Collet closer

This is a lever operated collet closer I made for my 7x10 mini lathe. I copied from pictures of different models but made it smaller and for 3C collets. It can open and close with the lathe running and works great with my bar feeder.

Like many older designs it pulls the collet into the spindle to tighten it, with the lever mechanism at the far end of the headstock. The collet seats in a MT3-to-3C spindle adapter from Little Machine Shop, and the drawtube screws onto the collet and passes through the spindle, supported by a bushed adapter screwed onto the rear spindle threads, replacing the bearing jam nut.

The lever shifts a cam to spread three lever fingers that press against the end of the spindle and pull the collet into the spindle nose. I think like old Royals, and the Rovi shown below, the cone-shaped working surface is on the outside of the cam, and it has flats at both ends of the cone to limit the motion of the fingers and prevent it from releasing itself. Clamping force is pre-set by screwing the drawtube into the the collet and then locking it with a dog point set screw in one of the slots in the rear spindle adapter.

It has been reliable so far - I haven’t made very many parts with it but hopefully it will be durable enough for my purposes. The drawtube is a piece of 1/8” wall 1/2” mild steel DOM tube but many of the rest of the parts are harder steel and bronze.

Attachment 27841 Attachment 27842

main view with guards removed; closed and open

Attachment 27843 Attachment 27844

shell guard tapped for the indexing screw and the slots that goes in; rear spindle adapter with closer removed

Attachment 27845 Attachment 27846

most of the parts before it was completed; some unused and undrilled fingers

Attachment 27847 Attachment 27848

Attachment 27849

Here is a very short video showing the collet in use, with it opening to let work feed up to a stop.

https://www.youtube.com/watch?v=55nNvSSKIWQ

threesixesinarow,

That is very, very nice workmanship on the collet closer. I am impressed! The lever style collet closer is indispensable for repetitive work. I had a 5C lever collet closer similar to this a few years back and loved it.
Thank you for sharing with us.

Thanks, Dick,

It’s very useful and fast for specific tasks - for me, anyways - I tried to make more than a handful of multiples using a 3-jaw chuck, once! But it’s limited and slow for more general stuff, so I pieced together a second mini lathe so I don’t have to remove it to use regular chucks.

The hardest part was making the lever fingers and the hub for them. I think some closers have two of those instead of the three I used (I think Schaublin, and even the the little Petermann automatic screw machine shown at lathes.co.uk)which might simplify things a lot.

I see Sherline sells a 3C lever closer now. https://www.sherline.com/product/302...r/#description I’m not sure but it looks like it works like the old South Bend one using modified ball thrust bearings instead of fingers for leverage from the cam.

- Clark

threesixesinarow,

I just found the plans you sent me over a year ago. I knew I had seen them before. Thanks!

threesixesinarow,

Clark,
Do you happen to know who makes the lever collet closer that uses the ball thrust bearing method?
I know my Logan used the three fingers.

Of all methods to operate collets, a lever is best. Against pneumatic, handwheels, or pinion gears, only the draw tube and lever can detects oversize/ undersize parts.

ive been meaning to make a 5c one of these or modify one to fit my 9x20 , I do have a collet chick thats supposed to be stationary and had a handle that I could remove and add smaller lever that would work or just a wrench,the same unit Ive seen for mounting on lathes so I know it will do it. or I could shell out $140 for a new 5c chuck....but not in a big hurry I wish there was some octagon 5c collet blocks like the er collett blocks and had a nut on the end pushing agnist the collett instead of the 5c type with the closer on the end or the round nut on the rong end pulling the collet. but thats me Im kinda different.

Quote:

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Originally Posted by old_toolmaker

threesixesinarow,

Clark,
Do you happen to know who makes the lever collet closer that uses the ball thrust bearing method?
I know my Logan used the three fingers.

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I’ve only seen the oblique parts list drawings for the ball ones. I think this South Bend works that way.

Attachment 27908

I wonder if along with modified thrust washers you could use a tapered roller bearing cup for the cam.


Here are some of the two-finger designs I remembered - Brown & Sharpe, Gorton/Petermann, and Schaublin.

Attachment 27909 Attachment 27910

Attachment 27911

Quote:

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Originally Posted by marksbug

ive been meaning to make a 5c one of these or modify one to fit my 9x20 , I do have a collet chick thats supposed to be stationary and had a handle that I could remove and add smaller lever that would work or just a wrench,the same unit Ive seen for mounting on lathes so I know it will do it. or I could shell out $140 for a new 5c chuck....but not in a big hurry I wish there was some octagon 5c collet blocks like the er collett blocks and had a nut on the end pushing agnist the collett instead of the 5c type with the closer on the end or the round nut on the rong end pulling the collet. but thats me Im kinda different.

