Rockwell Jawhorse HD RK9000 Workbench System – As Seen on TV!
More writeup about the Jaw Horse from my visit to the design engineers available here
Some of these images are giving a direct comparison to the SuperJaws, other are simply to highlight JawHorse features.
So let’s see what all the fuss is about!
The JawHorse, set up and ready for action. Some details to note here – 3 leg design means it is stable on all surfaces, irrespective of how uneven the ground is. These legs, and the whole tripod design is strong too – it doesn’t notice me sitting / standing on it. It can support up to 270kg (600 lb).
The two front feet have stirrups – good load transfer, but their primary role is so you put your foot into it if you need some extra stability. You can also bolt or peg it to the ground if need be.
The black stirrup in the middle is how you apply load to the jaws. You can apply a maximum of 100kg onto this stirrup (which is multiplied by 10 to get the 1000kg of clamping force). You don’t jump on it – a gentle push achieves a significant clamping force. You can completely starve a joint of all its glue easily if you get carried away (squeezeout). The benefit here is it does not require your hands at all, so you can support the work piece(s) with 2 hands, while applying clamping pressure.
Side by side with a SuperJaws (in this case the Chinese assembled version (ie current)) and you can see the similarities.
The jaw is locked by the mechanical switch at the front – you can either activate the switch then clamp up, of clamp up and while maintaining the pressure, activate the switch. To release the jaw, set the switch to unlock, then apply about the same amount of pressure to the foot stirrup as you did when setting the jaws. You will hear a click, then release the pressure on the stirrup.
In the old (Aussie) model, the pressure could be released without standing on the stirrup, and if you were in its way, it kicked back with amazing force, and gave your shin a very good whack. You never did it twice. And as I hear yesterday, someone (whom shall remain nameless) even managed to get their head in the way. Once! This is certainly not a problem with the modern design.
Now, for those familiar with the SuperJaws, lets look at a couple of notable differences.
On the current SuperJaws, there is a cam on each leg to lock the leg on the open position (shown here in the closed position fwiw). A cheap solution, and not particularly elegant. (Remember, I am a big fan of the SuperJaws as a tool, so don’t take these comparisons as me just bagging the SJ)
This is the JawHorse solution, and it is very stylish. Similar to a door latch, with a spring-loaded tongue. This is easily retracted with the finger-slot seen here. Very neat.
The next comparison surprised me when I took the photo – I knew there was a difference, but when I put them side by side, I did a double take to make sure I hadn’t set the photo up wrong and created an optical illusion.
Have a look at the difference in size of the JawHorse jaw compared to the SuperJaw jaw (covering). There is a huge difference in the area, and this is a big reason why the JawHorse is bulkier – it is stronger to cope with all this extra area.
Carrying the JawHorse to the site (if not in the shed) is very similar in both cases – both fold up neatly, and the rear leg becomes a handle.
(And yes, I am actually carrying it while taking the photo). As the leg is locked at the back, and engages a slot at the front, this leg (now handle) has no trouble at all supporting the Jaws while carried to the job.
But at 20kg or so, you might not want to carry it far. The JawHorse has something new:
The ability to use the rear leg as a handle, and roll the JawHorse to the job. A detail I have never realised from the photos, is the black area at the bottom of the jaw front is actually a large roller wheel!
Neat solution to transportation eh!
When the unit is folded up, it is easily stored / transported, and this is something all SuperJaws have been able to do.
From left to right, we have the JawHorse, the current model SuperJaws, and the older Australian-made model SuperJaws. Note the oldest model has cross bracing on the legs which has vanished, and will not be coming back on future models.
The oldest SJ did one thing that was really clever – it could stand upright on either end – those Engineers nailed that, when folded up like this, it is stable both ways up. I do miss that. I don’t miss all the blood blister manufacturing points (aka pinch points) on the old model (I found them all first-hand!). That original SuperJaws still is a kick-ass design though.
As you can see in each case, when folded up, the legs help hold components (and primarily the main stirrup) in place. In the case of the JawHorse, this has been optimised, so the 2 main legs are held in place by the stirrip, which in turn is held by the rear leg, which is locked in its position at both ends.
Something which has never been lost, is the amount the jaws can open. In their normal orientation, they can clamp about 450mm.
But then, by reversing that jaw you get…
940mm clamping range. And then, there is an accessory (coming or available?) that is an extended jaw to give even more range.
This is the heart of the jaw mechanism. On either side there is a spring loaded bearing that provides just the right amount of friction to the movable jaw. In the centre is the 4 toothed lever that advances the jaw by 1″ each press of the stirrup. Underneath the jaw, you can see the holes that the toothed lever engages in.
So that is the JawHorse – heavy, powerful, stable, and yet still portable. I like it!
Latest writeup here: SSYTC009 Rockwell JawHorse