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Shaving Giraffe #1: Firstborn

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Blog entry by RobynHoodridge posted 02-09-2013 05:20 AM 2184 reads 0 times favorited 7 comments Add to Favorites Watch
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I’ve been wanting a shaving bench. And since i can’t help but contemplate the design concepts behind what i’m about to build, i contemplated the fundamentals of how a shaving horse works. I thought “Great. But why not like this?” .. as an alternate mechanism for clamping a work piece in position sprang to mind. The contraption looks to me like a giraffe stretched out to drink, or the head of a giraffe, so I call it the shaving Giraffe rather than shaving Horse. Wanting to share the idea, and see if others were eager to help me develop the basic plan, i laid it out in a forum post.
http://lumberjocks.com/topics/45971
One of the recurring suggestions was to build one to help inform the design process. So we did just that. And the first real, live, giraffe was born.
We’re such proud parents. So i want to share some baby photos and what i’ve learned from the full scale with you here.

The idea is that the weight of the bench and the woodworker upon it cause the front half to pivot at the center, and clamp down on the work as it does so. There are some advantages to this approach rather than the traditional levering system of shaving horses. And once you add a way of un-clamping quickly and easily so that you can rotate the work, it’s quite a pleasure to use.
The clamped state asks nothing of the user other than being seated in the working position. So it’s easier to dedicate all your muscles to the task rather than to creating clamping pressure, and there should be less fatigue since the clamped state is the more common when you’re working a piece, and is automatic.

Since the clamping / de-clamping is merely reversed, there is still leg work necessary to release clamping pressure. But by taking a page from the shaving Horse book and leaving this this action to the legs, the arms are still free to turn the work piece and hold tools while the vise is opened.
The foot operated lever arm is merely a way to comfortably and effectively push down upon a cable (wire rope) that spans between the two ends of the giraffe. And in this way the front part (large swing arm) is made to pivot and release clamping pressure.

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Here’s Warren in the saddle showing a few things about how a person and Giraffe go together.


Both feet are naturallly out in front of the user, creating leverage against which to pull. Such as when using a drawknife. Also, note that the angle at which the work is held can be just right for drawknife work where the elbows are drawn almost straight backward.


It’s easy to lift a foot to the lever when it’s necessary to open the jaws of the vise. However, two legs on the ground aren’t always necessary and an option is to work with one foot on the lever when the task at hand demands a lot of turning of the piece.


With the foot-operated lever depressed, the vise opens up and the work piece is as quickly and easily rotated or moved as can happen in traditional shaving horses.


It’s not only drawknife work that a clamping bench is good for. And not having to activate the clamping with your leg(s) is especially great for some alternate tasks.

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I can think of about three ways to do any one aspect of the giraffe. Almost nothing has to be the way you see in our version. For instance, the un-clamping could be activated in some other way; or the cable attached in another way; or the rear legs could be permanent, attached, or fold away. Etc. Etc.

The original Giraffe concept didn’t (necessarily) have any legs at the back, and it would rest on whatever was available. But i found that the action of opening the vise and the forces involved tended to pull the whole bench forward horizontally when the rear isn’t firmly set in place. For instance on sturdy concrete steps with lots of friction as below.

So I made a stand system to prop up the rear and hold it steady.

The main beams in the giraffe are 38 mm by 100 mm (approx 2” X 4”) which was actually cut from wider stock (rafters). I used the ‘offcut’ strip (~38 X 50 mm) to make simple “A-frames” upon which the rear of the giraffe rests. The strips pivot on each other at a bolt through them. And the angle between them (thus height of the giraffe seat) is set by rope ties. So they fold up for storage, but aren’t attached.

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This “fold-away” aspect was important consideration in the design of our Giraffe.
The bench can simply collapse into something ‘flatter’ which could be stored against a wall (approx 2.2 meters long).

Or if space is really tight, the form can be made even more compact with a little re-ordering of the bench parts (approx 1.5 meters long).

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Simplicity
All levering action takes place from one pivot line. Which is merely a pipe onto which the beams of the bench slide, through holes of the appropriate size and direction. And upon which they slide to rotate.

The foot operated lever pivoting on this same pipe doesn’t have to be an open box construction as in this version. But it helps to keep it from twisting and generally moving in ways that aren’t helpful when applying foot power.

The end of this foot operated lever arm which meets the cable looks like this in our version.

But i’m sure there are many functional alternatives. The concept even works when you simply presses directly on the cable with your foot. Though this is awkward.

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It’s a good idea to round off the corners of the beams at the pivot pipe end, because they could possibly get in the way of very long work pieces. We haven’t done this yet, and you can see two little corners poking up into the ‘line-of-sight’ down the clamping platform.

With this done, the Giraffe can actually take very long stock.

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The top clamp bar is held in place with elasticated cord. This means that it rotates in its notch so that the flat face always meets the work piece. But also that it can quickly be moved to another notch in a series down the swing-arm.

