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Need help understanding differences between collets: ER32 vs. ER24, ect.
- Thread starter TacticalAnt
- Start date
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- Aug 22, 2012
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- 4,116
I did have a full report of how I made my ER 25 Collet holder for my 9x20 lathe but cannot seem to find it here anymore.
It was relatively easy considering I had only had 2 years experience owing a lathe with zero training.
I first cut the 39mm x M4 thread to fit the spindle nose in a chunk of steel.
Then screwed in onto the spindle to turn down and cut the external thread.
Then I set the top slide/compound to the angle to taper bore the inside to fit the collets.
No pics for this unfortunately but by doing it on the spindle I assumed it would run true which in practice it did.
Heres the finished product
Removing and replacing the holder on the spindle shows no measurable difference, removing and replacing the collets also the same.
Repeatability is around 0.00125" which is way superior to the three jaw chuck.
Also long bars can pass through.
Well worth doing.
It was relatively easy considering I had only had 2 years experience owing a lathe with zero training.
I first cut the 39mm x M4 thread to fit the spindle nose in a chunk of steel.
Then screwed in onto the spindle to turn down and cut the external thread.
Then I set the top slide/compound to the angle to taper bore the inside to fit the collets.
No pics for this unfortunately but by doing it on the spindle I assumed it would run true which in practice it did.
Heres the finished product
Removing and replacing the holder on the spindle shows no measurable difference, removing and replacing the collets also the same.
Repeatability is around 0.00125" which is way superior to the three jaw chuck.
Also long bars can pass through.
Well worth doing.
- Joined
- Oct 31, 2016
- Messages
- 2,645
Here is the link to the thread where I describe how I made my ER32 collet chuck No excuse not to make an er32 chuck for the lathe | The Hobby-Machinist (hobby-machinist.com)
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- Oct 29, 2020
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- 13
This has really helped. The video was great, especially the plywood animation at the end.
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- Nov 14, 2016
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- 3,004
ER32 is the most popular size, of ER collet so you can find many more options for it. I have ER32 collet blocks, and an ER32 spin indexer. You can find collet blocks in a few other sizes of ER, but not many. I have not seen any other ER collet size available in a Spin indexer, and until recently you could only get them from 5C collets. Individual ER32 collets are also significantly cheaper than ER40 or ER 50 collets.
ER40 and ER50 of course have the advantage of being able to hold larger stock.
5C collets have more options available, other than round shapes (I have seen square and hex for ER32 but they are rare, but easy to find for 5C), collet blocks, various indexers etc but they have a very narrow holding range compared to ER collets, so you need many more 5C collets for a complete set.
Of course you don't actually have to have a full set, you can just get the sizes you need, but if you need to hold something just a little bigger or smaller than what you have, there is little room for variance.
Apparently 5C collets hold one end of a work piece better than ER collets which need the piece to pass through the full length of the collet for a secure grip. So if you want to hold a part only 1/2" long an ER collet is not your best choice.
Don't look at collets as something to only have one type of. I have ER16, ER32 and ER50 collets and chucks, as well as WW watchmakers collets for holding very small parts. The ER16 chuck is only about 1/4 the size of my ER32 collet chuck and handy for small parts. My ER32 collets are my go to collets, I have collet blocks that fit them, a spin indexer than fits them, and the widest range of sizes of all my collets. The ER50 collet chuck is much larger than the ER32 chuck so will only fit my larger lathe (the chuck is bigger around than the swing of my Sherline), but I only have 4 or 5 collets for it, because they are not cheap, so I only have the sizes larger than 3/4" (the largest size collet I have in ER32).
ER40 and ER50 of course have the advantage of being able to hold larger stock.
5C collets have more options available, other than round shapes (I have seen square and hex for ER32 but they are rare, but easy to find for 5C), collet blocks, various indexers etc but they have a very narrow holding range compared to ER collets, so you need many more 5C collets for a complete set.
Of course you don't actually have to have a full set, you can just get the sizes you need, but if you need to hold something just a little bigger or smaller than what you have, there is little room for variance.
Apparently 5C collets hold one end of a work piece better than ER collets which need the piece to pass through the full length of the collet for a secure grip. So if you want to hold a part only 1/2" long an ER collet is not your best choice.
Don't look at collets as something to only have one type of. I have ER16, ER32 and ER50 collets and chucks, as well as WW watchmakers collets for holding very small parts. The ER16 chuck is only about 1/4 the size of my ER32 collet chuck and handy for small parts. My ER32 collets are my go to collets, I have collet blocks that fit them, a spin indexer than fits them, and the widest range of sizes of all my collets. The ER50 collet chuck is much larger than the ER32 chuck so will only fit my larger lathe (the chuck is bigger around than the swing of my Sherline), but I only have 4 or 5 collets for it, because they are not cheap, so I only have the sizes larger than 3/4" (the largest size collet I have in ER32).
