Using an ER11 collet chuck on long shank as a small drill extender

[mikey553]

Paul, both of my ER11 sets are in 0.5 mm increments. I also have ER25 in 1mm increments and ER32 in 1/32" increments. Although many ER collets can be clamped down to fully utilize their increments, doing so stresses the collets and the accuracy suffers. I prefer to use 6 mm collet for a 6 mm end mill although 1/4" collet would clamp a 6 mm mill just fine. Collets are ground when the slots are not completely cut through. After grinding they are split by cut-off grinding wheels or, in smaller sizes, by wire EDM.

For a 1 mm collet the slots cannot be wider than 0.3-0.4 mm near the bore, otherwise there would be little left from the bore. Bigger collets can afford wider slots. In theory the slot width is a limiting factor as to how much you can deform a collet to clamp smaller sizes. In real life however I would like to deform the collets as little as possible for the reasons stated above.

Circuit board drills with 1/8" shanks are widely available. They are very good tools, but they are very fragile since they are usually made from carbide. You need to run them as true as possible. HSS drills are much more forgiving, but they still need a good chuck or a collet.

[Fasturn]

Fasturn, I'm smiling, not laughing. For drills like that which are so lightly loaded holding the shanks in an aluminium holder would work fine. I think you'd be at more risk of bruising the holder with how you hold it on the other end. You're more likely to bruise the aluminium when you grip it in your big drill chuck.

Mikey, I saw your previous post and looked up some chucks on Amazon. I only found THESE 0.3 to 4mm CHINESE IMPORTS that come with a little brass adapter to permit fitting to a motor with a 1/8 shaft. Does this look anything like your Bangood chucks?

BC- you would be right with a drill chuck ( scrunching the tool ), but I use a ER-20 / R8 holder in the mill. Working small, I can use all the carbide endmills 1/8 and under + the PCB drills. Do alot if electronics and small stuff. Thank you for not laughing !! Cheers !

[DaveD44]

Mikey, I saw your previous post and looked up some chucks on Amazon. I only found THESE 0.3 to 4mm CHINESE IMPORTS that come with a little brass adapter to permit fitting to a motor with a 1/8 shaft. Does this look anything like your Bangood chucks?

That brings up a thought about something I've been needing for a long time, a small (short) drill or collet chuck for drilling, with a 3/8" shank that I can easily and quickly mount in a 3/8" mill holder on my Bridgeport mill, accommodating drill bits up to about 1/4". The standard R8-mounted drill chuck that I have adds four inches to the space between the head and the table, so I am constantly cranking the saddle up and down to accommodate. The reason for a 3/8" shank is because more often than not a 3/8" mill holder is mounted in the quill, as I use it for about everything, including most of the mill work that I do with the relatively cheap and very sturdy 3/8" mill, center wiggler, edge finder, coaxial indicator (itself a vertical space hog), laser finder, etc.

After seeing the Amazon link above I did a lot of looking but found nothing with a 3/8" shank, but many with metric sizes and a lot of 1/2" inch shanks. Any ideas about the best way to get to this?

[mikey553]

That brings up a thought about something I've been needing for a long time, a small (short) drill or collet chuck for drilling, with a 3/8" shank that I can easily and quickly mount in a 3/8" mill holder on my Bridgeport mill, accommodating drill bits up to about 1/4". The standard R8-mounted drill chuck that I have adds four inches to the space between the head and the table, so I am constantly cranking the saddle up and down to accommodate. The reason for a 3/8" shank is because more often than not a 3/8" mill holder is mounted in the quill, as I use it for about everything, including most of the mill work that I do with the relatively cheap and very sturdy 3/8" mill, center wiggler, edge finder, coaxial indicator (itself a vertical space hog), laser finder, etc.

After seeing the Amazon link above I did a lot of looking but found nothing with a 3/8" shank, but many with metric sizes and a lot of 1/2" inch shanks. Any ideas about the best way to get to this?

If you cannot find a 3/8" shank to buy, you can make one out of an old 3/8" tool, a dowel pin or a drill rod. I am talking about a drill chuck shank. 1/4" drill chucks are available from different sources.

[BCRider]

Dave, I'm in the same boat and I like the way you think! Lots of cranking to go back and forth from chuck to collets. I think a smaller chuck on a short 3/8 or 1/2" stub (or even one of each?) to fit the collets is a grand idea which I'll be following up on myself as well.

I don't think we will find a chuck like that with a suitable arbor on it right out of the package. But in checking on Amazon I found a lot of them that come with multiple threaded arbors like THIS ONE. It would be pretty easy to check the threads on the arbors and turn up a single point threaded arbor with a 3/8 straight section. Heck, if you're using a Weldon style set screw holder even with a flat on it to take the screw.

