Dog clutch for screwcutting

In message , lfoggy writes

It is (or rather was) standard on Holbrooks. The clutch is integral with the gear box so it works on either lead-screw or fine-feed and takes an awful lot of sweat and tears out of many jobs. If you are anywhere near Glos. then you can take a look at my Holbrook 8B.

There was a design published recently (last few years) in either Model Engineer or Model Engineer's Workshop magazines. It was for and about a metric conversion gear setup for the 7 series Myford lathes, and showed the details of a new quadrant and a dog clutch unit inline.

Know anyone that hoards these magazines on a steady basis? Should be able to track dowm an index online somewhere that you can get a better idea of which dates you are looking for. Try ME at around whole number

4145. Below is the exact text from an index at That reads Volume, issue , page, title.

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186,4145,429,"Lathe","Metric Screwcutting on the Myford",1,"D.A.G.Brown","Describes his versatile approach. Summary, thread cutting philosophy, the gear trains, turning the worm, changewheels required"

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Helpful, I hope!

Cheers Trevor Jones

The ML10 has a simple dog clutch on its leadscrew. The leadscrew is plain for several inches at the headscrew end, and it is cut just over one of the mounting lugs. A stud is screwed into both ends about an inch from the cut.. A sleeve is fitted over the break with slots at each end to fit the studs. A lever pivoted on a bracket from the bolt in the fixing lug has a bronze slipper which fits in a rebate turned in the middle of the sleeve. You operate the clutch by moving the sleeve to engage or disengage the RH slot from the stud on the threaded side of the leadscrew. Its a very simple arrangement and has worked well in my lathe for the last 30-odd years.

A couple of the pictures on this page show the dog clutch fitted

Jim.

Interesting to see that it had dissapeared from the later model -cost cutting?, or perhaps increasing the differences between the standard ML10 and the Speed 10

Regards Kevin

Kevin, also gives them the opportunity to sell another "vital" accessory from their vast stock of "vital" accessories. I always wonder, with cars particularly, if the basic models are actually cheaper to produce, it must at times cost them money to leave some of the improvement items off.

Regards Keith

Years ago we bought a Ford 400E diesel van with some extra's Heater, diesel engine, and heavy duty shocks.

On the receipt were chargeable extra's we had not ordered. Heavy duty diff, electric wipers and foot bar. When we queried these we were told they had to fit electric wipers as the diesel couldn't operate the vacuum wipers fitted to the petrol version. Same as the diff, the diesel needed the 4 pinion diff because of the torque. They were fitted this way on the assembly line but charged as extra's.

When we queried the foot bar which we hadn't ordered it was the bar in the passengers foot well that was welded in anyway. We flat out refused to pay for that one.

On our first mini vans paint was an extra, they came primed, top coat was extra.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

I think I read, the other day, how the Land Rover discovery II did not have a locking centre Diff as standard. This feature was re-introduced in later models. However, it had always been there but disconnected.

Pete Harrison

On the "frogeye" Sprite the list of "optional" extra's included heater, bumpers and passenger seat! I don't think you'd get away with that now.

Regards Kevin

PS no, I'm not old enough to remember -I just read it in a history of sprites

Yes it was still there on the Disco II but there is no linkage to operate it from the cab. But to be honest the electronic traction control is very good and I don't miss having it all.

What I do miss however is staying dry in heavy rain. Landrover have yet to make a Discovery with sunroofs that don't leak.

Peter

We had four 10MB Hewlett Packard hard disks at work. HP never made a 10MB disk.... After several years use we found the jumper inside the case that magically changed them into 20MB disks B.......ards!

Back to the original topic. Surely a leadscrew dog clutch would only be useful for threads that were a multiple of the leadscrew pitch?

Mark Rand RTFM

Kevin,

Sorry, I should have said that it was an 'extra' accessory - certainly for my ML10 which was one of the original models. The leadscrews on the basic ML10s had a groove turned at the appropriate position for the cut and you dismantled the leadscrew from the lathe and got to work with a hacksaw prior to fitting the clutch :-)

Jm.