# Seeking dimensions: 10L Lever Collet Closer



## SCLead (Aug 7, 2018)

My lathe came with a lever type 5C collet closer and spindle adapter, but it's unfortunately not the SB closer, nor is it set up for my lathe. The draw tube is threaded for 5C collets, and the spindle adapter is 5C as well, so I think I'm going to modify the closer I have to fit the machine. I'm looking for a couple dimensions to help me down my road, so I'm hoping somebody here has one knocking around the shop. If anyone can provide photos of one mounted on a machine, that would help even more!


I understand I need a new extended gear to mate to the draw tube "drive." I suspect this might have to be matched to the closer I have, and a stock gear may not work for me. I don't currently have this gear, so I plan to cut one myself eventually (first hack at gear cutting, why not!) I am curious to see how the draw tube actually interfaces to the gear extension, as well as how the extension fits through the gear cover. I've read some folks have issues with gear covers clearing the extended nut, so I"m curious if I should expect similar issues.

The lever arm that connects the closer mechanism to the machine itself is a mystery to me. I have a pretty good idea how it connects and where, but I haven't found any images of the factory closer mounted to know if I'm even in the right ballpark. Assuming I can make it work, a center-center distance between the holes on this arm would be amazing, probably saving me several hours' worth of trial & error headache.

Alternatively, if anybody wants to offload a lever type collet closer they're not using, let me know 

Thanks!


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## MrWhoopee (Aug 8, 2018)

Here you go. Not sure what you are talking about, there are no gears involved with the collet closer.


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## SCLead (Aug 8, 2018)

Aha! Thank you!

So my understanding is your spindle gear (right name?) is different from mine. Mine is a regular ol' spur gear, where yours (I'm told) has an extension with a keyway inside it for the collet closer to engage.


Gear engaged to collet closer in this image, but would be fixed on your spindle in real life.




The spindle gear on the right, with the collet closer key on the left.

I'm curious how this extended gear interfaces to the gear cover, because I'm not sure my gear cover will have the clearance for it.

Your pictures definitely clear a few things up in my head. Out of curiosity, when your closer isn't installed on the machine, do you leave the arm mounted near the back gear lever and remove the closer, or does the arm come off the machine as well? I don't recall if my machine has a hole at all, and if so whether or not it's tapped or just smooth to accept a drop in pin.

Thanks!


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## MrWhoopee (Aug 8, 2018)

OK, I had to go take mine apart. The gear is part of the carriage feed drive mechanism. I've never had it out, the gear remains in place when the closer is removed. You can see the end of the gear sticking out of the cover in the pictures. It has 3 set-screws, presumably for centering the closer. They are not tightened down. Not sure how mine works, it's missing the key but still has positive drive of the closer when fully inserted.

Yes, I leave the arm in place. I just remove the pin and take the closer off.


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## SCLead (Aug 10, 2018)

Thanks for your input MrWhoopee!

I was able to snag the machine mounting arm on ebay the other day, with a 15% off coupon - that should simplify some problem solving on my adaptation.

Just to clarify, those 3 setscrews are on the machine, not on your closer assembly? I've not stumbled across mention of setscrews on the collet closer before, so now I'm confused haha. I've also never scratched up any pictures as direct and clear as yours though, so I'm not sure what to think. I'm a fair ways away from being able to get into this project, but I might come back bothering you for more info when I get there.

Fortunately, my machine has the tapped hole for the closer to mount - I've read some machines came without that. I've got to cut the extended gear, and that's probably months away at this point. From there, modifying the draw bar I have and fitting it all together will take a little cobbling, I suspect.


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## MrWhoopee (Aug 10, 2018)

The set-screws are on the extended portion of the gear where the internal keyway is. You can just barely see them next to the cover. They may not be original. You might considered adding the extension to the gear you have instead of trying to cut a new one.


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## SCLead (Aug 10, 2018)

I looked at mine last night, and extending the spindle gear seems distinctly possible. But I also just bought a dividing head, am picking up a mill in the next couple weeks, and I've never cut any gears, so why on earth _wouldn't_ I make a new extended gear?


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## MrWhoopee (Aug 10, 2018)

Well, if you're looking for the practice, then by all means go ahead on. I would recommend that you purchase the correct cutter for the gear. It runs nearly all the time and a noisy gear would get a little tiresome. Besides, it will force you to study the technicalities of gears and gear cutting.