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I looked up 5c collet blocks a while ago, hoping they might be more practical solution than making something from scratch. I didn’t find ones that were suitable for working with long bars - the affordable ones seemed to use nuts threaded onto the collet that then clamped it with a lever cam that blocked to bore - but didn’t really know what to search for.

I did see a video where someone fitted one of those key operated, nose mounted 5c collet chucks to a mini lathe - it looked like it stuck out about 5” from the end of the spindle!

I would rather install an ER chuck than that, I use those on my smaller lathe. You could make a lever closer for them, too - but something with a big hand tightener like a Rubberflex chuck might be a lot more useful.


This video about Kiyoshi Kato’s workshop that produces “Space man” pens has one of my favorite collet closer designs, first shown in operation about a minute in.

https://youtu.be/SByOoh2XK6c

threesixesinarow,

Clark,
Thanks for the schematic drawings. That will sure help me while I search and think things through.

This might be useful even though it’s not for collets - I looked at mechanical stuff before settling on electric methods for mine, this is a clutch from a nice countershaft drive designed for a watchmakers lathe.

Attachment 27918

The instructions on the page for that Sherline closer I linked before include schematics, too.

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Thanks threesixesinarow! We've added your Collet Closer to our Lathe Accessories category,
as well as to your builder page: threesixesinarow's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-collet-closer-4"> <img src="/uploads/220641/homemade-collet-closer-4.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-collet-closer-4">Collet Closer</a> <span> by <a href="http://www.homemadetools.net/builder/threesixesinarow_2">threesixesinarow</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/lathe'>lathe</a>, <a href='http://www.homemadetools.net/tag/collet'>collet</a> </div> </div> </div> </div>
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hey tripple 6 the 5c collet blocks unse either then nut or the collet closer lever, not both at the same tyme. yes they would be great if they had a nut like the er or a nut like the rubberflexey ones, Ive used all three and the std lathe closer.as well as the 5c hex&square collet blocks&nut on the back or lever . buying a collet closer isant a issue for me as far as $ go's, the wife lets me buy whatever toys I want....but my lathe 9x20 enco has the small bore like 15/16, ( yes I know I need bigger lathe...but it is a bigger lathe!!! the 7x14 is right beside of it!! So ill have to make some parts to fit a exzisting unit to my lathe. ButI dont mind using a small collet block if it will do what I need,, Ill probably just end up getting a er 40 block & collets,why not I already have er11,16&32 sets..... or just get a 5c collet chuck...witch is probably the best thing to do for me.I cant run any thing big through the spindle any way....I kinda went brain dead when I get the er 32 and not the er 40 set.....the er32 stops just shy of where I need.....I do have some nice steel front hubs off my brothers 2012 dodge truck I may remachine to fit some collets into..... I ALSO HAVE WAY TO MANY THINGS BOUNCING AROUND IN MY HEAD... I love making my tooling&jigs but sometimes my brain gets in the way. KEEP UP THE GREAT WORK GUYS!!!! ( just what I need more great stuff in my over flowing head) Ive been buying reamers and diamond hones lately and my head hurts from that..crossing this hone stone to that stone..and charts that seem to defy reason....and look rong...

This is the 5c collet block lever closer I didn’t think would be useful for my purposes - I guess the collet screws into a short drawtube but I don’t know what to call the different parts.

Attachment 27930

What you described seems more versatile, but 5c and the parts that go with it is too big to use on my machines. Most of what I would hold in collets is smaller than 7/16” anyways, which combined with a 3mt spindle makes 3c a better choice.

The Sherline 3c lever closer wasn’t available when I started making mine. It looks like there are a few used ones for different lathes on Ebay right now for reasonable prices - I don’t remember if I didn’t consider adapting those because it seemed too difficult, or if there were fewer or prices were higher. At any rate, my home made one won’t do anything those can’t do, and won’t last as long.


Here’s a better drawing I found of the South Bend closer.

Attachment 27929

thats 2 blocks, 2 closer nuts to tighten the collet closed, and the 1 leaver closer, witch is manily used for milling machine & grinder opps. the nuts usualy have a few hole's in them to tighten with a peg/shaft like whats used when removing screw on lathe chucks.. I supose if you had long jaw chuck you could use the lever type but probably not a good idea. I need .830~875 currently so the small collets wont do for me. I get new ideas every day. my brother has er40 collets&blocks and 5c blocks I may try his to see if I like it before I decise on weather to buy a $40.00 set or make something. or buy a $85. set of er 40's.with r8 chuck. I wish somebody made a hex r8 block....I may just have to make a round r8 chuck for my lathe.

threesixesinarow<

I looked at the Shereline collet closer and it appears to be nice and compact. It is a little hard to envision how it functions though.
Even though I owned the Logan collet closer for many years I never took it apart to see how it functioned. I guess I will have to study the drawings a little more and maybe the light bulb will come on for me.

same with me,if it was worken good why reapir it...so I never got inside of one either.and that was 21 years ago... about all I remember was it was all flopy...looked like it was made out of some bearing races.I dont know if it was bought or made. in my head Im seeing something like a syncroizer for a manual trans for a car.to hole it open or closed..but probably not.as I have so much stuff rolling around in there ( my head)things seem to get morphed before they get out.