ER is a good general choice for work holding. If your objective is to compliment your other chuck types then you only need an ER size for the smaller work diameters that your other chucks might not handle as well. In my case the ER 32 collets of 1/2'' or less get used the most. Unless you have a specific purpose for getting larger ER collets, bigger is not necessarily better but it is certainly more expensive.
I would not buy or make an ER chuck for the lathe that does not have a pass through capability. An MT4 chuck would work well for tool holding but it would seriously limit work holding to short pieces.
Making your own ER chuck is not as difficult as it might seem. Buy the nut but make the body of the chuck as many others have done.
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- Apr 26, 2014
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I made a pass-through ER-32 collet chuck for my Boxford VSL500. This lathe has an L00 spindle, with 1-3/8 bore and a Jarno #13 internal taper (I know most people find the L00 VSL's with MT 4-1/2 bores, but mine is definitely Jarno #13!) 
The ER-32 collet and nut are on the right - they were purchased from Techniks and are excellent (around 0.0003 TIR). The chuck body is second from the right, Jarno #13 outer taper, ER-32 on the inside. Made this from a drop of 4130. Turned the tapers using the compound - the nice thing about a collet chuck is that you can start the part a little long and keep working the tapers until they fit well. If they don't, adjust and try again, the body just gets a few thousandths shorter
.
I ground the tapers using a Foredom handpiece mounted to the toolpost (one of several sub-projects that this collet chuck project spawned) You can certainly get a functional holder by turning only, but I was trying to see how well I could do. The two little punch marks were aligned with the outer key on the L00 spindle and for visual alignment only. This is a big advantage if you make the collet holder on the same lathe you will be using it on - near 0 runout of the chuck itself, at least until you drop it, heat it up, or actually use the thing! I don't have hardening capabilities so this will probably wear as time goes on.
The chuck body is bored through about 7/8", so it will take anything an ER-32 can pass, and the drawbar tube is about 1-1/8 ID, so plenty big. I tapped the inside rear of the collet body to accept collet stops. There are three of these shown of various configurations.
The design was inspired by one I saw from Mark Frazier here a long time ago, someone who used to be an old-timer here. He has a lot of his projects in the member projects section, and does impeccable work vs. my hacking.
The ER-32 collet and nut are on the right - they were purchased from Techniks and are excellent (around 0.0003 TIR). The chuck body is second from the right, Jarno #13 outer taper, ER-32 on the inside. Made this from a drop of 4130. Turned the tapers using the compound - the nice thing about a collet chuck is that you can start the part a little long and keep working the tapers until they fit well. If they don't, adjust and try again, the body just gets a few thousandths shorter
.I ground the tapers using a Foredom handpiece mounted to the toolpost (one of several sub-projects that this collet chuck project spawned
) You can certainly get a functional holder by turning only, but I was trying to see how well I could do. The two little punch marks were aligned with the outer key on the L00 spindle and for visual alignment only. This is a big advantage if you make the collet holder on the same lathe you will be using it on - near 0 runout of the chuck itself, at least until you drop it, heat it up, or actually use the thing! I don't have hardening capabilities so this will probably wear as time goes on.The chuck body is bored through about 7/8", so it will take anything an ER-32 can pass, and the drawbar tube is about 1-1/8 ID, so plenty big. I tapped the inside rear of the collet body to accept collet stops. There are three of these shown of various configurations.
The design was inspired by one I saw from Mark Frazier here a long time ago, someone who used to be an old-timer here. He has a lot of his projects in the member projects section, and does impeccable work vs. my hacking.
- Joined
- Oct 29, 2020
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- 13
I think I will go with an ER32 or 40 collet block. 4 side and 6 side. I like the simplicity, and inexpensive aspect, plus can use it for some simple indexing for drilling and grinding. Right now the project calls for Micarta rod with non critical runout.
I definitely like the idea of Machining my own chuck, and have gotten some really good guidance here toward that.
I definitely like the idea of Machining my own chuck, and have gotten some really good guidance here toward that.
- Joined
- Jun 26, 2018
- Messages
- 1,733
I have an odd one...so I just purchased this twist drill/end mill sharpener. I added on of my 1/8" ER20 to the set that came with it, so I need to look closer at it and maybe have @Buffalo21 take a look at his unit that uses the same. At least one for sure seems odd. If I'm not mistaken (and I'm 99% sure I'm not) but the wide end and tapered end should be relatively the same size (hole)? I have at least this one that appears to be, going off memory, about 2mm at the tapered and and maybe 11mm at the wider, flat end. That's not right....right? I'll grab my phone and post a pic in a moment. Weird. Even if it's one I added to the set, WTH would this be good for?