I just checked after the "EUREKA" light went out from reading your idea and my Bin'O Drill Chucks happens to have a 1.5 to 10mm chuck off an old hand drill. The thread size for it is 3/8-24 for this one. The old standard was the 3/8-24 like on my chuck. But this one is about 20 or more years old. The new ones might well be 10mm fine threaded. But it'll be easy enough to check the threads on the supplied arbors.

In my case I flip flop back and forth between 1/2 and 3/8 collets about half and half. I may have to pick up an extra chuck just because you KNOW that as soon as I commit to one size I'll need the other one or have to swap collets....

[mikey553]

Dave, I'm in the same boat and I like the way you think! Lots of cranking to go back and forth from chuck to collets. I think a smaller chuck on a short 3/8 or 1/2" stub (or even one of each?) to fit the collets is a grand idea which I'll be following up on myself as well.

I don't think we will find a chuck like that with a suitable arbor on it right out of the package. But in checking on Amazon I found a lot of them that come with multiple threaded arbors like THIS ONE. It would be pretty easy to check the threads on the arbors and turn up a single point threaded arbor with a 3/8 straight section. Heck, if you're using a Weldon style set screw holder even with a flat on it to take the screw.

I was always under impression the threaded drill chucks are for hand held tools and Jacobs taper chucks are for industrial applications on machine tools. A cylindrical chuck arbor is easy to make, I would concentrate on finding a good chuck or two in the size you want.

[BCRider]

Does it really matter if it's threaded or not? As long as the chuck ends up concentric I don't see any harm.

You're not wrong in that the hand drills typically come with threaded chucks. But that doesn't mean we can't re-purpose them.

[mikey553]

If you have a good threaded chuck, use it. All my chucks for mil and lathe are Jacobs taper. In my understanding the taper attachment is far superior to a thread if the accuracy is concerned.

[JRouche]

The 1/2" DA chuck I offered you is best at drilling, not milling. So I get why you declined.

Funny part about the DA line of collets, which I have. They carry a wide range of collets also. The 1/2" shank is most popular. All sizes. Oh well.. JR
PS>
All my stuff posted here is feebie. Anyways will be. JR

[DaveD44]

If you cannot find a 3/8" shank to buy, you can make one out of an old 3/8" tool, a dowel pin or a drill rod. I am talking about a drill chuck shank. 1/4" drill chucks are available from different sources.

I just checked after the "EUREKA" light went out from reading your idea and my Bin'O Drill Chucks happens to have a 1.5 to 10mm chuck off an old hand drill. The thread size for it is 3/8-24 for this one. The old standard was the 3/8-24 like on my chuck. But this one is about 20 or more years old.

Mikey and BCRider turned on a light for me, and I dug out my old Makita drill with its 3/8" Jacobs chuck, 3/8x24 attach. I repurposed it and made an adapter out of half inch drill rod, so as to have a shoulder for the chuck to seat on. It was a quick project and the chuck when mounted in a 3/8" ER mill holder shows no visible runout. It would satisfy my objective, except:

First, the smallest drill bit that this chuck will accommodate is 1/16". And that appears to be the case with most of the chucks of this type available on Amazon. I found a single keyless chuck that goes way down, but it appears to be quite a bit larger, and not cheap. I do a lot of work with tiny drills, down to about wire size 80. I don't expect any chuck to work with a drill that small and I use a pin drill vise in the drill chuck today for that stuff. But it needs to go smaller than 1/16. Second, including the ER mill holder, it saves just over an inch over the large drill chuck with its JT taper R8 adapter . That isn't enough of a savings to bother with.

So it looks like I may need to go with an ER11 collet setup if it is overall shorter, and I have a couple questions about that; hopefully someone who has one can provide some answers. First, are the ER11 collet chucks hardened at the top end or could they be easily machined to adapt to or include a short 3/8" extension? Second, how much length will the chuck have to retain to be usable. I don't need the wrench slot above the holder, as I can change collets (I believe) by holding the unit with the spindle brake, so my objective would be to take off as much as possible. Part of this has to do with how far into the chuck the ER11 collet recess goes. Finally, I read, probably somewhere in this thread, that the 1mm collets, the cheap versions available on Amazon, don't go much if any smaller than 1mm, or around 0.039".

Thanks for the suggestions and any further help.

Photos of my little Makita chuck with its 3/8" adapter follow.

[DaveD44]

The 1/2" DA chuck I offered you is best at drilling, not milling. So I get why you declined.

Funny part about the DA line of collets, which I have. They carry a wide range of collets also. The 1/2" shank is most popular. All sizes. Oh well.. JR

I did a quick look at the DA collet line and they appear to take more vertical space and are generally expensive. Plus, a multipage thread in this forum compared the ER to DA lines and the responders were almost unanimous in their opinion that the ERs are superior. See the link.

