Antique Bench Dog ...??

[bilspe]

Trying to get an ID on this
Heavy cast iron. Could possibly be part of something else.... or a bench dog ?

 

[The_Yellow_Ardvark]

Looks like a leveling jack.

 

[RobNichols]

If it's a bench stop, surely they (I presume you are looking at the ebay listing) are displaying it up-side-down. Wouldn't it screw to the bottom of the bench top and then the dog would pass up through the "base" and up through the bench top. So similar to the Record No 169 Bench Stop, but with a rack and pinion mechanism rather than just a push and secure system.

Actually, looking at the ebay listing, I think this is the most interesting view:

The rack mechanism is very close to the "base". If that was inverted and screwed to the bottom of a bench top the clearance hole would need to be large as it would need to accommodate part of the rack mechanism I think.

 

[RobNichols]

I must stop looking at this .... perhaps the insert is the wrong way up too. As it is shown in the photo I've posted above, the top of the rack is engaged with the top of the insert level with the "base". So as soon as it was ratcheted up, the rack will enter the hole - so you'll need the big clearance hole I mentioned to allow the rack to pass into the bench.

However, if you turn the insert the other way up there is an inch or so of clear insert beyond the rack. That would mean the insert could pass an inch or so into the bench top before the rack would get to the level of the bench.

 

[toolsntat]

 

[bilspe]

Thanks for the suggestions. Looking at the Tyzack above pretty much confirms it as a bench dog.

Still a bit puzzled by the spring under the wing nut. Obviously would disengage the rack and pinion if pushed in, except it's so strong you can't actually depress it.

BTW... it's my ebay listing

 

[ChaiLatte]

Still a bit puzzled by the spring under the wing nut.

Would the spring be the part that provides friction in the mechanism, to stop it dropping under gravity or as a result of the cyclic load on it in use (when you use it as a planing stop, it only sees load on the forward stroke of the plane)?

It seems to me that you would adjust the length of the wooden part to suit the thickness of your bench top. With the rack in its lowest position, the top of the wooden part would be flush.

Edit: the 'hand' of the spring might also indicate which way is up - turning the handle one way will 'open' the spring's coils and its springiness will resist your turning. Turning the handle the other way will 'close' the coils and rotation in that direction will be easier. So the 'coil closing' (easy) direction should raise the wooden part. In effect, the spring is acting as a ratchet mechanism with an infinite number of teeth.

 

[toolsntat]

Would the spring be the part that provides friction in the mechanism, to stop it dropping under gravity or as a result of the cyclic load on it in use (when you use it as a planing stop, it only sees load on the forward stroke of the plane)?

It seems to me that you would adjust the length of the wooden part to suit the thickness of your bench top. With the rack in its lowest position, the top of the wooden part would be flush.

Edit: the 'hand' of the spring might also indicate which way is up - turning the handle one way will 'open' the spring's coils and its springiness will resist your turning. Turning the handle the other way will 'close' the coils and rotation in that direction will be easier. So the 'coil closing' (easy) direction should raise the wooden part. In effect, the spring is acting as a ratchet mechanism with an infinite number of teeth.

Yes I believe you could partly be correct with the spring theory but even just with a decent amount of pressure it should resist any creep back down the recess.
As it is though,there is only one way up for mounting this device under a bench, as indicated by the counter sunk fixing holes, on the other hand it would appear from the Bilspe's pictures that he may have the toothed dog inserted upside down unless the hole goes all the way through. Even if it did I'd assume the larger tooth on the rack would be top side of the pinion to stop it being accidentally pushed down too far, disengaging from the pinion and allowing it to free fall out of the assembly.
Cheers, Andy

 

[Chubber]

The spring is indeed a means of inducing stiffness to the mechanism. There was one fitted to the long bench in the Shipwrights shop in HMS St Angelo in the 70s.