Quote:

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Originally Posted by marksbug

same with me,if it was worken good why reapir it...so I never got inside of one either.and that was 21 years ago... about all I remember was it was all flopy...looked like it was made out of some bearing races.I dont know if it was bought or made. in my head Im seeing something like a syncroizer for a manual trans for a car.to hole it open or closed..but probably not.as I have so much stuff rolling around in there ( my head)things seem to get morphed before they get out.

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Both you and old_toolmaker are close to the function. The gear 'syncronizer' is a cog, the teeth engage a lever to hold rotation of drawtube screwed into collet body, how you set the amount of pull [diameter] and attendant tension. The lever, essentially duplicates the throwout lever and bearing on a conventional manual transmission, with collet sort of acting as GM style diaphragm pressure plate.

marksbug, I emailed you through HMT.net offering a drawing. Goes for you too, old_toolmaker. You might be older than me..."51" hasn't anything to do with my age! Hereabouts most call me TM51...

Going by the drawings and the steps they suggest and what parts could be bought in I would make a ball one now. The yellow South Bend drawing I posted yesterday makes the mechanism pretty clear, here’s a photo, also from practicalmachinist.com, https://www.practicalmachinist.com/v...9/#post1859229

I’m curious if there are problems with them, though, I wonder why they aren’t more common compared to the finger ones.

threesixesinarow,

I am getting the picture now! The the single finger on my Logan collet closer was manually engage to hold collet position from rotating. The yoke was engaged and went slightly over center to lock. It was a very positive system.
I still need to study the ball system further to determine its pluses and minuses.

THANK YOU!!!! we all get different ideads from others ideas and thats what evolution is all about. and it keep us trying to make a better mouse trap. I remember one shop I ran&programed cnc mills and much more we had as old band saw, a big one I think it was a meat saw at one time.but it had a 4 speed volvo trans mission running it.oh so eazy to change speeds when you needed too with no fuss at all. I presume it only had 1 speed as a meat saw. I remember long ago in okanawa japan growing up with motorcycles and gocarts, when we needed something different to finish a build we just fired upo the big hibachi groll ( basicly the big green egg but 35 years before the big green egg) and we would make what we needed with whatever we had...Ive addvanced a bit since then but still love making things .and seeing other peoples stuff just adds to the brain power for all of us. remember there is always a better way.

These are less interesting, but still useful parts of it.

The first picture is to show the sleeve with a couple flats that unscrews from the spindle guard to release the 3c adapter. I made it soon after the first time swapping from collets back to a regular chuck. I also figured out pretty quickly using it that I needed a splash guard, but didn’t spend as much time on that.


Attachment 27990 Attachment 27991

threesixesinarow<

Thank you for the pictures. They are most helpful.

Quote:

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Originally Posted by threesixesinarow

Going by the drawings and the steps they suggest and what parts could be bought in I would make a ball one now. The yellow South Bend drawing I posted yesterday makes the mechanism pretty clear, here’s a photo, also from practicalmachinist.com, https://www.practicalmachinist.com/v...9/#post1859229

I’m curious if there are problems with them, though, I wonder why they aren’t more common compared to the finger ones.

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One time I made new 3 piece finger sets for a worn collet setups where I worked. I don't remember if they were chuckers, screw machines, or multi spindle. They were sawn from A2 and milled into shape, no CNC all rotary table and indexer. I bet ball operated closers outnumber finger closers for that very reason. High quality Class 7 balls; easy OEM procurement, accurate size and form, perfect heat treat, and replace when time comes. Another plus is engineering factor, more compact. I suspect fingers are preferred for mechanical advantage of leverage; bigger lathes, bigger material, heavier cuts.

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Thanks threesixesinarow! We've added your Chuck Guard to our Lathe Accessories category,
as well as to your builder page: threesixesinarow's Homemade Tools. Your receipt:

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hi,
do you all have any plans for a ball bearing version?
thanks,
matt

Quote:

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Originally Posted by whitehouse260

hi,
do you all have any plans for a ball bearing version?
thanks,
matt

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Hi, Matt,

I don’t - I’d like to see them, too, if someone else has them.

I don’t know how much this will help, but up the thread there’s a couple drawings for a South Bend that might make a good start toward making one, combined with the photos at Practical Machinist. That works like an inside out version of the watchmaker lathe clutch shown on the second page.