers ) where the problem lies. My collets are all metric and I want to use a 6mm diameter milling bit. So I select my 6mm collet, insert it into my locking ER16-A collet nut ( as you've shown in your video ), and then 'try' to insert my milling bit into that collet ................. no go! the collet is now too small : ( There are 2 numbers on some collets, example; On mine I have '6-5' ............. I assume this means collet open = 6mm / and collet closed = 5mm ( the clamping force basically ). I tried the next size up, my 7mm collet has '7-6' written on it, I assume this means when it's open it's 7mm and when tightened it's 6mm ............... not on your nelly! it doesn't clamp down on my milling bit at all. So what's the answer? Anybody had this problem before? TURK
Your correct on the numbering it’s the largest if there is one number and the range if there are 2. I have had the same problem with some cutter and collet combinations as well, I think they are a little closer to tolerance than others. What I find works is to insert the cutter in the collet before placing in the holder. Hope this works for you, certainly don’t want the collet oversized they just want grip enough as you have found.
@@SS-Workshop Hi SS WorkShop .............. Yeah, tried inserting the cutter in the collet first then into the collet nut, no go I'm afraid! : ( It's obvious that by inserting the collect into the collet nut ( clipping it in ) as in your video, that simple action already compresses the collet ( 6mm collet in my case ), and as it's already under compression there's no way of inserting a 6mm cutter or bit of any type. I found a solution however! .............. Your viewers my be interested if they have the same issue as myself - First of all I must point out that these collets are not the 'top of the range' 'super precision' types ( very very expensive! ). Nor are these the very very cheap nasty BanGood types! I think it's safe to say that they are Amazon 'best buys' as they offer good value for money, quality OK, not too expensive. But not cheap either ; ) As we all know as 'machinists' ( term used very loosely in my case! ), cheap tools ( hand tools and even machines ) are usually not finished to a degree of high quality. Same goes for collets no doubt! I was looking very closely at the offending parts, I say 'parts' as it may be coming from the collet nut as well. And I noticed that the slits on the collet were not exactly the same to one another! I inserted a metal nail file ( that's about 1mm thick .......... same as the slit as it happens ), and there were burs inside the slits! So in some slits the nail file didn't fit and in others it did! Once all the slits were filed down ( toward the front of the collet, and not the rear of the collet ), I can now insert my 6mm collet into the collet nut, and then insert my 6mm milling bit ; ) Call me a scenic if you wish but, I truly believe that most of these collets are probably made in the same factory, the more expensive collets are usually manufactured first when the tooling is brand new, and the lessor quality collets ( cheap budget ones ) are the result of old blunt tooling that leave burs and many imperfections, that are later sold the cheap-skates such as myself! : ) Anyway, hope it helps somebody. At the very least you'll know not to just throw them out, just file em down or even sand them down to a better finish. TURK
For a 6mm drill/shank, use a 5-6mm collet. For a 5.1mm drill use same collet. Ok? NEVER use a 5-6mm collet on a 5mm shank. It's too close to the bottom limit of the collects closure. Chances are, the tool will spin.
@@neilwoodward7336 No such thing as a 5-6mm collet!? ............... my guess is that's a typo! That would mean a 5mm collet closing down to 6mm! And they don't make 5.1mm milling bits either! No, the solution is not buying cheap collets ( or collet sets ) from Amazon! they're garbage! even if you buy the 'expensive' types on Amazon. They'll still be garbage as they're made in China ............... not really known for their precision work are they! I finally bought a decent set of ( expensive, expensive to me ) collets from a company that specialises in engineering/tooling for machinists. Precise to 5microns! No more worries! ; ) "Buy cheap .................. buy twice!" TURK
@@t4concepts But they make drills from 5.00mm up to 5.99mm. Mister, the point is those collets grip and run true if they're holding within their range. We're not just holding end mills! Reamers, form tools, drills, slot drills.....etc.... And don't forget the range of sizes obviously accommodates metric and imperial. (1/2" = 12.7mm, 1/4"=6.35mm.... You get the point?
I just started milling and have an ER collet set, I genuinely beloved it was mismanufactured, this has answered all my problems!!
Well said and to the point, thanks so much for the tips. Better to learn before using them than learning the hard way!
exactly what I needed to know before using my new er32 thanks.
Saved my bacon. I've never used a collet set before and thought it was broken or a rubbish cheap rip off. But as you said, in the video, All I needed to do was clip the jaws into the nut first, but I didn't do that the first time around and got the jaws locked into the body. After a struggle, I got them out then followed your instructions, and now it works just fine. Thanks very much buddy.
Same here. This video saved me. I was on the edge of sending my new collet set back and leaving a withering comment.
Said in another way - i was on the brink of making a complete moron out of myself. But then i found this video.