[mikey553]

Dave, I have attached a couple of pictures of my ER11 holder and 0-4mm drill chuck, installed on the DC motor. The smallest ER11 collet (1 mm) would not hold a no. 80 drill (about .3 mm), but the drill chuck would. The drill chuck is bigger in diameter and longer then ER11 holder business end, but we are talking about 1/2" difference. Is it that critical for you?

I think most of the ER holders would be heat treated to around 40-50 HRC, which should be very much machinable on a lathe with carbide tolling. But I think a small drill chuck is your answer. The chuck on the picture has No. 0 Jacobs taper bore (about 1/4" in diameter). You can make a cylindrical arbor and hold it in a R8 collet very close to a spindle. I bought my chuck from Banggood a few years ago. Actually I bought 5 of them very inexpensively, but only one of them was good enough for small drills.

[DaveD44]

Mikey, thank you for some informative photos. The best solution to the space problem is one of these two. I will start with the ER11 solution since the collets are less than 3/4" long, which means the chuck is probably not much deeper, if at all, since the nut covers part of the collet. So I have ordered a short collet chuck with an 8mm hole and will cut it as short as I should and press an 8mm-3/8" stub into it, truing the hole if necessary with my Dumore tool post grinder. I should be able to make the 8mm stub pretty short since it will never see radial loads, only axial, and never much of that. Perhaps 3/8" is all that is needed, which will put the whole assembly that is outside the end mill holder around an inch long.

If that doesn't work, well, Amazon returns are easy and the stuff is cheap; quality is not so good on the average. Then I'll try your other solution. The LP chuck is really inexpensive and I found one JT0 to 3/8 arbor at $10, but not Prime and with shipping that is more than the price of the arbor. (I really hate to pay shipping, so will hold off on this one until I determine that the ER11 won't work.)

I will update this item with my results.

Thanks again for all the ideas!

[mattthemuppet]

I've got an old 1/4" Jacobs chuck you can have for shipping. I had a 1/4 and a 3/8" chuck on threaded to 3/8" straight arbors that I made on the lathe. They're very useful on the mill, though most of the time I just use a different collet on my ER25>R8 chuck.

If you're making a threaded arbor you can turn the threads, collar (registers against the back of the chuck) and shank in one go, so it'll be as accurate as it can be.

[DaveD44]

I received my collet chuck and set of collets, from 1.0mm to 7.0mm along with a 1/8" and 1/4". I made a quick adapter 8mm to 3/8" for my end mill holder and cut perhaps 1/2" off the collet chuck to make it shorter, then pressed it in. The 8mm hole is ground and true to the chuck. I left most of the wrench flat on the flange, and I do need it. The chuck appears to have just a little runout, perhaps 0.0005 total, but it's hard to tell because the adapter I made is off a bit also. (If all this works out I will make another adapter in a single setup and use my Dumore tool post grinder to get it to a good 8mm press fit into the chuck and exactly .375 for the end mill holder.)

The collets, with the exception of the 1.0 and 1.5mm, are very accurate, with at most as little runout as needed for mounted drill bits to hit a center punch mark and drill without fear of breaking because of excess runout. I checked minimum and maximum drill sizes in each and they adequately cover the entire range from about #53 (0.0595) to size M (0.295). I didn't check the small supply of metric drill bits I have. But the 1.0 and 1.5mm collets are complete garbage. Part of the problem with these, and with the remainder up through 2.5mm, is that the bore only goes through about 1/4" to .4" of the collet, after which the collet bore expands. Additionally, the two smallest collets have fewer faces, four actually, and the bores feel rough when inserting a drill bit.

So what I might do is try to find individual collets in the .5, 1.0, and 1.5mm sizes.

. . . CTC Tools are good! No free shipping & a couple weeks shipping time but their stuff is very good and worth the wait. Their precision collets are reasonaby priced as well.

Dickey, are those smaller collets accurate? I see that CTC tools has a .5mm collet and that their photo of their set that includes the .5, 1.0, and 1.5mm collets show these collets with six faces against the bore. Is that so? CTC is a Hong Kong-based company, so these collets may be the same Chinese products that are on Amazon. Where do they ship from and what is the shipping cost?

Some photos: The ER11 collet setup is more than 1.1" shorter than the Jacobs chuck setup, so that pretty much satisfies the requirement for a shorter setup.

For those like me who aren't already familiar with the ER11 collet, they are really tiny. The setup in the 3/8" end mill holder can be compared to the photo I included earlier with the Jacobs chuck.

So, if I can get some good quality smaller collets, I will consider this solved. If not, I may also get Mikey's JT0 chuck.