Anyone tried this?

[COMachinist]

I saw that article and thought about building his designs into my Colchester but lucked into a Hardinge HLV that has the features. It looks doable. The Hardinge and I think his design uses a double dog clutch one central drive with mating clutches on each side for forward and reverse. The clutch on the Hardinge is geared off the spindle before change gears, it can only drop in in two positions so probably is 2:1 reduction from the spindle, then it doesn't mater where it engages the tread will pick up. The Hardinge drops out within 0.001 carriage travel every time.
You have to run back under power which is slower than cranking it back, but when your threading at 6 or 800 rpm its pretty quick.
Saw plans for his quick retract somewhere, was pretty much the same design as Hardinge used. Works nice.
Good Luck
Greg

LOL I have a better chance of winning the Power ball than getting one of those out here in Colorado. I feel very lucky just gettting my Clausing, that was a 2 year ordeal as it was.
CH

 

[COMachinist]

I would like to have seen more details on how he renegages the thread at the right place after disengaging the drive to the lead-screw gearbox. I believe if I did that to my lathe I'd have a hell of a time getting my threading dial re-indexed correctly.

In lieu of such a device, I've seen several simpler mechanisms which only disengage the half-nut at the bottom of the thread, which is a nice feature, and really takes most of the worry out of threading.

I've gotten very quick at threading using the adjustable stop on the cross slide to reset the tool for each pass and just use the compound for additional depth as usual without having to worry about the cross slide position.

If I have a difficult shoulder to thread up against I've also taken to turning the tool upside down and threading in reverse, moving away from the chuck.

Hi
There is a Thread over on the Model Engineering forum that has been running for like 3 years. Lots of info on these clutchs for a lot of different lathes they even have one in the works for the HF lathes. I have not seen anything for a Clausing but that is not a surprise the Clausings are orphans, that don't seem to get the respect other lathes do. The only reason I'm thinking of this because of the amount of custom screws and bolts I make for antique equipment I restore and work on. The !00 Mk!,II and III have threaded chucks, trust me you don't even want to think of doing the upside down threading thing. Don't ask how I know that!
Oscar
I want to make a retractable tool or a retractable slide attachment kind of thin Jim made for his G0602. The Graham Meek's clutch want work with out one, or the other. It is a must have for the fast threading. There seem to be a lot users of this over in the UK I just don't know why it has not caught on here.
Thanks for the input All
CH

- - - Updated - - -

You guys might be interested in "screwcutting in the lathe" by Martin Cleve. It is No3 in the workshop practice series of "Special Interest Model Books" ISBN 978-0-85242--838-2 He goes into detail about the dog clutch and retractable toolpost he built for a converted Myford which he used to earn a living cutting small batches of special bolts and threads. If screwcutting is your thing, I think this is one of the best books out there.
Phil.
UK

That book sells for 250.00 buck over here in the US I looked at a paper back for like 249.00 some place here in the US. From what I here the Martin Cleve book really does not cover these types of clutches. I could be wrong but just what I read some place. Graham's clutch is kind of a hybrid dog clutch any way. The worst part is getting the clutch in a package that will fit the lathe. The rest is just building the parts. I have a CNC mill for the case and other parts and the Clausing for the turned lathe parts.
CH

 

[f350ca]

LOL I have a better chance of winning the Power ball than getting one of those out here in Colorado. I feel very lucky just gettting my Clausing, that was a 2 year ordeal as it was.
CH

Pretty much the same here. Lucked into this one, was on a government sealed bid auction, think someone there was trying to scam it, was listed as "Industrial Lathe for parts only, minimum bid $100 " Was close so went and had a look, apparently had sat in storage for decades, the grease in the threading gears had turned to shellac, the belts had cracked and deformed where they were wrapped around the pulleys. They showed no tooling on the ad, it had 3 and 4 jaw chucks, full set of collets, follow and steady rest, and taper attachment, live centres, drill chuck. No appreciable wear but needed tore down to clean so painted it while I was at it. Don't want to admit what I got it for.