All of my 19 collets are fine, the holder is fine and the wrench also. And all that for under 80,- €.
Thank you. Answered some simple but important questions I had
nothing new for me here, but i can imagine very informative for beginners. Well done!
Thank you for your excellent video , I like your style , easy and simple to follow
AWESOME! Thanks for doing this video. I couldn't figure out how to get that thing in right to save me. LOL Great info. I needed this.
great stuff, thanks from the US, Paul
What a timely video!! I recently purchased an ER collet set and was dismayed they did not seem to fit. The horror! Now your video shows up explaining everything and the world is in a slightly better place. Thank you and a joyous Christmas.
I’m glad it was of assistance, we have all been there and it’s hard to believe they don’t provide instructions for these things but for some reason they never do. Enjoy your collets and Merry Christmas.
Thanks for sharing... wonderful..
Thank you, very helpful
So glad I came across your video. It's answered all of my questions 👍
another day i learnt something cheers chap
Great to hear, cheers
Thanks excellent info
Nice info. I have an ER32 collet chuck for my wood lathe, my metal lathe, and my benchtop mill (when I get it), and I have a full set of SAE collets. These have been very handy when I have had to hold small diameter rod stock for either machining, or for holding a ring mandrel on my wood lathe.
Great video, as always. Bearing collet nuts also have less run out than a plain nut, great for reamers and drills.
Thanks, Great tip, one more thing I should know...
@@SS-Workshop I have some er collets that grip from the narrow end.
Do you know what these are called?
Excellent!
Dang, clip it in the nut first. Glad I clicked on you!
Nice video. Is there an English version?
Great video, I just recieved my ER32 collet, and block set, first time user. I want to be sure on how to use them properly, thanks to your video I can use them with confidence, THANKS
Good tips!!!
yes, thank you, why would anyone dislike this video? it was quick and simple, and helpful.
Great Video! There's one thing that I think belongs on that list though and that's that ER collets and clamping nuts wear out with use. This is less important with larger tooling but if you're using micro end mills (e.g. 1/32" and smaller) the nut and collet must be in good shape to have acceptable runout.
Great to know, thanks for sharing.
Everything wears out eventually. With high quality collets and chucks it’s only a problem for heavily used collets and chucks in high speed CNC machines, not for the home. Ok, some questionable info here. Look at the back of the collet to see how long the gripping length is. It’s not the full length on all sizes. The smaller sizes have shorter gripping lengths. Also, each collet has a gripping range. These aren’t R-8 or “C” style collets that can only grip the stated size. ER collets have the gripping range on the face of the collet, such as 5-6, 6-7, 7-8 in millimeters, or in 32” in inch. There are half millimeter sizing collets as well.
Love the tips brother, Just learning all this stuff, I like how you keep the videos simple and quick 2 Thumbs Up from me 👍👍
Thanks for the feedback, much appreciated.
Finaly I know what are the collet numbers refered to!!! 🙏
Good video. Also the nut should be torqued down with a torque wrench.
Fantastic video, came here with questions and left satisfied with the knowledge I have received. One more question though: How to chose between the different ER size offerings for a particular application?
Thanks, as far as I know it’s driven out of the size range you need as each ER size has a maximum and minimum size available in the collet range. This is limited by the shape of the actual collets. There is also increase strength in the bigger collets.
How to release end mill cutter from its collet? Its very hard to release after being used.
Nice video
Another thing that took me a while to figure out is how to take a collet back out of the nut after you've clipped it in, since the tapered shape makes it hard to grip (especially with little ER11 collets). Instead of trying to pinch and pull it straight out, push from the side to tilt the collet in a circular motion and it will ride up the surfaces in the nut and come right out.
Agreed, even with the larger ones they are puzzling until you know the trick for removing them. I found they would come out sometimes and not others and you really have no idea why until you understand how they work.
Getting it out, that's what I was looking for. Thanks... Even after I've read your entry, I still can't get the thing out... :(
Hatur nuhun kang 🎉😊
great video, I especially appreciated #1 as today I stumbled on it the hard way, figured it out could have done it more efficiently and confidentially if I had watched this first. Thanks
Thanks much appreciated, I think there are more than would admit that they have struggled with this, it’s just not intuitive.
good products
What type of fitting was on those collets to fit into the machine? It looks like Morse taper?
Yes, Morse taper 3 which is standard for this size benchtop mill in nz.
I just had to double check there ...................... for a second I thought I was on 'ClickSprings' channel! hahahahahahah ; )
TURK
What's the "ER" stand for? I have a set of ER32 and I use it all the time. Always wondered about the "ER".
They were developed from the E series collet by the Swiss tooling firm Rego-Fix and patented by them in 1973. The E series, which I believe are now obsolete, didn't have the circumferential groove in the collet nor the eccentric in the nut.
