Crank Tilt Mechanism for Table Top

[Keith Downing]

I stumbled across something online that I'd never seen before, though it seems really simple. It's a crank mechanism for tilting a table top. Seems that the two hinges just run along a track and the attached supports adjust the table accordingly.

Has anyone ever seen this anywhere? I'd be interested in building some simple tables with this type of implementation, but don't need the custom iron legs (or the 2k-4k price tag) that the custom fabricator on Etsy has.

Curious if anyone has any ideas on a manufacturer for something like this or how to fabricate it with off the shelf pieces and parts.

example1.jpg

example2.jpg

[Jamie Buxton]

What I'm seeing there is that the handwheel rotates a shaft. The shaft is threaded rod -- or rather two threaded rods. One half is a normal right-hand thread, and the other half is a left-hand thread. Rotating the shaft drives both support rods in toward the center, or out away from the center.

To reproduce this mechanism exactly, you'll need to make or acquire that threaded rod with both thread directions. That surely is possible, but there are other ways to jack up a table which would be less effort. For instance, look at the mechanism that lifts the table on a drill press. Or if you like old-timey stuff, check into how the old barber chairs go up and down with a foot-operated jack. Or use a bicycle drive chain running around two sprockets. The handwheel drives one sprocket. The table edge is connected to the chain with a stiff arm. As the chain goes up and down, the table does too.

[Keith Downing]

What I'm seeing there is that the handwheel rotates a shaft. The shaft is threaded rod -- or rather two threaded rods. One half is a normal right-hand thread, and the other half is a left-hand thread. Rotating the shaft drives both support rods in toward the center, or out away from the center.

To reproduce this mechanism exactly, you'll need to make or acquire that threaded rod with both thread directions. That surely is possible, but there are other ways to jack up a table which would be less effort. For instance, look at the mechanism that lifts the table on a drill press. Or if you like old-timey stuff, check into how the old barber chairs go up and down with a foot-operated jack. Or use a bicycle drive chain running around two sprockets. The handwheel drives one sprocket. The table edge is connected to the chain with a stiff arm. As the chain goes up and down, the table does too.

Thx, Jamie.

Yeah, I was hoping for a miracle solution similar to what is pictured I guess. Just out of curiosity, do you know what those hinges are called (where the flat steel rod connects to the table and the threaded rod)? I haven't even been able to find those.

I am considering some other, less unique, options. But since the table is for drafting/drawing, it does need to be very sturdy. No wobble, very level.

[Jamie Buxton]

.. do you know what those hinges are called (where the flat steel rod connects to the table and the threaded rod)? I haven't even been able to find those..

What I think I'm seeing there isn't really a hinge, so to speak. It looks to me like a simple pivot. I think there's an axle welded to the round rod running horizontally right underneath the table. There's a sleeve that fits around the axle, and the sleeve is welded to the flat support rod. There's a similar arrangement at the bottom end of the support rod, where it hits the threaded rod.

The round rod just underneath the table must rotate just a bit as the table goes up and down.

[Paul F Franklin]

One half is a normal right-hand thread, and the other half is a left-hand thread.

This made me think of a handscrew clamp shaft....they are threaded this way so the jaws move in opposite directions. But the largest I've seen is a 12" clamp; not sure how long the shafts would be. Of course you could make your own with a left handed and right handed thread die. Or even just weld two pieces together, one LH thread, one RH.

[Malcolm McLeod]

Thx, Jamie.

Yeah, I was hoping for a miracle solution similar to what is pictured I guess. Just out of curiosity, do you know what those hinges are called (where the flat steel rod connects to the table and the threaded rod)? I haven't even been able to find those.

I am considering some other, less unique, options. But since the table is for drafting/drawing, it does need to be very sturdy. No wobble, very level.

You can find 2 threaded rods in a turnbuckle; one is LH, the other RH. You can find locknuts to fit each (which could be your 'traverse mechanism'), or devise a way to weld the rods together and split the connecting link into 2 pieces to use for traverse.

I believe you can approximate the upper pivot with a heim joint (most call it a "rod end") and a shoulder bolt.

Using these off-the-shelf components may give you a semi-modern, industrial feel, rather than the steam-age look of your pics...?? Hope this helps.

[Keith Downing]

You can find 2 threaded rods in a turnbuckle; one is LH, the other RH. You can find locknuts to fit each (which could be your 'traverse mechanism'), or devise a way to weld the rods together and split the connecting link into 2 pieces to use as for traverse.

I believe you can approximate the upper pivot with a heim joint (most call it a "rod end") and a shoulder bolt.

Using these off-the-shelf components may give you a semi-modern, industrial feel, rather than the steam-age look of your pics...?? Hope this helps.

Interesting take. Any idea where you would find a large turnbuckle? I have never seen one longer than a few, maybe 6, inches (at least if it's what I'm thinking of).

Thanks for the input by the way!

[Malcolm McLeod]

Interesting take. Any idea where you would find a large turnbuckle? I have never seen one longer than a few, maybe 6, inches (at least if it's what I'm thinking of).

Thanks for the input by the way!

Grainger is the first in a search....here

I filtered for 3/4" dia rod X 18" take up - - and got 69 matches - - and these are the 'small' ones! You can select for any number combo of sizes and end fittings.

If you need a bunch of these and have access to a tap and die (Paul posted this above), this might be cheapest way to go?? The BORG carries CR steel and you could crank out as many as necessary.

[Tim Offutt]

You don't have to go the turnbuckle route. You can buy right hand and left hand all thread at many places online, McMaster Carr, MSC, Grainger, Enco, etc. Also you can buy the nuts for the rod.

If you know someone with a lathe you can easily join the LH and RH rods together. Simply face the end of the rods off square, drill a hole for a dowel of the proper size, add a decent size chamfer or bevel and slide the LH and RH rods together then weld. If your careful and alternate the welding from side to side it shouldn't pull much.

The same online sources would have the pillow block bearings and the rod ends needed. They would also have a three spoke hand wheel if you wanted it.

I would check ebay for these items, you can probably find new old stock or used for much less than new price.

[Ken Fitzgerald]

Green Bay Manufacturing sells them as left-right ACME threaded rods: http://www.greenbaymfgco.com/ACME-threaded-rods.php

Also called twin lead screws as it is here: http://www.nookindustries.com/Produc...tCategory/1103

[Dave Richards]

With a screw from one of Ken's sources, you should be almost home. Working out the rest of the mechanism should be straightforward.

[Thomas Pratt]

Looks like an old drafting table.

[Keith Downing]

Thanks for the responses guys! I'll try to chase down some of these sources and see if I can piece together something.

My background is woodworking and laser engraving, so the welding and casting is somewhat new to me. But I'm hoping I can make it work.

[Bill Adamsen]

Another attractive solution are greenhouse vent window gears (see attached photos) which in this case were sandblasted and blued.

[Graham Wintersgill]

Or another option is an adjustable trestle table from http://www.ikea.com/gb/en/products/d...-spr-09001986/ I know it is not gadgets but it does work.

Graham