Sometimes you want the clamping to be done further back, and this moving between notches is an easier way to achieve this than in shaving horses’ where you have to get off the horse and re-position pivoting bars etc.. You could still include this aspect in the Giraffe design, and make it even MORE variable, settable, etc.. For instance, changing the relative lengths of the upper and lower ‘halves’ of the main swing arm would change the clamping pressure applied. Just remember that in the Giraffe design, the levers ARE the leg, so changing dimentions changes the height of the bench, or angle if only one end changes.

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Similarly to easy changes made possible at the clamping head, a series of holes in the top surface of the body of the bench would allow the ‘dogs’ in the picture below to be moved back and forth. The point of which is to have a lower clamping platform that can be positioned appropriately for certain tasks, and is also entirely removable for storage of the bench. Again, all while seated at the bench.

We haven’t installed them yet, but hinges between the horizontal board (white) and angled clamping platform should affix them to each other while allowing the angle of the platform to be changed at this hinge point by varying the support block at the front opening of the ‘wedge’. So that both the position and angle are variable.

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This style of vise bench uses two swing arms with a clamping bar between them (same as ‘english’ style shaving Horses). I found that if the arms are allowed to pivot individually, the giraffe isn’t very stable. Especially since the rear is very narrow and doesn’t offer ridgidity against rotating in place. The solution is to make the swing arms one. And this was done with a board between them on the ‘leg’ section or lower half.

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Future Versions
I found that the Giraffe works much better when the front feet can easily slide back and forth on the ground. We achieved this in our firstborn by tacking castors on to the feet.

If we planned this better, the ends of the swing-arm wouldn’t be rounded, they’d be cut off at 45 degrees and the castors attached on the angled face. Non-rotating castors would also be better.
However, castors aren’t the only way. And especially if you want to stick with the “pivoting around a pipe” approach throughout the bench, you could add wheels in the manner implied in the pic below.

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Wishful thinking, we placed an office chair on the Giraffe as the ‘ultimate’ saddle.

But some more comfortable seating would be a real asset. I’ve seen folks drape filled sacks over the seat, or carve out hollowed seats.

-- Never is longer than forever.



7 comments so far

View jap's profile

jap

1240 posts in 807 days


#1 posted 02-09-2013 01:22 PM

cool, thanks for sharing

-- Joel

View Rick M.'s profile

Rick M.

4509 posts in 1133 days


#2 posted 02-10-2013 09:20 AM

Heh, La-Z Giraffe. Well this worked out better than I expected.

-- http://thewoodknack.blogspot.com/

View mafe's profile

mafe

9690 posts in 1842 days


#3 posted 02-12-2013 04:08 PM

I love your thinking.
And most of all that you try and turn all arround, this is thue way of great inventions.
When this is said, I am not sure I think it became a revolution for the shaving horse for now.
I think the original horse is as easy and versitile as your new version.
The traditional horse can also be made and used without the back leg.
It can be used for several purposes.
It can sore away easy.
I think if you look in this blog http://lumberjocks.com/mafe/blog/24838 you will se the different uses of the horse and the wedge system makes it easy to fold down and take almost no space.
So as much as I love you for the thinking I still think the old version is easier to make, can be made from wood only and no screws if wanted and are more versitile.
I am deeply inspired and impressed by your thinking, so this is worth it all still, thank you.
Hope you take this in a good and positive way, it is meant so.
And perhaps with some more thinking you might get rid of the cables screws and wires and end up with what it started out to look like ‘a simpe and effective giraffe’.
Best thoughts,
Mads

-- Mad F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

View RobynHoodridge's profile

RobynHoodridge

126 posts in 1082 days


#4 posted 02-13-2013 09:38 AM

Hi mafe.

The forum discussion of the Giraffe concept might have been a better place for your comment.

I’m okay with it not being a revolution for the shaving bench. I never thought it should be. Each has its pros and cons, but we should know that there are ways other than the traditional or typical. And maybe through discussing the design we come up with something that is a revolution. Thus the forum thread that i started under the ‘design’ section.
The Giraffe is a concept for now. And different versions of it will take different input to make. But if it really does ask more than a traditional shaving bench, then that might be worth while input for some people in their specific situations. So not a revolution, an option.
For instance, i personally have no need to make it entirely out of wood and i love the relaxed nature of it being clamped just by sitting at it. So i like the cables and screws.

I am definitely going to build a Horse much like yours. That blog entry is great. In fact i think i might use the wedged support for the clamping platform on my giraffe.

Cheers

-- Never is longer than forever.

View JoeinGa's profile

JoeinGa

3698 posts in 760 days


#5 posted 02-13-2013 11:56 AM

I also read your design forum and wondered is you’d ever get to the “building a prototype” stage. I must admit, it happened a lot sooner than I thought it would,
Neat bench. I’m sure others will take a much closer look at your design page now

-- Perform A Random Act Of Kindness Today ... Pay It Forward

View RobynHoodridge's profile

RobynHoodridge

126 posts in 1082 days


#6 posted 02-13-2013 05:59 PM

Thanks joein10asee.
It happened sooner than i thought too, exactly because the concept needed a physical manifestation as somewhere to start thinking from.

-- Never is longer than forever.

View mafe's profile

mafe

9690 posts in 1842 days


#7 posted 02-16-2013 08:05 PM

;-) I am full of respect.

-- Mad F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

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