So ER started as a marketing name and became a widely recognised reference term.
The drop in collet nut is made for a "sealed collet" for a machine with through spindle coolant. The sealed collets don't have much flex. The standard spring collets just snap in.
Interesting, thanks for sharing.
My through tool coolant on HSS drills on lathe is actually coolant blasting through the saw cuts in collet lol
@@piter_sk Sometimes that's a blessing. I've used that trick several times to wash chips out of a milling cut when trying to mill a slot and not regrind chips.
@@Kaptn_Obvious actually with HSS drills, it´s the best way to get coolant to the cutting edge... it´s literally going down the flutes to the tip.... today, I was drilling 16.7mm hole like that, 0.12mm/rev feed and 550 RPM (which is between 20-30m/min recommended for HSS in mild steel).... the chips weren´t even slightly warm comming out of the hole...
so you need 12mm collet for 12mm endmill. can you help me.. Im looking to buy er11 for my spindle for pcb engraving. but all I could find are 0.5 to 3mm end mills all with 3.175mm shank. problem is all the er11a and er11 I could find only have 1, 2, 3, 4, 5, 6, 7 mm collets. so according to you none of them would fit a n end mill with a 3.175mm shank..
At the size you are looking at a 4mm will likely work without a problem, the issue usually comes when you use a 7mm collet with a 6mm endmill which is likely slightly under 6mm and outside the range of the collet. If you do have any trouble with them not gripping tightly or slipping the it looks like 3.175mm is the equivalent of an 1/8 inch so that would be the correct collet.
Late answer but ER collets also come in 0.5mm steps; 3.5mm ER11 collets are available from various manufacturers including Rego-Fix and Vertex; ER collets were originally developed by Rego-Fix.
You can buy 11 sets of just er16 collects, all of different hole sizes. But which ones do i really need. Do endmill shanks come in 11 different sizes.
Endmills only need a few sizes as the shanks are generally standard sizes, for metric 6,8,10,12... . The reason for having a bigger set is for work holding, such as in the lathe or with a collet block in a mill.
@@SS-Workshop so for er16 collet i only need size 6, 8 and 10mm.
You may also come across 4mm shank endmills for anything smaller than 4mm depending on the work you are doing, but other than that yes 6,8,10mm for end mills usually. ER16 is pretty small so assume the machine is relatively small if this is the case 10mm may be on the big side of what it’s capable of. The collets I use with my machine are ER32 if your interested here’s a link to a tour of it czcams.com/video/IhoZlG0Rj64/video.html
@@Z-add
Hi... to be honest it's probably best to have at least 2 collets of each size....
.5mm-1mm, all the way up to 9-10mm.
No, but drill bits do.
Hi, I wonder where do we use these ER collets? I'm engineering student
I never had a tool spin inside the collet. In fact I was taught to not tighten them overly.
👍👍😎
Hello, I use ER20 for coiling proccess, so I have to insert both ends of the 2 metres SS wire/mandrel that is 27” OD into collets, tighten them with torque wrench and start coiling procces. The problem is that the mandrel is lined with a extremely thin wall liner that is very fragile and of course it gets damaged after being squished inside the collets, whats better to do? Will I try to apply some kind of protective sleeves on the ends of mandrel before inserting them into collets or maybe there is a rubber inlets or something to add into collets ID? Also my mandrel tends to slip off of the collet, so I have to play around and once it holds quicklu tighten with torque wrench. Thank you.
Hi Sandra, that’s an interesting setup, certainly beyond my experience but hope one of the viewers can assist you. One thought that comes to mind, is there a lot of tension in your coiling process or could you tighten the collets less to reduce damage to liner.
آقا شما نباید برای محکم کردن مهره کولت ازگیره رومیزی استفاده کنی
یک هولدر مخصوص درست کن
For your nr 1 question. What did you think ER stands for ?
Excentric Ring.
It certainly something we all want to know, not sure it helps when you know the answer. www.productionmachining.com/blog/post/whats-in-a-name-er-collet
Nope. They were invented by a company called Rego-fix, who made several changes and improvements to the already existing "E-collet". Originally they named their invention *E*-collet by *R* ego-fix, but that was too much of a mouthful for them, so they abbreviated it to *ER* collet.
lets say i have 13mm collet and i need to use 12mm bit or 11 can i just put tin sheets around it and use it ? feels very tight and solid
Interesting question Alfonz, I can’t say I’ve tried it but the purpose of an ER collet is to run very true and give good side support. Adding a shim is counter productive to that. Another suggestion is to look at import collets which can be significantly cheaper than the brand name ones and true enough for the home workshop.
Never!
How many tpye er spring
i remember the day i found out there are A type and B type ER collets.. it wasn't a good day.
