Locking Devices

[Michael GilliganParticipant @michaelgilligan61133]

Further to my brief exchange with Rodney Entwistle, on Damian Noble's thread **LINK**

I have created an Album called Locking: **LINK**

… I will add a few notes, later

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

For Slides, etc. …

[Michael GilliganParticipant @michaelgilligan61133]

This one is from a Leitz Macro Stand:

The dovelail is quite light in section, but nicely cast and machined.

A thin, springy, gib strip is attached by screws at one end [just visible under the crackle paint] … the slides are well-matched, and it only takes light pressure on the knurled screw to lake it from free-sliding to locked.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

This one is from the Pantograph arm on my 'TN le Locle' machine … It locks a square-sided slide, but the system would be adaptable to a dovetail.

The loose gib-strip is rigid, dowelled at one corner, and much thicker than the Leitz one.

Behind the gib-strip is a 'cart-spring' which spreads the pressure applied by a single screw.

MichaelG.

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[Michael GilliganParticipant @michaelgilligan61133]

Third, but maybe most relevant to Rodney's requirement:

This is the system used to lock the slides on my BCA 'Jig Mill'

The loose piece is shaped to match the dovetail angle, and features a small ridge on the underside.

It is pulled into firm contact with the dovetail as the screw is tightened.

MichaelG.

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Pick'n'Mix from those, Rodney … unless someone can suggest a better lock for your shaper.

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 21/10/2016 19:27:08:

It is pulled into firm contact with the dovetail as the screw is tightened.

Just like the lock for my saddle stop.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 21/10/2016 19:36:26:

Just like the lock for my saddle stop.

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Shame you didn't advise Rodney; it would have saved me a lot of effort.

MichaelG.

[John OlsenParticipant @johnolsen79199]

On the Alba shapers the arrangement is a bit like what was shown on the other thread, except there are no adjusting screws, just three clamping screws. The gib strip is pulled up tight against the dovetail and the side of the cross slide and should not bottom out against the back of the cross slide. This works fine and clamps up very solidly. It would not be a good arrangement for something that was intended to slide in service.

So it seems to me that the arrangement on the Hercus could be used in the same way, eg adjust the screws on the side such that when the other screws are tightened, the gib strip clamps against the dovetail without bottoming out against the back of the cross slide.

John

[TendorParticipant @tendor]

Many thanks Michael for taking the time to photograph and post the various locks. I really appreciate it!

On Damian's Tom Senior, I think that the lock screw must act on a cylindrical plug (far end slanted to match the dovetail angle) that fits a hole bored through the 'solid' gib. That might also be a good way to do it.

Thanks again,

Rod.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Rodney Entwistle on 22/10/2016 13:27:41:

On Damian's Tom Senior, I think that the lock screw must act on a cylindrical plug (far end slanted to match the dovetail angle) that fits a hole bored through the 'solid' gib. That might also be a good way to do it.

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Rod,

Yes that's another pretty standard, and effective, lock [my 'TN le Locle' machine uses them on the main XY slides]. Just be sure to use suitable material for the plugs [Bronze is probably ideal].

MichaelG.

[TendorParticipant @tendor]

Damian has provided some information re the Tom Senior over at the original link. (See first post in this thread by Michael Gilligan)

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