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## SCLead (Aug 10, 2018)

Yessir! Since I don't have _any_ gear cutters currently, I certainly intend to purchase the correct involute cutter for this one, and not cut any corners at all. Plus, I have to justify new tools to my girlfriend somehow, "Well I _need_ this new widget so I can tweak the _other_ widget I already bought."


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## SCLead (Aug 12, 2018)

If you get bored enough, could you possibly tell me the bolt size and pitch that holds your collet closer onto the machine? It seems to be 3/8, but I only have a 16tpi bolt, and it doesn't want to thread in. I'm not sure if this is grimy threads, or wrong pitch.


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## Bob Korves (Aug 12, 2018)

I do not have one of those closers (or lathe), but I have seen a few.  You are calling the drive connection a gear.  That is not necessarily correct.  It might be a spline, of which there are many styles.  All it really does is couple the spindle to the closer.  Anything that would properly drive one part with the other would work.  All that said, a company making lathes also makes and uses plenty of involute gears, so that is probably a good guess of what was used.  But it isn't part of a gear train, it is essentially a spine drive, and does not need to be fancy at all...


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## SCLead (Aug 12, 2018)

Bob Korves said:


> I do not have one of those closers (or lathe), but I have seen a few.  You are calling the drive connection a gear.  That is not necessarily correct.  It might be a spline, of which there are many styles.  All it really does is couple the spindle to the closer.  Anything that would properly drive one part with the other would work.  All that said, a company making lathes also makes and uses plenty of involute gears, so that is probably a good guess of what was used.  But it isn't part of a gear train, it is essentially a spine drive, and does not need to be fancy at all...



Bob,

It most certainly is part of the gear train, and is absolutely a gear. The "drive connection," as you call it, replaces the lathe's spindle gear, and is the drive gear that transfers power from the spindle into the gear train. Without this gear, there would be no motion in the machine anywhere but the spindle. The spindle gear designed for the collet closer has an extended sleeve on it with an internal keyway that drives the collet closer; this was an option from the factory, which my machine does not have. See the attached photo. This gear transfers power through the reversing gears and into the geartrain overall.




I don't recall the specifics of the gear, but it's a 14.5 pitch angle with 40 teeth, I've got the DP and such written down somewhere around here.


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## Bob Korves (Aug 12, 2018)

SCLead said:


> Bob,
> 
> It most certainly is part of the gear train, and is absolutely a gear. The "drive connection," as you call it, replaces the lathe's spindle gear, and is the drive gear that transfers power from the spindle into the gear train. Without this gear, there would be no motion in the machine anywhere but the spindle. The spindle gear designed for the collet closer has an extended sleeve on it with an internal keyway that drives the collet closer; this was an option from the factory, which my machine does not have. See the attached photo. This gear transfers power through the reversing gears and into the geartrain overall.
> 
> ...


Thanks for the pic, you are quite correct.  If an extended gear drives the drawbar, then you will need to make or buy one.


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## MrWhoopee (Aug 12, 2018)

SCLead said:


> If you get bored enough, could you possibly tell me the bolt size and pitch that holds your collet closer onto the machine? It seems to be 3/8, but I only have a 16tpi bolt, and it doesn't want to thread in. I'm not sure if this is grimy threads, or wrong pitch.



The thread chasing dial uses a 5/16-18 HHCS

The collet closer arm is mounted on a 3/8-16 thread on a 7/16 diameter headless stud which has a screwdriver slot in the end. It's similar to a shoulder bolt with the head cut off. It was apparently intended that the arm could just be slipped off the stud. My forward/reverse switch is mounted above this and is too close to allow the arm to slip off.


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## SCLead (Aug 12, 2018)

MrWhoopee said:


> The thread chasing dial uses a 5/16-18 HHCS
> 
> The collet closer arm is mounted on a 3/8-16 thread on a 7/16 diameter headless stud which has a screwdriver slot in the end. It's similar to a shoulder bolt with the head cut off. It was apparently intended that the arm could just be slipped off the stud. My forward/reverse switch is mounted above this and is too close to allow the arm to slip off.



You're my hero right now! With a bit of tender loving care cleaning the threads up, I was able to get 3/8 and 5/16 bolts into each. You're not too far away, if we ever cross paths, I definitely owe you a beverage of your choosing. Thank you!


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