What's the difference?
Show us examples of work holding.
Great idea, seeing work holding setups is a great way to increase our options for future projects and even spur an even better one of our own.
AvE?
I guess I may be in 'toytown' here compared to your equipment! .............. I'm using ER16 collets. For use on a spindle motor on a CNC machine.
I have a bizzar issue, and you may know ( or your viewers ) where the problem lies. My collets are all metric and I want to use a 6mm diameter milling bit. So I select my 6mm collet, insert it into my locking ER16-A collet nut ( as you've shown in your video ), and then 'try' to insert my milling bit into that collet ................. no go! the collet is now too small : (
There are 2 numbers on some collets, example; On mine I have '6-5' ............. I assume this means collet open = 6mm / and collet closed = 5mm ( the clamping force basically ).
I tried the next size up, my 7mm collet has '7-6' written on it, I assume this means when it's open it's 7mm and when tightened it's 6mm ............... not on your nelly! it doesn't clamp down on my milling bit at all.
So what's the answer?
Anybody had this problem before?
TURK
Your correct on the numbering it’s the largest if there is one number and the range if there are 2. I have had the same problem with some cutter and collet combinations as well, I think they are a little closer to tolerance than others. What I find works is to insert the cutter in the collet before placing in the holder. Hope this works for you, certainly don’t want the collet oversized they just want grip enough as you have found.
@@SS-Workshop Hi SS WorkShop .............. Yeah, tried inserting the cutter in the collet first then into the collet nut, no go I'm afraid! : (
It's obvious that by inserting the collect into the collet nut ( clipping it in ) as in your video, that simple action already compresses the collet ( 6mm collet in my case ), and as it's already under compression there's no way of inserting a 6mm cutter or bit of any type.
I found a solution however! .............. Your viewers my be interested if they have the same issue as myself -
First of all I must point out that these collets are not the 'top of the range' 'super precision' types ( very very expensive! ). Nor are these the very very cheap nasty BanGood types! I think it's safe to say that they are Amazon 'best buys' as they offer good value for money, quality OK, not too expensive. But not cheap either ; )
As we all know as 'machinists' ( term used very loosely in my case! ), cheap tools ( hand tools and even machines ) are usually not finished to a degree of high quality. Same goes for collets no doubt! I was looking very closely at the offending parts, I say 'parts' as it may be coming from the collet nut as well. And I noticed that the slits on the collet were not exactly the same to one another! I inserted a metal nail file ( that's about 1mm thick .......... same as the slit as it happens ), and there were burs inside the slits! So in some slits the nail file didn't fit and in others it did! Once all the slits were filed down ( toward the front of the collet, and not the rear of the collet ), I can now insert my 6mm collet into the collet nut, and then insert my 6mm milling bit ; )
Call me a scenic if you wish but, I truly believe that most of these collets are probably made in the same factory, the more expensive collets are usually manufactured first when the tooling is brand new, and the lessor quality collets ( cheap budget ones ) are the result of old blunt tooling that leave burs and many imperfections, that are later sold the cheap-skates such as myself! : )
Anyway, hope it helps somebody. At the very least you'll know not to just throw them out, just file em down or even sand them down to a better finish.
TURK
For a 6mm drill/shank, use a 5-6mm collet.
For a 5.1mm drill use same collet. Ok?
NEVER use a 5-6mm collet on a 5mm shank. It's too close to the bottom limit of the collects closure. Chances are, the tool will spin.
@@neilwoodward7336 No such thing as a 5-6mm collet!? ............... my guess is that's a typo! That would mean a 5mm collet closing down to 6mm!
And they don't make 5.1mm milling bits either!
No, the solution is not buying cheap collets ( or collet sets ) from Amazon! they're garbage! even if you buy the 'expensive' types on Amazon. They'll still be garbage as they're made in China ............... not really known for their precision work are they!
I finally bought a decent set of ( expensive, expensive to me ) collets from a company that specialises in engineering/tooling for machinists. Precise to 5microns!
No more worries! ; )
"Buy cheap .................. buy twice!"
TURK
@@t4concepts
But they make drills from 5.00mm up to 5.99mm. Mister, the point is those collets grip and run true if they're holding within their range. We're not just holding end mills!
Reamers, form tools, drills, slot drills.....etc....
And don't forget the range of sizes obviously accommodates metric and imperial. (1/2" = 12.7mm, 1/4"=6.35mm....
You get the point?
the youtuber he referred to is AvE
Best advice... skip ER and go with an SK system.
well all of that was pretty much common sense as a tradesman. if you can't work that out you should not be anywhere near dangerous machinery
Another tip, you shouldn't be putting endmills in collet holders. They are designed for up force, not side force.
why would you take advise from a bloke with boogers all over his vise jaws