Greg

 

[hermetic]

"That book sells for 250.00 buck over here in the US I looked at a paper back for like 249.00 some place here in the US. From what I here the Martin Cleve book really does not cover these types of clutches. I could be wrong but just what I read some place. Graham's clutch is kind of a hybrid dog clutch any way"


That is crazy! It is on amazon listed at $21.00 (in the UK it is £5.99=$10) Martins book Does go into detail and also has detailed drawings of both a single tooth and a reversible dog clutch.

Phil
UK

 

[COMachinist]

Hi Greg
That is a beautiful lathe. You have done a wonderful job on it, and I bet it runs just as good as it looks. You have a piece to be proud of.

I have got an E-mail from Graham Meek he has offered to point me in the right direction to make one of these. He is no longer doing any new designs because of health. I will be doing the design and build myself under a word or two from him to help. "I don't plan to do any work other than for the Series 100 MK3 and MK3a. Once I get the experience of make one of these I will be more than happy to share the info with anyone wanting a clutch of there own, if I can that is. Jim Schroeder may be willing to help, I hope, but I have not asked him yet. This info is just too valuable to be lost. A day will come when America will need experience in the trades again, in the future at some point. So stay tuned but don't expect this over night.)
CH

 

[COMachinist]

Hi All
Well got the the first round of drawings off to Graham today he thinks this will be doable so should have a threading clutch sometime in the future. I'm real exited about this.
happy Machining
CH

 

[COMachinist]

Hi All
Just an update. I shot off the second round of drawings and measurement to Graham last nigh. Progress is slow because Graham is in UK and the time difference is a problem. He is a great engineer though, and I want to let everyone know how generous he is with his talents and time. This project will be free to any one who wants do a clutch for their lathes. The drawings will be available to all. If we get enough that want it, we maybe able to get the gear cases and gears from a CNC job shop like eMachine shop. We may even find a good CNC hobby member who can do all the gear cases for us. Just thinking out loud.
Happy Machining
CH

 

[mws]

You know, I’ve been thinking about this being a worthwhile project as I do a lot of single point threading for the benefits of concentricity and dimensional tweaking. But, in thinking about how this works (either too much or too little, I can’t decide) it appears to me that the gear ratios involved are not arbitrary. That is to say, each rotation of the spindle must result in exactly one rotation of the driving plate of the clutch to stay in sync with the thread being cut. Any misalignment with the work would be + or – one full thread. This would require the gear train be devised to accommodate the gear on the spindle for different machines such that clutch and spindle ratio is 1:1.


Anybody care to confirm or correct my thinking on this?

Mark S.

 

[f350ca]

You know, I’ve been thinking about this being a worthwhile project as I do a lot of single point threading for the benefits of concentricity and dimensional tweaking. But, in thinking about how this works (either too much or too little, I can’t decide) it appears to me that the gear ratios involved are not arbitrary. That is to say, each rotation of the spindle must result in exactly one rotation of the driving plate of the clutch to stay in sync with the thread being cut. Any misalignment with the work would be + or – one full thread. This would require the gear train be devised to accommodate the gear on the spindle for different machines such that clutch and spindle ratio is 1:1.


Anybody care to confirm or correct my thinking on this?

Mark S.

Haven't seen a breakdown of the Meeks design, but on the Hardinge the dog clutch has two teeth, so two chances to engage, Its driven at twice the spindle speed, so where ever it engages its output is in sync with the spindle.

Greg

 

[mws]

Haven't seen a breakdown of the Meeks design, but on the Hardinge the dog clutch has two teeth, so two chances to engage, Its driven at twice the spindle speed, so where ever it engages its output is in sync with the spindle.

Greg

That makes sense to me! If it's driven at 2x the spindle speed and has two dogs that results in a 1:1 engagement ratio. That's the first time I've heard mention of the clutch having more than one engagement position, I suppose it could have as many as you like provided the proper gear ratios. But I'd also expect the faster you spin the clutch the more likely it is to crash on engagement.
Thanks.